TinyCircuits Forum

TinyCircuits Products => Wirelings => Topic started by: philip.rowe@STRATH.AC.UK on January 16, 2021, 12:56:40 PM

Title: imu 9 dof wireling sampling rate
Post by: philip.rowe@STRATH.AC.UK on January 16, 2021, 12:56:40 PM
Dear All, am loving the wireling IMU
I have a 4 socket wireling interface attached to a tiny zero processor, sd card for storage and a wifi shield to send the data once it has been recorded.
There are  4 wireling imus connected to the wireling sockets on the interface board
I am using the RTIMU library like suggested by Tinycircuits but this is no supported or updated.
I can currently read all 4 and send the data but at current am only getting 12-16 Hz or so for each imu
Do you know how I can speed up the sample rate to more like 50Hz to 1000Hz ?
Any help appreciated as I have been trying to do this now for sometime
Phil Rowe
Title: Re: imu 9 dof wireling sampling rate
Post by: Ben Rose on January 20, 2021, 03:13:58 PM
Hi Phil, thanks for using our products. Right, RTIMU is pretty old, but works pretty well. I haven't found anything more appropriate.

The software can get a lot more complex when reading multiple IMUs at once and recording, so there are a lot of potential causes. Have you timed any particular sections of code to determine what's slow? It could be some 'simple' stuff like I2C clock, non-optimized SD card writes, etc.

I believe the Wireling library has a delay in it that is not totally necessary, and could cause a significant slowdown in this type of application.

With the amount of math RTIMU does, I believe it can run the algorithm at around 250Hz with the default settings on TinyZero. So I think 50Hz or better is achievable for four IMUs as long as the SD writing is optimized. This assumes that the fusion algorithm needs to run on the microcontroller.