Trying to build the ultimate Raspberry Pi computer (Zero Terminal V3)


That’s pretty cool. I just used a pi Zero W running opensprinkler along with a relay board to control my irrigation system. Now I can turn on my garden drip system from my phone :slight_smile:


Be sure to put snubbers across the contacts on the relays or you’ll bugger up their contacts over time. Those sprinkler solenoid valves can generate 400+volts of back-EMF when their fields collapse / power to them is shut off. I’ve seen relay contacts welded together from the arcing.

Good to know. I used this relay board which is supposed to be good for a/c restive loads, not inductive loads:

I probably should use this one instead since it has solid state relays with built in snubbers?

good for a/c resistive loads, not inductive loads

that’s even more good to know. Been looking to do some really interesting things with node-red, scada hacking and 3d printing. Love that the elegoo has a din rail mount on thingaverse ( but that 8-channel one looks interesting and might be easy to mount as well.

Depending on the coil load, some coils need suppressors. They can cause back emf as well.

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