General Advise


I built a valve controller that will control two 3-wire latch solenoids valves. the prototype works well with LEDs simulating the valves.

I attach the circuit fritzing.

Do you recommend adding resistors/capacitors/other parts to protect, add reliability, or enhanced the system?


Apart from free-wheeling diodes across the solenoids?

Yeah, inductive devices produce large voltage spikes when shut off. This will wear out the contacts in the relays. A diode installed "backwards" across the solenoid will help protect the contacts. Wikipedia describes how it works in Flyback diode - Wikipedia