Hybrid Instrument Cluster - I need help
 

Hey guys,

Im currently trying to build a hybrid instrument cluster. I want to remove the three small gauges and replace them with small displays. The goal is to read all data (at least to begin with) from the back of the cluster. I want this to run in a stock Miata NB (thats what I drive).
But I got a problem: I suck at electrics. Im currently trying to design/create a pcb on which I mount my Arduino & RaspberryPi, connect all the inputs to and do the electrical conversions needed, so I can read the data with my Arduino. I am able to create some simple voltage dividers n stuff but thats it.
I need help with creating (and validating) the circuits. Is somebody on this forum that is skilled with creating circuits, finds the project interesting and wants to help me? I would appreciate that because alone I will take forever to finish this...

It would be nice if that person lives somewhere in europe because of the time zones (Im living in germany) but I take everybody that is willing to help!

Thanks :)