NXT WifiBlock - User documentation
Contents
1. M dia d connect Suffixe DNS propre la connexion example org Carte Tunnel Connexion au r seau local Statut du m dia M dia d connect Suffixe DNS propre a la connexion Carte Tunnel Connexion au r seau local 6 X Figure 5 Ipconfig command result Find the wireless connection settings and write down your default gateway in our example 192 168 1 1 as well as the value for your network mask 255 255 255 0 in the screenshot above The IP address of the computer in our example is 192 168 1 20 You now need to find a free IP address that will be attributed to the WifiBlock Build a new IP address by taking your computer s IP and replacing the last number by another number between 1 and 255 Then type ping and this IP in your command prompt If the ping command gives an answer Ctrl C to stop the command this IP address is already in use so choose another one s WA Invite de commandes Wela 168 1 1 avec 32 octets de donn es de 192 tM 32 te ms TIL 64 de ak Be e de R ponse de Statistiques Paque 4 perdus 0 perte Dur e appro nillisecondes Minimum Oms Moyenne 14ms Figure 6 The ping command indicate the presence of a device at the looked up address Humarobotics Making your personal robot smarter Page 6 If you get a unable to reach the destination host answer the IP address is free so write it down for you2. button A window will ask you where to save in on your computer From this tab you can also delete or download files from your computer to the NXT Brick Page 26 Humarobotics Making your personal robot smarter
3. DEER 44 Status Read DET ik 45 Addr L l Returns the Tx data Returns the length of the Rx data Returns the Rx data Returns the Dataflash status Bit 0 Write data 1 write Bit 1 Write done 1 done Bit 2 Read data 1 read Bit 3 Read done 1 done Bit 6 4 Reserved Bit 7 Dataflash error Return the Dataflash address Table 4 Data accessible by the Read Wifi Block action Humarobotics Making your personal robot smarter 4 Sending requests using the Wifi Block In this part we describe how the WifiBlock asks and gets a piece of information on the web Remark At the moment only GET requests are available with NXT G blocks a new block with POST UDP and TCP requests will be released very soon Please check www humarobotics com 4 1 Sending a GET request using the Wifi Block A GET request asks data from an internet resource using its URL 4 1 1 Using the WifiBlockCommunication block to send a GET request If you haven t done it already import the WifiBlockComm NXT G block and drag and drop it on a worksheet like in the screenshot below m 192 168 0 z Need help bject to read about its function For gt ove the cursor over an obje dstPort 0 additional help click the More help link X URL Debuglogs O WifiBlock 1 0 Figure 12 The WifiBlockCommunication NXT G block This block works in the same way as the WifiBlock
4. Read Date 13 Gives the date Read Get Status 14 Returns the GET status Bit 0 Port ready 0 KO 1 OK Bit 1 Reserved Bit 2 Send request 1 send Bit 3 Request done 1 done Bit 6 4 Reserved Bit 7 Request error 1 error eer wwe dad 15 Returns the Wifi status Status Bit 0 Enable Wifi 0 dis 1 en Bit 1 Wifi save config 1 save Bit 2 Start scan 1 start Bit 3 Scan done 0 busy 1 done Bit 4 Wifi status 1 connected Bit 5 Disable Rs232 debug 1 no Rs232 Bit 6 Re connecton 0 dis 1 en Bit 7 Wifi erase config 1 erase Read se 16 Returns the Http last response code 3 bytes response INST WS Sreae DE 17 Returns the number of Wifi connection retry Read Get Length 18 Return the length of the last data received from a GET request Read Get IP 19 Returns the IP address of the last GET request Read Get Port 20 Returns the port of the last GET request Humarobotics Making your personal robot smarter Page 13 Description Read Get URL 21 Returns the URL of the last GET request the part after IP address that you enter in the data field see the GET request paragraph Read Get Data 22 Read Post Status 23 Returns the POST status Bit 0 Port ready 0 KO 1 OK Bit 1 Reserved Bit 2 Send request 1 send Bit 3 Request done 1 done Bit 4 Enable Dataflash Storage Bit 5 Enable Dataflash Retrans Bit 6 Reserved Bit 7 Request error 1 err
