Built myself a neat converter today :-)
A while back I spotted some console hack dongles on
sale for only $10, that have ATmega32U4 chips in them. I bought two, but unfortunately one was DOA. Oh well. The other one works fine. There's a
schematic for it.
It started off looking like this inside...
Then I...
Removed the card socket.
Removed the 3.3V regulator and replaced it with a bit of wire, so that everything was running at 5V.
Soldered some thin single core wire to two pins on the chip for data and clock, and two SD card socket pads for power and ground.
Used hot glue to (hopefully) keep them from coming loose.
Cut the trailing socket from a PS/2-USB adapter (a crappy Belkin that kept reconnecting).
Put some heatshrink on near the end of it to stop it pulling out of the case.
Joined it up to the single core wires, with heatshrink on each connection.
Filed a hole in the case for the cable exit.
And ended up with this...
:-)