J1850 VPW convert to 8192 aldl (Tacho signal)

[rostkov]

Congratulations. The question is, is it possible to write code to extract the tachometer data (rpm) from the J1850 VPW standard and convert it to the ALDL 8192 protocol.
Since I did a 1988 Buick Regal L67(3800 st,2) swap.
I apologize, maybe I didn't explain it that way.
I need a signal for my electronic tachometer which used to get it just from the diagnostic wire when the 1988 engine was standing. Now the motor is 1998 and the standard is J1850 VPW.
Thank you.


I found a project on the forum that should solve my problem. But he does it with the help of Arduino and takes the signal from the ICM. I did so used his code. But for some reason the indicator is incorrect for 800 singles instead of 2200. That is why other options are of interest.
http://www.gearhead-efi.com/Fuel-Inj...-project/page2

[steveo]

oh it's totally possible to make such a thing
i would use something like a raspberry pi and some off the shelf hardware to make it easy
the raspberry pi would run linux or whatever and would simplify things since you could use a store bought ELM interface for the J1850 VPW side and then you could use any old FDTI TTL chip of the 8192 side
of course it could do much more than just your tach
a simple program running in a loop could become bus master and transmit the ALDL message of your choice while also querying the OBD-II bus at the fastest rate possible
i've done stuff like this lots but to get it done you have to have some basic coding skills

[steveo]

of course i am a seasoned programmer with experience in ELM and 8192 baud ALDL protocol stuff, not sure what your skill level is

[rostkov]

Unfortunately, I do not write programs and codes, but I have a son who understands what needs to be done).
Maybe there are ready-made solutions or programs that can help. Maybe this device?
https://www.sparkfun.com/products/9555
SparkFun OBD-II UART