MEMS and sensors

Posted on January 27, 2014 at 11:37What are the best tool or equipment to evaluate the MEMS microphones?

Posted on January 22, 2014 at 15:04Which are the parameters that impact on the microphone frequency response? Which is the best way to evaluate the frequency response?

Posted on January 22, 2014 at 17:14Test

Posted on January 16, 2014 at 17:17Which are the parameters that impact on SNR? Which is the best way to evaluate the SNR?

Posted on January 14, 2014 at 16:34What are the main Acoustic parameters of a MEMS microphones? How are they defined?

Posted on January 13, 2014 at 18:35All the example code I've seen reads the acceleration and magnetic field values by polling the appropriate registers.For example:x.l = i2c_read(OUT_X_L_A);x.h = i2c_read(OUT_X_H_A);y.l = i2c_read(OUT_Y_L_A);y.h = i2c_read(OUT_Y_H_A);z.l = i2c_read(OUT_Z_L_A);z.h = i2c_read(OUT_Z_H_A);When does the sensor update the register values? How do I know when to read the registers?I am concerned that the chip could update the register value between polling the OUT_X_L_A and OUT_X_L_H, resulting in a corrupt reading.Thanks,Travis

Posted on December 31, 2013 at 19:26What document have package marking information for H3LIS331DL? Thanks. #h3lis331dl

Posted on November 27, 2013 at 15:26Hi,I need to read the accelerometer data from LSM303DLHC. I use the STM32F401 Discovery board and the ''stm32f401_discovery_lsm303dlhc.c'' library.I read carefully the datasheet, especially the section 7.1 in page 24 with the register setup but I would like to know if someone has any project example that could help me to understand how to use the sensor.Thank you in advance.Kind regards,Antho

Posted on January 14, 2014 at 11:04Hi,I would like to know : how did you calculate the L3GD20 sensitivity (LSB/dps) in the example?#define L3G_Sensitivity_250dps    (float)114.285f        /*!< gyroscope sensitivity with 250 dps full scale [LSB/dps]  */#define L3G_Sensitivity_500dps    (float)57.1429f        /*!< gyroscope sensitivity with 500 dps full scale [LSB/dps]  */#define L3G_Sensitivity_2000dps   (float)14.285f         /*!< gyroscope sensitivity with 2000 dps full scale [LSB/dps] */What does the ''f'' mean ? Because I tried to calculate these values and I found : 262.144 LSB/dps for a 250 dps full scale, 131.072 LSB/dps for a 500 dps full scale and 32.768 LSB/dps for a 2000 dps full scale. The 16 bit output data is expressed as two's complement so : Sensitivity (LSB/dps) = 2^16 (bit) /

Posted on January 13, 2014 at 10:10Hello, In the iNemo Engine Lite Version 1.2.0 (FW V.2.3.0) when analizing the EKF Prediction state I came to the conclusion that the quaternion update is not using the same mathematical function defined by the pMat_Fsys that is passed to the iNemo_PropagateP. If I am correct this does not seem to be a proper implementation of a Kalman filter.  Thus I have a few questions: 1- Is the iNemo Engine Lite implemetation correct (and if not is there an update planned any time soon)? 2- More generaly speaking where can I find a description of the iNemo Engine providing  details on the actual implementation, e.g. including, among others, the description of the mathematical  model used in the iNemo Lite Engine Kalman filter design? Thanks Gerard #inemo

Posted on December 23, 2013 at 15:01I would like to configure both the CS43L22 Audio DAC and the LSM303DLHC MEMS accelerometer to be used simultaneously. From what I have seen on the documentation, it seems that both of these devices are connected to I2C1. Is it possible to reconfigure one of these devices to use I2C3?Or maybe to disconnect I2C1 from the Audio DAC after the control information is sent, so that the information from the accelerometer doesn't interfere with the audio signal?ThanksJoe #stm32f4-cs43l22-lsm303dlhc

Posted on December 13, 2013 at 19:45If the LIS3DH range is set to +/- 2g, how does the chip behave if acceleration exceeds 2g's? Do the axis outputs limit, wrap around, go to some fixed value, etc?

