Credit card crystal radio
What do you think about the feasibility of a credit card sized crystal radio? (Fits inside a wallet)
Some possible i though so far are...
A simple pcb with a diode, and a capacitor and a coil wrapped(protected by duct tape) around it.
The antenna has to be tied to a hole on a corner. Or it is coiled to the card, ready to be unwrapped.
The ear piece can either be external... Or can be glued to the card itself, but you must put the card near you ear...
Instead of a winded coil, maybe it can be part of the pcb design itself... and to tune it, you unhook a beady wire and place it in the holes placed in a interval.
What do you think? Any more ideas?
In fact. a competition can be made for this idea.