I have a problem with a pair of relays that I can't quite fathom.
I have an Arduino Uno wired up to a 6v battery and two relays. They're meant to turn on and off at various times in the day, without anything hooked up this all works fine.
With the devices installed (one 6v one 9v with a step up converter), after being off for a while the whole thing struggles to turn on again, it just sits there repeatedly trying to turn the first device on then taking down the uno.
If I leave it clicking on and off for a while eventually it sorts itself out but this can leave the device in a state where it thinks it turned the devices on but it hasn't.
I'm thinking some sort of power smoothing might help but I'm not sure about how to set this up, or could it be something else?
If usb is connected everything works fine.
Any help would be greatly appreciated.