MEMS and sensors

Posted on July 31, 2012 at 20:12We use LIS3DH at 10Hz, with FIFO, low power mode, I2C for communication. We measure current at we get:- at 3.6V supply, 160uA- at 3.0V supply, 100uA- at 2.3V supply 60uAThe datasheet claims 6uA, what might we be doing wrong? #lis3dh

Posted on September 11, 2016 at 21:37LSM9DS1 unable to change FIFO mode #fifo #lsm9ds1 #imu

Posted on September 15, 2016 at 18:59I am trying to optimize the power consumption for bringing the L3GD20 out of Power Down mode, initialize a FIFO acquisition, acquire the data via I2C and then place the device back into Power Down mode. The register requirements to do this are well documented, however the datasheet and app notes are very sketchy on the required power on timing and the time to achieve FIFO data stability.The first decision I am trying to make is whether to switch from Power Down to Sleep then Normal, or go directly from POwer Down to Normal. The power supply current specifications would indicate some potential power savings by transitioning through Sleep Mode, can anyone verify this.The second decision relates to how long to wait after switching to Normal Mode before data becomes stable and can be acquired into the FIFO. Anyone know what the timing requirements are?

Posted on September 13, 2016 at 05:30Hi,Can anyone help me with installing the VL53L0X/P-NUCLEO-53L0A1 GUI on a Windows 10 machine?I'm using UM2072 as guidance but the exe installation is not completing due to me not having ''administrator privileges''. My user profile is definitely an admin and I haven't had any issues installing other software.Section 2.2.3 of UM2072 hints that this may be a problem but the solution offered (changing the program folder) doesn't work for me.Anyone got a work around I can try?Thanks #gui #vl53l0x #p-nucleo-53l0a1

Posted on April 21, 2016 at 18:57I`d like to know how to get samples of the UV index sensor UVIS25, data sheets also indicates the use of a ''Golden Sample'' for comparison, I`ve tried Farnell and Digikey sites but both even don`t know these two products! Maybe somebody can indicate me a place where I can purchase some samples for development. Many thanks #uv #sensors #uvis25

Posted on February 17, 2015 at 06:12Hi all, I need to some advice/help about getting angles by ''L3GD20''. I got the 3-axis angles by integrated angular rate from ''L3GD20''. However the calculated angles were less than real moved angles. The error is large. Is ''L3GD20'' not useful for measurement of angles? Only for angular rate? Do I have to select a accelerometer, ''LIS3DHTR'' and so on?  #l3gd20 #angle #accelerometer

Posted on September 08, 2016 at 12:33Hi,I run an experiment with several LIS2DH12 mems and noticed that there is a small deviation between mems ODR frequency (~2.8%)What is the maximum expectable deviation for this device?I found in other mems Datasheet deviation of +-5% in RC oscillator.Thanks,Dagan

Posted on September 07, 2016 at 15:14Hi, We have been using the LPS25HB in one of our designs.We have an LPS25HB device (soldered onto a flexible flat cable) and a second one, that we use to measure the absolute ambient pressure (soldered onto a PCB), The device on the flexi-cable is not reading the same value when open to ambient. The difference is -8mmHg, ie flexi cable is 8mmHg below the ambient.How can I tell what is causing this difference?I have read about the effects of soldering. I have also read about the factory trimmed calibration that should appear in the RPDS registers. When I read the RPDS on both sensors I get values of 0x00, 0x00 for each sensor.What values should I expect in RPDS, given that each sensor is factory calibrated?I have read about the effects of soldering, but how can I confirm that this is the root cause of the -8mmHg in this case?Cathal

Posted on July 30, 2016 at 02:09Hello, I am trying to access the HTS221 (TR) Temperature Humidity sensor. Firstly, the driver code of this sensor provided by ST Microelectronics states that the I2C address is 0xBE but I had been trying that address for a while and it did not work. Whereas on pinging the I2C port with different addresses, I understood that the sensor I2C address is 0x5F. So, I am using 0x5F address to access all the registers of the sensor. Secondly, Following are the temperature data that I can getting from the calibration registers: T0_OUT = -258T0_degC = 21CT1_OUT = 2570T1_degC = 35.63T_OUT = 30840    // this value looks too high On conversion, the room temperature comes to be 181C. which is definitely wrong. You mentioned about trimming the values in one of the discussion, please let me know about it.

Posted on September 02, 2016 at 07:47There is  HTS221 driver version 1.0.0 on ST website.In this driver function HTS221_Activate reset bit HTS221_PD_MASK, and function HTS221_DeActivate set this bit. In datasheet written: ''PD: power down control (0: power-down mode; 1: active mode)''. Is it bug in driver? Where should be sent report?PS: I am set this bit, and evrithing well. #hts221-activate

Posted on August 26, 2016 at 23:37Hello, I am currently trying to do some initial noise analysis of LSM6DS3 using STEVAL-MKI160V1 adapter board and STEVAL-MKI109V2 mother board. The software that I am using for obtaining data is Unico GUI. The problem is that gyroscopes and accelerometers noise levels are higher than I expected by more than 2 orders of magnitude. Here is how I did:I first changed a couple of registers for low noise operation; CTRL1_XL was set to 10(hex), CTRL2_G was set to 10 (hex) for the lowest bandwidth of the low pass filters.High-performance bit was set to 0 for the high performance operation for both gyro and acc. This gives me very high noise outputs (see fig.1 & fig.2: Y-axis unit is deg/h an

