MEMS and sensors

Posted on December 22, 2016 at 23:04HiI'm using multiple vl6180x devices and want them to work more quick.However, when the second device starts in pre-calibration time of first device, the range data looks wrong.When I set the interval more than 4ms between two devices, their range data looks correct.So, I guess that in the case that two devices work simultaneously in their pre-calibration time, the interference occurs.Then, I would like to ask whether I make pre-calibration time shorter than 4.3ms or skip pre-calibration phase.I read the data sheet of vl6180X and found the pre-calibration time is fixed.However, I want absolutely multiple vl6180x devices to work simultaneously.Otherwise, I want them to work more quickly (less than 4ms interval). Is it possible?Best regardsIshikawa#vl6180 #multiple-vl6180x #vl6180x

Posted on April 21, 2017 at 17:25I tried to read the default I2C password (address 2304 with E2 = 1) that should be 0000 0000h whilst I found FFFF FFFFh. For verification I also tried to read the other System parameter sector and the returned values are matching what explained into the datasheet.I haven't implemented the function to change the password so I'm pretty sure it should be the one sent out by factory.BR,Giorgio Cancelli#m24lr04e-r

Posted on March 24, 2017 at 11:48What is the meaningful of 'SPI only write' SIM bit of CTRL_REG3_M (22h) register?How magnetometer values can be read if SPI is in write only mode?

Posted on April 19, 2017 at 14:25Hi all,I'm trying to interface a LSM303AGR, to get the magnetometer and accelerometer values in I2C.The component is responding well to whoami requests (both compass and magnetometer parts), I manage to get mag values but the accelerometer values seems to be stuck.Here are my init parameters:    /* REBOOT ACCELEROMETER MEMORY CONTENT */    I2C_Write_reg(I2C2,I2C_LSM3_ACC_ADRESS << 1,I2C_LSM3_CTRL_REG5_A,0x80);    RTC_wait_ms(6);    /* REBOOT MAGNETOMETER MEMORY CONTENT */    I2C_Write_reg(I2C2,I2C_LSM3_MAG_ADRESS << 1,I2C_LSM3_CFG_REG_A_M,0x40);    RTC_wait_ms(6);    (void)I2C_Read(I2C2, I2C_LSM3_ACC_ADRESS << 1, 0, I2C_LSM3_WHO_AM_I_ACC, &whoamiacc ,1);    if(whoamiacc != 0x33) FAIL('LSM303AGR accelerometer side isn't responding');    else {        /* ACCELEROMET

Posted on April 19, 2017 at 23:28I'm using the LSM6DS3 to control a gimbal with a camera on it, and I'm noticing that my control is suffering due to delay in the system. I have configured the LSM6DS3 for an output datarate of 208Hz, with the fifo in bypass mode and I'm also sampling the sensor at 208Hz. However when I measure the delta between a physical input to the camera and the observable difference in the LSM6DS3 readings, I see about 20ms of delay. When I increase the datarate of the sensor to 833Hz, the delay is reduced to roughly 10ms, but this delay still seems rather large.Is there any spec on the bandwidth/ delay/ latency of this sensor? What can I do to get the absolute latest readings from it?#lsm6ds3

Posted on April 13, 2017 at 13:39Totally new to ST accelerometers, I can see that they're grouped into what look like three 'families' -- nano, pico and femto. Is there a short explanation of the differences between those three families? A link to a page explaining that would be just ducky, thanks.rday

Posted on October 18, 2016 at 09:49Hi!The HTS221 sensor and LPS25HB pressure sensor are together in the development board. The temperature difference between the output of the two sensors too high. HTS221 temperature value is close to the actual temperature, LPS25HB outputs 5~10'C lower than that at room temperature environment.The output temperature of the two devices is a 2's complement form of the same.I'm not sure about the cause of this difference is.Please give advice on this matter.Best regards.Kwon #lps25hb

Posted on April 18, 2017 at 07:48I'm using an LIS3DH accelerometer. It is configuring properly and returning valid data when manually read at a fixed interval. Now I'm trying to switch to the use of its XYZDA signal that is emitted on INT1.I have all other interrupts on INT1 disabled, and I'm enabling XYZDA by setting bit 4 of CTRL_REG3. If I clear the bit, INT1 stays inactive, and if I set the bit, INT1 starts showing activity, so I'm confident I'm setting the bit I think I am {grin}.A scope shows that INT1 goes active at ODR intervals, as expected. The problem is INT1 resetting to inactive. Section 3.1.2 of the LIS3DH's app note says 'the interrupt is reset when the higher part of the data of all the enabled channels has been read (29h, 2Bh, 2Dh)'. This seems clear enough... read the MSB of all three axes and INT1 should be cleared.However, what happens instead is that INT1 clears at variable times, often many tens of milliseconds after the last of the six data bytes has been succes

