MEMS (sensors)

Posted on March 18, 2014 at 13:54we are  working with lsm303dlhc compass sensor and  interfacing with lpc3250. we are using linux kernel version 2.6.34. and have taken driver codes (accelerometer and magnetometer) from your site. its working only one particular direction with 0 to 360 degrees angles. remaning directions its giving only 250 to 360 degrees angles only. i mentioned below what are calculations are using accelValue[0]= accx/sqrt((accx*accx)+(accy*accy)+(accz*accz));     accelValue[1]= accy/sqrt((accx*accx)+(accy*accy)+(accz*accz));   pitch = asin(-accelValue[0]);   roll = asin(accelValue[1]/cos(pitch)); xh = magx * cos(pitch) + magz * sin(pitch);   yh = magx * sin(roll) * sin(pitch) + magy * cos(roll) - magz * sin(roll) * cos(pitch);  heading = 180*atan2(yh,xh)/PI; so, i request you can give me any sugge

Posted on March 18, 2014 at 10:25Hello, can you please shift your datasheet to the level of both of this below at least ? http://www.st.com/web/en/resource/technical/document/application_note/CD00290365.pdf http://www.st.com/web/en/resource/technical/document/application_note/CD00215823.pdf First, in this is stated, that ''data-ready'' signal is reset after higher part of the data of all the enabled channels has been read. There are many questions in this forum... Second, I could read, that data is left justified. But why not in the right datasheet? But third, please answer tickets(!) and forum questions

Posted on March 17, 2014 at 20:19I have an application where the ST Micro part LSM303DLHC has been specified for a product which has a -50C storage requirement. This ST Micro e-compass is only rated down to -40C for storage (and operation). We are also looking at the LSM303D as the LSM303DLHC is marked as not recommended for new designs. Can anyone from ST Micro comments on the potential damage to this part at temperatures below -40C? Thanks, Peter

Posted on March 17, 2014 at 20:17I have an application where this ST Micro part (L3GD20)  has been specified for a product which has a -50C storage requirement. This ST Micro gyro is only rated down to -40C for storage (and operation). Can anyone from ST Micro comments on the potential damage to this part at temperatures below -40C? Thanks, Peter

Posted on March 14, 2014 at 16:11Hi, How can I get answers from you? Next try. This is a typical sequence with FS=00 and DR=11 and the chip lying on the table. How do you review this? Your spec says TyOff +-1g, and So=0.049. Where does this noise came from ( +3g on Z-Axis) ACCELERATION    ff70 ffd0 2c0   -0.439453 -0.146484 2.148438 ACCELERATION    fec0 fff0 190   -0.976563 -0.048828 1.220703 ACCELERATION    ff20 090 490    -0.683594 0.439453 3.564453 ACCELERATION    fff0 020 320    -0.048828 0.097656 2.441406 ACCELERATION    ffc0 0a0 20     -0.195313 0.488281 1.562500 ACCELERATION    ffe0 040 260    -0.097656 0.195313 1.855469 ACCELERATION    ff60 ffb0 250   -0.488281 -

Posted on March 14, 2014 at 14:55Maybe I'm dumb but I can't figure it out myself - I can't find download  links for iNEMO Engine Lite. http://www.st.com/web/catalog/tools/FM147/CL1818/SC1528/PF260129♯ this link just tells me that status is ''preview''. The same goes for all iNEMO software, I can't see any kind of download link or how to order instruction. Am I doing something wrong? #inemo

Posted on March 12, 2014 at 10:28Couple of questions ...1.  I have typically seen LIS3DH paired with Cortex M3 for e.g. in most of the health/fitness monitors. Is M3 required or could we use a M0/M0+. In other words what is the uC bandwidth required for ensuring no samples are dropped.As per my calculation M0 should be sufficient and M3 has been used in those products to support DISPLAY and/or USB. Could some one confirm ? 2. Further on does LIS3DH require a dedicated microcontroller or can it be shared with a uC (MSP430/8051/Cortex M0) which is part of say the Bluetooth connectivity SoC ? #lis3dh #microcontroller

