RFID 125kHz tags reader. Reader is attached to soundcard's line-in input. Shows 32bit(16bit.16bit format) number stored onto cards data area.
Adapter is powered from USB +5V supply line, no direct USB connection is used. Signal output is going to soundcard.
Does not work without external hardware.
Reader variant 1:
Reader variant 2:
PC software, Win32, EXE file
Microchip sourcecode, ASM file
Microchip code, HEX file
NB! Code might need some OSCCAL manipulation/tune-up to get out of chip a frequency exactly of 125kHz.
Pictures here below do show some experimental RFID cards in development/prototyping stage. Don't take it seriously. Just examples how it is possible to start to develop your own cards in small format.