MEMS (sensors)

Posted on April 01, 2018 at 17:28Hi, When using lsm6dsl_reg driver files I've stumbled on the following angular velocity conversion macros.The math seems wrong... Can ST verify this?Thanks#lsm6dsl_reg

Posted on April 02, 2018 at 19:18I'm using an LSM303DLHCTR in an application where I'm reading its X, Y and Z magnetometer values once per 20 ms, and have noticed that the chip seems to consume 10 mA or more of current from its 3.3V supply (VDD pin) - for a short interval of about 4 ms during each 20 ms cycle - presumably while it's doing a magnetometer ADC conversion. The 10 mA is much higher than I expected, since the data sheet says to expect only 110 microamps of current draw. Accelerometer is disabled in my application. Has anyone else seen this behavior? 

Posted on March 27, 2018 at 09:03Hello,I implemented the software for the HTS221 in my project and all is working. But what I find strange is this, some calibration coefficients are negative!H0_T0_OUT is -2H1_T0_OUT = -11728Although they are negative, the reading for temperature is OK  (seems to be < 1 degrees lower than my reference )But the Humidity reading is 10% off ( too low)Now in the examples from the datasheet, the coefficients were positive. For example my reading of H_T_OUT = - 784. and in the datasheet it is 5000 Why are these coeficients in the s16 format? Can they be really negative? They are like raw ADC value's right? Regards Remco

Posted on March 27, 2018 at 09:13Hi, I`m facing a problem to get data ready interrupt on INT1.Use I2C communication.Trying to make fifo work and stuck with that, so started from data ready. According to Application notes :1 Write CTRL9_XL = 38h // Acc X, Y, Z axes enabled2 Write CTRL1_XL = 60h // Acc = 416Hz (High-Performance mode)3 Write INT1_CTRL = 01h // Acc Data Ready interrupt on INT1Initialize 3 registers and try to read data in interrupt from INT1 according to chapter 4.2 in application notes.If i read STATUS_REG in interrupt then i stuck inside HAL_I2C_Mem_Read function in busy state. If I read it in my main while(1) then it start working, but interrupt generated in a strange way (picture attached.)I read:1 Read STATUS2 If XLDA = 0, then go to 13 Read OUTX_L_XL4 Read OUTX_H_XL5 Read OUTY_L_XL6 Read OUTY_H_XL7 Read O

Posted on April 03, 2018 at 18:10So the B-L072Z-LRWAN1 board is configured to be powered through the 3.3V pin by removing SB6 and R26. Furthermore, the ST-LINK was disconnected by removing SB28, SB29 and SB37. When testing with some example code and the X-NUCLEO-LPM01A power board everything works fine. However, when connecting the IKS01A MEMS shield to the B-L072Z-LRWAN1 board, either with the arduino connector or with the dedicated J2 header, the system voltage drops from 3V to approximately 1.4V causing the B-L072Z-LRWAN1 to halt correct operation. I haven't made any chaanges to the default solder bridge/jumper config of the IKS01A2 MEMS shield and its datasheet is wildly obscure when it comes to the power config. Has anyone had a similar problem and if so how do I fix this?#b-l072z-lrwan1 #iks01a2

Posted on March 16, 2018 at 11:40 I want to be able to when the device has detected movement, LIS3DH to wake up from sleep mode, and at a higher rate to detect more than I get a set of threshold, then the interrupt, to remind me of the MCU. I tried many times to combine two functions, but failed. Is there anyone who can help me with this? How should the relevant registers of LIS3DH be configured? Note: this post was migrated and contained many threaded conversations, some content may be missing.

Posted on March 04, 2018 at 10:22Hello,I have a SensorTile Kit (STLKT01V1) that I'm trying to test with the Blue MS Android application.As mentioned in the SensorTile http://www.st.com/content/ccc/resource/technical/document/user_manual/group0/bc/b1/ad/c8/36/de/40/92/DM00320099/files/DM00320099.pdf/jcr:content/translations/en.DM00320099.pdf I plugged in a USB-mini power source but no light blinks on the SensorTile board and the BlueMS app can not find any nearby device.What am I doing wrong? How can I troubleshoot this?Thanks.#sensortile-kit #sensortile

Posted on March 31, 2018 at 18:39Hi I am currently working on a project with MEMS Sensors (Near Infrared Sensors between 1and 5 micrometer wavelenght), I am no Expert and my challenge is to evaluate user benefits and find application fields e.g. The sensor is able to measure gas and you can use this benefit to measure the alcohol content etc., My question: what are benefits of such a sensor and who could need these features?