Posted on April 13, 2017 at 01:08With a 2g scale sampling @25Hz the FIFO fills with data and I am reading the contents up to the watermark. HR and LPen are disabled.With the Z-Axis pointing toward earth I get the following data for the X-Axis using the H and L bytes:DATX=128DATX=128DATX=128DATX=-64DATX=192DATX=-128DATX=-64DATX=0...First, why are the values multiples of 32? Second, why the variability when the chip is still and not moving? I have been using the LIS3DSH for a couple years now so this IIS2DH is a real downgrade for sure, but I must be missing something. I have read over the manual several times now and can't find my issue. -AP

Posted on April 13, 2017 at 12:58The detailed behaviour of the LSM303DLHC DRDY pin (pin 9) is not elaborated upon in the datasheet.We have observed that it generates active low pulse but this is not detailed in the datasheet. What are the timing requirements on responding to DRDY?At which point during this low pulse are the registers ready to be read?Should the DRDY bit in register SR_REG_M be read to verify that a new set of measurements is ready, or is just using the DRDY pin sufficient?

Posted on April 12, 2017 at 17:13I am moving to the IIS2DH from the LIS3DSH because it is end of life. I am having an issue with reading the FIFO. I can enable FIFO mode and it seems to fill and generate an interrupt on OVRN and WTM just fine, but the X, Y and Z high and low registers are all value 0x80. And reading the data does not empty the FIFO. Can you suggest what would cause this? Otherwise it seems very similar the LIS3DSH which I have no issues with. -AP

Posted on April 11, 2017 at 08:08 We are upgrading our IMU from a LSM9DS0 to LSM9DS1. However we are having issues with the magnetometer on the LSM9DS1. Even after min/max calibration it doesn't appear to give correct heading. We are aware that the orientation has changed and have taking this into consideration. When using this simple formula, i would expect some usable results (this works perfectly witht he LSM9DS0)... however this is not what we are seeing. heading = 180 * math.atan2(MAGy,MAGx)/M_PI To rule out our PCB design, we have purchased products which use LSM9DS1 from Adafruit and Sparkfun, and these also have the same issue. Below is the code used to initiate the magnetometer # CTRL_REG1_M (Default value: 0b0001 0000) # [TEMP_COMP][OM1][OM0][DO2][DO1][DO0][0][ST] # TEMP_COMP - Temperature compensation # OM[1:0] - X & Y axes op mode selection # 00:low-power, 01:medium performance # 10: high performance, 11:ultra-high performance # DO[2:0] - Output data rate

Posted on April 11, 2017 at 12:31Hi, I have designed a circuit which has 8 LIS3mdl sensor slot on 1 spi bus.The problem when I connect only one ls3mdl sensor (other 7 are empty) to the board it works well. but most of the when I connect another one ( sometimes 2 and sometimes 3 or 4 and more) all sensor stop working. ( it reads the register values but the wrong parameter get back) in this mode, I am reading sensors one by one.(make one of SS(chip select) 0 talk to sensor and make it 1 and then do the same with next sensor). Immediately when I reduce the number of sensors to 1 it works correctly and when and more sensor it goes wrong.I myself think that the problem appears because when SS pin for other sensors is high and it means they are in i2c mode and they talk in I2C on the bus and it makes conflicting(i saw wrong data coming in debug mode and in oscilloscope) I once though the problem is because of low current on spi bus so I enabled o

Posted on April 10, 2017 at 21:38Does LIS2DH support 12-bit high resolution mode with FIFO?

Posted on March 30, 2017 at 21:02Hello,     We are working with the LIS2DHTR and have had significant yield issues after running the board through the reflow oven.  For the next run we plan to lower the temperature.  But for now we are replacing the units by hand are are still having issues.     Has anyone ever dealt with MEMs failures after reflow or rework.  I have also noticed that units behave differently following rework.  For instance, we are setting a threshold in software to generate an interrupt from the accelerometer.  In different units, the force required to generate the interrupt can be significantly different.      Are there any tips on assembly for these parts?ThanksCraig

Posted on March 21, 2017 at 15:35I'm using the LSD6DSL in an application where the sampling rate (ODR for the MEMs) is important. The ODR in the datasheet is only given as 'Typical'. Could I get a more precise specification for the ODR, e.g. min/max values over the entire temperature range. I suppose this ODR is generated from an internal oscillator with tolerance, temperature drift, ...

