MEMS (sensors)

Hello, i read the AN4650 application note for the LSM6DS3 accle+gyro and i tried to implement the sensor hub routine with a MAG3110, like the one in the examples but it doesn't seem to work, is there another application note or a sample code that i can look at?Thank you in advance,Alex

This example describes how to set up a Finite State Machine to enable the built-in detection of e.g. the orientation of a phone screen (4D orientation). The picture here below shows the steps of the dedicated FSM. Basically, to get FSM output data you have to define input data and parameters such as a mask (to select the axis and direction to be monitored for the interrupt detection), thresholds and timeout frame to manage the latency. Finally, in attachment you can find an algorithm example for the upload in Unico.Input data are the axl output stream (select ODR >= 26Hz)Mask selects as interesting orientation axis x+, x-, y+ and y- (0xF0)Thresholds can be set to 0.8g both for x and for y (high threshold), and 0.2g for x and y (low threshold)Timeout selectable (e.g. 0x0D = 520 ms)Output is the OUTS register content for orientation (portrait up, portrait down, landscape left, landscape right)

Hello everyone. I recently designed a board, with stm32f303cbt6 MCU and MEMS audio sensor mp45dt02 which comes included with the stm32f407 disco board. I have a running configuration on the disco board, which captures mic data and sends it to the DAC out, but trying to run it with this MCU gives me trouble. I downloaded a few versions of libPDMFilter_CM4F_GCC libraries, trying to get it work, but here it is what happens: Using a -mfloat-abi=soft or softfp built library, there is some output, but it is only noise changing in amplitude when I "talk" into the mic.Using a -mfloat-abi=hard built library, the code gets stuck at this line exactly: PDM_Filter_Init((PDMFilter_InitStruct *)&Filter); and it is like the CRC is not enabled, but the thing is, I enabled it at the first line in main.The rest of the code should be fine, since I used this configuration on the other board and I just needed to make some small adaptation for th

Hi, I am using LSM303AGR reading accelerometer as well as magnetometer in the single mode. The problem is that sometimes I get wrong data and it seems like time between a single measurement request and measurement is changing. I could not find any details in the datasheet about latency in single mode. I request single measurement, wait 40ms, and check status register. If OVR or ZYXDA are set, I read a buffer. Sometimes these flags are not checked, even when I wait longer than 40ms or the buffer contains inappropriate values (like one of the samples before). Any ideas or reference how to use the single mode in a right way?

I’m trying to use the L3GD20 gyro to compute angular position from the angular velocity measurements returned from the gyro. Most of the time, everything works as expected. However, if I move the gyro in two directions (roll and pitch) at the same time, the measurements suddenly are way off.I ran across a posting on the Internet that said I should be representing angular position using quarternions rather than Euler angles because the latter is subject to something called gimball lock. I’ve never heard of this before, and wondered if it really does apply to MEMS gyro chips like the L3GD20.

Before starting with your first Fine State Machine, it will be helpful to have a further look at the Unico tool. With Unico you can easily interact with your device, setting the desired configurations, reading and writing the registers, stream data and export settings in a header file that can be included in the source code of your application.To create or import a Finite State Machine, you can select the FSM icon from the left bar of the Unico GUI, import a predefined algorithm (which will be useful for the following posts), check the output of the sensors, and debug the output of the state machine. You can also analyze a previous data logged file to check if the data stored enables the interrupts of your state machine.Please enjoy the below presentation form Mauro Scandiuzzo, ST fae, for a general summary.Link:

Two questions:(1) If I want to poll the status register instead of using interrupts, and don't want to use the FIFO, is the following initialization sequence sufficient? uint8_t cmd ; GYRO_IO_Init() ; // Enable Block Data Update and full scale = 2000 dps cmd = 0xA0 ; GYRO_IO_Write(&cmd, GYRO_CTRL_REG4, sizeof(cmd)) ; // Use output from high-pass filter cmd = 0x02 ; GYRO_IO_Write(&cmd, GYRO_CTRL_REG5, sizeof(cmd)) ; // Enable X, Y and Z channels cmd = 0x0F ; GYRO_IO_Write(&cmd, GYRO_CTRL_REG1, sizeof(cmd)) ;(2) Am I correct to assume that a set of new XYZ data becomes available (by default) every 10 msec (100 Hz), meaning that the GYRO_ZYXDA_FLAG of the status register is set once every 10 msec, and reset when the dataset is read?Thanks!Dan

