Raspberry PIs are amazing inexpensive micro computers! They are somewhat limiting for use the lab because they don’t have Analog In and Out, which is why we considered using the BBB. However if you extend the Pi with a hat you can increase it’s functionality. We decided to try the inexpensive and versatile Pi-Plate. Its only about $38! Pretty sweet.

For a while now a student has been working to build an inexpensive PID controller with the BBB. I have to saw it was so much easier with the pi and pi-plate. The programming is python nice and straight forward.

As always I did run into a bug (ish) when setting it up. I couldn’t find anything on the web that helped me search for the solution. So I am going to post the issue and solution here so hopefully it will help someone else.

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import piplates.DAQCplate as DAQC

DAQC.Poll()

Error: No DAQCplates found

Solution: When I stacked the pi-plate and pi in the pi case, the leads weren’t completely touching (though some did and LEDs turned on). They were like only 70% in. This is because the pi-plate was getting blocked from the pi case. That is why I ended up separating the two devices and connecting with a cable assembly.

Of course that seems like a simple solution. But it took me a while of banging my head into the wall to make it work.

The pi-plate team has an option that uses its own pi-case. I will buy that and get it set up at some point.