Posted on March 29, 2017 at 08:37Hi, I'm new with stm32 and mbed environment. I'm trying to use VL53L0X satellites as proximity/distance sensor but I have few unsolved questions: 1) in this datasheet I can see that only first six pin of satellites are used: <LINK NO LONGER ACTIVE> is right? 2) is there an easy example on how to use it like this for hcsr04 arduino sensor: <LINK NO LONGER ACTIVE> ?? (examples given by downloading his own software are little bit difficult based to my knowledge)3) which pins i have to connect if I don't want putting this board on the stm32 board?Thanks for the support

Posted on April 03, 2017 at 12:56Apple watch accelerometer axis range Hi good morning,I'm developing an apple watch health care application. After a search i discover an ST microelectronics accelerometer sensor mounted on a system on a chip internally.Here there is the sensor data sheet: http://www.st.com/content/ccc/resource/technical/document/datasheet/a3/f5/4f/ae/8e/44/41/d7/DM00133076.pdf/files/DM00133�I want to know one only thing: Which is the full scale range ? I read the data sheet but i've found 4 differents range for range on axys (2G, 4G, 8G, 16G)!I'm not very expert with data sheet reading, someone can help me ?Thanks in advance, have a good lunch!#applewatchaccelerometer #fullscalerange #accelerometer

Posted on April 07, 2017 at 08:14I'm using the LIS3DH set at 1 Hz ODR.  My SPI hardware seems to be working since DATA_RDY interrupts come in fine at a steady 1 second interval and the accelerometer data looks good.  In fact I get good data at all speeds.  However I can't seem to get the threshold interrupts working.  I read the app notes, found setups on the web, and tried a lot of different configurations.  Below is a sample setup.Could you send me a register sequence that you know works to trigger an INT1 interrupt?Also the ADC seems to give me 2032 to -2032 for a range of .9 to 1.8 volts maybe this is a clue.  The temperature gives me -16 so I haven't been able to get this working either.  Self test seems ok.ThanksJeffrey Wedekind #define LIS3DH_CONFIG_CTRL_REG1 0x17 // 1 Hz, Zen, Yen, Xen #define LIS3DH_CONFIG_CTRL_REG2 0x00 // Default Settings #define LIS3DH_CONFIG_CTRL_REG3 0x40 // #define LIS3DH_CONFIG_CTRL_REG4 0x80 // #define LIS

Posted on April 06, 2017 at 21:58Couple of questions regarding the LSM6DSL (iNEMO intertial module) setup via the SPI interface.1. Should it possible to program the IMU at 10 MHz SPI interface or does the programming need to be done a slower speed?2. Is there a delay required when doing Read followed by a Write or vice versa? It appears that a small delay of 4-5 us is required after a read and before a write otherwise the write doesn't go through as intended.Thanks for your pointers and suggestions.

Posted on April 05, 2017 at 00:02Although powering an LSM9DS1 with 2.8V to VDDIO and VDD, I would like to use a 1.8V-logic line for one of the chip selects for ease of retrofitting an existing design with minimum upheaval.  The line is push-pull, not open collector.The sufficient-voltage threshold for a '1' digital input is usually labeled V_IH, but I could not find that parameter listed in the published specifications.  What is V_IH for the LSM9DS1 digital inputs, especially the chip selects?A corollary question -- even if 1.8V will be sufficient fully to deselect the chip-select, would using 1.8 instead of 2.8V lead to increased power consumption?Thanks!#lsm9ds1

Posted on September 02, 2016 at 18:04We are developing a product using the VL53L0X IR Time-Of-Flight sensor. The sensor must be inside a plastic case looking through a IR transmissible window material. To test such an arrangement the X-NUCLEO-53L0A1 comes with airgap spacers and cover glass materials. I would like to know what this cover glass material is, can you give a manufacturer name, article/product name or something? #vl53l0x-x-nucleo-53l0a1

Posted on April 06, 2017 at 08:15for Doing FMEDA I need FIT rate value for IC LIS3DHTRIn data sheet ,reliability data  it is not mentioned.

Posted on April 05, 2017 at 11:44I have an LSM6DS3 gyro / accelerometer connected to a Raspberry Pi 3B using i�c. I'm using the internal FIFO to get samples from the gyro and accelerometer. The data is plausible most of the time, however, every now and then there is a strange sequence of values when I read the FIFO:sample output:47    -240    -371    143    -238    -378    ...138    -240    -369    141    -238    -361    ...137    -238    -381    134    -247    -373    ...130    -229    -367    133    -235    -370    ...134    -236    -364    127    -241    

Posted on December 13, 2016 at 20:28I have an issue with a batch of LSM6DS3 and I would like to check the chip mark code. I was able to convert the barcode into a code (785320G709QQ) but I couldn't find a place to identify what each number means. The datasheet doesn't mention anything about the barcode/markcode. I just don't know where can I find this information.#lsm6ds3