bperrybap:
In the bigger picture, i'm not sure why you are not worried about shorts in your cables, as a true cable tester should test for both continuity of each wire as well as any shorts between wires.
And as a true aid, it would be useful to indicate which wire(s) has the issue(s).like mentioned above, I'd use arduino "output" pins to detect continuity and shorts rather than full voltage.
However, to avoid any high current issues,
i'd use arduino pins in INPUT_PULLUP mode and then drive the Arduino "output" pin connected to the wire low to test for continuity.
I'd also never use high outputs.
i.e. I'd change the pin connected through the wires connected to the input pins between OUTPUT and INPUT_PULLUP
that will change the signal from driven high to pulled up.
There is no need to actually use digitalWrite() as the default bit state in the register is zero.
Simply changing the mode will flip between the two states.The input pins will then see a LOW when the "output" pin is set to OUTPUT mode and HIGH when the "output" pin is set to INPUT_PULLUP mode -or- there is no continuity like a broken wire.
You can easily detect the difference between the "output" being INPUT_PULLUP and a broken wire because if you see the input drop low when the "output" pin is set to OUTPUT, then you know there is continuity.This avoids any type of short issue and there is never any signal driving 5v on the wires.
--- bill
This sounds like good stuff. I'm new to arduino and have only 1 semester of programming in c++ so I'll have to do some reading on what all that means.
I'm not sure why they don't care about shorting (this is for work) but if I can detect shorts and also detect which wire is giving a continuity issue that's a bonus. I've thought about it myself just wasn't sure how I'd make it work.
Thank you all for your help and ideas.