5. application x www form urlencoded type You have several key value pairs with possibly duplicate keys the key being separated from the value by The character amp is used to separate key values pairs and for spaces other non alphanumeric characters being encoded with URL encoding See http en wikipedia org wiki POST_ HTTP for an example The data in the Post field will be included in the message body where a GET request only sends a message header and a URL 1 96 190 16 18 Port 0 m a Action POST request Data data php Debuglogs O www humarobotics com WifiBlock 0 1 Post Name Jonathan Doe amp Age 234Formula a 2E Figure 16 The WifiBlockCommunication block configured for a POST request 4 3 UDP and TCP data transmission and reception using the Wifi Block 4 3 1 Usages of UDP and TCP The User Data Protocol UDP and the Transmission Data Protocol TCP are both core protocols of the Internet Protocol Suite the set of network protocols used for the internet UDP is simpler and does not require handshaking dialog packet exchange to initiate the transmission Therefore it is quick but unreliable data can arrive out of order duplicated or be missing without notice TCP is a bit slower as it needs three packet exchange to before starting data transmission But this protocol ensures a reliable ordered delivery of the data It is the most used protocol fo
6. data logging is a function consisting in saving on a file for example a dataset of measures made by a system Once saved these measurements are available for further analysis or visualization In the case of the Lego robot it can be sensor measurements for example ultrasounds telemeters data Data logging can of course be made directly on the Lego Brick writing a local file that will be stored in the memory The main advantage brought by the WifiBlock is the ability to send data almost in real time to a computer that can use much more memory and computational power A graphical visualization or more complex analysis could then be performed by the computer using the data received from the Lego robot for example to build a representation of the robot environment 1 2 Remote control In this case the computer sends information to the Lego Brick using the WifiBlock connection It is possible to design a control interface on a computer and to send control commands to the robots over the wireless network 1 3 A Robot PC connection As seen in the two previous examples the WifiBlock creates a true bridge between the robot and connected computer enabling unprecedented capabilities for the Lego Mindstorms NXT robot like long distance remote control with sensor return Humarobotics Making your personal robot smarter Page 3 2 Comparison between Wifi and other wireless communication technologies 2 1 Bluetooth By default the Lego Mindstorm
7. gt HumaRobotics making your personal robot smarter Wifi Block User documen tation Version 1 0 1 Introduction to the WifiBlock The WifiBlock for Lego Mindstorms NXT is a standalone enclosure containing an electronic board with a Wifi device Useful features are 1 2 leds one green and one orange 2 ANXT compatible female connector 3 An ON OFF switch Figure 1 Overview of the WifiBlock The WifiBlock is powered by 3 AA LR6 batteries not supplied that must be inserted into the WifiBlock as shown on the battery hatch marking Figure 2 Battery hatch The WifiBlock connects to your Lego Mindstorms NXT brick enabling it to have a complete TCP IP connectivity with an access to the internet With such equipment your NXT robot will be able to send data to a computer over the internet or receive information from this computer Let s introduce some use case for the WifiBlock Humarobotics Making your personal robot smarter Page 2 the network login PWD motors connected to the and IP address if no NXT Brick DHCP is available aA NXT G block to configure Webpage to control the Webpage to store and use data coming from the sensors connected to the NXT Brick USB connection NXT G block to make a get post http request on any URL and to parameter the answer Using this block the user can create his own webpage Figure 3 Use case for the WifiBlock 1 1 Data logging The
8. LED Switch Figure 11 Visualization of the connection state with LEDs When you switch your WifiBlock on the two LEDs blink alternatively showing that the device is not connected Once you inject the IP configuration the orange LED shuts down while the green one still blinks showing a connection attempt Humarobotics Making your personal robot smarter Page 10 Once connected the green LED stays on stable The orange LED will blink if the WifiBlock receives or emits information To see this try to ping your WikiBlock using its IP address in you computer s command prompt and you will see the orange LED blink Connection time depends on your Wifi encryption When there is no security OPEN network connection is quick On the contrary if you have a strongly secured network like WPA2 connection time can increase up to 30 seconds because the calculation of the encrypted key takes more resources and time 3 4 Advanced functionality of the WifiBlockUtils block The WifiBlockUtils block offers other possibilities than writing the Wifi configuration on the WifiBlock The DebugLogs box allows you to ask the NXT Brick to store logs in a file that you can retrieve for debug purpose see Troubleshooting section 3 4 1 The Wifi State action This action allows you to do some actions on the WifiBlock once it is configured Description Wifi ON Enable Wifi checked wifi enabled Auto Auto reconnection if connection l