Posted on December 21, 2013 at 21:50Hi, i'm a german student and i'm working on a private project. It's a UAV (UnmannedAirVehicle), which controls it's altitude by pressure. For this, i want to use a LPS331AP, but the raw-data output oscilates with a frequency of about 0.05 Hz. Normally, i would use a bandstop filter to reduce / minimize this noise, but if the UAV moves up or down, the frequency can be / will be often the same, so this doesn't fit. In the application note ''Hardware and software guidlines'' it says on page 16: '' For indoor navigation when sub meter detection is required, a special recursive filter could be used. Tailoring the S/W filter for the sensor characteristic and the application requirement is usually a good move. Sensor fusion is the most advanced filtering which uses all available information and uses them to reduce the positioning noise. '' But i can't find any

Posted on March 06, 2014 at 21:21Short of removing and reapplying power, is there a way to reset an LSM303DLCH?  I'm having an issue where some device on the I2C bus is driving the SCLK low after a reset of the host processor, making it impossible to communicate with any devices after that.  The only way to clear the problem at that point is to cycle power on the system.  I don't know which device is driving the bus low, but there are only two options; the LSM303 or a Maxim RTC.  I'm hoping to get to the bottom of this issue and prevent it from happening in the future, but as a failsafe I'd like to be able to reset the devices if this condition is ever detected.  I'm a software guy, so maybe I overlooked something obvious in the data sheet, but I don't see an sort of reset line.  Thanks,John

Posted on March 06, 2014 at 11:08Hello, Please give me information about the following questions. 1. What is the sensibility of the LIS331DLH accelerometer sensor? 2. What is the minimum acceleration that LIS331DLH can detect? Is there anyone who can tell me clearly about the above two questions? Please.

Posted on February 27, 2014 at 11:27What are the recommended soldering parameters (i.e. solder paste thickness) for MEMS microphone manufacturing?

Posted on March 04, 2014 at 17:58 There is a linux sysfs file for accessing data from LIS331DLH. cat /sys/devices/platform/lis3lv02d/position What does this actually retrieve. Cartesian co-ordinates? If yes, with respect to what? Can this be used for ''Inertial navigation'' ? Or it is actually acceleration data itself? Kiran G #lis331dlh #position

Posted on March 03, 2014 at 22:56There is  a low pass filters LPF1 which is after ADC(page 22 of the data sheet Doc ID 022162 Rev 2 ).There is no words about this filter can anybody tell me a bit more about it? for example what is the cut off frequency, what's the order? What kind of low pass filter? My sample rate is 760Hz. Thanks in advance.

Posted on March 03, 2014 at 08:43I have calculated Tilt/Gradient in Non-accelerated systems(System acceleration  = 0); How to measure Tilt/Gradient in accelerated systems.As MEMS will give the X,Y,Z component of the resultant acceleration(g and a ).Also bike acceleration(Both magnitude and direction) cannot be predicted.Simply,How to seperate sytem acceleration(a) from g(Acceleration due to gravity). Please suggest over this point.

Posted on March 01, 2014 at 10:23HelloI have read that impact detection functionality can be performed by LIS3DH. I am unable to find any information on HOW to configure the device for impact detection.Is it identical to ''click'' detection? If no - than how to configure device for impact detection? #lis3dh

Posted on February 27, 2014 at 23:51I am using an Aardvark SPI/I2C USB adapter and a Labview VI I have written to acquire accelerometer data from the STEVAL-MKI122V1(LSM330DLC).  I am noticing at an output data rate of 1Hz, the OUT_X_L_A, OUT_X_H_A, OUT_Y_L_A, OUT_Y_H_A, OUT_Z_L_A, and OUT_Z_H_A registers do not update at the same rate.  There are times when the X and Y Axis registers update and the Z Axis registers remain the same and vice versa.  What is the best way to acquire accelerometer sensor data and ensure the desired output data rate stays intact without using the FIFO?  Or is the FIFO the best way to go? 