Good morning,I am trying to read the WHO_AM_I register from LSM6DSO, but it doesn't respond as needed. I will attach a picture from signal analyzer (D0 is CS, D1 is CLK, D2 is MISO, D3 is MOSI). It looks like its respond is 0x50 instead of 0x6C. What should I change?I tried with a MAX32630 and it was working (8 bits transfer mode).When I try with RS14100 (16 bits mode) it responds with 0x50 instead of 6C.Gabriel

The best way to start experimenting with the LSM6DSO is with the STEVAL-MKI196V1, a daughter board integrating the MEMS that will significantly hasten the prototyping phase as its schematics will show exactly how to port it to a final PCB. The board uses a DIL 24 socket, which makes it compatible with the STEVAL-MKI109V3 motherboard. You just need to insert the sensor board onto the platform and connect it to a Windows machine using the onboard USB port to enjoy the Unico, or Unico Lite, GUI.But what is Unico? Unico is a graphical user interface (GUI) that enables you to configure registers, see the sensor’s behavior on a chart, and export settings in a header file to include in the source code of your application. Among its features, the software assists you by giving a graphical representation of the FSM through a workflow model that enables you to easily configure it.We will see some

Hello,i studied extensively the "sensor_hub_lis2mdl_lps22hb_no_fifo_simple" example so i can use the LSM6DS3 with an external magnetometer. There are 4 lines that i cannot understand, in the main example there is the code below /* * Configure LIS2MDL on the I2C master line */   lis2mdl_operating_mode_set(&mag_ctx, LIS2MDL_CONTINUOUS_MODE); lis2mdl_offset_temp_comp_set(&mag_ctx, PROPERTY_ENABLE); lis2mdl_block_data_update_set(&mag_ctx, PROPERTY_ENABLE); lis2mdl_data_rate_set(&mag_ctx, LIS2MDL_ODR_50Hz);that passes all the desirable options to the registers of the external LIS2MDL magnetometer, i cannot understand how this is possible since it doesn't use the sensor-hub pass-through feature or the required steps to write to an external slave sensor.Thank you in advance, you have been very helpful

Dear ST Community Members,I have question,Related with ST LIS2DE12 1LSb = 16mg @FS = +/- 2g ,What does it mean in math calculation ?Datasheethttps://www.st.com/resource/en/datasheet/lis2de12.pdfpage 43Thanks

I have several boards with the LSM6DS3 mounted. Some of them (about 50%) work fine, the others show strange results on the acc values. Gyro and temperature seems OK.The ACC show strange values (0x33db 0xffb9 0x07e4), which results in approx 5G if they lay flat on the table. I compared all registers, the content seems identical for the good ones and the bad ones. Is there something like a calibration?We have cleaned the PCBs with ultrasonic in Isopropanol. Might that harm the sensors?Best regardsHarald

To get a deeper insight of the FSM, a brief explanation of the "instruction section" is needed. It's one of the last steps towards a complete understanding of the LSM6DSO FSM.Instruction section is made by a set of commands and conditions. When the interpreter executes a command (structured on 8 bits and sometimes followed by parameters), the program pointer is set to next command/condition line and the interpreter evaluates the new line immediately.Conditions are structured on 8 bits: 4 bits for RESET condition and 4 bits for NEXT condition. If RESET is true, the program pointer is set to last configured Reset Point (can be changed in runtime by using CRP and SRP commands); if NEXT is true, the program pointer is set to next line and the interpreter evaluates the new line when next sample occurs; finally, if NONE, then the program pointer does not change and the interpreter evaluates the same line when next sample occur

Hi,I installed the Unico 7.0.0, the driver for the MKI109V3 and the DfuSe application contained in the MKI109V3 package. I wanted to upload the firmware on the board as the instruction manual UM2116 says. Therefore I changed the board to DFU mode and I uploaded the firmware eMotionV5.0.0.dfu that is in the folder named FIRMWARE (also contained in the package). After the upload was completed I clicked on the option of "Leave DFU mode" in the DfuSe program. Suddenly the LED stopped blynking and the board disappeard of the Windows Device Manager. Now I cannot use the board. My supposition is that I uploaded the wrong firmware that makes the board unuseful. Do you know what can be done in this case? How can I upload the right firmware?