Posted on June 19, 2015 at 09:09I am interfacing LSM303C magnetometer and accelerometer to microcontroller via 3-wire SPI, where SIMO and SOMI from uC are connected together via R 10k to allow the slave LSM303C to drive this single signal line when responding.Clock SCK polarity is set to high and the right phase for LSM303C is selected in microcontroller USART configuration registers. I am actively pulling down CS pins on LSM303C to enable SPI communication with the particular part. Measuring with oscilloscope on the shared SDI/O line, SCK and CS it seems that LSM303C is receiving the right input according to datasheet.However I didn't have success to get a reply from LSM303C on simple ''WHO_AM_I_A/M'' address readings - LSM303C does not pull the communication line. I have tried enabling the SPI operation, disabling I2C, turning to continuous operation and enabling reading of registers in the control register

Posted on March 17, 2017 at 17:25Hello,I want to use MP34DT01 microphone in our application. But data stream format is unclear. Explain this please. I guess this is the usual delta modulation. Is not it? Analog Devices for ADMP521 was describe it transparently.Thanks in advance.#pdm #microphone #mems-microphone

Posted on March 28, 2018 at 16:24Is there any documentation about the theory of operation on the lsm303agr's magnetometer? (hall effect, magnetoresistive,...?)

Posted on August 10, 2016 at 16:46Hy,what would be the easiest way to use the VL53L0X Nucleo Expansion board (X-NUCLEO-53L0A1) with Nucleo F030R8?All given examples rely on a F401, the source code would not work immediately, because there are some features used, that are not available on F030. Is it possible to use F030? Is there source code available?Best regardsHarald #nucleo #vl53l0x #f030r8

Posted on March 09, 2018 at 11:44The LIS3DH is configured to use INT1 to interrupt the MCU when the acceleration value on any of the 3 axis exceed the threshold that is set by the MCU. Firstly, as my understanding, the LID3DH does not stop sampling acceleration data even if the interrupt is triggered (even in stream-to-fifo mode, it does not stop sampling until the fifo gets full). Is this correct? If it's correct, is there a good way to get the acceleration data corresponds to the exact time when the interrupt is triggered? Thanks.

Posted on March 21, 2018 at 15:51Hello,i'm quite new to the embedded world and purchased the VL53L1X evaluation kit with the F401RE and thehttp://www.st.com/en/ecosystems/x-nucleo-53l1a1.html. I installed all the drivers and the System Workbench on my Windows 10 setup and got the example application running. Now to my problem:After trying out different stuff my applications were always stuck in HAL_Delay(). On the first debug everything always worked, but when I restarted the applications to debug again it always went infinite in HAL_Delay(). The only thing that helped was to startup Vl53L1X GUI to reset the microcontroller paired with an hard reset by pushing the button on the microcontroller. But it just takes too much time to do that, so I tried reinstalling everything (STSW-

Posted on March 07, 2018 at 14:03Hi Sir,I am using ST accelerometer Sensor  LIS3DH (adapter board STEVAL-MKI105V1) with I2C interface.I can now read the registers. But for the registers which doesn't have default value, for example,OUT_X_L (0x28),OUT_X_H (0x29),OUT_Y_L (0x2A),OUT_Y_H (0x2B),OUT_Z_L (0x2C),OUT_Z_H (0x2D),the value read are all zero.My questions:1. How to get the correct accelerometer value for the registers which doesn't have default value? Any configurations needed before reading the registers?2. “AN3308â€� chapter 4 Startup sequence to write the registers, but what values should be written? Could you help to advice?Thanks,Arna Lee

Posted on January 16, 2017 at 13:36 Hello guys, I'm using LIS3DH accelerometer in my current design. I need it to detect the movement. ODR is set to be 10Hz. According to http://www.st.com/content/ccc/resource/technical/document/application_note/77/ed/e7/e1/28/5a/45/d6/CD00290pdf/files/CD00290pdf/jcr:content/translations/en.CD00290pdf document (page 10), LIS3DH should consume about 4uA of the current in both Normal and Low power modes. However, when I measure the current consumption, I get the value of about 78uA (@2.5V power supply). When I remove the accelerometer from the power rails and measure the current consumption of mcu in a sleep mode, I get the value of 3.2uA. Th

Posted on March 20, 2018 at 18:33Hi!Fairly new to programming and embedded software in general but I'm having a problem with interpreting the values I am receiving from the magnetometer registers.I'm able to get a value between 0 and 255 for each register (both high and low for X,Y and Z). I can't seem to workout what to do with these values; any help would/point in the right direction would be greatly appreciated!Thanks,FraserEDIT:For anyone searching this in look for help, I have a github on this project: https://github.com/FrazLaw/RoboPot . The code isn't perfect but it may help someone else, like myself, looking for some assistance as it can be a fairly difficult task if you've never done something like this before.Fraser#e-compasses #e-compass #lsm303agr

Posted on March 21, 2018 at 07:58I know for lis3dh, the normal mode gives 10-bit resolution while the low-power mode gives 8-bit resolution. But for lis3de, both normal mode and low-power mode gives 8-bit resolution. So what's the difference between them.Also the following picture shows ODR 1.6KHZ is not supported by normal mode and low-power mode can achieve larger maximum ODR as 5.376KHz while in normal mode it's only 1.344KHz. That means if I want to achieve ODR up to 5.376 kHz, I have to use low-power mode? This gives me higher ODR and lower power? But what do I lose?

