I am finally getting around to revisiting my train signal project. I currently have a pretty basic code that seems to do what I want, my next problem is now the relay board.
Ok, the relay board I have is Low for on so that when there is no power/ signal the relay is off, makes sense to me. After a bit of searching this is probably done with a pull up resistor on the actual relay module.
Ideally I need the relays to remain off anytime the program is not asking them to be on as they points motors will burn out if constantly left on.
When the arduino is initially turned on all is fine I.e. The relays are all off until a button is pressed as it sends all the pins high as it is programmed to.
When the relay board is just powered up (nothing connected to the input pins) the relay is off, the pins are high due to the pull up resistor, all is good.
But if the arduino is connected to the relay board but the arduino is powered off the pins are sent low and the relays are turned on. As soon as I also power up the arduino they are sent high as programmed.
Is this normal? It there a way I can resolve this problem