SparkFun Redstick

The RedStick combines some of our favorite features such as the Optiboot bootloader of the Uno, FTDI, its small size, and the ability to plug directly into a computer's USB port (no FTDI board or USB cable required).

The RedStick can be programmed simply by plugging the board into your computer using the Arduino IDE: just plug in the board, select "Arduino UNO" from the menu, and you can upload your code. The RedStick also includes the usual hardware features: 14 digital I/O pins with 6 PWM pins, 8 analog inputs, UART, SPI, I2C, and external interrupts. All of this is housed in a tiny case that can be plugged directly into your computer.

You can power the SparkFun RedStick via the USB connector or through the power input (which supports a JST connector for a single-cell LiPo). The built-in boost circuit can regulate anything from 2-6V. While the board does not have a battery charger, it can be powered by a single LiPo cell or even 2 AA batteries.

Features:

* A boost regulator that powers the Atmega328p with 5V from an input voltage range of 2 to 6 volts.
* 16 MHz system clock (enabled by the additional supply voltage).
* Uno-compatible in the Arduino IDE. Just select the "Arduino/Genuino Uno" board and go!
* The USB end conforms to standard USB thickness and width.