What's smaller than a Feather but larger than a Trinket? It's an ItsyBitsy! Small, powerful, Arduino-compatible - this microcontroller board is perfect when you want something very compact, but still with a bunch of pins.
ItsyBitsy is only 1.4" long by 0.7" wide, but has 6 power pins, 6 analog & digital pins and 17 digital pins. It packs much of the same capability as an Arduino UNO. So it's great once you've finished up a prototype on a bigger Arduino, and want to make the project much smaller.
The ItsyBitsy 32u4 5V 16MHz uses the Atmega32u4 chip, which is the same core chip in the Arduino Leonardo as well as the same chip we use in our Feather 32u4. It runs at the same speed and voltage of an Arduino UNO or Leonardo. So you'll be happy to hear that not only is ItsyBitsy programmable using the Arduino IDE as you already set up, but a vast number of Arduino projects will work out of the box!
We recommend this as an upgrade from the Pro Trinket 5V because this has native USB so it will work with all computers, USB serial debugging, and a more reliable bootloader. You can even use the Pro Trinket LiPo backpack with this board to add recharge-able battery.
Here's some handy specifications: