imu 9 dof wireling sampling rate

[philip.rowe@STRATH.AC.UK]

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
regards
Phil Rowe

[Ben Rose]

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.

Thanks,
Ben