9. S Figure 14 Data transmission between the WifiBlockCommunication block and the Display one The problem with this is you won t have time to see what is displayed on the brick screen because the program will stop right after displaying the result This is a classic problem with NXT G Therefore you will have to add a Wait block after the Display one to have some time to visualize your GET request s result In the configuration panel of the Wait block select time in the Control dropdown menu and set the number of seconds you want for example 10 in the Until field Humarobotics Making your personal robot smarter Page 18 Finally you get this program 8 Until Seconds 10 Figure 15 NXT G code displaying on the brick screen the result of a http GET request Download and run your program from the command panel 4 2 Sending a POST request using the Wifi Block Remark At the moment only GET requests are available with NXT G blocks a new block with POST UDP and TCP requests will be released very soon Please check www humarobotics com A POST request allows you to send data to a server You can do your request the same way as the GET request but you have an additional field at your disposal the Post field Humarobotics Making your personal robot smarter Page 19 In this field you can enter all the data you want to transmit to the server encoded in
10. Utils used before The configuration panel allows you to choose the action to be done Select GET request to make a GET http request on the internet Humarobotics Making your personal robot smarter Page 16 Like for the previous block it is important to configure correctly the connection port The right part of the panel contains the following fields e IP The IP web server on which you want to make the request dstPort The destination port used for connection The default port for internet communication is 80 e URL character chain that will be placed after IP address containing html page or any kind of extension you want to call including parameters You can check the DebugLogs box so your WifiBlock will store logs in a file in the NXT Brick for debug purpose For example if you wish to call http www humarobotics com data php sku 23 amp tr 47 webpage you divide the URL into the IP part 88 190 16 18 for www humarobotics com and the additional data and parameters here data php sku 23 amp tr 47 Your configuration panel will look like below LE Port Oi 02 63 04 IP ss 190 16 18 dstPort 80 Action GET request X URL data php sku 238tr 47 Debuglogs O www humarobotics com WifiBlock 1 0 Figure 13 Configuration panel of the WifiBlockCommunication to do a Get request on http www humarobotics com data php sku 23 amp tr 47 To know the IP ad
11. WifiBlock Any error at this stage will result in a connection error as the various encryption modes are not compatible This is the password or passphrase of your Wifi network Please refer to the documentation provided with your Wifi router or modem Here again make sure that you have entered the right password Table 1 IP configuration data fields Humarobotics Making your personal robot smarter Page 9 Enter the parameters you determined during step two If you check the Save box your Wifi configuration will be saved and will remain until you choose to modify it Therefore if you shut your WifiBlock down and then up it will try to connect directly to the Wifi using the previous configuration Once all the parameters are entered make sure that the NXT brick is switched on and connected to your computer using the USB cable and that the WifiBlock is also switched on and plugged to the correct sensor port Then click on the play button of NXT G in order to launch the compilation of the program and the transmission to your NXT brick ml uai i a Figure 10 Download and run button at the center of the command panel of NXT G In order to check with your configuration has been sent to the WifiBlock and if it has successfully connected to your network you have to look at the LEDs placed on the side of the block E Not connected a Connected m Transmitting data ty fal Connecting External LED Internal