Posted on December 12, 2013 at 18:48hi, I use LIS3DSH and a problem appear sometime at init, in fact we catch false value from chip (offset error on x axis). Only offset is not correct (same offset value in case of pb). SPI bus reading is correct , value come from chip. Do you have any reason for that , may we use any control to indentify error ? Thnaks in advance, Regard,

Posted on December 06, 2013 at 12:00Hi, I don't know, the interrupts work. I have the testcase attached. Here is the logged sequence: BEGIN: STAT_REG = 0 .. STAT_REG = 0xF // here should come the Int, shouldn't it? .. STAT_REG = 0xFF // Overflow, new_lis will be set LIS331DLH_ResetInt1Latch() LIS331DLH_GetAccAxesRaw(&axesraw);  -> here comes the Interrupt new_lis will be set LIS331DLH_GetAccAxesRaw(&axesraw); GOTO BEGIN Why do I have to poll STATUS_REG. No interrupts occur without polling!? When exactly comes the interrupt, and when will it reset(?!). Regards, Steffen #h3lis331dl #interrupts

Posted on November 06, 2013 at 17:41Good morning, I am having some trouble in working with the magnetometer with the 12 and 8 gauss range. I am using an SPI communication. All the data from accellerometer and gyroscope are correctly  as well as for the magnetometer with the scale setted up to 2 and 4 gauss but not with 12 and 8. In particular by using an external magnet I can not get any saturation of the device with this scales settings . I am using not an STM32 to drive the sensor but I am free to share all my settings and register configurations to understand what is the problem regards, Marco Beccani

Posted on December 19, 2013 at 20:05Can anybody point me to any additional reference material on the LSM9DS0.  Such as any reference designs and source code.  Interested in proper implementation of read/write sequencing.  Thanks. #lsm9ds0-reference-material

Posted on November 28, 2013 at 07:09hi guys, i am working with the LIS331DLH accelerometer, i was able to read the product ID but when i am going to set the config register 1  i am not getting acknowledgement, what may be the cause? #lis331dlh

Posted on November 30, 2013 at 16:19 I've just read the thread: Data output format of the LSM303DLHC the accelerometer data is left�?justified, in normal mode, the data is in 12�?bit representation which means the lowest 4 bit in LSB are always 0s Is this true also for the H3LIS331DL? In the LIS331DLH_GetAccAxesRaw of your API, all values are shifted by 4. regards, Steffen

Posted on December 11, 2013 at 08:06I want to use lsm303dlhc as outdoor thermometer. I use next code       int8_t value= 25+data[0];        uint8_t sign=value&0x80;        uint8_t cels=0;        if(sign)            cels=(~value)+1;        else            cels=value; but when temperature is minus i have value 11, it is wrong. How can i use this right?

Posted on December 09, 2013 at 13:31Hello to all, In order to ease the self learning process and setup ST's LSM330DLC, attached to this post is an example of its drivers setup for a general application. Thank you, Thiago Reis #lsm330dlc

Posted on December 09, 2013 at 13:29Hello to all, In order to ease the self learning process and setup ST's LSM303D, attached to this post is an example of its drivers setup for a general application. Thank you, Thiago Reis #lsm303d

Posted on December 09, 2013 at 13:20Hello to all, In order to ease the self learning process and setup ST's L3GD20, attached to this post is an example of its drivers setup for a general application. Thank you, Thiago Reis

Posted on December 08, 2013 at 13:47Currently evaluating KIT EVAL DISCOVERY STM32F3. Where can i download IAR workbench for KIT EVAL DISCOVERY STM32F3.Thanks,

Posted on November 27, 2013 at 22:37I am trying to setup the LIS2DH to detect movement and drive INT1.  The documentation is not clear what needs to be configured to do this. CNTL_REG3 appears to select the sources for INT1.  There are two that are AOI options.  I am assuming since the 6D movement function is associated with the AOI (Table 51, Interrupt Mode), that at least one of these bits needs to be set in this register. In INT1_CFG, it is clear that bits 6 and 7 can be set for ''6 direction movement recognition'', but do the other bits also have to be set? Is there an example of using this mode for this part or similar parts? #lis2dh

Posted on November 27, 2013 at 14:38Hi, my INT1-Line is static low: with:     response = LIS331DLH_SetIntHighLow(MEMS_ENABLE);  // Interrupt active low; and     response = LIS331DLH_SetInt1DataSign(LIS331DLH_DATA_READY); I get the data only about polling STATUS_REG. Any Idea? Regards, Steffen #interrupts #h3lis331dl