Hello, i need the wisdom of the smart electronics people. The project is im building a speedo corrector for a car (im basically putting a focus 2ltr zetec engine into a car built in the 70's).

The car uses a 3 wire sensor which outputs 10v when in front of metal and 0v when non present.
The issue is i need to take this 10v signal from the sensor get it down to a safe 5v to feed into the MCU (top circuit) then in the Teensy mess with the signal timings and then out put it back to the ecu (bottom circuit) which im guessing is expecting 10v as normally the 10v signal from the speed sensor goes straight to the ecu.

I got the idea for this project from this site (https://members.rennlist.com/tom8695...r%20Page1.html) but this one uses a Schmitt Trigger which im not sure i need


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Does the structure of the circuits look good to do the job? i chose to use opto isolators to protect the microcontroller.

Many thanks

Trev