12. b fields Like for any data hub in NXT G you can retrieve this data unchanged as output of the hub There is only one additional output the Buffer one containing the result of the request Humarobotics Making your personal robot smarter Page 21 5 Troobleshooting In this part we will show you some possibilities to debug your programs understand what went wrong during communication and hopefully what to do to repair it 5 1 The WifiBlockQuery block This block can be downloaded on the Humarobotics website and should be imported into your NXT G software following the procedure described in appendix Using this block you can ask a set of questions to your WifiBlock and receive Boolean yes no responses This allows you to check if your WifiBlock sends and receive information correctly and to precise where a problem can be The DebugLogs box allows you to ask the brick to store logs in a file for debug purpose The list of available questions is the following OTM Description Error on GET port 1 Error on POST port 2 Error on UDP port 3 Error on TCP port 4 Error on Dataflash port 5 Wifi enabled 6 If 0 use a WifiBlockUtils block with Wifi State action to activate Wifi Scan in progress 7 If 1 scanning for Wifi please wait Should no last more than Wifi connected 8 If 0 check your Wifi config and your Wifi On parameter Re connection enabled 9 GET port ready 10 If Oand no GET requ
13. dress of a website you can ping in from your command prompt ping www humarobotics com You have to be sure that the server answers if called by its IP address particularly in the case of virtual hosts To test this you can call the IP address in your web browser and see if you get an answer for example http 88 190 16 18 won t give you an error 4 1 2 Displaying the result To visualize the return data from the GET request you can use a Display block so the return data will be displayed on the NXT Brick s screen Drag and drop a Display block after the WifiBlockCommunication one Then connect the Buffer output from the WifiBlockCommunication block to the Tex input of the Display one like in the figure 14 You can also retrieve the http response code using the HttpCode output Text output It should be 200 if the request was successful Check this page to interpret other codes http en wikipedia org wiki List_of HTTP status codes Humarobotics Making your personal robot smarter Page 17 The two other outputs are Error Boolean type telling you if any error occurred and DataLength Number type containing the length in byte of the request s result In the configuration panel of the Display block choose Text from the Action dropdown menu apale a gk Mr Acton TP Ter EH EI Display 0 2 Clear Bre E
14. e sure that you have set up this to the correct value as it is a very common mistake Drop down menu allowing to choose the action that will be performed by the WifiBlock In our case we have selected Write Wifi Config as we want to provide connection information to the WifiBlock This is the IP address that we want to assign to the WifiBlock This address has been determined in the previous step using the ping command This is the addressing mask for your IP address This is the one that we discovered using the ipconfig or ifconfig command The value of this mask depends on your network configuration This is the IP address of your network router in the case of a personal network it is often the IP address of your modem or Wifi router This address has also been discovered using the ipconfig or ifconfig command This is the name of the wifi network you are going to connect to This is the name that you see when hovering the Wifi Icon on your computer if of course it is connected to a Wifi network This is the encryption and authentication protocol for your Wifi network OPEN No Security and no encryption Your network is entirely open and anyone or any device can connect to it WEP fixed key encryption It is a basic setting for many networks WPA More secure than the WEP security setting WPA 2 2 version of the WPA setting offering advanced security Please make sure to select the right security mode to connect the
15. est error transmission in progress GET request done 11 GET request error 12 POST port ready 13 If O and no POST request error transmission in progress POST request done 14 POST request error 15 Dataflash storage enabled 16 Dataflash KEOMO 17 enabled UDP port enabled 18 Humarobotics Making your personal robot smarter Page 22 Description UDP Tx done 19 UDP data ready 20 UDP send error 21 TCP port ready 22 TCP request done 23 TCP send error 24 Dataflash write done 25 Dataflash read done 26 Dataflash error 27 Table 6 Data accessible by the Read Wifi Block action 5 2 The debug logs In all the blocks we presented here there was a possibility to active the DebugLogs You can retrieve this logs by uploading the WifiBlockLogs txt file of your brick You can find it in the Other section follow the procedure in the appendix The information you can get by looking at the logs are TO COMPLETE Humarobotics Making your personal robot smarter Page 23 6 Appendix import NXT G blocks To import new blocks to your block palette follow these steps e In NXT G the graphical programming environment for Lego Mindstorms open Tools Block Import and Export Wizard The following window appears Figure 17 Block import and export wizard e With the Browse button select the folder where the source code of your block lies i e where you unzipped the f