Posted on March 19, 2018 at 20:14I would like to make a waterproof microphone. I.e. I need it to withstand water spray from time to time and at the same time maintain functional microphone, not kill the performance completely.I therefore am thinking about introducing a waterproofing membrane and glue on top of the MP34DT01-M microphone.I would like to know the predicted effects of this to the frequency response? Do you have any recommendations?BRjonnsi#mems #audio #microphone #waterproof

Posted on March 20, 2018 at 07:43FSS[4:0] contains the unread samples stored in the FIFO. So when the EMPTY is 1, the FSS[4:0] is 0. But when the OVRN_FIFO is 1, the FSS[4:0] should be 32 but it can't. So when FSS[4:0] is 31 we should check the OVRN_FIFO flag to judge the real unread sample number. Is that correct?

Posted on March 12, 2018 at 23:50Hi,I am working on a project where we are using the H3LIS331DL accelerometer.I am trying to understand what is happening with the interrupts, because I see some inconsistant behaviour.I got the following samples sampled at 400Hz with a max range of 200g. The threshold is set to 2, which should correspond to a value of 512 in the data registers ((2/128)*32768). I have the latched option enabled and configured INT1 for the threshold interrupt and enabled the high pass filter for data and interrupt generation.X:288       Y:416    Z:-1648  (INT1 NOT active)X:-272     Y:-144    Z:400    (INT1 active)X:32        Y:-64      Z:576    (INT1 active)

Posted on March 09, 2018 at 00:18Hey! I am using the accelerometer LSM303AGR to read some acceleration values on external interrupt. If the threshold is overcome, and interrupt will be triggered and in the ISR, I am reading the FIFO of the accelerometer (I am using STM32F405 btw). The values seem to be correct half of the time as shown below. As you can see in the third interrupt and fifo reading, the zAxis exceeded the threshold and then, out of nowhere, the axis-values are getting weird (and wrong!). They won't return back to normal and therefore, no more interrupts are triggered. If I stop, reset and run it again, no interrupts can be triggered because the values are still weird and wrong. The only thing that helps is to cut the power supply for a second and plug it in again. But even that does not help sometimes. readINT1_SRC: 86FIFO samples: xAxis exceeds thresholdx: 3189.199951 y: -375.200012 z: 750.400024 x: 35

Posted on February 21, 2017 at 18:07Hello,I am having an issue with the H3LIS331 thresholds. I have all the thresholds setup in high interrupt mode for all axis. The high pass filter is enabled, my range is 400Gs, my sample rate is 100Hz and my communication spi clock is 1Mhz. Sometime when I read a the acceleration values after an interrupt I get value less than my threshold. Sometime these values are even all below 1G. I have measured with a O-scope that I am reading the results faster than my sample period, 130uS. It seems like the threshold itself is working because I only get an interrupt when an event occurs but values seem wrong.Is there some other register setting that I need to do?Is it possible that the value of the acceleration registers change in less than a sample period from the interrupt? We are close to production and this issue has people worried.Thanks,John#h3lis

Posted on March 14, 2018 at 09:22Hello,We used the LSM303D and now we use the LSM303AGR for a roll and pitch sensor (+/-45°C).The LSM303 components are factory calibrated (cf. datasheet of the LSM303D, DocID023312 Rev 2) :'The IC interface is factory calibrated. The trim values are stored inside the device innonvolatile memory. Anytime the device is turned on, the trimming parameters aredownloaded into the registers to be used during normal operation. This allows the user touse the device without further calibration.'Could you me give more details about it ? For the LSM303AGR, there are more details :'The IC interface is factory calibrated for sensitivity (LA_So, M_GN), Zero-g level (LA_TyOff) and Zero-gauss level (M_TyOff). The trim values are stored inside the device in nonvolatile memory. Anytime the device is turned on, the trim parameters are downloaded into the registers to be used duri

Posted on March 18, 2018 at 21:35I am using a LIS3DH to measure a machine's vibration, I understand that mems accelerometers are not usually used for this application, but nevertheless, I set up the acc to High resolution mode which gives me a bandwidth of 150Hz. I have the LIS3DH set up and comparing its data with a piezo accelerometer that I have. I noticed that at low frequency (under 40Hz) peak to peak values of both accelerometers are very similar. but when I go over that (80-100 Hz) I start to see a drop in the LIS3DH p-p compared to the other one. Is the LIS3DH just not suitable for this application ?#lis3dh-machine