The Cruizcore XG1300L
Contents
1. If not why What additions to the data sheet do you think would enhance the structure and subject What deletions from the data sheet could be made without affecting the overall usefulness ls there any incorrect or misleading information what and where How would you improve this document How would you improve our software systems and products Other Comments From Name Company Address City State ZIP Country Telephone Application optional Would you like a reply Y N Questions FAX i ie Microinfinity reserves all rights in this document and its subject matter The recipient acknowledges these rights and assures the use of this document only for the purpose it was delivered 122. 0 LCD_LINE1 Resetting Device false Wait XGL_TIME_ OUT Change accelerometer range if user presses the right key rbArgs Index BTNRIGHT SysReadButton rbArgs if roArgs Pressed XglAccSF TextOut O LCD_LINE5 Changing Range false Wait XGL_TIME_ OUT Wait 100 M lt MICROINFINITY Microinfinity reserves all rights in this document and its subject matter The recipient acknowledges these rights and assures the use of this document only for the purpose it was delivered CruizCore XG1300L USER S MANUAL 2 10 Technical Specification Performance Physical Electrical Environmental Gyroscope Input Dynamic Range Rate Noise 10 50Hz bandwidth Scale Factor Error Sensitivity Bandwidth Bias Drift Accelerometers Measurement Range Sensitivity Output Update Rate Weight Size Power Consumption Input Voltage Operating Temperature Storage Temperature Shock M MICROINFINITY 100 sec Continuous 150 sec Instantaneous lt 0 1 sec 0 5 Typical 0 01 sec digit Rate 0 01 digit Accumulated angle 50 Hz 10 hr Typical 2G 4G 8G Selectable 1 mg digit Typical 2G setting 2 mg digit Typical 4G setting 3 9 mg digit Typical 8G setting 100Hz lt 15 grams 48 mm X 32 mm X 21 mm lt 60mW 5V 3 3 55V 20 80 C 40 100 C 200 gRMS Microinfinity reserves all rights in this document and its subject matter The recipien
3. XGL_PORT n_read STAT COMM PENDING if I2CBytes XGL_PORT cmd count data Assemble data Xg lData mAng data 0 data 1 256 Xg lData mRate data 2 data 3 256 Xg lData mAccxX data 4 data 5 256 ACC_RANGE 2 Xg lData mAccY data 6 data 7 256 ACC_RANGE 2 XglData mAccZ data 8 data 9 256 ACC_RANGE 2 Microinfinity reserves all rights in this document and its subject matter The recipient acknowledges these rights and assures the use of this document only for the purpose it was delivered CruizCore XG1300L USER S MANUAL task main XGLpacket xg string msg ReadButtonType rbArgs Mnitialize system SetSensorLowspeed XGL_PORT Resets sensor and waits for hardware to settle XglReset Wait XGL_TIME_OUT Main loop while 1 ClearScreen XglReadPacket xg TextOut 0 LCD_LINE1 lt lt RESET SENSOR false Print sensor data TextOut 0 LCD_LINE2 ANGLE NumOut 40 LCD_LINE2 xgl mAng TextOut 0 LCD_LINE3 RATE NumOut 40 LCD_LINE3 xgl mRate TextOut 0 LCD_LINE5 gt gt ACC RANGE NumOut 92 LCD_LINE5 ACC_ RANGE TextOut 0 LCD_LINE6 ACC_X NumOut 40 LCD_LINE6 xgl mAccxX TextOut 0 LCD_LINE7 ACC_Y NumOut 40 LCD_LINE7 xgl mAccY TextOut 0 LCD_LINE8 ACC_Z NumOut 40 LCD_LINE8 xgl mAccZ Reset sensor if user presses the left key rbArgs Index BTNLEFT SysReadButton rbArgs if roArgs Pressed XglReset TextOut
4. programming tools The CruizCore XG1300L has been verified to work reliably with the following programming tools and environments NXT G and nxtOsek Source code and examples for these two environments can be found in our web site at http www minfinity com eng page php Main 1 amp sub 1 amp tab 5 NXC Source code and examples can be found in our web site at http www minfinity com eng page php Main 1 amp sub 1 amp tab 5 The next release of BricxCC and NCB NXC will provide native support to the CruizCore XG1300L thanks to John Hansen Users may use the test release built from http bricxcc sourceforge net test_releases RobotC Support for RobotC has ben added by Xander Soldaat and can be found at http botbench com driversuite Lejos Support for this environment has been contributed by Daniele Benedettelli and is available starting with LejOS 0 9 x at http lejos sourceforge net 2 9 Source Code Example The following program shows all the functions available in the CruizCore XG1300L For explanation purposes we chose the NXC programming language The program reads and displays the complete device data packet Users can reset the device by pressing the left button or change the accelerometers scale factor by pressing the right button The angle and rate measurements are presented in units of hundredths of degrees and hundredths of degrees second while the acceleration measurements are presented in thousands
