Why not get RPM direct from the coil? You need a suitable filter to cut the signal down and maybe use an opto isolator on the input to the Arduino.
I've been considering using an ESP32 with a camera to see if you could measure the needle lift on an SU carb and link that to throttle position, RPM and O2 reading. In theory you could tell if the needle is the correct one across the entire range. In practice would take a lot of fiddling I think.
I have ordered a ESP32 to play with but don't think I get will get beyond that. The time it would take to get such a system working reliably I can better spend manually turning the car then getting it finished so I can drive it!
I did start playing around with emulating the Innovate serial protocol (ISP2) using an Arduino so I could use their data logger software to measure things but then I bought a proper Innovate unit so that need went away.
Simon
I should add that's tapping off the LT side of the coil of course, where it connects to the distributor. Looking at how the Megasquirt people do it might help: http://www.bgsoflex.com/v22/msv22.html
Of course this is no help if the car isn't a coil one!
Simon
I've been considering using an ESP32 with a camera to see if you could measure the needle lift on an SU carb and link that to throttle position, RPM and O2 reading. In theory you could tell if the needle is the correct one across the entire range. In practice would take a lot of fiddling I think.
I have ordered a ESP32 to play with but don't think I get will get beyond that. The time it would take to get such a system working reliably I can better spend manually turning the car then getting it finished so I can drive it!
I did start playing around with emulating the Innovate serial protocol (ISP2) using an Arduino so I could use their data logger software to measure things but then I bought a proper Innovate unit so that need went away.
Simon
I should add that's tapping off the LT side of the coil of course, where it connects to the distributor. Looking at how the Megasquirt people do it might help: http://www.bgsoflex.com/v22/msv22.html
Of course this is no help if the car isn't a coil one!
Simon