Author: averaldofh
It is just an atempt to get an on-board computer in an '69 VW Beetle. schematics: https://easyeda.com/averaldofh/obc-vw
It's going to simply show the speed, odometer, 2 parcial odometers, oil temperature, battery voltage and fuel level.
Speed: There's a hall effect sensor attached to the wheel hub, as well as 4 magnets attached to the wheels. These will give us the RPM of the wheels, then we can get the speed of the car.
Odometer: With speed and time we can sum our mileage very easily and store in non-volatile memory.
Oil Temperature: Still figuring out how i will attach an NTC to monitor oil temperature, probably at the oil cooler. But the NTC uses a Steinhart-Hart equation.
Fuel level: I used a scraped aircraft fuel sensor, which works between aprox 20 and 50 ohms.
Battery Level: Simplest thing on the whole project.
this sketch for testing purposes, is runing ok on a ESP32 with built-in OLED screen. still under development.
Thanks to youtube.com/user/interlinkknight for his awesome piece of code, regarding RPM counting.