Posted on February 27, 2014 at 23:34I have acquired both the STEVAL-MKI122V1(LSM330DLC) and the STEVAL-MKI109V1(eMotions Motherboard) and have been using them together for some time now.  But now, I want to use the STEVAL-MKI122V1(LSM330DLC) by itself and I have figured out a way to power it and want to make sure I am powering up the LSM330DLC correctly and I am not damaging the device.  I am currently applying 3V to pins 1 and 2 of the JP1 header.  I am applying the Ground to pin 13 of JP2 header.  Is this configuration correct? #lsm330dlc #steval-mki122v1

Posted on February 26, 2014 at 11:06I've set up the LSM9DS0 to the +/-16g range by setting AFS2 - 0 as 100 as per datasheet. Normal g comes out as 0.7g, yet all other ranges are fine. What am I doing wrong? Chris

Posted on October 26, 2013 at 09:15There are no figures for clock stability over time and temperature. These are going to effect the sample rate times. For example, if the accelerometer DOR is 100Hz, what spread can be expected. I take it that in all of the three sensors types, that the time from commencing a conversion to the Interrupt, the time is roughly the reciprocal of the DOR. Is this true for the Magnetometer, where I assume the Set/Reset takes a fixed time during every sample, irrespective of the DOR. I am wanting to have a fixed data update rate of 100Hz, generated from the host processor, has anyone done this sort of thing, or are you just free running the LSM9DS0, and accepting the rate programmed into it? I accept that I will only get an effective 50Hz from the magnetometer at the rate I require. I am new to this device, have used analogue parts previously, where I could get better control of the sampling rate.Any comments would b

Posted on February 20, 2014 at 08:31I connected LIS3DH in the following way , but the device does'nt give the correct reading.          What is wrong with this configuration? Vin = 3.3V, SPI 4 wires. I configured the registers with the following string  at SPI: 0x60,0x77,0,0x10,0xC8,0,0 (command 0x60 , Reg1 0x77, Reg2 0, reg3 0x10, reg 4 0xC8, reg 5 & 6 0.) I can read this conficuration back and it's stored OK at the device. I read data by command 0xE8+6 bytes of zero But the OUT_XY&Z give me wrong values .  Eg 0xFE,0xA0,0x01,0xA0,0xFD,0x70 0r 0xFE,0x90,0x01,0x90,0xFD,0x40

Posted on January 27, 2014 at 07:06Hello, what is the difference between these two modules? Why DLC is so much expensive? #lsm330 #lsm330 #lsm330dlc

Posted on February 23, 2014 at 06:04The description page of the L3G4200D gyroscope says that it is an angular rate sensor able to provide unprecedented stablility of zero rate level and sensitivity over temperature and time. Does that mean that there is no need to fuse it with an accelerometer for calculating angle? #l3g4200d-gyroscope

Posted on February 12, 2014 at 17:44HelloI am trying to use the LIS3DH in FIFO Mode with Filter enabled.In this mode, the X-Axis, and Y-Axis values get some normal values (they oscillate between -10 and +10) but the Z-Axis value seems to have a bypass to the filter mode, the Z-Axis gives for example -616 witch is not the value for Z-Axis if i disable FIFO and Filter.Is this some kind of limitation of LIS3DH? or am i making something wrong at initialization.In my initialization code the registers are initialized with the following values:CTRL_REG1 = 0x17CTRL_REG2 = 0x88CTRL_REG3 = 0x00CTRL_REG4 = 0x40CTRL_REG5 = 0x40CTRL_REG6 = 0x00FIFO_CTRL_REG = 0x40Thank YouArtur Vieira

Posted on December 16, 2013 at 14:53In LIS3DH datasheet (Doc ID 17530) on table 25 we can see: Default value 00     ODR3-0 (0000:50Hz Others:...) on table 26 we can see: 0000 Power down mode So what is ODR = 0000  Power down or 50Hz? #lis3dh

Posted on February 19, 2014 at 07:36Since there is a hole in the top of the LPS331APTR package, are special precautions needed during the assembly process? Is it OK to wash the boards?