16. h is your machine loopback address that you should not take into account for wifi connection Write down your computer s IP address in our example 192 168 1 20 your default gateway in our example 192 168 1 1 and the value for your network mask Oxffffff00 equivalent to Humarobotics Making your personal robot smarter Page 7 255 255 255 0 if you divide the hexadecimal number by groups of two digits and convert them to decimal numbers You now need to find a free IP address that will be attributed to the WifiBlock Build a new IP address by taking your computer s IP and replacing the last number by another number between 1 and 255 Then type ping and this IP in your command prompt If the ping command gives an answer this IP address is already in use so choose another one If you get a unable to reach the destination host answer the IP address is free so write it down for your WifiBlock 3 3 Third step Configuring the WifiBlock Now that you have determined your network parameters you have to provide to the WifiBlock the information in order to allow it to connect to your network Launch NXT G the programming environment for Lego Mindstorms To configure the WifiBlock and allow it to connect to the web we are going to use the block called WifiBlockUtils You can find this block as well as the WifiBlock Communication and the WifiBlock Query ones that we will use later on the Humarobotics webs
17. ite here You will need to download them and to import them into NXT G Please refer to the appropriate appendix of this document or to the NXT G user manual in order to know how to add third party blocks to NXT G gt LEGO MINDSTORMS NXT Sr File Edit Tools Help DSBs omasa OVS o RRS bp W Need help Move the cursor over an object to read about its functio For help documentation examples and much additional help click the More help link Action Help X Debuglogs O www humarobotics com WifiBlock 1 0 Figure 8 The WifiBlockUtils block in NXT G more Visit us at www humarobotics com Humarobotics Making your personal robot smarter Page 8 This block allows writing the IP configuration of the WifiBlock used to make a connection to your network To enter the parameters choose Write Wifi Config from the Action dropdown menu You ll then see the panel displaying various parameters that have to be fill out O 02 63 04 wil 192 168 0 223 T IP Mask 255 255 255 8 Write Wifi Config l Gateway 12 168 0 1 owe 5510 seat www humarobotics com WifiBlock 1 0 Password Figure 9 Configuration panel for the WifiBlock The data to be filled out are described in the following table DA Description Port Action IP IP Mask Gateway SSID Security Password Number of the Port on the NXT where the WifiBlock is plugged Mak
18. nfiguration will be saved Wifi configuration will be erased Debug logs enabled Table 3 Data accessible by the WifiBlockUtils data hub Humarobotics Making your personal robot smarter Page 12 3 4 3 The Read WifiBlock action When you choose the ReadWifiBlock action you have read access to all values saved in the WifiBlock Select one using the Value to read dropdown menu The data will be accessible in the Buffer output of the data hub with a Text data type The following table describes the accessible data The numbers correspond to the numbers you have to enter in the Value to read field of the data hub see previous paragraph De Description Read Version 1 Read Product ID 2 Read Sensor Type 3 Read Voltage 4 Returns the firmware version Returns the product ID should be HRWB Returns 10 times the battery voltage Don t forget to divide this value by 10 to get the real voltage Read Mac 5 Returns the MAC address of the wifi device works only if the WifiBlock is connected to a network Read IP 6 Returns the configured IP address Read IP Mask 7 Returns the IP mask of the Wifi network Read Gateway 8 Returns the gateway of the Wifi network Read SSID 9 Returns the SSID of the Wifi network Read Security 10 Returns the Wifi safety type OPEN WEP WPA WPA2 Read Passphrase 11 Returns the password of the Wifi configuration Read Get Result 12 Returns the result of the latest GET request
