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1. etc hostapd hostapd conf In hostapd conf file is defined the parameters of wifi network generated in its case wlano interface wlan0 driver nl80211 ssid ltemlog hw_mode g channel 6 wpa 3 ignore_broadcast_ssid 0 wpa_key_mgmt WPA PSK rsn_pairwise CCMP wpa_passphrase ltemlog1 wpa_pairwise TKIP logger_syslog 1 logger_syslog_level 2 30 logger stdout 1 logger stdout level 2 debug 4 dump file tmp hostapd dump wpa 3 is used to define wifi security protocol There are three security protocol WEP WPA and WPA2 WEP is a simple and non secure protocol because is easy to infringe So in this project is used WPA If wpa 7 indicates that WPA protocol is used if wpa 2 indicates that WPA2 protocol is used and if wpa 3 this situation indicates that WPA and WPA2 are enable Interface wlan0 indicates which interface is configured Ssid Itemlog indicates the name of network generated Hw_mode g indicates which wifi standard is used b or g standards can be chosen but finally g standard is the choice because it is able to have fast transmitions Ignore_broadcast_ssid 0 indicates if broadcasting the ssid is enable or disable In this case is not allowed Wpa_key_mgmt WPA PSK indicates what key management algorithms a client can authenticate with Rsn_pairwise CCMP indicates WPA2 s data encryption is CCMP Wpa_pairwise TKIP indicate
2. 8 3 9 void mcs int fd This function set to on or set to off output pins of inductive proximity sensor 57 Specifically set to on pin four or data terminal ready signal and set off pin seven or request to send signal 8 3 10 char format time This function is similar to temps but the returned string has the following format ddmmyy where d is day m is month and y is year 8 3 11 int main This function has two parts the initialization and the infinite while loop The initialization part consists on Create databases if it doesn t exist it is used ITEMLOG csv database Write header of databases Get file descriptor and open inductive proximity sensor Configure output pins of inductive proximity sensor Check if output pins have been configured correctly Initialize all variables that would be used The infinite while loop part consists on Update status of output pins of sensor If this status is different that initial one it means that something has been detected Once something has been detected enter to a while loop Within this loop size of ITEMLOG csv database is checked if it is more than 70 it means that there is almost a tag saved if it is less than 70 it means that there is not any tag saved If there is almost one tag saved in actual date is compared with date last time field If they are different date last time field and today count are updated On contrast if two dates are e
3. Choice of Operating System 3 1 What is an Operating System An operating system OS is a set of software that manages computer hardware resources and provides common services for computer programs The operating system is a vital component of the system software in a computer system Application programs require an operating system to function For hardware function such as input and output and memory allocation the operating system acts as an intermediary between programs and the computer hardware Operating systems can be found on almost any device that contains a computer from cellular phones and video game consoles to supercomputers and web servers 3 2 Features of our Operating System Nowadays there are a lot of Operating Systems To choose one of them for this project is essential to decide some features that project need These features are Free Operating System which has no monetary cost Small size As Manual made by PC Engines ALIX proposes there are some OS options FreeBSD Linux NetBSD OpenBSD Others Commercial Each above category is composed by more than one possibility But commercial category could be removed of the list because don t fulfil with rule of no cost OS About other categories there is no subjective reason to choose one of them but the OS choose is in Linux category because is one of the most used OS with Windows and MAC OS but the other two are commercial and have a
4. To get this is used TIOCMSET operation and TIOCM_DTR flag Once the device is configured it is known that status is 2 only has activated DTR pin in the program is called status off So to know if sensor detects something only needs to check its status in the program is called status on So using TIOCMGET operation status on is continuously updated until status on and status off are different what it means that Carrier Detect pin is on or in other words sensor detects something When it happens status on value changes from 2 to 66 8 2 2 Proximity sensor deactivation When sensor activation is detected there is a while loop To exit of this while loop status off and status on have to be equal so when Carrier Detect pin is off It is important not forget to update status on inside while loop using TIOCMGET because if it is not done it will be an infinite loop 8 2 3 RFID ID tag detection ID tag detection is implemented in two functions int reader static int start rfid libusb device handle rfid handle These are the two essential functions to detect some ID tag 50 int reader function has to implement basic operations described in section 4 3 2 2 to open configure start and stop RFID reader because it works correctly So every time that is necessary to read a tag all this operations have to be done static int start rfid libusb device handle mid handle function is which read the ID tag It is divided in two
5. reader s response frame ENNEN 56 Figure 8 7 example to close the program cccceeeeeeeeeeeeneeeeeeeeeeeeeeetneeeeeeees 60 Figure A 1 useradd example EE 63 Figure A 2 open vsftpd chroot_list evample 63 Figure A 3 vsftpd chroot list document example cceeeeeeeeeeeeeeeeeeeeneeeeeeees 64 Figure AA delete FTP user evample ENNEN 64 Figure A 5 delete FTP user example 2 64 Figure A 6 list of System USES EE 65 Figure A 7 add new web page user example rrrnnnnnnnnnnnnrrrrnnnnnnnnnrnnnnrrrnnnnnnnennn 65 Figure A 8 example htpasswd file NENNEN 66 Figure A 9 open hipasswd file ANNE 66 Figure A 10 delete a web page USEF cocccccccccccnooooonnccnnnccnonnnannncnnnnnncnnnnnnnnnnnncnnnnn 66 Figure A 11 open bostaocd comte 67 Figure A 12 ssid and password fields of wifi network seese 68 Figure A 13 reboot b rd au 68 Figure A 14 open interfaces fie 68 Figure A 15 wifi network Confguratton 69 Figure A 16 example of inductive proximity sensor detection rrnnnrrrrnnnnnnnrn 70 Figure A 17 example of RFID tag reading 70 Figure A 18 example of web ACCESS ccccccccccnnocoooncccnnncccnnnnnnnnononnnnnncnnnnnnnnncnnnnnns 71 Figure A 19 example of FTP access e 72 Table 4 1 RFID frequency DANOS estoi dude 15 Table 4 2 RFID reader LEDS status 17 Table 43 lt 1D nd T EIES EE 20 Table 6 1 relation between pin signal and its b
6. 0x02 Tari data 11 0x00 Session data 12 0x00 PilotTone 25 data 13 to data 16 0x00 Password 8 bytes data data 17 0x01 maskBank data 18 0x00 maskAddr data 19 0x00 maskLen data 20 to data 51 0x00 selectMask data 52 Ox0A tryNo data 53 crc data 53 CRC footer data 54 0x03 EoF end of frame Above example shows Command send is 0x4002 which means cmd ids2 config or that this command configures parameters of the Gen2 protocol These parameters are stored in the RAM After reboot the reader there is necessary to set it again LinkSpeed 0x04 which means a 160 kbps LinkCoding 0x01 which means a miller 2 codification Tari 0x02 which means 25 us Session 0x00 which means that us SO PilotTone Password maskAddr maskLen selectMask are 0x00 which are not used for this communication maskBank 0x01 which means EPC tryNo Ox0A which means it has 10 times before connection fails After send this data computer wait for a confirmation USB ACK to know that this frame was receive correctly USB_ACK command is 0x00 26 Chapter 5 Wireless communication 5 1 Why needs wireless connection A wireless connection is a system that transmits and receives radio signals over the air It is interesting for this project because it lets to access to the mini pc without any wire making it more simple and easier Also this kind of connection lets to access to the device more than one per
7. 1 as host direction and correct user and password you would be able to see and download all csv files 48 Chapter 8 Program made 8 1 Goals The main of this program is that inductive proximity sensor and RFID reader work together to get ID tags information This program has to be simple and robust and it has to work well in extreme situation warning when problems appear It has to start without human interaction and try to fix for itself its problems Finally all information provided has to be correct 8 2 Flowchart diagram One way to make clearer the program s structure is to draw a flowchart diagram YES ID TAG IN DATABASE eg Figure 8 1 programs flowchart 49 In Figure 8 1 can be distinct five situations when program is waiting proximity sensor activation program is waiting proximity sensor deactivation RFID id tag detection CRC checkout and update databases 8 2 1 Proximity sensor activation This situation of the program has two parts first of all configure the proximity sensor and after detect proximity sensor activation The sensor will be activated when detects some metallic object in its working space To configure the proximity sensor has implemented one function void mcs int fd This function mcs int fd configures output pins As seen in section 6 3 it is necessary to have Data Terminal Ready pin with true value on and Request to Send pin with false value off
8. 80 35 05 00 00 15 06 12 13 08 46 15 06 12 13 09 30 004 00 00 00 00 00 00 00 00 00 00 11 22 15 06 12 13 09 06 15 06 12 13 09 19 ftotal count T Delete An 2012 CENTRE OF AUTOMATIC IDENTIFICATION All Rights Reserved Figure 7 2 final web page structure 7 3 1 Privacy It is essential to manage the access of the web page because users can see and modify the information file To get privacy a login and password access is implemented Firstly was done using databases form and php language This was good to identify and allow or not the access from a user and login But the problem was that an unauthorized user can access to the final web page writing the direction So it was an unsecure method To get more security and as apache server is used it is possible to use htaccess and htpasswd method 14 43 Se requiere autenticaci n EEE El servidor 10 1 10 1 80 requiere un nombre de usuario y una contrasefia Mensaje del servidor ITEMLOG Nombre de usuario Contrasefia Iniciar sesi n Cancelar Figure 7 3 authentication popup htaccess is a configuration file for use on web servers running the Apache Web Server software When a htaccess file is placed in a directory which is in turn loaded via the Apache Web Server the htaccess file is detected and executed by the Apache Server software enabling disabling additional functionality and features that Apache
9. Figure 7 6 delete all popup The php script consists of open the file with the command fopen and w flag which would create or reset the file After this command only needs to close the file descriptor and redirect to the previous web page 7 4 ftp server The second way to access to results is using ftp connection FTP acronym of file transfer protocol is a standard network protocol used to transfer files from one host to another host over a TCP based network It is often used to upload web pages and other documents from a private development machine to a public web hosting server With ftp would be possible to get all csv files generated not only ITEMLOG csv file but all ITEMLOG ddmmyy csv files and ITEMLOG_ERROR csv To connect via ftp minipc needs to be an ftp server 16 The ftp server used is vsftpd because it has a simple configuration and is considered one of the most secure To install it only needs to execute the following command gt gt apt get install vsftpd Once it has been installed it is necessary to configure it To configure vsftpd has to edit etc vsttpd conf file All has been commented less next lines listen YES local_enable YES dirmessage_enable YES use localtime YES 47 xferlog enable YES connect from port 20 YES chroot list enable YES chroot list file etc vsftpd chroot list secure chroot dir var run vsftpd empty pam service name vsftpd rs
