Pin out of pump boards

[harrison]

Hi Eric,
Interesting idea! In principle it could work, but I must say, I am not sure this approach will be easier than messing with app.py. Probably you WOULD have an easier time sitting down and understanding what app.py is up to with the pump control, then building upon that.
Nevertheless, the inputs to the pump board are:
-6V
-unused
-GND
-SCL
-SDA

So the main difference with what you wrote is the 6V input. This is the power used to actually run the pumps, and needs to be able to supply ~0.5A minimum since they generally draw quite a large current when they start turning. Thus, you would need to make whatever hardware system you propose to develop supply this current or it would not be able to run them at all. Currently there is a regulator inside the Chi.Bio reactor doing this…

I hope this helps – as I said IMO you would be better doing it using the existing hardware infrastructure and making your changes in code. Once you do understand how it works, it is not so difficult to make changes!

Best
Harrison

[nahanoo]

Hi Harrison,

Thanks a lot for this fast and useful reply. You are right, I need to consider if it’s worth getting into it or not.
What I like about my idea is that it would also allow us to make use of the pump boards independently from the chi.bio.
We usually don’t run many reactors simultaneously so we have a lot of spare pump boards. With independent control we could make use of the boards for other projects as well.

Since there is the voltage regulator on the pump board do you think for prototyping a lower input voltage would work as well? As long as enough current is available.

Best,
Eric

[harrison]

Hello,

The voltage reg on the pump board is only outputing 3.3V for the digital components. It is NOT regulating a 6V input for the pumps. That 6V comes in raw from the cable.

That said, making a 6V supply is not outrageously difficult so I imagine what you propose can work! Maybe it would get by with 5V input – the limiting factor is whether that is enough to get the pumps spinning (IMO it should be).

[Author]

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