19. olders you downloaded from the Humarobotics website containing the blocks presented in this documentation e The name of the found block is displayed in the list of blocks to import e Select in the Add Blocks to Palette dropdown menu in which palette you want to import your blocks e The Import button become clickable only when you select the block to import from the blocks list Humarobotics Making your personal robot smarter Page 24 Figure 18 Import wizard before importation e Click on the Import button e The Status text is updated to Import successful Figure 19 Import successful Do this for each block you want to import or update Humarobotics Making your personal robot smarter Page 25 7 Appendix upload a file from the NXT Brick With your NXT Brick connected to your computer and switched on click on the NXT Window button Figure 20 The NXT Window button Anew window will open showing information on connected devices Find your Brick and you can see its name battery level and firmware version Figure 21 NXT window Go to the Memory tab to access to the documents inside your Brick Click on the names of the different sections here Unused Other and Program to see the contents WifiBlockLogs ot Try Color rtm Figure 22 NXT window with Memory tab Select the file you want to retrieve and click on the Upload
20. or Read Post Length 24 Return the length of the last data transmitted by a POST Read Post IP 25 Returns the IP address of the last POST request Read Post Port 26 Returns the port of the last POST request Read Post URL 27 Returns the URL of the last POST request the part after IP address that you enter in the data field see the GET request paragraph Read Post Data 28 Retu Read UDP Status 29 Returns the UDP status Bit 0 Port enable 0 dis 1 en Bit 1 Send Tx data 1 send Bit 2 Send Tx done 1 done Bit 3 Rx data ready Bit 4 Rx data read Bit 6 5 Reserved Bit 7 Send error 1 error Read UDP dest IP 30 Returns IP address for UDP e elses 31 Returns destination port for UDP Read UDP src port 32 Returns source port for UDP ion Oe ie bere 33 Returns the length of the Tx data Length Read UDP Tx Data 34 Returns the Tx data een UY ts bee 35 Returns the length of the Rx data Length INST DDIS DER 36 Returns the Rx data Read TCP status 37 Returns the TCP status Bit 0 Port ready 0 KO 1 OK Bit 1 Send request 1 send Bit 2 Request done 1 done Bit 6 3 Reserved Bit 7 Send error 1 error Read TCP IP 38 Returns IP address for TCP Read TCP port 39 Returns port for TCP iio Oe ie bere 40 Returns the length of the Tx data Length Humarobotics Making your personal robot smarter Page 14 Data Read TCP Tx Data 41 NRO eN 42 Length Read TCP Rx Data 43 Read
21. ost checked auto reconnection activated EraseConfig Erase the saved Wifi configuration checked config will be erased Table 2 Wifi state actions Utils LE Port O1 O2 33 O4 C wii ONO 2 Action Wifi State Auto O goss O EraseConfig O www humarobotics com WifiBlock 1 0 Figure 12 The Wifi State configuration panel Humarobotics Making your personal robot smarter Page 11 3 4 2 Write Wifi Config with dynamic parameters In the previous example we hard coded the Wifi configuration But if you want some setting to depend from what happened previously in your program you can dynamically change the parameters using the block s data hub To open the data hub of a block click on its lower edge You get access to the following settings Data type Action Numbe Value to Read Number Security Number SSID Text Password Text Jel ome Numbers IP4 Pe em Ome Numbers MSK3 MSK4 CETA ve N R eN N Numbers GW3 GW4 Wifi On Boolean AVM RENDTE RE Boolean Save Boolean EraseConfig Boolean DebugLogs Boolean Description 1 help 2 Write Wifi Config 3 Wifi State 4 Read WifiBlock Value to be read in the WifiBlock registers see next paragraph 0 Open 1 WEP 2 WPA 3 WPA2 The Wifi network name The Wifi network password IP address divided into 4 numbers IP mask divided into 4 numbers Gateway divided into 4 numbers Wifi enabled Auto reconnection enabled The Wifi co
22. r internet applications 4 3 2 UDP transmission and reception Remark At the moment only GET requests are available with NXT G blocks a new block with POST UDP and TCP requests will be released very soon Please check www humarobotics com 4 3 3 TCP transmission and reception Remark At the moment only GET requests are available with NXT G blocks a new block with POST UDP and TCP requests will be released very soon Please check www humarobotics com Humarobotics Making your personal robot smarter Page 20 4 4 Do parametrized requests Like for the Wifi configuration you can dynamically set the parameters for your requests by using the data hub The available parameters are Data type Port Number Action Number IP1 Number IP2 Number IP3 Number IP4 Number dstPort Number URL Text PostData Text anita Kye Boolean Description The NXT port where the WifiBlock is connected 1 GET request coming soon 2 POST request 3 UDP Tx 4 UDP Rx 5 TCP Tx 6 TCP Rx First part of the IP address Second part of the IP address Third part of the IP address Fourth part of the IP address The port used for connection The additional data html page with parameters that will be added after IP address The data to transmit when you use the POST request The logs will be stored in a file on the brick for debug purpose Table 5 Description of the WifiBlockCommunication data hu
