X issue with speedo voltage.

[JiNxXx0013]

Hey mick,
First of all thanks for making this accessible for everyone. I’m having a issue with my incoming voltage from the rpm it’s s 9 Volts. I’m trying to see what I can do to step it down, I’ve tried a higher resistor but hasn’t changed the voltage. Any suggestions? The car is a 99 Honda civic. Also I redid your schematic with a change on a pin location is this correct?

[MickTheMechanic]

That looks good, you should be seeing a square wave on d4 as long as the input is also a square wave.

You’d have to lower the 47k or increase the 10k resistor.

Flash is with a basic sketch that prints analogRead() from d4, and check how it looks during operation via the serial plotter