MEMS and sensors

Posted on November 04, 2015 at 15:37I'm using the LPS25H pressure sensor and have noticed a strange stairstep behavior where one LPS25H seems to step or jump 10-20 Pa for several minutes to a few hours, then jumps back.  This behavior is quite differentfrom the normal RMS noise from sample to sample.  I first noticed this when running several sensors sitting onthe same desk over a weekend using the other sensors as a reference.  Note that step seems be some kind of fixedoffset since the relative pressure changes during the step does track with the other sensors.I have also see nthis behavior when doing a temperature sweep.  In certain temperature bands the reading jumps out of the background atmospheric pressure trend, then snaps back when the temperature changes.  In particularbelow 10C and a band around 20C.Is this behavior expected?  I cou

Posted on April 11, 2014 at 14:58Hi all,i'm currently working on an inclination sensor using a.m. gyroscope. I encounter random spikes in the digital values - @ still device.The spikes generally are either +255 above signal or -255 below average signal.It basically happens on all 3 axis. Especially when the average signal is around 0!In my opinion - there is a problem in the chip like NOT LOCKING the Hi byte when reading the Lo Byte of a particular 16 bit value to keep Hi and Lo Byte consistent. So i'm ending up reading the Lo Byte of the ''old'' value and the Hi Byte of the ''new'' value.This might look like: old value: 0xFFFF (-1)new value: 0x0002 (+2)combined wrong Reading: 00FF (+255) - making a difference of about 255 as stated aboveThe data sheet won't help, as it doesn't say anything about a locking mechanis

Posted on November 03, 2015 at 10:27Hi,I'm planning to get 3200Hz data rates for ADXL345 sensor with Nucleo board. The SPI speed is 5MHz. And i initialized exactly as per the data sheet.the initialization process is as below:accelerometer.setPowerControl(0x00);accelerometer.setDataFormatControl(0x0B);accelerometer.setDataRate(ADXL345_3200HZ);accelerometer.setPowerControl(0x08);Here I'm using high baudrate.Suggestions would be appreciated. Thank you.

Posted on November 02, 2015 at 22:59Hello, We couldn't find any firmware source code example for STM32F1 series support with in STM32CubeExpansion_MEMS1_V1.4.0 .Is there such HAL drivers for lsm6ds3 with STM32F1 series 32 bot controllers?Thanks, #lsm6ds3 #stm32cubeexpansion

Posted on October 07, 2014 at 19:06We are planning to use LPS331AP in one of our design. LPS331AP will be interface to MCU using 4-wire interface. I could not find conclusive information on whether Data out (pin 7) is tri-stated/high impedance when SPI communication is terminated (CS = high). Need to use couple more devices on same SPI bus.Also, CS pin is used to put sensor into SPI / I2C mode, so when SPI communication needs to terminated, MCU will have to drive CS=high, this will in turn put sensor into I2C mode, is this not conflicting ? Also, do INT1/2 pins need external pull up/down resistors on board ? #lps331ap #spi

Posted on October 27, 2015 at 12:42Hi,I'm programming the ADXL345 3-axis sensor for my thesis project. Initially i made the program in I2C and its working fine. Later on i switched to SPI mode for better speeds. Unfortunately the device is not working in SPI. The device address is 0x00  always. I double checked my all connections. They are perfect.  I put some delay after CS also. still no output. Kindly some one help me out. Thank you.

Posted on September 16, 2015 at 11:35Hi all, I am testing a board that uses a LIS3MDL as a magnetic reference sensor communicating with a 3-wire SPI. I am testing the sensor using a Helmholtz coil that I built (that, by the way, has been tested and generates correctly the magnetic field). When reading the magnetic data from the LIS3MDL I see that magnetic data tracks correctly the generated magnetic field for positive fields. However, negative magnetic fields are not correctly measured and show a different slope in a Breal vs B measured plot. This error in the measurement is far higher than the +-0.12% nonlinearity expected from this device. I have tested three prototype boards and all of them have this issue. I have studied the raw binary data coming from the sensor and I have discarded any conversion from binary to Gauss error. So finally, my question is: Is this performance normal? Are the t