5. 0x62 Select 4G accelerometer range 0x63 Select 8G accelerometer range Microinfinity reserves all rights in this document and its subject matter The recipient acknowledges these rights and assures the use of this document only for the purpose it was delivered MICROINFINITY CruizCore XG1300L USER S MANUAL 2 3 12C Communication Speed The CruizCore XG1300L has been tested to work reliably using the low speed I2C setting at 9 6 Kbps Internally the sensor updates the measurement 100 at 100 Hz 2 4 Scale Factor The inertial sensors in the CruizCore XG1300L are factory calibrated and the measurements provided in the form of signed short integers 16 bits or two bytes The two bytes represent the sensor reading multiplied by a scale factor of 100 The angle and rate outputs can be estimated using the following equations ANGLE MSB 256 LSB 100 degrees RATE MSB 256 LSB 100 degrees second For example a two byte reading from the register 0x42 LSB and MSB angle bytes that gives the byte sequence 0x1D and 0x32 should be interpreted as LSB 0x1D hexadecimal 29 decimal MSB 0x32 hexadecimal 50 decimal ANGLE MSB 256 LSB 100 50 256 29 100 128 29 degrees The accelerometer output takes in consideration the accelerometer range ACC_RANGE and is computed as follows ACCELERATION MSB 256 LSB 1000 ACC_RANGE 2 g The ACC_RANGE value can be 2 4 or 8 corresponding t
6. M MICROINFINITY CruizCore XG1300L USER S MANUAL The Cruizcore XG1300L Digital Gyroscope and Accelerometer for the LEGO MINDSTORMS NXT User s Manual rev1 1 2013 05 20 Copyright Microinfinity Co Ltd http www minfinity com EMAIL support minfinity com TEL 82 31 546 7408 FAX 82 31 546 7409 Note This product is not connected to or endorsed by The LEGO Group LEGO MINDSTORMS are trademarks of The LEGO Group Microinfinity reserves all rights in this document and its subject matter The recipient acknowledges these rights and assures the use of this document only for the purpose it was delivered MICROINFINITY CruizCore XG1300L USER S MANUAL 1 Introduction to Inertial Sensors Inertial sensors are self contained devices that can measure rates of rotation gyroscopes and linear motion accelerometers These devices do not require external signals or references in order to operate 1 1 Gyroscopes A gyroscope or gyro is a sensor that can measure rate of rotation about a specific axis The output of these devices can be added up integrated over time in order to estimate the angle of rotation Most common applications use gyros as angle measurement devices For example a robot turning at 30 deg sec degrees per second can make a 180 deg turn in 6 seconds TIME If a gyroscope is attached to the robot at any given time its output will be 30 deg sec Suppose that the gyro updates its outp
7. he robot hit an obstacle 2 The CruizCore XG1300L The CruizCore XG1300L is a digital device containing MEMS gyroscope and accelerometer sensors This device is compatible with the Lego Mindstorms NXT kit The CruizCore XG1300L internally processes the sensor signals eliminating the most significant errors that affect these type of inertial devices The sensor outputs from the CruizCore XG1300L are near free of errors and can be used without further processing in many types of applications 2 1 Sensor Description The CruizCore XG1300L contains a single axis MEMS gyroscope The internal signal processing applies factory calibrated scale factors and compensates for the most significant errors that affect gyroscopes such as changes in bias drift The CruizCore XG1300L internally computes the accumulated angle and makes it available to the user as an additional measurement Users interested in measuring angles are encouraged to use this measurement because of the following reasons 1 Applications with limited computational resources will not need to integrate the rate measurements in order to obtain angle information Furthermore some applications can choose a lower update rate of the angle value and still get the maximum accuracy since the integration is always performed at the maximum update rate 100 Hz For example for position estimation in low dynamic robotic applications users can use an angle update rate of 10 Hz witho
