I actually read your thing a long while ago too! I took it a step further, and made a small coil and amp, and played the recorded data back through the coil, an

I actually read your thing a long while ago too! I took it a step further, and made a small coil and amp, and played the recorded data back through the coil, and placed the coil next to a one-track card reader. It actually worked, which was neat.