Posted on October 21, 2015 at 04:18HiDoes anyone know what the correct chip marking for the LIS3DH(TR) should be? I've seen many different markings, incl. 2220 C3H 8F2CB. However, mine has this marking http://i.imgur.com/1OyaTUe.pngSo is there a correct marking?Thanks

Posted on October 16, 2015 at 15:10Hello everyone.Does anybody know where can I find AIS326DQ failure modes/rates?Datasheet does not help much.And, may be the arrangement of the physical sensors (i.e., whether it is a combination of three independent on-axis senors or a single 3D mems)? #failure #mtbf #accelerometer

Posted on October 08, 2015 at 15:52I've recently purchased the STMF4 Discovery Board and am looking to write an application making use of the on board LIS3DSH accelerometer. However, the examples provided (and pointed to by the documentation) all make use of the old LIS302DL accelerometer. Does anyone have or know of a sample application that reads data from the LIS3DSH for the STMF4 Discovery? #discovery #stm32f4 #lis3dsh

Posted on October 06, 2015 at 14:20Hi ,We have bought inemo sensors and made connection as per the datasheet. We made usb connection(without ESD protection) and provided jumper for boot mode.I have installed inemo-suite which does driver installation also. But now I are not able to detect the board on the PC. I see SMbus controller and usb bus controller. So I wanted to know is there any driver separately available. or is the ESD protection is mandatory. Also is there any default program in main flash or system flash so that i can boot from it.Kindly help in this regard.Thanks in advance,Nishal

Posted on October 05, 2015 at 20:55My name is Mikheil Tsitsishvili, I am acoustic guitar and ukulele performer living in the Republic of Georgia (East. Europe). I am very much interested in the amplification of acoustic instruments; all my instruments are equipped with small internal electret condenser ECM mics, they all perform great as well as feed back easily, that is the only issue I have got with the microphones and the most effective way is using of a rubber feedback covers in the instruments. A few years ago I found some articles about new MEMS mics, today these mics are widely used in many different ways .... I would like to kindly ask you on how close in musical quality are the MEMS to ECM mics and whether the MEMS mics are used in the acoustic musical instruments' pickup systems ? if so, which particular MEMS models are of the highest characteristics for using them into the musical pickup systems ?

Posted on September 30, 2015 at 21:51Hi, I'm using the HTS221 with an STM32F205. The communication channel is SPI. I'm finding that when I reboot my processor without cycling power, once the processor is back up and running it is unable to write to any of the HTS221's control registers so I am unable to put it in active mode. I am running the SPI bus at ~1MHz.Any advice/ideas would be greatly appreciated!Thanks,Doug #hts221

Posted on September 28, 2015 at 13:17I am getting one hardfault error after calling the osx_MotionAR_Initialize() API. I am using STM32F401 Nucleo board with X-NUCLEO-IKS01A1 sensor expansion board. I have installed required software and i tried to run the example project available from the directory Projects\STM32F4xx-Nucleo\Applications\DataLogActivity\EWARM in IAR IDE. But i am getting hardfault after calling osx_MotionAR_Initialize() API.What could be the problem? i didn't changed anything in the project, just opened the existing project in the workspace. I have tried the same in keil also but result is same. Please help me to figure out the problem.As per the user guide i have edited the osx_license.h file. I am getting license error when osx_mar_license[3][4]  buffer filled with zeros. After editing the license buffer with license, i am getting hardfault error.License wizard generate following three