10. Mon Jul 24 15 05 44 GMT 2023 from 10 1 10 165 on pts 0 Linux voyage 3 0 0 voyage 1 SMP PREEMPT Mon Oct 24 01 49 56 HKT 2011 i586 The programs included with the Debian GNU Linux system are free software the exact distribution terms for each program are described in the individual files in usr share doc copyright Debian GNU Linux comes with ABSOLUTELY NO WARRANTY to the extent permitted by applicable law NN Useful Commands VINN K SEN remountrw mount disk as read write NAN HN EN EN IN remountro mount disk as read only ef SH remove docs remove all docs and manpages Voyage Linux lt http linux voyage hk gt Version 0 8 Build Date 20111030 AT S7 45 S0 0 L1 V1 X4 amp cl El 00 root voyage AT S7 45 S0 0 L1 V1 X4 amp cl El Q0 1 1830 bash AT command not found bash cl command not found 1 Exit 127 AT S7 45 S0 0 L1 V1 X4 root voyage ff CTRL A Z for help 38400 8N1 NOR Minicom 2 5 VT102 Desconectado Figure 3 1 minicom response Voyage Linux access screen needs to introduce a username and password Default values are username root password voyage For default Voyage Linux is mounted as a read only OS if you want to modify something is important to know how to mount it as a read write OS It is done with gt gt remountrw read write OS gt gt remountro read only OS 3 4 Additional packages As is a small and concentrate Operating Sy
11. Wireless communication orransnsnnnnrrrnnnnnnnnnnnnnnnrrrnnnnnnnnnnnnnnnrrnnnnn 27 5 1 Why needs wireless connection EEN 27 5 2 Kinds of wireless connection ENNEN 27 53 IEEE 802 11 st nd rdg vecindades 28 HA MANE EE 28 5 5 Board configuration eat 28 A EE 28 5 5 2 Board files e ee 29 553 PUY EE 32 Chapter 6 Inductive proximity Sensor rrrrnrrrrrnnnnnnnrrnnnnvrrrnnnnnnnnnnrnnnnrrnnnnne 35 BCL What iS 17 eege gege EES A AT 35 62 EE 36 EIDEN E EE EE ac 36 6 34 Ne TEE 36 BE PT 37 6 3 3 Serial USB adapter eeng a 39 6 4 Basic operations E 39 Chapter 7 Access to results rrsnnnrrnnnnnnnnonnnnnnrrrnnnnnnnnnnnnnnnrrrnnnnnnnnnnnnnnnrrnnnne 41 7 aM RE 41 TAPA RESUlIS OA ane Gen 41 TS NED DQ EE 42 TT PN 43 lte dn e A EE 45 733 Delete tag Egeter 46 7 3 4 DGGE Al Lune 46 7 ATID SOIVOR Lade 47 Chapter 8 Program made 49 ke ele 49 82 Flowchart d dram ina 49 8 2 1 Proximity sensor activation EE 50 8 2 2 Proximity sensor deactivation ENEE 50 82 3 RFIP ID Tag AGE EE 50 8 2 5 Update databases vcomnordas iia KENE lees te ceiver EE AE 51 8 3 FUNCIONS quiet een 52 8 3 1 static unsigned char crc unsigned char data int length 53 032 SAG NA TEMPS Ten 53 8 3 3 char prep char NUM EE 53 8 3 4 void check_and_send char sortida ooooonnnccccccccnnncccnnnanaooncnnnnncnnnnnann cnn 53 8 3 5 static int conf reader libusb device handle rfid handle
12. a remote connection between computer and ALIX board Weld inductive proximity sensor with rs232 connector Make a program that manages inductive proximity sensor Make a program that manages RFID read and sensor at same time Write csv output files of results Programing of a web page that shows results Install a web server on ALIX board Install a FTP server on ALIX board Configure start up to add program made During this project some problems had to be fixed Working with RFID reader at beginning it doesn t work After reboot it it works once correctly but following times bad It was like this until found that after every read when stop_rfid command is send the RFID reader has to be reset Working with libusb library when ALIX board is not connected to the Internet by Ethernet it didn t compile c file It said that the last compilation had been in a later date and in that moment saw that the date was bad To fix it only had to change the date to actual hour In my opinion the date is always rebooted because battery is over The weld of inductive proximity sensor with RFID reader had been done twice First time was used one pin to connect GND but it did that the input signal had pulses so it was instable After change this output pin from GND to another one the input signal was stable easier to work with it At the moment when inductive proximity sensor has to be connected by serial port it didn t wor
13. big size To be one of the most used OS is important because it would mean that there are a lot of documentation and Forums which can help during development of the project So the last step is chose one of the Linux OS Like is made before the choice will be in ALIX provider s list Alix Rescue rescue AstLinux asterix gt VoIP CentOS small community Debian for Alix small community gOS 3 Gadgets no information Tal IPCop firewall PFire firewall LEAF Linux Embedded Appliance Firewall firewall Meshlium no information OpenWRT small community Ubuntu Linux big size Voyage Linux Xubuntu Linux big size Zeroshell servers In the previous Linux can be organized in some groups Those with small community CentOS Debian for Alix OpenWRT those with big size Ubuntu Linux Xubuntu Linux those with specific use such as firewall Alix Rescue AstLinux IPCop IPFire LEAF Zeroshell and those without enough information gOS 3 Gadgets fli4l Meshlium After this classification the only one which satisfies all features is Voyage Linux and this is the OS used in this project Finally features that have been used to choose OS are larger than which was thought at beginning Free Operating System which has no monetary cost Small size Big community Not specific utility Good papers and FAQs frequent answered questions 3 3 Voyage Linux 3 3 1 Voya
14. board Figure 2 2 behind of ALIX 2D3 board 2 2 Features and characteristics Here are some highlighted features of ALIX 2D3 CPU 500 MHz AMD Geode LX800 DRAM 256 MB DDR DRAM Storage CompactFlash socket 44 pin IDE Power DC jack or passive POE min 7V to max 20V Expansion 1 miniPCI slot LPC bus Connectivity 3 Ethernet channels Via VT6015M 10 100 I O DB9 serial port dual USB port Board size 6x6 152 4 x 152 4 mm same as WRAP 1E Firmware tinyBlOS Others Three front panel LEDs push button 2 3 Additional components The ALIX board has all connections but need two more components CompactFlash card as a storage device and wifi card as Input and Output device 2 3 1 CompactFlash card The CompactFlash card used in this project is CompactFlash Kingston 4 GB standard card COMPACT Figure 2 3 CompactFlash Kingston 4GB standard card This card is designed for basic storage without speed requirements It storages the Operating system and all programs made 2 3 2 Wifi miniPCl card This board doesn t have hardware to connect by wifi so it is necessary to use an external hardware To get a wifi connection is plugged in miniPCI connector a wifi miniPCI card 5 At same time this card is connected with an antenna as is shown in Figure 2 5 III MAC D 00086B2FF815 JAN OA LGA DCMA B2 C149645001EACO1 Figure 2 4 Wifi miniPCI card Figure 2 5 Wifi antenna Wifi miniPCI card and board Chapter 3
15. frame To stop the RFID reader is used three libusb functions ibusb_claim_interface libusb release interface and libusb bulk transfer 8 3 7 static int start rfid libusb device handle rfid handle This function sends an order to read RFID tags and read readers response About sent frame it has the following parameters sloNo 0x02 adjustSlotNo 0x00 emptyTriesStopNo 0x02 oneLoop 0x00 selectCmd 0x00 targetCmd 0x00 firstInitOnly 0x00 Table 8 2 start reader parameters A deep explanation of these parameters can be seen in Binary Protocol Specification RFI21 1 of Metra Blansko 17 The frame has the structure of Figure 8 5 Figure 8 5 reader s start frame 55 The fields Got Len Cmd and EoF have to be these values Data is all above parameters so 7 bytes CRC field has to be computed with crc function If it is received correctly for reader it will response with an acknowledge frame and a cmd ids2 epc frame To read correctly the response is essential to know the structure of this A cmd ids2 epc frame has the structure of Figure 8 6 Figure 8 6 reader s response frame Where first eight fields are the header following seven fields are data and last two are footer ID tag is EPC Len field So to read an ID tag after send starting frame is necessary to save cmd ids2 epc frame to a vector of unsigned char The length of this vector is dependent of EP
16. functions and an antenna for receiving and transmitting the signal 4 1 3 RFID frequency bands Band Regulations Range Data speed Remarks 120 150 kHz LF Unregulated 10 cm Low Animal identification factory data collection 13 56 MHz HF ISM band im Low to Smart cards worldwide moderate 433 MHz UHF Short Range 1 100 m Moderate Defence Devices applications with active tags 868 870 MHz Europe ISM band 1 2m Moderate to EAN various 902 928 MHz North high standards America UHF 2450 5800 MHz ISM band 1 2m High 802 11 microwave WLAN Bluetooth standards 3 1 10 GHz Ultra wide To200m High Requires 14 microwave band semi active or active tags Table 4 1 RFID frequency bands 4 2 Our RFID equipment 4 2 1 General Description The aim of this task is to get identification numbers of RFID tags To do this we have an RFI21 1 Development Kit of Metra Blansko a s company Figure 4 3 RFI21 1 Development Kit RFI21 1 Development Kit includes all necessary components for read tag identifiers which are in the field of an antenna It also allows reading and writing the user data when this property is supported by tags This project is only interested in read tag identifiers The content of this Development Kit is RFAO1 UHF RFID Antenna RFI21 1EU UHF RFID Reader Power supply Sunny SYS1421 0605 W Galvanically isolated converter UART RS 2
17. offers So there are two files that have to be modified First of them is in etc apache2 sites enabled In this project case it is called 000 default In this file is necessary to comment two commands and add four more First of all is necessary to look for the directory that has to be protected In this projects case is var www If your directory doesn t appear you can add with the same structure that other ones Once directory is found inside it will be some commands as only chosen users are allowed to open the webpage is necessary to comment or delete the following commands order allow deny allow from all Once this commands or lines are commented is necessary to add next commands inside lt Directory var www gt and lt Directory gt tags AuthType Basic AuthName AuthFile etc apache2 htpasswd Require valid user The first and last commands indicate that it is used a basic authorization and that only valid users can enter The second one is the route of the htpasswd file 44 The other essential file is htpasswd which has all users and passwords information This file has to have the same route defined on the last file In this project has been create this file with a dot at the beginning because to hide it There is a basic command to add users gt gt htpasswd c etc apache2 htpasswd lt user gt The first time that this command is used is necessary to us
18. only has to add one user the command is the same above but without option with same behaviour Once you add a user if you open hpasswd you will see something like Figure A 8 Figure A 8 example htpasswd file What it means that the password is encrypted because the password introduced was demo Web page Delete user If it is necessary to delete some user only has to remove or comment it from htpasswd file using your text editor Figure A 10 delete a web page user A 1 2 Program parameters There are two kinds of parameters parameters of RFID reader and parameters of program made About parameters of RFID reader they are explained in Binary Protocol Specification RFI21 1 of Metra Blansko 17 and can be modified in following functions static int conf reader libusb device handle rfid handle static int start rfid libusb device handle rfid handle On the other hand parameters of program made are 66 IDVENDOR IDPRODUCT IN READ IN WRITE ENDPOINT READ ENDPOINT WRITE REINTENTS NUMBER CHECKS LOG DEVICE IDVENDOR and IDPRODUCT are parameters to connect with RFID reader because are its Vendor and Product identification Following 4 parameters IN READ IN WRITE ENDPOINT READ and ENDPOINT WRITE are to configure input output configuration so ibusb h library defines that if you want to use ibusb_bulk_transfer you need to know endpoints And each time that you want to claim or release an in
19. parts the first one which send a message to tag and the second one which read the response So first is necessary to send 0x4001 command to indicate that reader has to look for tags This command has to be sent with some configuration shuch as slo No which sets the default number of slots for reading and emptyTriesStopNo which indicates how many attempts where you hear no tags is closed the repetition A deep explanation of these parameters can be seen in Binary Protocol Specification RFI21 1 of Metra Blansko 17 Once 0x4001 s command is sent it is reading moment To read RFID reader response is used bulk function It works like when it writes but using correct endpoint Now in vector would be the reader response It is necessary to read more than twice because two first responses are acknowledge of writings of configuration and 0x4001 commands Number of times of reading is managed with a parameter called REINTENTS So the maximum number of responses read would be REINTENTS 2 because there are two responses of acknowledges This is the maximum because if one correct response is read before it stops reading A correct response has the following structure Figure 8 2 response structure So elements seven and eight have to be 0x40f0 which it means that is the response of 0x4001 s command with a structure with ID tag Also is needed to check if ID tag is empty or not it is done checking element nine ID tag length of the resp
