MEMS and sensors

Posted on April 01, 2015 at 15:19I've got a LIS3DH interrupting on a threshold. I went by the example in CD00290365.pdf for a filtered example, operating on a >300mg threshold.My problem is when it interrupts. The int line is held low for one output-data-rate-length samples. So, about 700us for 1250Hz output, or 2.5ms for 400Hz, and so on. I've tried to clear the interrupt line by reading the INT_SRC register, by clearing and re-setting the INT1_CFG register (back to 0x2A for XYZ high ints) and also by reading the axis data registers. I've also tried reading the status registers to see if there's an overrun, which there wasn't.So am I stuck with a latched interrupt (I tried clearing the latch interrupts bit in CTRL_REG5 but no luck) for as long as the sample rate is set?I'd like to know if I can clear this interrupt down, and how.

Posted on October 16, 2013 at 18:02Hi, We have developed a product which uses the LIS331DLH accelerometer and are happy with the results so far. My issue concerns the self test output change which can be higher than stated in specifications. The datasheets indicates between 120 and 550 or 140 and 750 lsb depending on the axis. However, I have seen output changes above 1000 lsb. Can we still use the boards, does it mean that the component has been damaged during the assembly process? The measurements seem consistent otherwise when comparing with the gravity. Should we raise the level of the thresholds in our code, if so what level would be recommended? Thanks Marc

Posted on March 26, 2015 at 15:40The VL6180X's typical supply voltage is listed as 2.8V.  Is there any problem with operating it at 3.3V which is less than the 3.6V absolute maximum?

Posted on March 25, 2015 at 08:13VL6180X datasheet mentions only the dry reflow process can be applied to it because the vent hole on top of its package. if the vent hole is sealed of by some epoxy, will this cause some troubles for the sensor ? what is the purpose to open a vent hole on the module package ? Thanks. #proximity-sensor

Posted on March 24, 2015 at 15:13Hello, In both the datasheets of the LSM330DLC and LSM303DLHC, it is indicated that a factory calibration is performed and its results are stored in the device (both sensitivity and offset). Where are these registers? I have not been able to find them in the datasheets, whereas for the LSM330 (not DLC) datasheet, that contains the same paragraph about factory calibration as the two others, includes a reference about these registers, at addresses 10H, 11H, 12H for the offset. Thank you #lsm330dlc-lsm303dlhc-calibration

Posted on March 05, 2015 at 18:58we are using the LSM303DTR.  4 wire spi. we initialize CONFIG 1,CONFIG5 and CONFIG 7 only....assuming defaults on all others. on power up, we get the pitch and roll always returning 0x8008 (our gui displays this as -35.244ish deg for pitch and roll). This happens ''sometimes''... Other times, the device appears to operate normally..... I checked the amount of time before we actually write to the device on power up.. it appears the 3.3V is stable by the time we hit the SPI buss (~210mS)... We cant figure this out...... any clues suggestions??? when this happens we can still get the WHO_AM_I correctly... and reading back the config registers...they appear to be what we set them at.... This is killing us right now. any ST mems guru's out there with suggestions?.... jyoung AT lauferwind DOT com. #mems-ecompass-lsm303

Posted on March 23, 2015 at 23:28Why if the LSM303D a steady-state on a horizontal surface measures 0 g on the X-axis and 0 g on the Y-axis, whereas the Z-axis measures 1g = 1000mg?Direction of  Z detectable accelerations is upward (see pag. 8/52 DocID023312 Rev 2 DM00057547), this would imply that the Z-axis should measure -1g = -1000mg #lsm303d #z-axis #accelerations

Posted on December 05, 2014 at 21:12I only seem to be able to power the LIS3DSH down to about 70uA by writing a 0x00 to CTRL_REG4 (0x20). CS is High. SEL is Low. I am using I2C. Running at 2.5V What do I need to do to get to the spec power down current? #lis3dsh-power-down-current

Posted on January 19, 2015 at 10:35how can i manage the self test in LIS3DSH.after enabling this option what i do? where can i found the result of  test?

Posted on June 13, 2014 at 10:07after power up the LIS2DM the current consumption is about 100uA ?!The connection is:Pin1 : SCL with a external 4K7 to 3VPin2 : SDA with a external 4K7 to 3VPin3 : SA0 connected to GNDPin4 : /CS connected to 3VPin5: INT2 openPin6: INT1 to Input Port uPPin7,8: 3VPin9-14: GNDCould it be that there is an internal pull-up on Pin3 and I should connect the SA0 line to 3V to get a low power consumption ? #lis2dm-i2c-sa0

Posted on February 15, 2014 at 11:59Hi, I am looking for SPI driver interface for magnetometer LSM303D thanks #lsm303d-spi-driver

Posted on March 17, 2015 at 13:38Does ST have any mems engineers?.... specifically an expert on the LSM303??? I'm having hardware issues with this part...(it is connected properly, board layout 100%, spi interface working.....not a hobby/hack deal...this is in a real product)....no love from local reps...no love from ST.....is it time to move to AD parts?.....

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Posted on December 23, 2014 at 16:39I have installed UNICO v4.0 to acquire data from the STEVAL-MKI154V1 accelerometer/gyro. However, it seems I am unable to establish a connection with the evaluation kit. The STMicro Virtual COM Port appears in the device manager. When I connect to the port, the blue LED on the STEVAL-MK109V2 turns on. I launch the UNICO software and select the appropriate device. When I go into the various tabs nothing happens when I try to read registers or observe data. I tried selecting 'Easy Configuration', but this does nothing. I try to get out of 'Power Down Mode', but it wont let me get out of this mode.Any suggestions? Thank you.