Posted on August 29, 2014 at 11:28I have using HTS221 , and I have get the value from HTS221 via I2C.The value is like the following:Read HTS221 CTRL_REG1: 0x20 value is 0x81Read HTS221 CTRL_REG2: 0x21 value is 0x0Read HTS221 CTRL_REG3: 0x22 value is 0x0Read HTS221 STATUS_REG: 0x27 value is 0x0Read HTS221 HUMIDITY_OUT_L: 0x28 value is 0xAARead HTS221 HUMIDITY_OUT_H: 0x29 value is 0x10Read HTS221 TEMP_OUT_L: 0x2a value is 0xB5Read HTS221 TEMP_OUT_H: 0x2b value is 0x0Read HTS221 T0_degC_x8: 0x32 value is 0xBFRead HTS221 T0_degC_x8: 0x33 value is 0xBFRead HTS221 T1/T0 msb: 0x35 value is 0x4Read HTS221 T0_OUT-3C: 0x3C value is 0x0Read HTS221 T0_OUT-3D: 0x3D value is 0x0Read HTS221 T1_OUT-3E: 0x3E value is 0x0Read HTS221 T1_OUT-3F: 0x3F value is 0x0It seems the data of the temperature and t

Posted on September 08, 2015 at 20:23Hi,I am getting the accelerometer and magnetometer raw data from the device. I calculated the max and min for magnetometer and somehow got the heading correct to an extent when device is flat and stationary. I am not able to do the tilt compensation right. I tried different methods but I am getting the final value wrong. Can someone suggest the conversion of raw data using tilt compensation? #lsm303d

Posted on September 07, 2015 at 14:59Hi,I would like to use 2 digital sensors with PDM interface for stereo ultrasonic recording (currently I am looking at Knowles SPH0641LU4H).Which ST MCU has such capabilities?Thanks,Amit

Posted on August 18, 2015 at 22:24 Dear Community, I am trying to setup the LSM6DS3 Accelerometer/Gyrochip. The datasheet states the following startup procedure for this device: 1 Write CTRL9_XL = 38h // Acc X, Y, Z axes enabled 2 Write CTRL1_XL = 60h // Acc = 416Hz (High-Performance mode) 3 Write INT1_CTRL = 01h // Acc Data Ready interrupt on INT1 My interpretation of this procedure is the following code (which runs on aSTM32F302 µC): //APB1 @36 MHz //SPI3 setup SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_32; //IRQ Handler char Rx_Idx = 0x00; char Tx_Idx = 0x00; void SPI3_IRQHandler() { /* SPI in Master Tramitter mode--------------------------------------- */ if (SPI_I2S_GetITStatus(SPI3, SPI_I2S_IT_TXE) == SET) { SPI_SendData8(SPI3, Tx_Idx); SPI_I2S_ITConfig(SPI3, SPI_I2S_IT_TXE, DISABLE); } // SPI in Master Receiver mode----------------------------------- if (SPI_I2S_GetITStatus(S

Posted on September 01, 2015 at 12:11 Hi, i've some problem reading magnetic data from LIS3MDL. I initialize LIS3MDL: //configure device response = LIS3MDL_W_FullScale(LIS3MDL_FS_16Ga); response = LIS3MDL_W_OutputDataRate(LIS3MDL_DO_80Hz); response = LIS3MDL_W_BlockDataUpdate(LIS3MDL_BDU_ENABLE); response = LIS3MDL_W_OperatingModeXY(LIS3MDL_OM_ULTRA_HIGH); response = LIS3MDL_W_OperatingModeZ(LIS3MDL_OMZ_ULTRA_HIGH); response = LIS3MDL_W_SystemOperatingMode(LIS3MDL_MD_CONTINUOUS); Then i read data from register but i receive data that varies too (i.e. from -1000 to +2000, this values are only the reading from the registers) LIS3MDL_Get_Magnatic(u8_t *buff) { u8_t i, j, k; u8_t numberOfByteForDimension; numberOfByteForDimension = 6 / 3; k = 0; for (i = 0; i < 3; i++) { for (j = 0; j < numberOfByteForDimension; j++) { if (!LIS3MDL_ReadReg(LIS3MDL_OUTX_L + k, &buff[k])) return MEMS_ERROR; k++; } } i16_t va

