I have built a LIDAR unit to warn me when there are vehicles in my blind spots. It works (in the breadboard stage), but I only want to alert the driver when either turn signal is on.

I am suspecting that I could look at the flasher relay. Does anyone know where I could see the wiring diagram for the flasher circuit?

For the electronically-minded forum members, I will use an opto-isolator to detect if a turn light is on, and program a missing-pulse detector in the code to smooth the on-off-on-off of the turn signal. I am just looking for the easiest point to tap into the turn signal circuit.

1 Answer 1


Usually the turn signal unit is between the positive supply and the indicator switch.

So if that wire leading to the switch is live then you have the signal you need for either side. If you try after the indicator switch you will need diodes or equivalent to keep the signals separate.

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