20. pattern of bits which would be modified with the request This field is an integer but there are some variables defined Pin String variable Integer value DTR TIOCM_DTR 0x002 39 RTS TIOCM RTS 0x004 CTS TIOCM_CTS 0x020 DCD TIOCM_CAR 0x040 DCD TIOCM_CD 0x040 RI TIOCM RNG 0x080 RI TIOCM_RI 0x080 DSR TIOCM_DSR 0x100 Table 6 2 relation between pin string variable and integer value So in this project only two operations are used TIOCMGET and TIOCMSET The first One is used to check pins status to know if sensor detects something and the second one is used to configure the sensor that how was seen before DTR pin has to be one or true and RTS has to be zero or false 40 Chapter 7 Access to results 7 1 How to access to results For this project there are three possibilities to access and see the results web page ftp access to the Operating system explained in section 5 5 3 It is important to have a simple easy and secure way to obtain results For these reasons the expectation is that web page and ftp would be two most used ways because you only need a web browser or an ftp client In each option only is necessary to be in the minipc s network to access obviously it is necessary also a browser or an ftp client 7 2 Results format Before to explain two access methods implemented is important to know how its information is saved For thi
21. rfid libusb device handle rfid handle int reader void mcs int fd char format_time int main 8 3 1 static unsigned char crc unsigned char data int length This function calculates CRC of the ength first elements of one unsigned char vector and returns calculated value 52 CRC is computed like simply 8 bit XOR It is essential to send correct frames to the RFID reader because is a mandatory field Also it works to check if a received frame is correct or no because CRC value received can be compared with CRC calculated with all frame less CRC and EoF fields 8 3 2 static char temps This function returns a string with following format dd mm yy HH MM GG Where d is day m is month y is year H is hour M is minute and S is seconds The time returned is local and actual machine time so is the time of minipc To get it is necessary to use time h library 8 3 3 char prep char num This function is used to manage counter field numbers It is important because it prepares counts numbers before to be updated So it receives a string of integers it has to convert to integer add one and convert to string again To convert to string format is important to know the number of digits because string has to be three digits not more or less is allowed So this is a limitation of this program the maximum number of tags read is 999 This function returns a string with the integer value updated 8 3 4 void check a
22. the return link tag to interrogator This protocol is bit oriented 18 Each command and each response are contained in a frame Each command are divided with the following fields Preamble Detect no modulation of the RF carrier preamble delimiter command code parameter fields depending on the command application data fields depending on the command and CRC 16 Figure 4 9 General command format Each response consists of the following fields quiet no modulation of the RF carrier return preamble application data fields and CRC 16 Quiet Return Preamble Data CRC 16 Figure 4 10 General response format 4 2 3 4 Protocols EPC Class 1 generation 2 EPC Class 1 generation 2 protocol is similar with ISO 18000 6 A and B protocols The main difference is that ISO 18000 protocols only defines air interface while EPC protocol defines structure of data physical reader implementation networks etc This specification has some main points RFID tags can use any frequency between 860 960 MHz RFID tags are able to work with three different modulation schemes DB ASK Double Sideband Amplitude Shift Keying SS ASK Single Sideband Amplitude Shift Keying and PR ASK Phase Reversal Amplitude Shift Keying RFID readers choose which scheme is used RFID tags can transmit with four different speeds 80 Kbps 160 Kbps 320 Kbps or 640 Kbps What it means that RFID reader can read more than 600 tags sec RFID
23. 32 LGA KN232 Galvanically isolated converter UART RS 485 LGA KN2 Interface cable RFC21 Interface cable USB Antenna cable RFCO1 2m CD with documentation and software Tags UPM ShortDipole In this project are used RFID Antenna RFID Reader Power supply cable USB and Antenna cable Also tags UPM is used to check that program works correctly 15 4 2 2 RFID Antenna RFAO1 RFID antenna is made of ABS plastic This antenna is designed for indoor use in industry logistics trade or other similar applications The antenna is fed through concentric cable with an impedance of 50 QA connected by the hole on the side housing to the antenna SMA connector It is a circularly polarized fixed reader antenna Read range which is designed to work in a band from 865 to 870 MHz is increased by high gain typ 8 dBi and low VSWR 1 2 1 minimizes wasted power in the reader Figure 4 4 RFAO1 RFID antenna 4 2 3 RFID Reader RFI21 1EU UHF RFID Reader cover is made from the stainless Steel finished by vamishing and has aluminous cooling plates lt is constructed for the use inside in the industry logistics stores and other similar applications The reader requires a direct current 5V power supply The antenna is connected by the coaxial cable with 50 Q impedance and the standard SMA connector The cable should have a low attenuation with respect to a reading distance in the required RFID application The antenna tog
24. 54 8 3 6 static int stop rfid libusb device handle d handle 55 8 3 7 static int start rfid libusb device handle id handle 55 A OE EE NET 57 8 3 9 Void MESTE EE 57 8 3 10 char SE Nene 58 EC fe bin el NEE 58 GL E E 59 Chapter 9 Conclusions ANEN 61 9 1 Projects development EE 61 9 2 Sie EE 62 93 MO SAA 62 Aa ETC A SO see ear Pe Se ee eae 63 A 1 Configuration Manual ee scasecessed rr ENEE ENEE 63 ATI Add Me EE EE 63 A 1 2 Program Eu 66 A 1 3 Wifi network configuration ENNEN 67 EAT EE REE 69 A 2 1 how it WOrkS A EN 69 A 2 2 Interpretation Of errors ainda 70 A 2 3 How to access to the results ENEE 71 B Summary of figures and tables ooooononocccccnnnccccccconoccccnoncconnnnnnn occ nn nnnnnnnnnns 73 C E DEE 76 D TE 77 vi Chapter 1 Introduction The aim of this project is to get a machine which can control and track movements of goods in a factory or store So the main idea is to have some of these machines strategically placed in the building and managed all from a comfortable distance To control and track movements are used two parameters RFID tags and proximity of goods These would be possible with help of RFID reader and an inductive proximity sensor which with an ALIX board are three devices with which this project begins This project consists on interaction of these devices and programming their software as well as choice of Operating Syste
25. C Len because is the unique variable field A correct RFID tag has 12 bytes so at least this vector has to have 28 elements To read correctly the tag has implemented one security method which works with two parameters REINTENTS and NUMBER CHECKS and a global variable crc ok Before to enter to the while loop crc_ok is equal to zero Within loop there is another while loop Within this second while loop is where response is read To exit the second while loop is checked if the response has the correct structure so is mandatory that it have OxFO in element 7 0x40 in element 8 and cannot have 0x00 in element 9 So if some response satisfies these conditions it exits the loop To avoid an infinite loop parameter REINTENTS is implemented which is the maximum number of times that this loop is swept Once second while loop is swept there are two possibility situations it has read a correct response or a wrong response If it has read a correct response it enter to an if condition which copy this vector to a global variable and check if this frame is correct using crc method To check if this frame is correct it is done a comparison between crc field and crc computed with crc function If crc comparison is correct crc_ok variable is modify to one if not nothing is done To exit of the first loop there are two possibilities if crc_ok is one or to avoid infinite loop a second parameter is implemented NUMBER OF CHECKS which controls
26. Career Final Project PROGRAM AN EMBEDDED SYSTEM WITH INDUCTIVE PROXIMITY SENSOR AND RFID READER Author Angel Maria F bregas L pez Supervisor of project Lukas Vojtech Prague June of 2012 Table of contents Chapter 1 Introduction rrrnnnnnnnonnnnnnrrrrnnnnnnnnnrrnnnrrrnnnnnnnnennn Chapter 2 Board eaestgedegengekEgetede neng geed 2 1 Introduction E 2 1 1 Basic EE 2 12 BOA USC NEE 2 2 Features and characteristics ANEN 2 3 Additional components rrvnnnnnnnnnnnnnrrrrnnnnnnnnnrnnnrrrrnnnnnnnnnnn 2 3 1 CompactFlash card vunne SEENEN unni 2 3 2 Wifi miniPCI card aa salda Chapter 3 Choice of Operating System cee 3 1 What is an Operating System rnnrrrrrnnnnnnnnrnnnnvrrrnnnnnnnrnnr 3 2 Features of our Operating System NENNEN 3 3 Voyage LINUX ci 3 3 1 Voyage Bn E E Gera 33 S HOW 10 NSA sverte 3 3 4 First stepS ee Ke Keene Keene 3 4 Additional packages ANEN Chapter 4 RFID reader rorrnnnnnnnnnnnnnnnnrrnnnnnnnnnnnnnnnnrrnnnnnnnnnnnn 4 1 RFID technology ji E RTL EE AS eie eaea eana REEERE ARE ERRE 4 1 3 RFID frequency bands AAA 4 2 Our RFID equipment ANEN 4 2 1 General Description ENNEN 4 22 RFIDAntenna unrated Gebees rapa 7 4 23 REID Read GF ua 16 4 3 Communication with RFID reader ccs eeeeeeeeeeeeeeeeeeeeeeaaeeeeeeeeeeteeae 20 4 3 1 General description of data packet rrrrrnnnnnnnnvrrrnnnnnnnnnnnnnnrrrrnnnnnnnrrnnnnnnn 20 4 3 2 BIS Gel EE 21 Chapter 5
27. Target disk dev sdc 1 partition 1 mnt voyage directory to mount OS image 10 iii Select Target Bootstrap Loader grub 1 iv Configure Target Console 1 serial terminal 5 38400 v Partition amp Create file system 1 Partition flash media amp create Filesystem vi Copy Distribution to target Yes vii Exit Once Voyage Linux is installed correctly only has to connect CompactFlash card on PCI socket and boot ALIX board 3 3 4 First steps Once Voyage Linux is installed and ALIX board booted How to access There are some possibilities in this project is used a serial communication Our Computer doesn t have serial connector so it is necessary to use a serial USB adapter When host computer and ALIX board are connected is easy to access to ALIX board using minicom communication 1 First time is necessary to configure minicom command with gt gt sudo minicom s And modify default values to Address dev ttyUSBO Speed 38400 After configuration connection is done with gt gt sudo minicom 11 Now terminal will show Voyage Linux access screen as Figure 3 1 Termina File Edit View Search Terminal Help Welcome to minicom 2 5 OPCIONES I18n Compilado en May 2 2011 10 05 24 Port dev ttyUSBO Presione CTRL A Z para obtener ayuda sobre teclas especiales Last login
28. With these functions is possible to implement all basic operations above described only is necessary to implement one more function control checksum CRC calculation The program is organized as follows firstly there is a part to open session and connect with RFID reader which consists of eight functions followed for a part of reader configuration Third there is a function called start_rfid which has two parts one that sends needed commands to ask for Identification Number of RFID tags and another which reads tags response Once all responses are read stop rfid function sends a command to stop the reader Finally two functions which close session and close handle for the reader To obtain RFID reader handle is used the libusb_open_device_with_vid_pid function what it means that is necessary to know the IDVendor and IDProduct of reader used In this project s device the IDVendor is 0xa600 and IDProduct is 0xe130 They have to be changed in case of use another reader 4 3 2 4 Bulk command The most important function of this program is libusb bulk transfer It has been used 4 times RFID reader configuration Send command to tags Read response of tags Stop reading of the RFID reader This command has following structure int libusb_bulk_transfer struct libusb_device handle dev handle unsigned char endpoint unsigned char data int length int transferred 24 unsigned int timeout The direc
