Re: Best way to control relays? New
« Reply #20 on: March 29, 2018, 03:25:27 PM »
Not sure this is best way to control relays, (Buffered shift register IC's passing data from an Arduino UNO probably better) but I saw that people suggested using microcontrollers and I made a coarse and very un-elegant PCB some years ago that uses th transistors to buffer relays off a Mega (40+ I/O) card.  I have some extra PCB's if you wanted to play around.

Edit: This is a fairly project specific PCB, as each card pairs to 16 non-latching buttons that are backlit. The switch to led to relay relationship on board is non-native, in that you would need to program the Mega to receive the button presses, and then return low and high signals back into the buffer card, which would then light the led's and send the relays a CV gnd.  I chose to use 2-leg bi-color led's in the switches, so led buffer voltages are reversible.  An additional circuit (found elsewhere around the forums) would be required for the relays to accept a CV and assist in reducing contact bounce.

I suppose you could call this just an over-engineered, under-sophisticated, arduino 'shield'.   :)
« Last Edit: March 31, 2018, 05:29:00 PM by boji »