Posted on August 17, 2015 at 13:26The datasheet implies that sleep-to-wake functionality allows the detection of above threshold accelerations even between samples at the low power mode samples:�2.5.3 Sleep-to-wakeupThe �sleep-to-wakeup� function, in conjunction with low-power mode, allows to further reduce the system power consumption and develop new smart applications.The H3LIS331DL may be set in a low-power operating mode, characterized by lower date rate refreshments. In this way the device, even if sleeping, continues to sense acceleration and generate interrupt requests.When the �sleep-to-wakeup� function is activated, the H3LIS331DL is able to automatically wake up as soon as the interrupt event has been detected, increasing the output data rate and bandwidth.With this feature the system may be efficiently switched from low-power mode to full performa

Posted on August 07, 2015 at 07:08We are using lis2dh accelerometer to determine the vehicle motion.For this we have configured the accelerometer for 6d direction detection.From the accelerometer readingsHow can we distinguish accelerometer readings as acceleration or deceleration?If we get a negative value from accelerometer out register ,does it means it is deceleration? or does it indicates it is accelerates/decelerates in the negative direction?

Posted on February 25, 2015 at 18:11Hello peers and engineers, I have a VL6180X proximity sensor in my project (I only measure a range), and I want to use its GPIO1 pin as a wake-up trigger for some other electronics. Is it possible to configure VL6180X to generate interrupt and put GPIO1 in HIGH state once the distance from the target is below some threshold (e.g. 20mm) ? I tried myself to achieve this by configuring some internal registers of VL6180X but with no success. I configure SYSTEM__MODE_GPIO1 register by writing 0x20 to it (to activate GPIO Interrupt output). I also put 0x14 (20mm) into SYSRANGE_THRESH_LOW register Finally, I setup Interrupt mode source for Range readings by writing 0x01 into SYSTEM__INTERRUPT_CONFIG_GPIO register. However, my system do not behave as expected when I start it. Is there anything I'm missing in t

Posted on July 09, 2014 at 13:17 Hi Guys, I'm trying to generate Interrupt on INT1 to allow LIS3DSH to wake up my uController in order to read and manipulate the data. the below code with Registers configuration was used but not luck so far: /* Send Configuration command for MASK1_A */ sendToLis3dsh( 0x5A, 0xFF); /* Send Configuration command for MASK1_B */ sendToLis3dsh( 0x59, 0xFF); /* Send Configuration command for SETT1 */ sendToLis3dsh( 0x5B, 0x82); /* Send Configuration command for CTRL_REG1 */ sendToLis3dsh( 0x21, 0x01); /* Send Configuration command for CTRL_REG2 */ sendToLis3dsh( 0x22, 0x00); /* Send Configuration command for CTRL_REG3 */ sendToLis3dsh( 0x23, 0x48); /* Send Configuration command for CTRL_REG4 */ sendToLis3dsh( 0x20, 0x67); /* Send Configuration command for CTRL_REG5 */ sendToLis3dsh( 0x24, 0x00); /* Send Configuration command for THRS1_1 */ sendToLis3dsh( 0x57, 0x55); /* Send Configuration c

Posted on August 03, 2015 at 18:01I'm trying to talk to a LSM6D3 over PCI. Everything's connected according to the datasheet in mode 1 (3.3v to VDD and VDDIO, SCx and SDx tied to GND) . I'm starting slow, so here's clock (SPC) and chip select (CS):https://drive.google.com/file/d/0B979a_DgADKmUFNhOGtFdXR0bDg/view?sp=sharingHere's clock and MOSI (SDI/SDA):https://drive.google.com/file/d/0B979a_DgADKmVkl2SlpSOXRPTWs/view?usp=sharingAs you can see, the clock polarity and phase are good, the bits on the rising edge of clock are clearly 10001111, or 0x8F, which indicate a read of register 0x0F (''WHO

Posted on August 03, 2015 at 07:46Can anybody tell me that Why Audio sensor requires R/L selection as audio sensing is omni directional. I agree for audio reception (e.g. headphones) it's right choice to have..