23. r WifiBlock Gam Invite de commandes estination destination 92 16 4 recus Figure 7 the result of a ping command showing that no device replies on a given IP address 3 2 2 Linux Launch a command prompt and run the ifconfig command This command displays the network configuration of your computer and the parameters of your network Find the wireless connection settings and write down your default gateway the value for your network mask and the IP address of the computer You now need to find a free IP address that will be attributed to the WifiBlock Build a new IP address by taking your computer s IP and replacing the last number by another number between 1 and 255 Then type ping and this IP in your command prompt If the ping command gives an answer Ctrl C to stop the command this IP address is already in use so choose another one If you get a unable to reach the destination host answer the IP address is free so write it down for your WifiBlock 3 2 3 Mac Launch a terminal located in Applications Utilities then type the ifconfig command IP addresses are on lines that start by inet to get only these lines you can type ifconfig grep inet Find the line that looks like inet 192 168 1 20 netmask Oxffffff00 broadcast 192 168 1 1 The IP address will be between inet and netmask Warning there will always be a line with the 127 0 0 1 IP whic
24. s NXT smart brick offers a wireless connection It is the Bluetooth technology The Wifi has several critical advantages compared to the Bluetooth e The bandwidth Wifi allows to transmit more data up to 11Mbps theoretical max to be compared with the 460 kbps maximum rate for NXT bluetooth http www tau ac il stoledo lego btperformance html e The range The Bluetooth present on the NXT has a 10m range only The Wifi range is much better up to 50 or 100m according to the norms and the surrounding environment and in addition if we consider that the WifiBlock equipped robot can communicate over the internet this range is no longer a limitation 2 2 XBee Xbee is a radio protocol with a bandwidth that is better than the Bluetooth but is still out of reach of the Wifi Even if the Xbee range is more important it only remains a point to point connection with no TCP IP connectivity and the lack of internet connection To learn more on the Xbee modules for Lego Mindstorms NXT please refer to http www generationrobots com wireless communication module nxtbee pro dexter industries mindstorms nxt us 4 NXTBeePRO cfm Humarobotics Making your personal robot smarter Page 4 3 Connecting and configuring the WifiBlock 3 1 First step connect the WifiBlock Make sure that the 3 batteries are correctly inserted in the WifiBlock Connect the WifiBlock using a standard Lego Mindstorms cable to one of the sensors ports of the Mind
25. storms These ports are labeled from 1 to 4 Figure 4 Connection between the Lego Mindstorm Brick and the WifiBlock Warning Never connect the WifiBlock to one of the motor ports A B and C ports The voltage on these connectors is not suitable and could do irreversible damages your WifiBlock 3 2 Second step Find out your network parameters The WifiBlock doesn t offer a DHCP feature that would allow it to automatically obtain an IP address from your wireless router Therefore you will have to configure your WifiBlock to allow it to communicate with your Wifi network by providing the following information e An IP address for the WifiBlock e A network mask Adefault gateway e The login for your wifi The password for your wifi The following paragraphs will explain you step by step how to find these information 3 2 1 Windows Humarobotics Making your personal robot smarter Page 5 Launch a command prompt by entering cmd in the program panel of your computer windows button R to get the program panel Enter the ipconfig command This command displays the network configuration of your computer and the parameters of your network as shown in the example below gt ipconfig Configuration IP de Windows Suffixe DNS propre a la connexion de liaison locale Masque de sous r seau Passerelle par d faut Carte Ethernet Connexion au r seau local Statut du m dia
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