Saw one of these at Active Surplus for $1.50, so I figured, for the price, why not grab one: **broken link removed**
How would I interface it to a PC? Ive looked at tutorials for making readers, but they all suggest using a TTL reader - Im assuming that Im missing this circuitry. Is it feasible to build a DSP to read from the reader, or am I better off just buying a better one off eBay (for what it would cost me to make a DSP).
I recollect that you can treat this like the playback head on a magnetic tape player, you know the kind that plays music (I'm old). The head is a magnetic transducer and needs a low noise preamplifier to boost its output. The magnetic info is probably written onto the card with an AC bias, but I think the read head can ignore this bias. I'm not sure if the playback head needs any DC bias or not, but it can't hurt to just experiment to see. So, the main job is to attach a low noise amplifier to boost signal that you get from the head. Once you have a strong enough signal, you can observe it on a scope and you will see a data waveform. Next you have to figure out how to decode the data.