29. YYY mm DD HH MM SS 4 3 2 2 Basic Operations A communication between computer and RFID reader has some mandatory operations which has to be executed every time reader has to read Initialize library and session Look for RFID reader Open RFID reader port and start communication Liberalize RFID reader port necessary to claim interface correctly Claim interface Required UO instruction Release interface Close RFID reader port Close session I O instructions are read or write Both of them use bulk transfer type instead of interrupt transfer type Because communication reader computer always use bulk type but computer reader communication can be interrupt or bulk type To make it simple only bulk transfer type is used 4 3 2 3 Functions and structure of program One part of program made is the RFID tag reading so it is interesting to comment about this part 23 Basically the goal of this part is to implement all basic operations seen in 4 3 2 2 section and understand how they work Libusb 1 0 8 has implemented some useful functions some of them have been used in program such as libusb init libusb get device list libusb open device with id pid lipbusb free device list lipbusb reset device libsb kernel driver active libusb detach kernel driver libusb set configuration libusb close libusb exit libusb claim interface libusb bulk transfer and libusb realease interface
30. a la conexi n Adaptador de t nel Teredo Tunneling Pseudo Interface Sufijo DNS espec fico para la conexi n Direcci n IPu6 E 2001 0 S5ef5 79fd 4f0 291 3f57 7e62 V nculo direcci n IPu6 local fe80 4F0 291 3 57 7e62 15 Puerta de enlace predeterminada Zi Estado de los medios e medios desconectados Figure 5 3 networks configuration of computer In the Figure 5 3 there is the computer network s configuration after do an ipconfig in windows 7 which shows the configuration of wireless connection In the red box there are IP direction and default gateway IP direction 10 1 10 165 Default gateway 10 1 10 1 The IP direction has to be in the 10 1 10 X range and the default gateway is the IP direction of the host which is configure before in point 5 5 2 in etc networks interfaces file It confirms the connection with the minipc After using appropriate access software it is possible to access to the minipc with the IP direction configured in etc networks interfaces Finally only has to put your user and password of Voyage Linux O S Some access software is for Windows O S Putty for Linux O S ssh command Tor mac O S JellyFiSSH for Android ConnectBot 33 In this project the computer which wants to access the minipc has Windows O S so putty software is used The configuration of putty is host name or iP address 10 1 10 1 port 22 default connec
31. a_cert_file etc ssl private vsftpd pem The explanation of all this lines is in the same etc vsftpd conf file but highlights are it is running when start up Operating System only local users who are part in the file list etc vsftpd chroot list are allow to log in Port transfer connections originate from port 20 Once ftp server is configured is necessary to add some users To add users is used useradd command with some options gt gt useradd s bin false d var itemlog lt user gt gt gt passwd lt user gt First of all etc shells file has to be modified adding the following line bin false This line will avoid that ftp users can use the console making the server be more secure After useradd command can be used This command is used with two options the first one s is to avoid that ftp users can use the console and the second d is to define the user s folder All users have the same user s folder the folder where there are all csv files In this project is used var itemlog After to configure the user s password is done with the second command passwd which would ask for a password twice Finally the last thing to configure a new ftp user is add it to the ftp list This list is in etc vsttpd chroot_list Only has to write user s name Once ftp server is configured only needs to be connected in the minipc s network and an ftp client Using 10 1 10
32. ary the option to delete some tags To get this is used a link programmed with php This link links to a php script that with the number of file passed as a variable can open the file and write all tags less which one has to be deleted After write all tags only has to save this new table in the file All this process is made without user s perception To get this method is necessary that the file has read write privileges if not an error message will be send The unique row that is impossible to delete is the first one that is not a tag but it is the definition of all fields 7 3 4 Delete all For this project is necessary the option to delete all tags so to have an empty csv file Unlike the previous sections to get this method is used Javascript The main reason to use Javascript is because a confirmation message is implemented so it is necessary an interaction with the host and php is a program language oriented to server This method is composed for two things one button with delete all text and a confirmation message that ask if you are sure to delete all tags When button is pushed a popup window appears This window asks if you are sure to delete all tags and there are two optional buttons one to confirm and another to cancel If confirms button is pushed a php script starts if cancels button is pushed you are sent to the previous web page 46 Mensaje de la p gina 10 1 10 1 You really want to delete all
33. board is used serial connection The ALIX board has an rs232 db9 plug so it is necessary to adapt three output sensor wires with an rs232 db9 connection 6 First of all is essential to know the rs232 pins It is achieve with Figure 6 5 and Table 6 1 Data carrier detect Data set ready Receive data Protective ground Figure 6 5 rs232 37 Pin Signal IN OUT behavior 1 Carrier Detect INPUT 2 Receive data INPUT 3 Transmit data OUTPUT 4 Data terminal ready OUTPUT 5 Signal ground 6 Data set ready INPUT 7 Request to send OUTPUT 8 Clear to send INPUT 9 Ring indicator INPUT Table 6 1 relation between pin signal and its behavior So it is necessary to choose three pins The first time one input one output and signal ground pins had been chosen Data terminal ready 4 as plus brown wire Carrier detect 1 as output or signal black wire Signal Ground 5 as minus blue wire Figure 6 6 Voltage sensors output first option But this choice had one problem the received signal from Data terminal ready pin was instable what it means that when sensor detects something its output was pulses it was caused because the threshold was so close to the maximum and minimum values This problem made more complex programming and it didn t work like it has to work To solve this problem pins rs232 connections were changed Data terminal ready 4 as plus
34. brown wire Carrier detect 1 as output or signal black wire Request to send 7 as minus blue wire Figure 6 7 Voltage sensor output second option 38 With these new connections there is more difference between maximum and minimum values and instability disappears 6 3 3 Serial USB adapter Initially inductive proximity sensor has to be plugged using serial port but ALIX board has a limitation only RXD and TXD are available for control handshake signals cannot be observed or controlled So a serial usb adapter is necessary to connect the sensor with board 6 4 Basic operations To observe and control proximity sensor is used ioctl function To use this function is necessary to include some libraries asm ioctls h sys ioctl h 9 termios h This function is composed for three fields ioctl int fd int request amp argument fd is the file descriptor of device so it is necessary open and acquire this file descriptor with open function request describes the operation to realize There are four possible operations TIOCMGET in argument it is save the pattern of bits showing input and output status of device TIOCMBIS activate put value to one outputs indicated in argument without modifying others TIMBIS deactivate put value to zero outputs indicated in argument without modifying others TIOCMSET activate outputs indicated in argument and deactivate others argument indicates the
35. data always as soon as the board is switched off the memory becomes empty or resets itself 3 RAM chips provide the communication link between the central processing unit and the storage device All software used is loaded on to the memory The CPU or processor then reads the RAM for the instructions and then does the calculation and executes them by writing back on to the RAM Another memory is dynamic memory or volatile memory which stores data that is fixed and does not go off even if the computer is switch off This is read only memory ROM which stores critical boot up information of the computer This chip allows the computer to start up and provides information on its hardware devices 2 1 1 3 Input and Output devices Input and Output devices purpose is to provide either input into the board system or to provide an output from the board system These are devices used when interacting with the board such as a keyboard or serial wire to connect with the computer 2 1 1 4 Storage devices Storage device is the disk drive or the hard disk The disk is broken up into many sectors and these sectors house the data such as programs inside the board They act as a cabinet or a filing system where all the data is stored in its raw form 2 1 2 Board used The board used in this project is ALIX 2D3 This board is optimized for wireless routing and network security applications And its size is small Figure 2 1 front of ALIX 2D3
36. device If the minipc is a client it means that is connected only when the server is on and in minipc coverage This situation has the limitation that only can be connected to the minipc one computer or device at same time But if there are some minipcs in the industry all of them could be connected at same time 28 tent Tent Figure 5 1 client server behavior To simplify access of a new device to the minipc the best situation is when minipc acts as server and devices as clients 5 5 2 Board files configuration To configure the minipc as a server only has to modify or create 3 files hostapd conf hostap and interfaces Likely Voyage Linux has installed hostapd 10 11 12 and wireless pci card drivers so it is no necessary to install anything before modify files etc network interfaces interface file contains the configuration of how its system is connected to the network Wifi network uses wlan0 interface So the file has the following content mac80211 based drivers auto wlan0 iface wlan0 inet static address 10 1 10 1 network 10 1 10 0 netmask 255 255 255 0 29 broadcast 10 1 10 255 etc default hostapd hostapd file is used to make etc hostapa hostapd conf work on boot so every time that minipc is booted this configuration is load To get this behavior only has to add two commands to this file RUN DAEMON yes DAEMON CONF etc hostapd hostapd conf
37. diagram Online http sensoresdeproximidad galeon com 8 Inductive sensor Programmable automatons Online http galia fc uaslp mx cantocar automatas PRESENTACIONES PLC PDF S 24 S ENSORES INDUCTIVOS PDF 9 Source to sys ioctl h Online http unix superglobalmegacorp com Net2 newsrc sys ioctl h html 10 Wifi Access point Online http enchufado com post php ID 341 11 Wifi access point Online http www crice org q node 329 12 hostapd conf datasheet Online http www daemon systems org man hostapd conf 5 html 13 syslog datasheet Online http publib boulder ibm com infocenter tpfhelp current index jsp topic 2Fcom ibm zt pf ztpfdf doc put cur 2Fgtpc2 2Fcpp syslog html 14 htaccess tutorial Online http www sitedeveloper ws tutorials htaccess htm 15 start up in Linux Online http luauf com 2008 06 05 ejecutar procesos al inicio de gnulinux 16 configure an FTP server Online http jrballesteros05 blogspot cz 201 1 04 configurar un servidor ftp en gnulinux html 17 All RFID Metra Blansko document Online http www metra cz en measuring equipment downloads instructions for operators rfid 77
38. e c option which indicates that it is necessary to create it so lt user gt would be the unique user all other would be removed Once this command is executed would be answered for password twice Figure 7 4 example htpasswd command If only has to add one user the command is the same above but without option with same behaviour Once you add a user if you open hpasswd you will see something like Figure 7 5 Figure 7 5 example htpasswd file What it means that the password is encrypted because the password introduced was 1234 If it is necessary to delete some user and password only has to remove it from htpasswd file 7 3 2 See information To see information is used two program languages HTML and php With HTML is structured the web page using a table to show information This table is composed of six fields each one for an information field saved in csv file and another more to choose if you want to delete the tag 45 On the other hand there is a mechanism to refresh website every five seconds to have the table updated This is possible using the next command lt meta http equiv refresh content 5 gt These five seconds is a parameter that can be change Php language is used to fill in the table It is a good language to manage csv files because has the fgetcsv command which can get a full csv field at same time 7 3 3 Delete tag by tag For this project is necess
