Need a bit of help here( i'm a mech engineer so i'm right out of my depth please be gentle).
Need to find a way of turning on a LED through about 6mm of glass. was originally going to use a reed switch but that will conflict with other functions.
was thinking along the lines of some sort of induction/ transponder sort of thing. LED can have an active supply. Button cell battery would be ideal to keep size of component down.
Any ideas would be really wecome.
regards