I bought a Sainsmart relay board for a sprinkler project that will be directly connected to an RPI. The documentation says it can work this way but I find that 2 of the relays "chatter" when turned on. The chatter is very frequent on one of the 2 but very intermittent on the other. The relay board is getting 5V from the RPi and it looks rock solid and clean on a scope. The driver input pin is going low and staying low and it too is nice and quiet. The output of the opto-isolator is showing the chatter. Once the chatter starts, I would guess the relay is activating/deactivating 10-20 time per second and it can last several seconds. That would pretty much raise cane with the sprinkler valves.
Has anyone else experienced this? Is there anything that can be done to fix it?
Is there a better 8 relay board out there that works with RPI?
BTW: This is the second item I purchased from sainsmart that doesn't seem to work as advertised. The other item was a 6 DOF accelerator/gyro.