I am also considering putting a diode (IN4001) on the GRD wire going to the Relay board to try and suppress the surge from the relays when they disengage going back the mega 2560, but this is also a theory.
Can the EMF travel on this line
and should I also have a diode running between the relay pins and the arduino pins?
I might have to try them on the signal wires also.
What about the use of a pull down resistor on the input pins of the relay board?
I was playing last night and noticed that only the relays that have a load on them (pump) will give me enough EMF to cause LEDs to blink.
The diodes were going to be my first choice but I have been reading about a Opto-Isolated relay board. It is made just for this kind of problem.
Quote from: Wmtasker on Apr 13, 2013, 03:46 pmThe diodes were going to be my first choice but I have been reading about a Opto-Isolated relay board. It is made just for this kind of problem. From your earlier posts, the red relay board you have already has optoisolation capability. It requires that you remove that jumper and use another power supply for the relay coil side.http://arduino-info.wikispaces.com/ArduinoPower
How much of a load and what voltage are we talking about?Are the relays rated to handle what you want them to?An underrated switch could cause a spark when it is turned on and off.Have you ever turned a switch and noticed a spark are heard a crack, signs of a switch about to fail?
I saw the ratings of the relay but wasn't sure about the pump.I'm stumped.But will let it chew in the back of my mind.