39. e RFID reader It is necessary to configure every time before the start function There are some parameters LinkSpeed 0x04 LinkCoding 0x01 Tari 0x02 Session 0x00 PilotTone 0x00 Password 4 0x00 maskBank 0x01 maskAddr 0x00 maskLen 0x00 selectMask 32 0x00 TryNo OxOA Table 8 1 configuration reader parameters A deep explanation of these parameters can be seen in Binary Protocol Specification RFI21 1 of Metra Blansko 17 The frame has the following structure Sor un 0x02 med LL LL LL oeagl PJ 0x03 Zen Seq Time Cmd Data CRC EoF Figure 8 3 reader s configuration frame The fields SoF Len Cmd and EoF have to be these values Data is all above parameters so 45 bytes CRC field has to be computed with crc function If it is received correctly for reader it will response with an acknowledge frame 54 To configure the RFID reader is used three libusb functions libusb claim interface libusb release interface and libusb bulk transfer These three functions are essential for every frame sent to the reader 8 3 6 static int stop rfid libusb device handle rfid handle This function stops reading It doesn t use parameters so the frame sent has the following structure ooo LI ox ox f 0x03 Len Seq CRC EoF Time Cmd CRC Figure 8 4 reader s stop frame If it is received correctly for reader it will response with an acknowledge
40. ed only has to write the new user like Figure A 3 63 Figure A 3 vsftpd chroot list document example In the Figure A 3 there are two users who are allowed to access to the ftp server Itemlog and user demo FTP Delete user There are two options to deny access to ftp server for a user delete or comment its name from the etc vsftpd chroot_list Figure AA delete FTP user example delete user from Operating system and etc vsfipd chroot list gt gt userdel lt user gt Figure A 5 delete FTP user example 2 About the second method is important don t use r because this option would delete user s home directory and this directory is the same for all users To verify is one user has been added or deleted there is the following command which shows you all users of the Operating System An example could be Figure A 6 64 Figure A 6 list of system users It is easy to see that user demo user doesn t exist after userdel command Web page Add user There is a basic command to add users gt gt htpasswd c etc apache2 htpasswd lt user gt The first time that this command is used is necessary to use c option which indicates that it is necessary to create it so lt user gt would be the unique user all other would be removed Once this command is executed would be answered for password twice Figure A 7 add new web page user example 65 If
41. ehaviour ocooooonccccccccncccccnnnnaannnnos 38 Table 6 2 relation between pin string variable and integer value sseeesesss 39 Table 8 1 configuration reader parameters oooccccnnccoccccccnncccnnnnanannncnnnnncnnnnnnnnnnnns 54 Table 8 2 start reader parameters oooooococccccncccccnononancncnnnnnncnnnnnnnnnncnnnnncnnnnnnnnnnnos 55 75 C Passwords Voyage Linux User root Password voyage Wifi network Ssid Itemlog Password ltemlog1 Mysql User root Password voyage Phpmyadmin User root Password voyage Mysql application for phpmyadmin Password voyage Default access web page User Itemlog Password ltemlog1 Default access FTP server User Itemlog Password Itemlog1 76 D References 1 ALIX board serial console HOW TO Online http download gooze eu embedded doc alix board serial console howto pdf 2 Installation of Voyage Linux in ALIX board Online http download gooze eu embedded doc alix board serial console howto pdf 3 Voyage README file Online http download gooze eu embedded doc alix board serial console howto pdf 4 How to install Build essential Online http www adslzone net postt226493 htmi 5 How to install wifi card Online http Awww taringa net posts linux 10242878 Instalar de Tarjetas Inalambricas Atheros en Debian Squeeze html 6 RS232 serial cables pinout Online http www lammertbies nl comm cable RS 232 html 7 Inductive sensor
42. electromagnetic field oscillator Figure 6 1 sensor behaviour Figure 6 1 shows the two possible situations of inductive sensor If metallic object is in the operating area electromagnetic field is deformed and affect coil This affection generates an electrical inductive voltage drive by external wire to control system which acts like it is programmed 35 6 2 Features In this project is used an EI 1204pposs inductive proximity sensor of Carlo Gavazzi Figure 6 2 El 1204pposs The sensor has the following features and specifications Stainless steel housing cylindrical Diameter 12 mm Rated operating distance 4mm Output type transistor PNP make switching normally open LED indication for output ON 2mcable Rated operational voltage 10 to 40 VDC Rated operational current 0 2 mA Frequency of operating cycles 500 Hz 6 3 Connection 6 3 1 Diagrams The connection between ALIX board and the sensor is using serial port or RS232 db9 To make serial plug on the sensor is essential to know how every wire work Therefore the best option is to know the wiring diagram 7 36 Grnt Kee PNP transistor Figure 6 4 Wiring Diagram with transistor So with these two diagrams Figure 6 3 and Figure 6 4 it can be concluded that Blue wire minus input Brown wire plus input Black wire output or signal 6 3 2 rs232 To connect the inductive proximity sensor with the
43. et of standards for implementing wireless LAN computer communication in the 2 4 3 6 and 5 GHz frequency bands The 802 11 family consists of a series of half duplex over the air modulation techniques that use the same basic protocol The most popular are those defined by the 802 11b and 802 11g protocols which are amendments to the original standard 802 11b has a maximum raw data rate of 11 Mbps using 2 4 GHz band and uses the same CSMA CD media access method defined in the original standard This protocol is used in a point to multipoint configuration wherein an access point communicates via an omnidirectional antenna with one or more nomadic or mobile clients that are located in a coverage area around the access point 802 11g is the third modulation standard of wireless LANs It works in the 2 4 GHz band but operates at a maximum raw data rate of 54 Mbps or about 19 Mbps net throughput The modulation scheme used in 802 11g is orthogonal frequency division multiplexing OFDM 5 4 Hardware 5 5 Board configuration 5 5 1 Server client First of all it is necessary to know if minipc will be the server or a client because behaviour and configuration will be very different If the minipc is a server it would be that it is always generating a network and everyone who want to connect only needs to know user and password of wifi network This situation has the limitation that only can be connected one minipc at same time for the same
44. ether with a cable must have SWR lt 1 5 at the reader antenna connector in entire working frequency range lt is not allowed to operate the reader with a disconnected or unmatched antenna which could cause reader damage To connect the reader with a computer is used an USB 2 0 interface with the USB micro type B connector The reader could not be powered through the USB interface The reader has two signal LED s Green one signals power voltage presence and the yellow one signals a reader status 16 The RFI21 1 is compact multiregional multiprotocol RFID reader intended for data reading and writing from to passive transponders tags and offering them to a computer The reader works with the protocols EPC Class 1 generation 2 iP X ISO 18000 6B and ISO 18000 6A It provides wide range of configuration utilization of transfer speed up to 640 kb s and easy installation including integration to the system Reader status is indicated by the yellow LED as follows Yellow LED Status No light If the green LED lights simultaneously the reader si prepared to communicate with a computer the reader neither transmits nor looks for tags Permanent light Boot loader active Blinking 4 Hz The reader transmits and looks for tags according to settings tags are detected Blinking 1 5 Hz The reader transmits and looks for tags according to settings Alternate 5 no tags are detected Blinking 1 Hz Error status power s
45. ge Linux Voyage Linux 3 is Debian derived distribution that is best run on an x86 embedded platforms such as PC Engines ALIX Typical installation requires 128 MB disk space although larger storage allows more packages to be installed Currently Voyage Linux has the following editions Voyage Linux the basic version Voyage MPD Music Player Daemon Voyage ONE VoIP software The edition that is used in this project is Voyage Linux which has six releases i386 0 8 0 i386 live cd i386 sdk amd64 0 8 0 amd64 live cd 3 3 2 Features Here are some highlighted features of Voyage Linux Basic features Based on Debian Sarge r3 1 Etch r4 0 Lennyr 5 0 Squeeze r6 0 stripped down only 128MB disk space required Highly extensible through apt package management The kernel Linux 3 0 2 6 kernel always latest Full PC Engines ALIX WRAP board support watchdog gpio temperature reading and LED patch WiFi support Built in ath9k ath5k madwifi ng hostap prism54 optional ndiswrapper drivers and tonnes of wireless drivers Wireless access point support in NAT or bridge mode WPA WPA2 support via hostapd and wpa_supplicant WDS support via nl80211 hostap or madwifi drivers Hostap txpower and non volatile firmware download support Captive Portal built in nocatsplash support optional nocatauth package available 3 3 3 How to install The installation 2 is done on the Compac
46. grammed to control the device Access to results in this chapter there is an explanation of web page and ftp server and about format of databases Program made in this chapter there is an explanation of high level code Conclusions in this chapter there is a global view of whole project as well as problems and solutions found and possible future improvements Manuals A precise explanation of how to use and configure the program Summary of figures and tables Passwords where there are all passwords used References Chapter 2 Board 2 1 Introduction The brain of this project is this device the board The board is the union point of all devices and the interface which all software and programs run To run programs is necessary an Operating System task explained in chapter 3 2 1 1 Basic hardware Hardware is the term given to the components such as circuits electronics and anything that you could touch on the board Hardware can be broken up into four parts Processor Memory Input and Output Storage 2 1 1 1 Processor The processor is the most important piece of hardware It is the brain the very intellect of this electronic machine The processor decodes and executes instructions that are sent to in via the many lanes within the board 2 1 1 2 Memory The most common memory is known as the random access memory RAM because of itis a static memory Static memories are memories that do not store
47. gs are saved there are two ways to access the information web page and ftp connection 1 First of all you have to connect to the network So you have to look for the name of the network generated In default case Itemlog and write the password in default case temlog1 Once you are in the ltemlog network if you want to access by web page go to point 12 if you want to use ftp connection go to point 8 Open your web browser Write servers direction in default case is 10 1 10 1 A popup would appear write user and password In default case is user Itemlog and password ltemlog 1 Now you are able to see tags read delete some of them or all of them Your session will be until you close your web browser If you want to access by ftp connection open your ftp client Write on server blank the servers direction in default case is 10 1 10 1 10 Write ftp user and password in default case is user ltemlog and password 11 Itemlog1 Download csv file that you want to see or modify 12 Open csv file with a text editor or spreadsheet program Figure A 18 example of web access 71 227 Entering Passive Mode 10 1 10 1 222 130 Ver 150 Here comes the directory listing 226 Directory send OK Calculando compensaci n de la zona horaria del servidor MOTM ITEMLOG csv 213 20010401110716 Compensaciones de zona horaria Servidor 347155200 segundos Local 7200 segundos Diferencia 347148000 segundos Direct
