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. So while we still carry the Trinket so that people can maintain some older projects, we no longer recommend it.Please check out the Trinket M0.It has built-in USB, more capabilities, and is comparable in price!

The 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. 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 expensive dev board and you aren’t willing to take apart the project you worked so hard to design. It’s our lowest-cost Arduino-IDE programmable board!

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. In fact, we even made some simple modifications to the Arduino IDE so that it works like a mini-Arduino board. You can’t stack a big shield on it but for many small & simple projects, the Trinket will be your go-to platform.

This is the 5V Trinket. There are two versions of the Trinket. One is 3V and one is 5V. Both work the same but have different operating logic voltages. Use the 3V one to interface with sensors and devices that need 3V logic, or when you want to power it off of a LiPo battery. The 3V version should only run at 8 MHz. Use the 5V one for sensors and components that can use or require 5V logic. The 5V version can run at 8 MHz or at 16 MHz by setting the software-set clock frequency.

Note: Breadboard is NOT included

Even though you can program Trinket using the Arduino IDE, it’s not a fully 100% Arduino-compatible. There are some things you trade off for such a small and low-cost microcontroller!

• Trinket does not have a Serial port connection for debugging so the serial port monitor will not be able to send/receive data
• Some computers’ USB v3 ports don’t recognize the Trinket’s bootloader. Simply use a USB v2 port or a USB hub in between

Here are some useful specifications!

• 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 when you want to reprogram.
• We really worked hard on the bootloader process to make it rugged and foolproof, this board won’t up and die on you in the middle of a project!
• ~5.25K bytes available for use (2.75K taken for the bootloader)
• Available in both 3V and 5V flavours
• 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. 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 analogue 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! Yeah!
• Really really small

For a lot more details, including a tour of the Trinket, pinout details and Arduino IDE examples, check out the Introducing Trinket tutorial

Revision History

• As of August 1st, 2024 We updated this PCB withAdafruit Pinguinto make a lovely and legible silkscreen – you may get the new PCB or the older version with vector fonts – both are identical other than the fancy silkscreen.

Specifications

• Dimensions: 31mm x 15.5 x 5mm
• Weight (no headers): 1.85 grams

Resources

• Tutorial and Downloads

Deprecation Warning: The Trinket bit-bang USB technique it uses doesn’t work well on many modern computers. We no longer recommend it; consider the Trinket M0 for better capabilities and built-in USB.

The Adafruit Trinket is a tiny yet powerful microcontroller board based on the Atmel ATtiny85. Designed to be small and low-cost, it fits into any project without sacrificing functionality. It is ideal when you want a compact and affordable Arduino-IDE programmable board.

The ATtiny85 features 8K of flash memory, 5 I/O pins including analog inputs, and PWM outputs. The USB bootloader allows programming over USB like an Arduino, making the Trinket a mini Arduino board for simple projects.

Key Features:

• ATtiny85 microcontroller with 8K flash, 512 bytes SRAM, 512 bytes EEPROM
• Internal oscillator at 8 MHz, configurable to 16 MHz via software
• USB bootloader with LED indicator for easy programming
• Micro-USB connector for power and programming
• On-board 3.3V or 5.0V regulator with 150mA output
• Automatic power switching between USB and external power
• Reset button to enter bootloader or restart
• 5 GPIO pins (2 shared with USB), including analog inputs and PWM outputs
• Hardware I2C and SPI support for sensor interfacing
• Compact size with mounting holes

This is the 5V version of the Trinket, capable of running at 8 MHz or 16 MHz. The 3V version is also available for 3V logic applications.

Limitations:

• No serial port support – no serial debugging capability
• USB v3 ports on some computers may not recognize the bootloader; use USB v2 or a USB hub instead

The board dimensions are 1.2″ x 0.6″ x 0.2″ (31mm x 15.5mm x 5mm) and weight is approximately 1.85 grams (without headers).

For more detailed information including pinouts, tutorials, and programming examples, see the Introducing Trinket tutorial.