Quick Tip: Tracing PCB Tracks with an Aluminum Finger

Quick Tip: Tracing PCB Tracks with an Aluminum Finger


What a great idea! I just discovered this very clever way of of tracing connections on a printed circuit board on Instructables, from 2012. Rather than having to probe every single solder/contact point on a board, Instructable user “hertzgamma” starts out with a special fingertip testing probe, made out of a wire attached to a clip on one end and some aluminum foil on the other (wrapped around his fingertip).

Clipping this makeshift tester to a multimeter probe needle, he then places one probe on a contact point of the PCB and then tests areas of the board with his finger probe until he gets a signal. When he does, he simply switches to the normal needle probe and begins testing the contacts in that area until he finds the correct trace. Voilà. Easy-peasy, lemon-squeezy and why didn’t I think of that?

The above videos and description tell you pretty much all you need to know, but there is an Instructable that goes into a bit more detail. Also, see the comments on the Instructable post for cautions about capacitors, shorting and shock risk, and some additional tweaks to the design which could be useful.


Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. And he has a new best-of writing collection and “lazy man’s memoir,” called Borg Like Me.

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