ebay - cardamatic

[Tom Jennings]

On Sun, 13 Feb 2005, Geoff Reed wrote:

> isn't it just conductive traces on plastic?

You computer people, you so advanced!


Nope. Plastic card (credit card thickness, or less) with
pencil-sized holes in it. The "reader" is a matrix of electrical
contacts. You shove the card in it, it insulates the non-punched
contacts. Simple!

Alas, hard to reproduce the cards automatically. Easy with a hand
punch though.