Adafruit PocketBeagle - Pocket Size BeagleBone Linux Computer [ADA4179]
Want a powerful 1GHz AM3358 powered Linux single board that's ultra-tiny and open-source? PocketBeagle offers a wealth of computer power in a small footprint (pawprint?). This board is just like the BeagleBone Black but small enough to fit in your wallet. It has a fully-integrated chip that combines the processor and RAM all on one chip, so it's super small. Despite the compact shape, there are 72 total breakout pads, a microSD card slot for your filesystem and OS, and a native USB connection
Compared to other single board Linux computers, what differentiates the BeagleBone is that it has multiple I2C, SPI and UART peripherals (many boards only have one of each), built in hardware PWMs, analog inputs, and two separate 200MHz microcontroller system called the PRU that can handle real-time tasks like displaying to RGB matrix displays or NeoPixels .
It's not too much larger than our Feathers , but comes with 72 expansion pin headers, high-speed USB, 8 analog pins, 44 digital I/Os, and plenty of digital interface peripherals.
You can also add a USB host connection by wiring a USB A socket to the broken out USB host connections labeled VI, D+, D-, ID and GND. Then plug in any USB Ethernet, Bluetooth, and Wi-Fi device with available Linux drivers.
You will need to also pick up an SD card, at least 4GB in size, to burn on the Debian operating system - there's no built-in storage.
Get started over at the BeagleBoard site where they have quick-start tutorials, operating system images, and even some projects to inspire your first build.