48. is less than 3 minutes Now equipment is ready to work Once equipment is ready to detect a RFID tag 5 6 7 Put a metallic object in sensors work area sensor s LED has to switch on Take the metallic object away from sensors work area Put a RFID correct tag in RFID readers work area 69 8 RFID reader LED will be blinking When it stops blinking it means that tag was read 9 Repeat from point 5 Figure A 16 example of inductive proximity sensor detection Figure A 17 example of RFID tag reading A 2 2 Interpretation of errors There are two kinds of errors which program can fix non critic and which program cannot critic If a non critical error has happened final user doesn t know that it happens but it is saved in a csv file ITEMLOG ERROR csv A non critical error could be two situations the tag is not correct or communication with RFID reader has some problem This csv file has two columns the first which indicates of which kind of non critical error is and the second column which save time when this error has happened If a critical error has happened program will stop working It can be known because last tags are not saved or because sensors LED is not working To fix it is necessary to enter to the minipc s operating system and restart the program or reboot the minipc This kind of error is because a program bug that has to be fixed 70 A 2 3 How to access to the results Once some ta
49. k It was because ALIX board blocks the configuration of serial port To fix it an USB adapter is used 61 Some memory problems had been found For example after a RFID reader error the program had a segmentation fault lt was because the variable that has name of the ITEMLOG csv file was removed and when it was tried to open it sends an error It was fixed updating this variable every time Another problem was with day change and today count field has to be reset Firstly it works correctly less when ITEMLOG csv file was empty because it writes the actual date and 000 counter to the ID tags field To fix it one new function was used Hell to know the size of the file Web authentication can be broken If you write the correct password and add some letters behind it allows you to enter It has not been fixed So it is important to use longer passwords to avoid this problem 9 2 Project conclusions With this project we achieve an embedded machine with two devices that can control some kind of goods without any commercial software So it shows the big potential that free software has Also that easy is modifying Voyage Linux configuration to adapt for your personal project On the other hand the program made works correctly and has some security methods to avoid possible uncontrollable errors Also it can be personalized its performance modifying some parameters Finally this method to identify and control goods is much better
50. m and configuration of a wireless connection On the other hand goals of this project are also Achieve a robust and simple program that works with RFID reader and proximity sensor Improve programming skills especially in c language Working in something similar a business project Knowledge and use of different devices such as RFID reader and proximity sensor Use of ALIX board and improve my knowledge about this board This paper is organized starting with some unrelated chapters that finally are related on chapter 8 1 Introduction chapter which we are In this chapter there are the presentation of the project marked goals and organization of paper Board this chapter explain the board used as well as its features and characteristics Choice of O S in this chapter there is a discussion about which could be the best O S for this project how to install it and some packages that would be necessary in next tasks Therefore after this chapter ALIX board is prepared to other tasks RFID reader in this chapter there is an explanation of how RFID reader works its specifications and features of RFID reader used and software which controls it o Dow Wireless communication in this chapter there are an explanation of wireless connection used their features and configuration Inductive proximity sensor in this chapter there is an explanation of used proximity device features and how it works Just as software pro
51. mmunication with RFID reader 4 3 1 General description of data packet Communication between computer and reader takes place through a virtual serial port Every packet consists of three parts header data and footer typedef struct uint8_t SoF start of frame every time 0x02 20 uint8 tLen length of the data section uint16 t Seq sequence number 1 65535 0 reserved uint16 t Time timestamp of packet free running in milliseconds uint16 t Cmd code CDC PACKET HEADER data part typedef struct uint8_t CRC control checksum CRC uint8_t EoF end of frame every time 0x03 CDC_PACKET_FOOTERS The reader is managed by a computer Every packet from the computer is confirmed or the reader sends some response The response has the same sequence number as the command from the computer This means that the computer have to generate a sequence number which has to be in range 1 65535 The reader can send packets without request e g information about the tag ID when inventory mode is turned on In this case the reader generates a sequence number by an internal counter These packets are not confirmed by the computer Loss of a packet is recognized by the missing sequence number Every packet from the reader has timestamp in the header from the free running counter with resolution to milliseconds Packets form the computer can have this part zero CRC is computed like simply 8 bit XOR from SoF to last da
52. nd send char sortida This function update database csv file It receives a file route and uses a global variable which has the read RFID tag The main part is a do while loop which would check all tag saved on database with the read tag This loop would finish when tag is found or if it is not on the database Before to loop database is opened It is important to put the pointer in the correct place To do this is used an fseek operation and the knowledge of databases structure So is necessary to avoid header which would have the description of all fields so how it is described in section 8 2 5 only need to move the pointer 66 positions So it is very important no modify the header because if it is modified the program will no work 53 Within this loop there is an if condition which compare all tag of database with the read tag if they are equal a variable is modify to one and update date last time total count and today count fields using functions temps and prep described above Once do while loop finishes there is an if condition to know if the read tag was found on the database if it was not found the database is update with this new tag Finally a system message is sent This message is composed of the tag ID time of last reading twice and number of times that this tag has been read And it is in users syslog 13 8 3 5 static int conf reader libusb device handle rfid handle This function configures th
53. nt server behaviour rrnrnrrnnnnrrrnnnnnnnnnnnnnnnrrnnnnnnnnnrrnnnnrrrnnnnnnnennr 29 Figure 5 2 wifi ele EE 32 Figure 5 3 networks configuration Of Computer 33 Figure 5 4 putty configuration oia nnne 34 Figure 5 5 voyage CT 34 Figure 6 1 sensor behaviour rnnrrrrrnnnnnnnonnnnnnrrrnnnnnnnrnnnnnnrrrnnnenensrernnnnrrrnnnenntennn 35 73 Figure 6 2 El 1204Pp056 100000 36 Figure 6 3 Wiring Diagram PNP make awitchmg 37 Figure 6 4 Wiring Diagram with Iransistor 37 Figure 6 5 16292 EE 37 Figure 6 6 Voltage sensors output first option oooocnnnnncnnnccccnnnncconccannanccnnnnons 38 Figure 6 7 Voltage sensor output second Option oooccccnnccnoccccccnccccnnnnaannncncnnnons 38 Figure 7 1 information siruchure n 41 Figure 7 2 final web page structure oooooccccnnnnoocccccnnnnccnannnnanonononnnonnnnnnnnnnccnnnnnos 43 Figure 7 3 authentication POPUP EEN 44 Figure 7 4 example htpasswd commande 45 Figure 7 5 example htpasswd le 45 Figure 7 6 delete all poopup ENEE 47 Figure 8 1 programs TloweRart ivr acne ia 49 Figure 8 2 response structure ico 51 Figure 8 3 reader s configuration frame nn ccnnnnn 54 Figure 8 4 reader s stop frame srrrnnnnnnnnnnnnnnnrnrnnnnnnnannnnnnnrrnnnnnnnnnrrnnnnnrrnnnnnnnennr 55 Figure 8 5 reader s Start frame rrrnnnnnnnonnnnnnrrrnnnnnnnnnnnnnnnrrnnnnnnnnnrrnnnnnrrnnnnnnnennr 56 Figure 8 6
54. ond one which executes the program It is very important to add amp symbol after execution line because this program has an infinite while loop so this program has to be executed on background but the Operating System never would be loaded This script is called startup_itemlog After script is written three commands have to be executed gt gt update rc d startup_itemlog defaults gt gt In s etc init d startup_itemlog etc rc2d startup_itemlog gt gt chmod 775 etc rc2d startup_itemlog Which update start up of all services create a virtual link with etc rc2d and give it permissions 59 If it is necessary to stop the program one way is using command kill To use it first of all it is necessary to know the PID of the program so ps e command is used with a pipe and grep srfid to obtain only the program with this name or t srfid that is the same It is necessary to use grep command because ps e shows a lot of process An example can be seen in the Figure 8 7 Figure 8 7 example to close the program 60 Chapter 9 Conclusions 9 1 Projects development This project has been done in four months since March to June of 2012 It has been divided in some tasks each one independent that at the end had been joined These tasks had been Make a program that read a tag from a RFID reader Install Operating system to ALIX board Execute RFID reader program on ALIX board Configure
55. onse 8 2 5 Update databases There are three two functions to update database and it has updated also in main int main int reader void check_and_send char sortida 51 Function int main update date and today count when a new detection is made and there are some tags detected some day before So it has to put a cero the today counter and indicate that a new day has been started On the other hand int reader update every time that a tag is read the header of the csv file so it writes the next sentence ID tag date first time date last time total count today count n It is important to have always this header and exactly how it is wrote above Finally the main updates function is void check and send char sortida which has to update or add new RFID tags on databases So there are two possibilities the tag belongs to the database so just has to update date last time field and each counters fields or if the tag doesn t belong to the database so it is necessary to add all fields 8 3 functions In this section all functions made would be explained what they do and why they are implemented like this First of all all functions implemented are static unsigned char crc unsigned char data int length static char temps char prep char num void check and send char sortida static int conf reader libusb device handle rfid handle static int stop rfid libusb device handle rfid handle static int start
56. orio listado correctamente Nombre de ar Tama o Tipo de arc Unidad de Unidad de Unidad de Disco local Disco local Za ITEMLOG_021012 csw d ITEMLOG 081012c5v Es ITEMLOG 121012 c3v a TEMLOG 131012c5v Es ITEMLOG_141012 csv S TEMLOG_150612 csv EA TEMLOG 151012 csv Tama o d 148 394 394 394 148 148 148 476 148 312 394 394 230 Tipo de Archivo Archivo Archivo MN Encola 130MiB 00 Figure A 19 example of FTP access 72 B Summary of figures and tables Figure 2 1 front of ALIX 2D3 board EE 5 Figure 2 2 behind of ALIX 2D3 board va cocine 5 Figure 2 3 CompactFlash Kingston 4GB standard Card 6 Figure 2 4 Wifi miniPCI e EE 6 Figure 2 5 Wifi antenna Wifi miniPCI card and board srrrrrvnnnnnnonvnnnrrrrnnnnnnnnnnr 6 Figure 3 1 minicom response erp a eege E 12 Figure 4 1 RFID Header 13 Fig re E IR GE 13 Figure 4 3 RFI21 1 Development kt 15 Figure 4 4 RFA01 RFID antenng AAA 16 Figure 4 5 iP X packet structure Ak 17 Figure 4 6 Short command fommat nn nccnnnnns 18 Figure 4 7 Long Command formats EE 18 Figure 4 8 General response Tomat 18 Figure 4 9 General command format 19 Figure 4 10 General response format 19 Figure 4 11 query command structure eee eeeeeeee cece ee eeeeeneeeeeeeeeeeteeeenneeeeeeeees 20 Figure 4 12 example of packe 21 Figure 5 1 clie
