I'm having difficulties trying to trigger solid state relays with the industruino D21G proto. I only seem to be able to get an input tension on the relays of 2,70V, and not 3,3V. Tried a pull-up resistor on the digital out to 5V, I do get 5V with no load attached to the industruino, but still 2,70V when connected to a relay.
I took everything out of the circuit, and it's the same with 2 different relays. There are no other components than the relay, the industruino, and the pull up resistors I added (it behaved the same before and after adding the resistors).
Does that ring any bell ? A regular arduino uno has no issue whatsoever driving these relays with the same wiring...
Please try to give a substantial answer. If you wanted to comment on the question or answer, just use the commenting tool. Please remember that you can always revise your answers - no need to answer the same question twice. Also, please don't forget to vote - it really helps to select the best questions and answers!