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I grow tomatoes really well, now I'm trying my hand at automating the entire process


Feb 11, 2024
Feb 11, 2024
Granted this thread has been quiet for some time and I'm bumping it, but wanted to provide an update that could hopefully help someone.

So, I busted a couple solenoids but worked with a friend to figure out a solution.

We made this little circuit on a board that allows me to control 220v solenoid valves, provide EMF kickback protection and is a real joy to work with.

The JST connector goes towards the ESP 32. The Red attaches to the GPIO while the black goes to GND.

The top Green connector is 220v input while the the lower green connector is where we attach the solenoid valve.

Between Both Green Connectors, I have the BT136-600D Triac.

The White Component is the CT 3021 Octocoupler.

The resistor to the right of the CT 3021 is 560 Ohms

The resistor to the left of the CT 3021 is 390 Ohms

The resistor next to the LED Bulb is 680 Ohms.

Essentially, according to my friend, the Octocoupler isolates the Solenoid from the ESP32 while the Triac acts as a trigger and further protected from the EMF kickback.

Using this, I was able to deploy two solenoid valves per greenhouse (one for irrigation and one for overhead misting). I was able to connect a single ESP32 WROOM board to both solenoids, remotely access the valves and trigger them as and when was required.


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