I recently bought a few UNO boards with the cheaper 'Atmel' chip and noticed that the standard relay boards I've used in the past do not work on UNO board (knockoffs) with this chip. I noticed that the power indicator LED on the relay board is very dim and relays will not respond at all. VIN and 5V lines measure fine on the UNO board with a voltmeter. I've tried powering the UNO board directly from a computer USB port and a 2amp USB charger but neither correct the problem. Anyone have any experience with this problem or know a solution besides returning the cheap-o boards?
Cheap as in $4 shipped. I purchased four of them and tested the relay board on all of them and the same thing happens. The relay board works just fine on the boards with the atmega chip with the removable IC socket. My knowledge is limited and I don't know the major differences in the boards, chip types, etc.