Well... you could read the mag value, and use pwm to pulse the led depending on the value of mag, so the stronger would make a led brighter.
Set it up so it does this with a setwatch on the button....
That was what my friend thought: WIP, he just got the puck.js so he has a learning curve where in the first test, he couldn't get it to work
I post results if he gets it to work
It's likely only to work if there is current flowing through the wire (= a magnetic field) - if it's just electricity it could be more difficult.
I gave a friend who is retiring ... a puck.js (there is no un-selfish act: I want him to do things for me).
However, he did ask "Can it be used to trace electrical wiring in a wall?"
I said ... dunno
In case someone has the answer, I ask here.