The SD2IEC is a mass storage device using an SD/MMC card and interfacing with the IEC bus. It is based on the ATmega644 microcontroller from the Atmel AVR microcontroller family. The most prominent use of SD2IEC is as a substitute to Commodore-1541 disk drive for a C64 but it also works with other Commodore line of computers. The hardware and the microcontroller sd2iec firmware are available as open source (GPL).
This is the external version of this famous device and is powered by a standard USB phone charger that everyone has at home nowadays. You can use any USB mobile phone charger that outputs 5V and has a micro USB plug. SD2IEC devices sold by other manufacturers draw power from USER or JOY ports effectively blocking them in effect. You will not have this problem with USB powered SD2IEC.
This SD2IEC version is described in details at retrohax.net blog section