Posts: 90
Joined: Wed Aug 22, 2012 11:25 am
Location: Melbourne, VIC

A different way to mount a Pi Zero

Sat Sep 10, 2016 10:44 am

A project I have been working, rather slowly, is an irrigation controller, which uses a Pi Zero as the brains.

I am using a MCP23017 GPIO expander for my outputs, with ULN2803A Darlington transistor arrays providing the conversion from 3.3V to 5V (and allowing me to get enough current to drive my relays).

Given that the Pi Zero is so small compared to my relay board, it makes sense just to mount the zero on my board. To do this, I have used a stacking header, which will still allow me stack another board or connect a ribbon cable on top later (for expansion).

I have not finished the power supply or inputs yet. (Another couple of solder sessions to go, and still waiting for some Schottky diodes.)
20160910-IMG_9499.jpg (62.58 KiB) Viewed 1012 times
20160910-IMG_9500.jpg (57.75 KiB) Viewed 1012 times
The 3 pin header to the left of the Pi provides access to the serial console.
The little blue board which is connected vertically is a RTC. - I believe I cannot assume that the controller will boot with network connectivity. If it comes up with the wrong time, that could have some undesired effects on my irrigation times.

I guess, in a way you could say I have used the Pi Zero as a "Poor Man's Compute Module".

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Posts: 1549
Joined: Tue May 28, 2013 3:24 pm
Location: North Texas

Re: A different way to mount a Pi Zero

Sun Sep 11, 2016 11:43 am

When I needed a pump/irrigation controller, I went with a Teco PLR. It would up being cheaper than a Pi based solution.

I do use a Pi in my shop as both a air valve controller and music source.
Doing Unix since 1985.
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