Adafruit Trinket - Mini Microcontroller - 3.3V Logic - MicroUSB
➤ ATtiny85 on-board, 8K of flash, 512 bytes of SRAM, 512 bytes of EEPROM
➤ Internal oscillator runs at 8MHz but can be doubled in software for 16MHz
➤ USB bootloader with a nice LED indicator looks just like a USBtinyISP so you can program it with AVRdude (with a simple config modification) and/or the Arduino IDE (with a few simple config modifications)
➤ Micro-USB jack for power and/or USB uploading, you can put it in a box or tape it up and use any USB cable for when you want to reprogram.
➤ ~5.25K bytes available for use (2.75K taken for the bootloader)
➤ Onboard 3.3V or 5.0V power regulator with 150mA output capability and ultra-low dropout.
➤ Up to 16V input, reverse-polarity protection, thermal and current-limit protection.
➤ Power with either USB or external output (such as a battery) - it'll automatically switch over
➤ On-board green power LED and red pin #1 LED
➤ Reset button for entering the bootloader or restarting the program. No need to unplug/replug the board every time you want to reset or update!
➤ 5 GPIO - 2 shared with the USB interface. The 3 independent IO pins have 1 analog input and 2 PWM output as well. The 2 shared IO pins have 2 more analog inputs and one more PWM output.
➤ Hardware I2C / SPI capability for breakout & sensor interfacing.
➤ Works with many basic Arduino libraries including Adafruit Neopixel!
➤ Mounting Holes
➤ Really really small
➤ Dimensions: 1.1" x 0.6" x 0.2" / 27mm x 15 x 4mm
➤ Weight (no headers): 1.85 grams