8. n section 2 6 Device Reset Function During reset the XG1300L will recomputed the bias drift value therefore is must remain stationary The bias drift value will change randomly over time due to temperature variations however the internal algorithm in the XG1300L will compensate for these changes We strongly recommend issuing a reset command to the XG1300L at the beginning of the program The reset function also resets the accumulate angle value to a zero Since the accelerometers measurements are taken with respect to the sensor reference frame see Sensor Reference Axes section the reset function will have no effect in the accelerometer measurements 2 Sensor Reference Axes The gyroscope sensitive axis is perpendicular to the flatter area of the sensor and pointing down The accelerometer X axis is pointing towards the side of the device the Y axis points forward and away from the sensor connector and the Z axis points down as shown in Figure 1 Figure 1 The CruizCore XGL1300L sensor reference frame 2 8 Programming Tools and Environments The CruizCore XG1300L implements a communication protocol compatible with Lego NXT Microinfinity reserves all rights in this document and its subject matter The recipient acknowledges these rights and assures the use of this document only for the purpose it was delivered MICROINFINITY CruizCore XG1300L USER S MANUAL therefore giving users freedom to work with their favorite
9. nent the output of these sensors could be integrated once to estimate velocity and a second time to estimate position In the practice this sensors are also affected by errors and the double integration needed for estimating position produces unpredictable results within seconds of operation The most common use of these sensors is to measure the gravity acceleration component which in Microinfinity reserves all rights in this document and its subject matter The recipient acknowledges these rights and assures the use of this document only for the purpose it was delivered MICROINFINITY CruizCore XG1300L USER S MANUAL turn is directly related to the tilt angle of the sensor A pair of accelerometers mounted on a robot with the X axis ACC_X pointing towards the side and the Y axis pointing forward ACC_Y can be used to compute tilt angles ROLL and PIT CH as follows sin PITCH ACC_Y GRAVITY sin ROLL ACC_X GRAVITY cos PITCH This solution assumes that the measurements are taken when the robot is either stationary or moving at constant speed For small angles the equations can be further simplified as follows PITCH ACC_Y GRAVITY radians ROLL ACC_X GRAVITY radians Another application for accelerometers is as a robot collision detector A robot hitting an obstacle will experience large changes in velocity accelerations for very short periods of time These large accelerations can be used as an indication that t
10. o 2G 4G or 8G accelerometer ranges For example a two byte reading from the register 0x46 LSB and MSB X accelerometer bytes with a scale factor set to 4G ACC_RANGE 4 that gives the byte sequence Ox8F and 0x01 should be interpreted as LSB Ox8F hexadecimal 143 decimal MSB 0x01 hexadecimal 1 decimal ACCELERATION MSB 256 LSB 1000 ACC_RANGE 2 1 256 143 1000 4 2 0 798 g 2 5 Static Bias Drift Static bias drift affects all gyros and is defined as a non zero output that can be observed when a gyro is stationary The CruizCore XG1300L estimates this value during startup this process takes approximately one second in which the sensor must remain stationary Failing to observe this recommendation will produce unreliable results which are shown as a constant drift on the angle value when the unit is stationary Since in many cases the XG1300L sensor will be mechanically attached to the NXT controller it is likely that when the power button is pressed the XG1300L will Microinfinity reserves all rights in this document and its subject matter The recipient acknowledges these rights and assures the use of this document only for the purpose it was delivered M MICROINFINITY CruizCore XG1300L USER S MANUAL also move causing it to miscalculate the bias drift value This effect can be reversed by sending a reset command to the device as explained in the following section Device Reset Functio
11. of gravities or mg Define constants define XGL_PORT S1 define XGL_ADDR 0x02 define XGL_DATA_REG 0x42 define XGL_RESET REG 0x60 define XGL_ACC SF REG 0x61 define XGL_DATA_PACKET 10 define XGL_COMMAND 2 define XGL_TIME OUT 500 Current accelerometer range value byte ACC_RANGE 2 Microinfinity reserves all rights in this document and its subject matter The recipient acknowledges these rights and assures the use of this document only for the purpose it was delivered MICROINFINITY CruizCore XG1300L USER S MANUAL 4XGL1300L sensor data packet struct XGLpacket short mAng short mRate short mAccX short mAccY short mAccZ Reset XGL1300L sensor void XglReset byte cmd XGL_COMMAND byte n_read 0 ArrayBuild cmd XGL_ADDR XGL_RESET_REG while I2CStatus XGL_PORT n_read STAT COMM PENDING I2CWrite XGL_PORT 0 cmd ACC_RANGE 2 Change scale factor to 2G 4G or 8g void XglAccSF byte cmd XGL_COMMAND byte n_read 0 ACC_RANGE ACC_RANGE 8 2 ACC_RANGE lt lt 1 byte register XGL_ACC_SF_REG ACC_RANGE 2 gt gt 1 ArrayBuild cmd XGL_ADDR register while I2CStatus XGL_PORT n_read STAT COMM PENDING I2CWrite XGL_PORT 0 cmd Reads the full packet from XGL1300L void XglReadPacket XGLpacket amp XgIData byte data XGL_DATA_PACKET byte cmd XGL_COMMAND byte count XGL_DATA_PACKET byte n_read 0 ArrayBuild cmd XGL_ADDR XGL_DATA_REG while I2CStatus
