Hateful7
Posts: 3
Joined: Wed May 04, 2016 9:42 am

6 Sensors, 800sps each via I2C

Wed May 11, 2016 1:13 pm

Hello everybody!

My task is to take around 800 samples per second (800 would be nice, but if that is not possible: as many samples as possible) from 6 sensors for an experiment that lasts around 3 minutes.
I have access to a Pi2 and a Pi3 and am planning to use ADS1115 and read from those via I2C.
I already found the WiringPi Library and am able to read data from a ADS1115.

At the moment i don't know how to continue. So i am asking you guys if you can give me information on the following topics or if you can point me to articles or subjects that cover these things so i can find out how this can be done:

1) Will i be capable of sampling with 6 ADS1115 at around 800sps each?
2) Will the sampling rates be somewhat constant?
2.5) Maybe use an os-extension/modification that enables real time tasks?
3) What can i do to control the sampling rate? What is the bottleneck?
4) Would you recommend using the WiringPi Library in this case or is it linked to a lot of overhead?
5) I am planning to use C for reading from the I2C-bus but will it be much faster than the same thing done in Python?

That's all that comes to my mind right now.
Thanks and best regards
Hateful7

Hateful7
Posts: 3
Joined: Wed May 04, 2016 9:42 am

Re: 6 Sensors, 800sps each via I2C

Sun May 22, 2016 7:04 pm

Nobody in the mood to help?

danjperron
Posts: 3502
Joined: Thu Dec 27, 2012 4:05 am
Location: Québec, Canada

Re: 6 Sensors, 800sps each via I2C

Sun May 22, 2016 8:07 pm

I did 5000 samples / sec using a small cpu

viewtopic.php?p=530500#p530500

But because I had a cpu I was able to buffer the data. This way I didn't have any problem with the user space.

Did you try you A/D converter? What is your sample rate and your problem with the user space when the kernel access something else.

Daniel

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