Old Harley diagnostic tool, Input Questions/Suggestions

Looking for Suggestions and ideas to my upcoming project, as well as some questions.

I'm starting to design (in thought process currently) a diagnostic tool for my '76 Harley Shovelhead (FXE).

Plan is to permanently install on the bike a Arduino Pro Mini 5v. The Mini would read realtime signals from 5 different parts of the bike, then display via 16X2 LCD. (eventually via bluetooth to android phone in future design).

The LCD would have 3 screens to scroll through:

Screen 1 1rst line: "Battery Status: 'X'V" (X = Displays Voltage in battery and charging system) 2nd line: "Battery Charge: 'Y'A" (Y = Displays Amps in Charging system)

Screen 2 1rst line: "Coil 1: 'A'A" (A = Displays Amps in front cylinder coil input or coil 1) 2nd line: "Coil 2: 'B'A" (B = Displays Amps in rear cylinder coil input or coil 2)

Screen 3 1rst line: "Tachometer: 'C'RPM" (C = Displays RPM from Coil Pack)

Power supply will be provided by the bikes internal charging system. 12vDC to 5vDC. No, i'm not using the vRaw IN on the Mini, I'm going to build a regulator to even the voltage from the inconsistent output of the mid '70's Harley generator.

The power supply, LCD display, LCD scroll - Hardware and software I don't have a problem setting up.

What I am unsure about

  • Taking readings from an operating Motorcycle
  • Battery readings are not too much a concern
  • Coil and tachometer reading from the bike, I'm not sure how to safely convert those to a readable signal without, one frying the Mini, two damaging the coil pack and/or tach

I'm sure given enough time I can figure it out, however, input is always nice.

All of those have been discussed on this forum: powering from and interfacing to a road vehicle; instrumenting a vehicle; measuring RPM; displaying results on an LCD. Spend some time with Google searching this forum.

Blink-without-delay will be a welcome companion on your journey. An understanding of finite state machines will be a good map to your destination.

The more specific the question the better the answers.

Even prior to posting this, I was looking at other forums and doing research. I think I'm more just looking to see if anybody had different and unique ideas.

I will investigate the "Blink-without-delay,"

Thank you, I appreciate your help

You are welcome.

@Robin2's variation with discussion is available at the top of this forum section...