Topics created by adds666

Hi OSD, thanks for your input. Those are the 4 relays on IO-MCU. I buzzed out the circuit and found that I had an open circuit on the 12v line to the relays. Furthermore 2 of the relays indicator LEDs were illuminating, 2 were not. I suspect, when I first juiced up the circuit on this MCU, the 2 relays fired, but I'd made the trace too thin for the required current. I wired up some jumper wire on the reverse of the PCB and the 2 relays started working. The 2 that remain inoperable? https://forum.arduino.cc/t/using-pins-a6-a7-on-pro-mini-compatible/118050 A6 and A7 can only be analogue inputs, cannot be digitally written to..... - so this part of my PCB is now redundant. However, all in all, some good fault finding, found the two issues, and I'm now going away to re-think my PCB trace widths and reading the datasheets more accurately Thanks

No way - found it. Large comment at the top of sketch (not copied to this forum) had a line of *********s across the top. Removed and all ok. Thanks for your help anyway @mfalkvidd

@mfalkvidd many thanks for coming back. I think I'll keep more complex things seperate, however will explore multiple binary sensors and relays on the same node. Thanks