E-Ink (or LCD?) keychain fob

(or: one fob to rule them all)

problem: too damned many keychain fobs for all the supermarket and other retail discount clubs

each one is designed to be nothing more than advertisement on one side (store logo) and a bar code on the other.

solution: electronic keychain that can be programmed to display a store’s logo and discount club’s UPC code. a small LCD might work, but would be difficult to properly scan with bar code scanner. plus, LCDs drain batteries whenever they’re on.

something like electronic ink would work better. it’s more reflective, only uses batteries when changing the pixels, and the display only needs to be black and white, so why bother with LCD?
(http://www.eink.com/)

the whole thing could be really tiny, needing only the controls to scroll through the programmed UPCs, the display itself (maybe .5′’ x 1.25′’), a small battery and a mini-USB port (for plugging into a computer to program in the UPC codes).

anybody want to build me one? my keychain’s getting a little cramped.

westfw10 years ago
My most common supermarket (Safeway) allows you to enter your phone number instead of having to carry the card or fob around. There would be an interesting intermediate step of a multi-card; several barcodes simply printed on a credit-card size thing with some sort of sliding window to expose the proper code... Or, how about a palmtop (or phone?) app?