But how is structured, in detail, a FSM program? Basically, there is a data section, composed of a fixed part (same size for all the FSMs), and a variable part (size is specific for each FSM), and an instructions section, composed of conditions and commands. Both data and instruction sections registers details can be found at the link below.As regards data section, the fixed part is made of 6 bytes at the beginning of each FSM where the user must specify the amount of resources he will use in the instructions section and some parameters useful to the interpreter. Some examples: ODR, HW configurations, etc (see p.23 in the attached link). The variable data section is composed by a variable number of bytes after the fixed data section where the user allocates the necessary space for the resources. Some examples: thresholds, hysteresis, masks, etc (see p.25 of the attached link).

Hi, I’m using the embedded tap feature in LSM6DSO. While reading the datasheet, I noticed that it’s possible to implement a finite state machine for the tap activity recognition. Which the advantages, if any?

can someone help me in this.

I have prepared an application in which I am reading accelerometer x,y,z axis data from its registers @every 2 sec. Now what i observed is that if I keep my board at stable position without disturbing board or any surroundings still I see some spike value in one of the axis data. I have kept a threshold value for each axis. Now due to this spike one of the axis crosses the threshold value. I do not understand that in idle position why such spike is observed.If required I can share my application in which I have configured the registers at Init time and using X,Y,Z axis registers to read.Please guide me in this issue.Thank You,Arjav Parikh

I can't find it in the datasheet but it is behaving this way in my application.

I have a 10k pulldown on SPI SDO. I am seeing this pin sit at 1V when the device is not driving SDO, as if there is a pullup inside the device. There is nothing mentioned in the datasheet. When the device is transmitting on SDO the signals look fine. Has anyone seen this before?

Hello, I have X-NUCLEO-53L0A1 kit and now I want to work with VL53L1X sensors using this kit. As I understand, the only differences between X-NUCLEO-53L0A1 and X-NUCLEO-53L1A1 are:1. Different top sensor component2. Absence of 4 digit display on X-NUCLEO-53L1A1.So, if I disable top sensor by grounding XSHUT_2.8V signal, I'll could work with left and right sensors VL53L1X, placed on CONN LEFT and CONN RIGHT. And it really works, but with the following limitation:I have to initially disconnect XSHUT_L and XSHUT_R signals before launching VL53L1X_GUI, because these signals are kept low on GUI startup and the SW could not find any sensor. If after startup I reconnect these signals, everything works fine.The question is what is the reason of such strange behaviour? And what could be done to solve the problem?Thanks in advanc

Based on some other forum posts I can see with reasonable certainty that this pin is indeed held internally high. This is not mentioned anywhere in the current data-sheet, which advises that this pin can be held high or low to set different addresses. Please see this post for other feedback about this: https://community.st.com/s/question/0D50X00009XkaNASAZ/lis3mdl-large-power-consumption

Hello,I would like to ask you a question. I would like to use the LPS33HW in my application with I2C bus, before I move with the software development I would like to check if the sensor works with given ambient conditions. I thought that it will be great if I can reuse the STEVAL-MKI109V3 board and the GUI to read the data. Unfortunately I cannot connect with the sensor if I am do it like on schematic ( see attach ). Could you be so kind and help me to understand what I should do in order to verify if the sensor sense :)Thank you in advanceJacek Pieczaba

The LSM6DSO is the first smart sensor (accelerometer + gyro) with an embedded 16 Finite State Machine.But why is (and will be) a FSM so important? Unlike a traditional computer, FSMs hold a finite number of states or outputs in response to a particular input. Hence, they need very little memory or computational resources because they are incredibly efficient, but their capabilities are also minimal.For this reason, the LSM6DSO is fundamental because it prepares the way for Artificial Intelligence in embedded systems and gives developers the ability to start working on these popular features before they become mainstream.But how to use these innovative characteristics in practice? Daily follow our community posts till the end of the month to understand how to do it yourself ;) For more information:

I have followed the DT097 (design tip for 6d orientation detection). When I moved from vertical position (face up) and rotated the board around X (or Y) axis the interrupt that I got ia when it is angle-complement of what I have selected e.g. 20 degree when I have selcted 70 degree). When I rotated back then the interupt happened at the angleas was selected e.g. 20 degree.The registers setting: CTRL2=0xA4, CTRL4=0x80, TAP_THS_X=0x20, CTRL1-0x30, BS_INT_CFG=0x20.BTW, when I have selcted 4D it works as was expected!