Posted on August 18, 2016 at 12:12Hello, I am trying to use LIS2DS12's activity/inactivity functionality, settings according to https://my.st.com//content/ccc/resource/technical/document/application_note/69/fd/10/6c/42/38/4f/f2/DM00218428.pdf/files/DM00218428.pdf/jcr:content/translations/en.DM00218428.pdf (4.7). The WAKE_IA flag seems to be triggered alright (also tweaking the wake threshold seems fine) but the SLEEP_STATE (in status register or WAKE_UP_SRC register) flag doesn't seem to trigger. Did anybody have this problem before? Are there any specific settings I am missing maybe? #lis2ds12-inactivity

Posted on August 29, 2016 at 20:03We have an LIS2DH accelerometer on our board which is running linux 4.1 kernel connected by I2C and I'm trying to get it to work but have had no luck.Here is what I did:I got the linux driver from here: http://www.st.com/content/st_com/en/products/embedded-software/mems-and-sensors-software/drivers-for-mems/stsw-mems021.htmlAdded lis2dh.h to /include/linux/inputAdded lis2dh_acc.c to /drivers/input/miscAdded this to /drivers/input/misc/Makefile:obj-$(CONFIG_INPUT_LIS2DH)    += lis2dh_acc.oIn /drivers/input/misc/Kconfig+config INPUT_LIS2DH+    tristate ''STMicroelectronics

Posted on August 01, 2016 at 15:13Does anyone know if the LIS3DSH average samples when running at lower data rates? E.g. if the ODR is 100 Hz, will it sample at a higher rate and average the results (in order for example to reduce noise)? Or perhaps the nature of the method used to determine the acceleration in the first place will naturally average the data since the last sample?Thanks!Paul. #accelerometer #filter

Posted on March 17, 2016 at 16:34Hello,I  created my own PCB with iNEMO with USB communication, similar to STEVAL evaluation board. But I can't download any driver to establish communication - my comp shows message: ''...this computer malfunctioned, and Windows does not recognize it''!. I try with STSW-inemo001 (http://www.st.com/web/en/catalog/tools/PF257504#) but i can't download it.Please help me :) 

Posted on August 23, 2016 at 15:29Hi, I'd like to perform a SET/RESET procedure on the LSM303AGR magnetometer. As explained in the AN4825 pag. 17, if the user performs a single read, the bit OFF_CANC in CFG_REG_B_M must be set to '1' to invert the impulse polarity between a single read and the next one. Has this bit to be set high before the two consecutive readings or between the first read and the second one? #offset #reset #lsm303agr #set

Posted on February 18, 2016 at 06:53Hello,I just wonder where i can get a referece code for fusion of gyro+ACCfor LSM6DS3 / LSM9DS1 

Posted on August 16, 2016 at 12:39Hi! I'm trying to read Who Am I register and get 0x32 reply from the accel. Not sure what SPI mode to use, 3? I see on the scope: byte 0xF1 come out of master on MOSI, eight clock cycles on SCK and SS line go low, but nothing on MISO line. Shouldn't slave register bits come out by the mere fact that there is SCK (full-duplex) and SS is low? I'm not sure what is wrong, comments? Thanks. #4-wired-spi

Posted on August 16, 2016 at 19:32I am trying to produce 6 matched sensors. I have soldered them and I can query them via I2C, but their values are significantly off true air pressure. I know I'm supposed to use the RPDS_L and RPDS_H registers, but the data sheet does not clarify what that offset represents and what the units are. I thought at first that it was supposed to be multiples of 4096 like normal readings, but it doesn't appear to be so. Please clarify.Thanks. #lps25hb

Posted on August 15, 2016 at 17:56 I am trying to use the API for VL53L0x proximity sensor over one smt32F4Discovery developement board and I am not able to do it. The steps that I am doing are the following: In a Keil project that it compiles and links without problem, I am adding the source file of API, these files are separated in two folder: core and platform. I have added the files of two folders to project. After do it, I have also added related path to header file (*.h) in options for target --> C/C++ --> include paths. After do it, I try to build target files and there are several errors, output is the following:

Posted on June 13, 2016 at 14:41I could find the resolution of this sensor, 8 LSBs/DegC, but I couldn't find any information about how the absolute temperature is specified. Does anyone have more information about it? #ecompass #lsm303d #temperature

Posted on August 10, 2016 at 15:35Is there any FIT and/or reliability data available for the IIS2DH accelerometer?

Posted on July 04, 2014 at 15:19Hello,I got good results reading accelerometer data but the temperature register is about 36 (decimal), the datasheet mentions 8LSB/°C, 36/8 = 4.5°C, this is quite cold ;) Room temp is 24°C, the other sensors located near the LSM are indicating 28°C.What is the good conversion factor?

Posted on July 20, 2016 at 15:35The LIS3DSH was implemented into one of our systems and currently we are having an issue with the Temperature readings across multiple units in the same environment vary from one another up to 15ºC. Is there a way to calibrate the temperature on the LIS3DSH, or is it not recommended to use?The reason we are tracking temperature with it, over a temperature range the values change as described in the datasheet. And during our calibration process we are taking multiple temperature readings and normalizing the variance. Is it possible to ''reset'' the temperature in a controlled environment, or is this something where we would have to use a software offset? Also, those that show a large swing between actual temperature and readings, does this cause any adverse effects to the accelerometer measurements?

Posted on July 08, 2016 at 14:55Hi, We are looking for and 9 DOF sensor which should have good frequency response. I go through datasheet but was not able to fetch the frequency response details. Can you tell me the frequency responce of Part♯ LSM9DS1. As we wanted to have body motion + heart beat calculation through this Accelerometer. Waiting for your positive feedback soon. #lsm9ds1-frequency-response