Vehicle speed signal?

I am working on a totally stupid project that I'll never actually finish. Per usual.

I would like to determine instantaneous vehicle speed with a microcontroller. On principle I don't want to use GPS. And out of ignorance, I don't want to tap into the can bus. I would like to measure something such as frequency, voltage, or duty cycle.

Does anyone know specific details of how the wheel speed sensors work on these trucks? Or the speedometer?





For the wheel speed sensors... it looks like I could tap into these on the ABS module in the engine bay. I would only need one sensor--not worried about turns or wheel slip. For example the green or red wires for the front LH sensor above. Does anyone know how many teeth there are on the wheel hubs, or which of the two wires to tap, or what the voltage range is?





For the speedometer... it looks like there might be a single-wire signal signal conveying the value to the dash (red-yellow) but I'm not sure. (In my case it would be from the Skid Control ECU.) Does anyone know whether the speedo runs off the bus in these trucks, or if it's conveyed by this red-yellow wire? If the latter, does anyone know what type of signal is used?

I can of course probe these to figure it out, but if anyone knows, that would be helpful.

 

I mean you can read vehicle speed via OBDII with any scan tool or other OBDII monitoring device but I guess if you wana do it the other way that's fine too.

Everything I know about the vehicle speed circuit can be found in the post linked below (Scroll down to P0500), it is a digital signal (aprox 0-12v) although I don't know the exact number of pulses per rotation I think it's around 4.
https://www.tacomaworld.com/threads/2nd-gen-information-diagnostics.784008/#post-28042157

Also scope captures of both ABS sensors and and the Vehicle Speed input and output can be found in the thread below.
https://www.tacomaworld.com/threads/4-0l-scope-captures.759406/

 

This is perfect. I apologize for asking something so easily answered by searching, not that I didn't try, but I didn't find this. Thanks!