I do not plan on running any more batches of this board. The design is open (see links below), and you can buy the remaining PCBs that I still have here. Thank you for your interest!

What is it?

It's a SMT kit for a small programmable USB stick (ATMEL's xmega chip), which can be used as an encrypted microSD storage, or as a Rubber Ducky (i.e. emulate a keyboard and/or mouse and emit a sequence of keypresses/mouse movements), or a mood light.

If you don't want to go into SMT soldering, already soldered (by me), ready-to-use sticks are available as well (it might take a few days though).

Some notes about soldering the stick can be found the in the documentation --->

Features

• ATMEL's ATxmega128A4U (128kB flash + 8kB boot section, 8kB SRAM, 2kB EEPROM, up to 32MHz), DFU bootloaded.
• microSD socket (hinged)
• RGB led
• two pushbuttons: one triggers RESET and the other one is routed to xmega's general pin
• a reasonable amount of xmega's pins are routed to standard 2.54mm PTH holes (all pins from analog PORTA, digital PORTC, plus two DAC pins, pins for PDI programming and crystal)
• onboard 250mA 3.3V voltage regulator with a PTC fuse

It is designed to be hand-soldered (I soldered it with just a regular soldering iron and liquid flux :) The smallest parts are 0805, and the xmega comes in TQFP-44 package with 0.8mm pitch.

Firmware

The above mentioned firmware are in development. You're welcome to fork/contribute. Current status:

• The enstix firmware to use it as an encrypted microSD storage works. Note that the speeds are quite slow (I'm getting 130kB/sec for reading), so perhaps it's not so good for large backups.
• The Rubber-Ducky-alike firmware only does keyboard (no mouse yet), and it only emits text found in a file on the microSD card (i.e. no modifiers, delays, etc... yet).
• Mood light works.
• Another possibility for use (firmware doesn't exist yet) is as an authentication stick, a-la YubiKey.

Of course, to get the most fun out of this stick, you should write some firmware yourself! The chip is supported by avr-gcc (windowed people can use WinAVR) and Dean Camera's incredible LUFA library for USB functions. Alternatively, you can use ATMEL studio on windows.

The ATxmega comes with ATMEL's DFU bootloader preprogrammed, and it is triggered by pressing the general purpose button during startup (power up or reset). So after it's soldered, you can just plug it into the computer and program it, no external programmer needed.

The through-hole pads with standard spacing make it easy to extend the functionality on a breadboard, or with a "shield".

Why did I make it?

I wanted an USB stick that has a microSD socket and a chip which is easily programmable using avr-gcc and has a native USB capability, so that I can use it as open source/hardware encrypted usb stick. I decided to use ATxmega (as opposed to atmega32u4 or similar), since it's cheaper, accessing a microSD card is much faster, and it has hardware AES-128 encryption. And programming it is not that different from the popular atmega series / Arduino.

What makes it special?

• It has an xmega chip (almost as easy to program as atmega??U? (known from Arduino, Teensy, ...), but more powerful, AES, DAC, ...).
• It has a microSD socket and a RGB LED.
• It plugs directly into a USB socket.
• It's small.
• It's doesn't need any external programmer.
• It's easily extensible via headers with standard spacing (and e.g. a piece of protoboard).
• It's hand-solderable.
• It's relatively low-cost.
• It's open hardware (EAGLE files here and schematic here).

What do you get?

The kit comes with all the electronic parts needed to make the stick. You'll need your own soldering iron, solder and flux.

List of parts

• 1x blue 1.6mm thick PCB
• 1x ATxmega128A4U in TQFP-44 package (preprogrammed with DFU bootloader and ubiquitous "blink" firmware)
• 1x male USB A through-hole connector
• 2x SMT pushbutton
• 1x microSD socket
• 1x RGB LED (1210)
• 1x 250mA PTC fuse (1206)
• 1x 3.3V 250mA voltage regulator (MCP1703 in SOT-89 package)
• 3x 1kR resistor (0805)
• 4x 0.1uF ceramic capacitor (X7R, 0805)
• 1x 0.1uF ceramic capacitor (X7R, 1206)
• 1x 1uF ceramic capacitor (X7R, 0805)
• 1x 10uF ceramic capacitor (X7R, 1206)
• 1x 22uF ceramic capacitor (X7R, 1206)
• 1x ferrite bead (220R@100MHz, 0805)