12. t acknowledges these rights and assures the use of this document only for the purpose it was delivered 10 MICROINFINITY CruizCore XG1300L USER S MANUAL Contact Information Corporate Office Microinfinity Co Ltd 8F KANC 906 10 lui dong Yeongtong gu Suwon si Gyeonggi do 443 270 Korea Tel 82 31 546 7408 Fax 82 31 546 7409 Email support minfinity com USA Technical Support P O Box 131284 Ann Arbor MI 48105 USA Tel 1 734 223 5904 Fax 1 866 400 3125 Email usa support minfinity com Homepage http www minfinity com Microinfinity reserves all rights in this document and its subject matter The recipient acknowledges these rights and assures the use of this document only for the purpose it was delivered M lt MICROINFINITY CruizCore XG1300L USER S MANUAL CUSTOMER RESPONSE It is our intention to provide you with the best documentation possible to ensure successful use of your Microinfinity product If you wish to provide your comments on organization clarity subject matter and ways in which our documentation can better serve you please FAX your comments Please list the following information and use this outline to provide us with your comments about this manual and product 1 What are the best features of this document and product How does this document meet your hardware and software development needs Do you find the organization of this data sheet easy to follow
13. ut 100 times per second FREQUENCY the number of samples N that the gyro will output during the 6 second rotation will be N TIME FREQUENCY 6 100 600 The sampling period PERIOD is computed as the inverse of the frequency PERIOD 1 FREQUENCY 0 01 seconds And the heading angle can be computed by integrating the individual gyro readings as follows ANGLE RATE O PERIOD RATE 1 PERIOD RATE N PERIOD ANGLE 30 0 01 30 0 01 30 0 01 180 degrees In the practice gyros are affected by several factors such as bias drift temperature and acceleration Suppose now that in our previous example the contributions of these sources of error make the gyro output 1 larger than the true rate value in this case the estimated angle at the end of the turn will have an error of about 2 degrees ANGLE 30 3 0 01 30 3 0 01 30 3 0 01 181 8 degrees Some errors such as drift will affect the gyro output even if the robot is stationary and if not taken in consideration can create significant errors over time In mobile robotic applications gyros are commonly used to determine the robot orientation or heading furthermore the gyro output can be combined with wheel encoder data in order to estimate the robot position 1 2 Accelerometers An accelerometer is a sensor that can measure velocity changes acceleration as well as the gravity acceleration In theory after removing the gravity acceleration compo
14. ut loosing accuracy 2 The internal angle estimation is the most accurate because the XG1300L computes it using full floating point precision The XG1300L also includes a three axis accelerometer This device can be configured to use one of the following ranges 2G 4G and 8G As in the case of the gyroscopes these sensors are factory calibrated 2 2 Communication Interface Microinfinity reserves all rights in this document and its subject matter The recipient acknowledges these rights and assures the use of this document only for the purpose it was delivered MICROINFINITY CruizCore XG1300L USER S MANUAL The CruizCore XG1300L communicates with the Lego Mindstorms NXT using the I2C bus It includes a connector compatible with Lego NXT cables The CruizCore XG1300L I2C address is set to 0x02 Sensor data is stored internally in different registers that the NXT can access by sending read commands to the appropriate registers See Table 1 In addition to the register read operations the CruizCore XG1300L provides some additional functions that can be accessed by sending write commands to specific registers as shown in Table Table 1 The CruizCore XG1300L internal registers REGISTER Hex value Sensor Value 2 These functions allow resetting the sensor as well as changing the accelerometers scale factor Table 2 The CruizCore XG1300L special function registers REGISTER Hex value XG1300L ACTION
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