Posted on March 10, 2015 at 10:18It took me a while to understand it, but the datasheet for the LIS3DSH chip is dead wrong. It's a pretty obvious copy/paste mistake while creating that datasheet from another chip, but there is no such thing on that chip as a multibyte flag on the SPI protocol.Let me say that again: the pages 25 to 28 of document http://www.st.com/web/en/resource/technical/document/datasheet/DM00040962.pdf describe the bit ''MS'', which, in fact, doesn't exist. Also note that every piece of code that is provided within STMCube or SPL is wrong when dealing with that chip.On page 35, table 29, there is a description of the bit ADD_INC from Control Register 6, which does just that: automatically increments the address value when reading sequentially. So it'd be redundant and contradictory with any bit from the SPI protocol itself.It took me a while to figure that one out because I was

Posted on March 09, 2015 at 19:36I was able to get the 6d movement detection working and below I have the register configurations that I've done.My application logic is to configure for normal fifo mode and after a certain application delay switch to configuring for 6d movement detection,on movement configure it back to fifo mode.On reconfiguring the accel to 6d movement, when full-scale is set to +/-2g and the THS set to 4, I see false wake-ups everytime when the accelerometer is configured for wake-up,because of this an accel generates an interrupt as soon as it is configured for 6d movement even when the accel is resting on a table.(Although I understand the THS is low, I'm pretty sure there is no movement big enough to cause wake-up).However, this cycle goes on for about an hour and then the configuration from fifo mode to 6d movement detection works fine.REG1 0x20

Posted on March 06, 2015 at 10:29Hello,Does anybody knows what is the start up time of LSM9DS0 chip? I am having a problem  that chip is sending the same data from accelerometer or gyroscope all the time and I have to reset the device and it is working again. Is there any time that I should wait before asking for measurements from chip? #lsm9ds0-start-up

Posted on March 04, 2015 at 10:15The subject said it all. This is my first day of trying to download the SDK and I'm surprised I could not find any direct link to it. Any kind hearted fellow, kindly help me post the direct link to download them from. Again, is it possible to use Android Studio for development and just integrate the SDK into it? #sdk #smt32l #spirit1

Posted on November 07, 2013 at 17:35Could you please give a overview how to initialize the chip. I miss a description of the diverse adjustments. There are obvious errors in the Data-Sheet of LIS331DL. I.e. HP_FILTER_RESET <-> HP_RESET_FILTER      Where is the ''The H3LIS331DL features a data-ready signal (RDY)'' regards, Steffen #h3lis331dl-configuration #accelerometer #h3lis331dl #h3lis331dl

Posted on March 04, 2015 at 13:19We need to determine the pitch, roll and heading of a handheld device.We are looking to obtain the best accuracy realistically possible.Which part would you suggest and what accuracy could we expect after calibration?The size and power consumption of the sensor are not critical,Thanks.

Posted on September 30, 2014 at 21:25I have been assembling and testing small breakout boards with castellated pin connects using the LSM9DS0 sensor and they all return the proper WHO_AM_I register contents for both the accel/mag and the gyro. And when I jumper connect them to a microcontroller, I get expected readings from the accel and gyro. However, occasionally, the mag reports strange results; either very low values that jump around erratically or the data read correctly on the first loop then is pegged at 2000 mGauss. I am hoping this might be due to the fact that the jumper connections are poor and there might not be enough current flow to satisfy the magnetometer draw in some cases. Has anybody noticed erratic or malfunctioning magnetometer behavior while the rest of the sensor responses are fine? I don't want to have to solder the boards just to test them but I am afraid that just ensuring the I2C works might no

Posted on November 16, 2014 at 23:55I am unable to detect an interial interrupt from the LIS3DH accelerometer as a result of moving the sensor on a flat surface. The sensor is interfaced with an Arduino Uno using I2C. I am using the example in section 6.3.1 of AN3308, LIS3DH application notes. I can successfully read acceleration values. I also tried checking both interrupt ports, int 1 and int 2.Please see attached Arduino code below.&sharpinclude <Wire.h>const int LIS3DH_ADDR = 0x18;int pin = 13;int int1Pin = 2;int int2Pin = 3;/* I2C Communication Set-up ---------------------------------------------------------*/unsigned int readRegister(byte reg) {  Wire.beginTransmission(LIS3DH_ADDR);  Wire.write(reg);  Wire.endTransmission();    Wire.requestFrom(LIS3DH_ADDR, 1);

Posted on October 09, 2014 at 20:52I am using the LIS3DSH. Does anyone have any experience using both state machines at once? Both of the State Machines can be used when run by themselves, but when both operate at the same time, after a few interrupts the accelerometer ends up in an unknown state, where neither state machine will operate (even if all the registers remain the same and both machines are on.) Are there some settings or another way to set up the machines when using both at the same time? Thanks

Posted on March 02, 2015 at 08:27When I measure range of a transparent object like glass or acrylic, with a near background, the sensor measure the background instead of the object.Is there some setting I can use to handle this? may be something to do with the crosstalk setting?Sincerely,Heri #vl6180x