57. owser and go to 10 1 10 1 direction To connect to the web page minipc has to be a web server There are different web server distributions apache2 distribution is the choice because is free and it has a big community So there are some package that have to be installed apache2 mysql and php Commands used to install its packages are gt gt apt get install apache2 gt gt apt get install mysql common mysql client mysql server gt gt apt get install php5 gt gt apt get install php5 gd During installation of mysql package is necessary to configure the root user In this project was used the following configuration User root Password voyage This web page has to have some characteristics Privacy only allowed users can enter See information of ITEMLOG csv red square on Figure 7 2 Delete one by one tags of the file blue square on Figure 7 2 Delete all tags of the file orange square on Figure 7 2 42 CALCVUT CZ CZECH TECHNICAL UNIVERSITY IN PRAGUE CENTRE OF AUTOMAT IDENTIFICATIO IC N ITEMLOG DEMO ID TAG date first time date last time 00 00 00 00 ac 1 36 81 ec 88 04 68 15 06 12 13 08 09 15 06 12 13 08 24 003 30 05 fb 63 ac 1 36 81 ec 88 04 68 15 06 12 13 08 12 15 06 12 13 08 25 007 58 58 20 58 58 20 58 58 20 58 58 20 15 06 12 13 08 32 15 06 12 13 08 32 001 30 08 33 b2 dd d9 04
58. qual doesn t do anything The condition to exit from this while loop is that the sensor doesn t detect anything so to change again the output pin status to the initial one Once it is out of while loop it enter to another while loop This one consists on correct communication with RFID reader reader function is started and if all libusb functions work good it exits the while loop and go back to update status of output pins of sensor and wait until it changes On the other hand libusb functions doesn t work it enters inside while loop This while loop creates if it doesn t exists or update the ITEMLOG ERROR csv database with this error and executes again reader function To avoid an infinite while loop there is a maximum number of errors in a row of 5 58 8 4 Start up This program has to work since board is booted because it has to work without human interaction 15 This is achieved with a script in etc init d The script done is the following one bin bash BEGIN INIT INFO Provides Angel Required Start syslog Required Stop syslog Default Start 2345 Default Stop 0 1 6 Short Description Description END INIT INFO echo start Isrfid homel lsrfid sre Isrfid amp Above script has two parts lines with that are needed to execute update rc d command and the script part which has two lines first one to write that Isrfid program starts and the sec
59. readers choose which speed is used This protocol include one method for support multiple readers and reduce their interference For above main points this protocol is known as multiprotocol protocol Each command has a specific structure All starts with a preamble and a command or response fields The following fields depend of command used For example query command has the structure of Figure 4 11 Preamble Command sei f 10 T f mode f Rate Y x Parity ESE NE EANET EN A EAT Description 0 S 0 FMO 00 x1 0 15 Odd tS 1 Subc 01 x2 parity 10 x4 on X 11 RFU Figure 4 11 query command structure The ID and T field choose which tag population shall respond to the query according to next table Tags that participate in interrogation round singulation 5 donteae 1 unchanged o umehanged don t care 0 unchanged 1 don t care 1 unchanged 0 Table 4 2 ID and T fields IDS and IDL are identified flags of tags 4 2 3 5 Choice of protocol Finally chosen protocol is EPC Class 1 generation 2 because it was designed to work internationally and has other enhancements that are significant but the real benefit of Gen 2 is that it works anywhere in the world and major manufacturers of chips and tags have lined up behind it And because EPC Class 1 generation 2 protocol can be seen as an update of ISO 18000 6 A and B protocols since it was approved as ISO 18000 6 type C 4 3 Co
60. s identification information This may be only a unique tag serial number or may be product related information such as a stock number lot or batch number production date or other specific information RFID tags can be either passive active or battery assisted passive An active tag has an on board battery and periodically transmits its ID signal A battery assisted passive BAP has a small battery on board and is activated when in the presence of a RFID reader A passive tag is cheaper and smaller because it has no battery Instead the tag uses the radio energy transmitted by the reader as its energy source The interrogator must be close for RF field to be strong enough to transfer sufficient power to the tag Since tags have individual serial numbers the RFID system design can discriminate several tags that might be within the range of the RFID reader and read them simultaneously Tags may either be read only having a factory assigned serial number that is used as a key into a database or may be read write where object specific data can be written into the tag by the system user Field programmable tags may be write once read multiple blank tags may be written with an electronic product code by the user RFID tags contain at least two parts an integrated circuit for storing and processing information modulating and demodulating a radio frequency signal collecting DC power from the incident reader signal and other specialized
61. s WPA s data encryption is TKIP Wpa passphrase ltemlog1 write a pre shared key that is used for wpa authentication To log in you can use two option use the encrypted key or the no encrypted key key written in woa_passphrase if encrypted key is the choice to know this key is needed to know the wpa passphrase and the ssid With these two values is possible to know the 64 hexadecimal digits key using an algorithm For example if ssid voyage and wpa_passphrase voyage WPA key is 0x97d8be323ba90a716a5e2b443cdbe731f26855866d0d934faab13c8119f08a92 logger x 1 which x could be syslog or stdout are two output methods In this case are equal to 1 what it means that all possible modules are logged The possible modules are IEEE 802 11 IEEE 802 1X RADIUS WPA driver interface IAPP and MLME logger X level 2 which X could be syslog or stdout It means that the minimum value for logged events is informational messages dump file tmp hostapd dump make a file which is dumped all state information Debug 4 indicates that the debugging is excessive 31 There are more commands that are not used in the configuration such as macaddr ac which controls mac address filtering and auth algs which is used in WEP configuration 5 5 3 Putty Once wifi network is made all devices with wifi compatibilities can access to it To get it is necessary to use some software First of all is basic being connected with minipc wifi ne
62. s project is necessary to save some information ID tag date of the first reading date of the last reading number of times read in total and number of times read today ID TAG Date first time Date last time Total count Today count Figure 7 1 information structure On the other hand every day it is generated two files one of them with total results since the first day that minipc is booted and another which only has information about one day These files are called ITEMLOG and ITEMLOG ddmmyy which ddmmyy will be day dd month mm and year yy of the information saved in Once is known the information and the number of files that is needed is time to choose the best format of these Firstly xml format was choose because is a standard format and easy to understand But finally csv format is the final choice because it is as simple as xml to implement and it can be directly interpreted using EXCEL software 41 CSV format consists on write information separated by an element In this project is used semicolon So every day will be generated one file ITEMLOG ddmmyy csv and modified another one ITEMLOG csv Obviously ITEMLOG ddmmyy csv count fields would have the same value 7 3 Web page The web page is the simplest and faster method to see the information of the ITEMLOG csv file or the file with all information Once you are in the minipc s network only has to start a web br
63. son at same time So goals of this wireless connection are Access to minipc from medium distance without wire More than one device can access to minipc at same time If there are more than one minipc be able to know which one is each Limit coverage area of connection inside building 5 2 Kinds of wireless connection Wireless connections are organized according its coverage So they can be divided as Wireless PAN wireless LAN wireless MAN and wireless WAN Wireless PAN acronym of personal area network is a small coverage network generally a room Typical technologies of WPAN are Bluetooth and Infrared Data Association Wireless LAN acronym of local area network is a medium coverage network generally a building Typical technology of WLAN is IEEE 802 11 standards marketed under the WiFi Wireless Fidelity brand name Wireless MAN acronym of metropolitan area network is a big coverage network generally a city Typical technologies of WMAN are IEEE 802 16 standards the most famous of these standards is WiMAX Wireless WAN acronym of wide area network is a huge coverage network generally a country or continent 27 For this project the most interesting wireless network is LAN because the goal of this wireless connection is to access to the minipc from anywhere in the factory since it is necessary more coverage than PAN and less than MAN 5 3 IEEE 802 11 standards IEEE 802 11 standards or WiFi is a s
64. stem there are some applications that are not installed Basically there are two build essential and emacs Build essential is necessary to compile programs 4 Emacs is not essential but is a good text editor and which was used in this project 12 Chapter 4 RFID reader 4 1 RFID technology 4 1 1 Definition RFID acronym of Radio Frequency IDentification is the use of a wireless non contact system that uses radio frequency electromagnet fields to transfer data from a tag attached to an object for the purposes of automatic identification and tracking The tag contains electronically stored information which can be read from up to several metres away Unlike a bar code the tag does not need to be within line of sight of the reader and may be embedded in the tracked object Figure 4 1 RFID Reader Figure 4 2 RFID tag 4 1 2 Operation A radio frequency identification system uses tags or labels attached to the objects to be identified Two way radio transmitter receivers called interrogators or readers send a signal to the tag and read its response The readers generally transmit their observation to a computer system running RFID software or RFID middleware 13 The tag s information is stored electronically in a non volatile memory The RFID tag includes a small RF transmitter and receiver An RFID reader transmits an encoded radio signal to interrogate the tag The tag receives the message and responds with it
65. tFlash card using a USB card reader of a computer which has installed Linux Mint OS Could be necessary that execute all commands as a root so sudo command was used Firstly is important to know the path of CompactFlash card Once it is known in this project is dev sdc must be empty After a primary partition has to be done and formatted with ext3 Secondly Voyage Linux image has to be downloaded and mounted in hosted computer Finally installation script has to be executed Following all indications Voyage Linux will be installed correctly Following scheme shows the installation step by step 1 Prepare the card Delete everything on the card Create a primary partition using cfdisk and mark it as bootable gt gt sudo cfdisk dev sdc Format primary partition as ext3 gt gt sudo mkfs ext3 dev sdc1 Delete checking every X seconds gt gt sudo tune2fs c 0 dev sdc1 2 Prepare the installation Make adirectory which mount OS image gt gt sudo mkdir mnt voyage Download OS installation file this project use Voyage Linux i386 0 8 0 Unpack file gt gt sudo tar numeric owner jxf voyage 0 8 0 tar bz2 Enter the unpacked folder gt gt cd voyage 0 8 0 3 Installation Execute script and follow steps gt gt sudo usr local sbin voyage update i Create New Voyage disk ii Select
66. ta byte without CRC and EoF The multibyte numbers format is little endian that means LSB first RER Po 8x03 sor zen seg Mime cmd Data cRC kor Figure 4 12 example of packet 4 3 2 libusb 1 0 8 Communication between computer and reader takes place through a virtual serial port using USB connection To get this communication is used an open source library which let to write and read to USB port After check some libraries such as JSR 80 JUSB javax usb and JcommUSB Finally libusb library was the choice 21 The main reason to choose this library is because it has a clear and simple explanation and examples Libusb is a library for USB device access from Linux userspace It is written in C and licensed under the LGPL 2 1 and was programed for Daniel Drake Johannes Erdfelt and Nathan Hjelm 4 3 2 1 How to install It is necessary to install this library to configure the package for our system It is easy and fast to install and only has to follow few commands First of all you have a zipped file with a tar bz2 format First step consists of unzipped the file and enter to the unzipped folder Once it has done configure script has to be executed which configure the package for our system Running configure might take a while When configure script finishes it is time to compile the package using make command Optionally can use make check to run any self tests that come with the package Finally
