I have an embarrassing EMF problem. I forgot to pay attention to the 5V rail, which powers the relay, and the 12V rail, which powers the solenoid. Now whenever the solenoid is turned off, back EMF is generated, resulting in resetting the Arduino, which powers and controls the relay circuit board. Attached are photos of the PCB layout highlighting the 5V and 12V rails. As you can see, the 5V and 12V rails run parallel to each other, which is foolish. I have gone through cutting the traces on several of these boards, and found out that by cutting the 12V at the point shown in the photo, the occurrence of the back EMF is about 20%, instead of 100%.
Now even more embarrassing - I have 250 of these boards! I am wondering if there is a solution which involves cutting tracing and soldering, so I can salvage these 250 boards. Many thanks!
