I have been searching the Internet for a sensor that can read the magnetic field strength variations on a magnetic strip of cards.
I also wanted to read the magnetic field changes on an (audio) tape, not to render it in high detail, but to encode data on it with a magnet, then try to read it back. Low spatial resolution is fine.
Now I could use the head from a tape recorder, or disassemble a magnetic card reader, but what I am really after is some basic modern component, that can read magnetic fields, like a hall sensor.
The only issue with hall sensors I could find so far, is they all seem to lack the ability to sense such weak magnetic fields, even with amplification.
What are the sensor components in magnetic stripe card readers? Does anyone have a specific recommendation?
Alas it's not a simple case of using a normal hall sensor as it needs to be very sensitive and needs flux guards to limit the detection area to a very small area so it only reads one bit at a time instead of several either side of the required bit.
You would be better off using the purpose designed sensors.
I doubt a solution with a modern general purpose sensor and some custom housing or whatever you plan for it will ever give better results, or even be able to match, a purpose built part designed 20 years ago. On top of that, the old purpose built part is sure to do the job. Your DIY contraption may or may not work and in any case take many hours to build.