Cable harness tester with 3 connectors (<30 test points)

[sahbi97]

Hey everyone, I'm still struggling with implementing the resistance test for my project.it's the only part I haven’t been able to figure out yet. I think the issue is mainly with the hardware setup.

I was considering adding a dedicated push button specifically for triggering the resistance test, but I’m not sure how to make it work. Someone suggested connecting a 100-ohm resistor to ground through the sender multiplexer, but I’m still confused about how to proceed.
Schematic_DIY-Harness-Tester_2025-04-17.pdf (83,4 Ko)

[LarryD]

• Sorry, you are just not paying attention to even the basic things.

• Post #44 is a functional working example, put the effort in and learn from it.

• You are making serious mistakes and are not taking direction.
  Stop and clean up all your mistakes before proceeding.

• Your schematic needs to be accurate, these connections make no sense.
  

  
  
  
  
  
  
  

[STEFANIUC]

I used a Mega with extensions, MCP23017, 3 of them. My tester is now 6 years in production.

Check 24 wires/ connection, the first 6 conection, are singel of multi conection ( Y ), max 4 / connection, marking the harness, locking too…. Arduino Mega ADK ( scanning labels ), FRam ( count harness made ), 3 X Mcp 23017, 24 Adafruit LED’s ( data in/out ), 4X20 LCD, and of course conectors, to connect test bord with tester