I have a circuit that is shown in the image bellow. I use 5 V reed relays to turn ON/OFF 12 V LAMP. I have to check if the circuits is connected propery - so the rules here are: after we turn on relay with Arduino, if the circuit is connected properly, tle lamp is ON, otherwise the lamp is OFF. It is not necessery that when we turn on Relay, the lamp is ON. It is also possible that some connectivity isues happened in the circuits and the lamp is them OFF. So, we have to read somehow if the lamp is ON or OFF when we turn on relay.
Since Arduino can only read 5 V signal, I have to ask any of you what is the easyest way to read that signal (that will tell us if the lamp was ON/OFF). I know that we can do it by voltage dividor bit this is too much to integrate in the existing circuit...
any advice very welcome