We wanted to design a microcontroller board that was small enough to fit into any project, and low cost enough to use without hesitation. Perfect for when you don’t want to give up your Flora and you aren’t willing to take apart the project you worked so hard to design. It’s our lowest-cost sewable controller!
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. We designed a USB bootloader so you can plug it into any computer and reprogram it over a USB port just like an Arduino (it uses 2 of the 5 I/O pins, leaving you with 3). In fact we even made some simple modifications to the Arduino IDE so that it works like a mini-Flora. Perfect for small & simple projects the Gemma will be your go-to wearable electronics platform.
Here are some useful specifications!
Super small, only 1.1″ / 28mm diameter and 0.28″ / 7mm thick.
Easy-to-sew or solder pads for embedding in your wearable project
Low cost enough, you can use one for every weekend project
ATtiny85 on-board, 8K of flash, 512 byte of SRAM, 512 bytes of EEPROM
Internal oscillator runs at 8MHz
Ultra low power, draws only 9 mA while running
USB bootloader with a nice LED indicator looks just like a USBtinyISP so you can program it with the Arduino IDE (with a few simple config modifications)
Mini-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.
We really worked hard on the bootloader process to make it rugged and foolproof
~5.25K bytes available for use (2.75K taken for the bootloader)
On-board 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.
3 GPIO – The 3 independent IO pins have 1 analog input and 2 PWM output as well.
Hardware I2C capability for breakout & sensor interfacing.
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.