In fact we even made some simple modifications to the Arduino IDE so that it works like a mini-Arduino board. We designed a USB bootloader so you can plug it into any computer and reprogram it over a USB port just like an Arduino. The Attiny85 is a fun processor because despite being so small, it has 8K of flash, and 5 I/O pins, including analog inputs and PWM 'analog' outputs. It's our lowest-cost arduino-IDE programmable board! Perfect for when you don't want to give up your expensive dev-board and you aren't willing to take apart the project you worked so hard to design. We wanted to design a microcontroller board that was small enough to fit into any project, and low cost enough to use without hesitation. Trinket may be small, but do not be fooled by its size! It's a tiny microcontroller board, built around the Atmel ATtiny85, a little chip with a lot of power. It has built-in USB, more capabilities, and is comparable in price! So while we still carry the Trinket so that people can maintain some older projects, we no longer recommend it.

Deprecation Warning: The Trinket bit-bang USB technique it uses doesn't work as well as it did in 2014, many modern computers won't work well.

Underclock adafruit trinket 5v