I am creating an all digital dashboard for my van. I’ve already worked out the interface and a number of sensors, using Arduino and Raspberry Pi, but I’m going to have to connect the Arduino with a number of circuits (8-10) in order to see if they are powered (or grounded in some cases) and light up the proper icon on the dash. For example, low or high beams, turn signals etc.
I’ve thought about voltage dividers, but it seems that it would be best done using optocouplers. This should allow me to use digital inputs on the Arduino, and even some interrupts. I do not need to know how much voltage is on each circuit, just that they are on or off.
My question here is to verify if this would make sense in order to use not just one, but several optocouplers connected to different input pins, and if not, how I would need to modify it. This diagram shows 3 optocouplers (PC817) receiving input from 3 different 12v circuits, and connected to the car’s ground. Each opto has a resistor for the LED, and there’s a 10k resistor on the 5v source from the Arduino. Also added a diode for protection on the car’s ground connection.
Thanks for any tips.