Automotive fuse box indicator ESP32 / Teensy 3.6

Thread Starter


Joined Feb 20, 2020
Good Day

I am trying to make an automatic IOT fuse box indicator, that shows what fuse is blown in a 12/24v automotive machine environment. there are 12 fuses that need to be monitored. I know its an open/closed value and that is simple enough to get to the IOT BOX. But how do i jumper into the fuses and what resistors components do i use to drop 12/24V fuses down to 3.3 volt logic. All it must do it say fuse 10 is blown and signal the IOT box. I am a bit stumped by this.

any assistance would be valued.



Joined Jun 22, 2012
You can use a 2K7 resistor and 3V3 Zener diode to drop down to 3V, across the 12V /24V fused supply, so when the fuse blows your 3.3V signal will be lost.