67. terface a port has to be use REINTENTS is a parameter to define maximum times that the reader reads or waits for a correct tag NUMBER_CHECKS is a parameter to define maximum times that the reader reads a tag when it has a wrong CRC LOG is a parameter to define where databases are and which names they have databases DEVICE is a parameter to define the direction of inductive proximity sensor A 1 3 Wifi network configuration To modify ssid or password of the wifi network you have to modify etc hostapd hostapd conf with text editor Figure A 11 open hostapd conf file 67 Figure A 12 ssid and password fields of wifi network In the picture above the ssid name of the network is ltemlog and the password is Itemlog1 After change it is necessary to reboot the board Figure A 13 reboot board On the other hand if what you want to change is the network s direction you have to modify etc network interfaces with text editor Figure A 14 open interfaces file 68 Figure A 15 wifi network configuration And again the board has to be rebooted A 2 user manual A 2 1 how it works In this manual would be described all necessary steps to keep the equipment in working order 1 Be sure that all wires are connected Switch on the board board s led has to be on Wait until sensor is working when you put something metallic in sensors work area and its LED is switch on usually
68. than bar codes because with bar codes you need a direct sight and with RFID tag you don t Also the wifi connection makes it more comfortable because you can check it without being close to it 9 3 Future work There are some features that can be improved or made Program the low level port serial and use it instead of an USB adapter Improve web security changing method used to fix the problem above described Implement a more robust data access to avoid possible problems with pointers 62 A Manual This manual would be divided in two sections configuration manual and user manual A 1 Configuration Manual With this manual you will be able to add or delete users modify some parameters of the program and web page and configure minipc s network A 1 1 Add delete users There are two kinds of users FTP users and web page users These two groups are independent so one user can be able to access to web page but not by ftp FTP Add user To add a new user you have to use following command don t care in which directory is executed gt gt useradd s d lt user gt Figure A 1 useradd example Once user is successfully created is time to allow him to access to the ftp server Using your favourite text editor in this case emacs modify etc vsftpd chroot list this file is specified in etc vsftpd conf Figure A 2 open vsftod chroot_list example And when the file is open
69. the maximum times that a response has read Finally if no correct response has read after two loops it is notified with an update of the ITEMLOG ERROR csv file which registers that is a wrong tag error and the moment of this error 56 To send a frame or read the response is used three libusb functions libusb claim interface libusb release interface and libusb bulk transfer 8 3 8 int reader This function prepares and executes all needed functions to use correctly a RFID reader So it is necessary to initialize libusb library get all usb devices plugged in the ALIX board get RFID reader handle reset RFID reader activate driver if it is not possible detach it set configuration configure RFID reader connection start read RFID tag stop read RFID tag Once ID tag is saved in a global variable it is time to write databases Each day would be three possible databases the total database called ITEMLOG csv the day s database called ITEMLOG_ddmmyy csv and optionally can be ITEMLOG ERROR csv This last one is not used or modified in this function To avoid possible errors of segmentation fault every time is created or opened databases Also every time the header of each database is overwritten Once databases are ready to update with the correct format to avoid pointers errors check and send function is called twice once for each database Finally RFID handle is close and libusb library closed
70. the following fields SoF RFU field reserved for protocol extension command code parameters or RFU CRC 5 Optional parameter fields depending on the command application data fields CRC 16 and EoF And each response consists of the following fields SoF flags mandatory and optional parameters fields depending on the command application data fields CRC 16 and EoF This protocol is bit oriented A single field is transmitted most significant bit first There are two forms of commands short commands of 16 bits Figure 4 6 and longer Figure 4 7 sor ru commana sen EEN fi em fame fem Figure 4 6 Short command format SOF RFU Command Parameters CRC 5 SUID Data CRC16 EOF code or flags optional optional ra em am soe om Figure 4 7 Long command format The response from the tag as explained before has the structure of Figure 4 8 Preamble Flags Parameters Data CRC 16 Figure 4 8 General response format 4 2 3 3 Protocols ISO 18000 6 type B ISO 18000 6 B protocol is based on the concept of interrogator talks first like ISO 18000 6 A In this protocol data is encoded and presented in slightly different ways in the constituent fields For interrogator to tag communication data is sent using an on off key format For tag to interrogator communication data is sent using backscatter techniques This requires that the interrogator provide steady power to the tag during
71. tion of the transfer is inferred from the direction bits of the endpoint address For bulk reads the length field indicates the maximum length of data you are expecting to receive If less data arrives than expected this function will return that data so be sure to check the transferred output parameter If libusb bulk transfer returns a 0 it indicates that the function worked correctly if returns another value it means that an error was done Two of these six areas need more attention endpoint and data Endpoint indicates if computer send commands or read data If computer wants to send some command to reader the endpoint used is 0x04 on the other hand if computer wants to read some data from reader the endpoint used is 0x83 About data there are two opposite behaviours when computer read some data from the reader in this case the most important part is value of length or computer send some command to reader In the second case data has to be structured like Figure 4 11 An example of sent data to reader is when computer sets the reader In this case data is defined as data 0 0x02 SoF start of frame data 1 0x2d length data 2 0x12 sequence number low bytes data 3 0x00 sequence number high bytes header data 4 0x00 time low bytes data 5 0x00 time high bytes data 6 0x02 command low bytes data 7 0x40 command high bytes data 8 0x04 LinkSpeed data 9 0x01 LinkCoding data 10
72. tion type SSH N Category Session Basic options for your PuTTY session Logging Specify the destination you wantto connect to Terminal p Y f Keyboard Host Name or IP address Port Bell 10 1 10 1 22 eo Connection type 7 Raw Telnet Rlogin SSH Serial Appearance Behaviour Load save or delete a stored session Translation S lection Saved Sessions Colours Connection Default Settings Load Data voyage_client_101 Proxy voyage_server Telnet Rlogin Delete SSH e Serial Close window on exit Always Never 9 Only on clean exit About Open Cancel Figure 5 4 putty configuration After this configuration computer has access to minipc Figure 5 5 voyage terminal 34 Chapter 6 Inductive proximity sensor 6 1 What is it A sensor is a device designed to receive information of external magnitude and transform it to another magnitude generally to electricity that can be quantified and manipulated Inductive proximity sensors are used for non contact detection of metallic objects Their operating principle is based on a coil and oscillator that creates an electromagnetic field in the close surroundings of the sensing surface The presence of a metallic object actuator in the operating area causes a dampening of the oscillation amplitude The rise of fall of such oscillation is identified by a threshold circuit that changes the output of the sensor housing
73. to install the programs and any data files and documentation using make install Optionally can be removed the program binaries and objects files from the source code directory using make clean Above explanation can be summarized with following points 1 Download libusb library from http libusb sourceforge net 2 Unzipped downloaded file gt gt sudo tar xvf libusb tar bz2 3 Enter to unzipped folder gt gt sudo cd libusb 4 Execute configure script gt gt sudo configure 5 Execute make command gt gt sudo make 6 Execute make install command gt gt sudo make install Optional 7 Execute make clean command gt gt sudo make clean 22 8 Execute make distclean command gt gt sudo make distclean In this project this library has been modified removing not necessary files for trying to minimize size of file Also a program which can read RFID tags has programmed When configure is executed an error could be produced gt gt configure Check in for a BSD compatible install usr bin install c checking whether build environment is sane configure error newly created file is older than distributed files This error is caused because operating system s date is out of date In this project the date was Thu Mar 15 09 14 15 GMT 2001 So date has to be update gt gt date set Y
74. twork using the correct password Conectado actualmente a Je Red 3 Acceso a Internet Red no identificada Sin acceso a la red Conexi n de red inal mbrica A Farewell a RDC_505 al Itemlog al eduroam all v FEL syl TN ITA CATON Figure 5 2 wifi connection 32 iC Users Angel ipconfig Configuraci n IP de Windows Adaptador de Ethernet Conexi n de 4rea local Sufijo DNS espec fico para la conexi n V nculo direcci n IPu6 local fe80 8f2 1e7f 6c97 ddac7 12 Direcci n IPu4 192 168 129 157 M scara de subred P 255 255 255 0 Puerta de enlace predeterminada a 192 168 129 1 Adaptador de LAN inal mbrica Conexi n de red inal mbrica Sufijo DNS especifico para la conexi n V nculo direcci n IPu6 local fe80 9452 bb75 F571 b163 11 Direcci n IPu4 v e 10 1 10 165 M scara de subred 255 255 255 0 Puerta de enlace predeterminada 10 1 10 1 ladaptador de t nel isatap 42240F47 06F4 4E27 AEOS C64CB7DYFES7 Estado de los medios Fa A at a medios desconectados Sufijo DNS espec fico para la conexi n Adaptador de t nel isatap 13B1BE8D 9128 4D1C B4CB 41B6FFB553E8 Estado de los medios e medios desconectados Sufijo DNS espec fico para la conexi n Adaptador de t nel 6704 Adapter Sufijo DNS espec fico para la conexi n Puerta de enlace predeterminada Adaptador de t nel isatap D4876C6E CF3C 441B 90CC 66FCFC694OA1 Sufijo DNS espec fico par
75. upply or temperature or SWR antenna Alternate 50 are out of operation range Blinking 10 Hz Error status service action is required contact the reader supplier Table 4 2 RFID reader LEDs status 4 2 3 1 Protocols iP X iP X acronym of Internetwork Packet eXchange is an implementation of Internet Datagram Protocol IDP protocol of Xerox Is a fast and connection orientated datagram protocol and it sends data using the network each packet has to include destination address It belongs to the network layer level 3 of OSI model and is similar with IP protocol but iP X is simpler and less trust An iP X packet consists of eleven fields Checksum packet length Transport control packet type destination network destination node destination socket source network source node source socket upper layer data sum Packet length Destination network Destination node Destination socket Source network Figure 4 5 iP X packet structure 17 4 2 3 2 Protocols ISO 18000 6 type A ISO 18000 6 A protocol is based on the concept of interrogator talks first This means that the tag shall wait to receive a correctly decoded command from the interrogator before transmitting So the protocol is based on an exchange of a command from the interrogator to the tag and a response from the tag s to the interrogator Each command and each response are contained in a frame Each command consists of

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