Electronic – Schematic Feedback


I am looking for design feedback regarding the following schematic.
The idea is very simple.
The Controller board pulls the relay coil terminal low on the relay board to activate the relay.The relay board is 6 feet away from the controller board.

Once the relay is activated the brushless pump turns on.
The 220uf caps on the 12v line is used to keep the voltage high enough momentarily to have the microcontroller save a value in EEPRom before shutting down.
Looking to hear your comments/feedback.
The relay contact generates a bit of contact noise upon closure. Attached is the scope shot taken across the relay Common contact as it forms contact with the pump 12v line.

Will the contact noise interfere with the microcontroller function at some point?
Thank you

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Best Answer

that should work ok.

one possible improvement would to separate the 330uF used before the 5V regulator from the 12V supply using a diode, this stops the the pump sdtart-up current from draining the capacitor, and reduces wear on the relay contacts.


simulate this circuit – Schematic created using CircuitLab