Adafruit
Adafruit Trinkey QT2040 - RP2040 USB Key with Stemma QT
The Adafruit Trinkey QT2040 is an RP2040-based microcontroller that plugs directly into any USB-A port on your computer or laptop. With a STEMMA QT / Qwiic c...
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The Adafruit Trinkey QT2040 is an RP2040-based microcontroller that plugs directly into any USB-A port on your computer or laptop. With a STEMMA QT / Qwiic connector on the end, it turns any I2C sensor or accessory into a plug-and-play USB device — no breadboard or soldering required.
The board features an RP2040 dual-core Cortex M0+ processor running at ~125 MHz, 264KB RAM, and 8MB of QSPI flash for storing CircuitPython code and files. An RGB NeoPixel, reset button, and bootloader/user button round out the compact design. The main body matches the size and mounting holes of most STEMMA QT boards (1.0" × 0.7"), so you can stack a sensor board directly on top.
Key Features
- USB-A Plug-In Design – Extra-thick PCB slides directly into any USB-A host port
- RP2040 Processor – Dual-core 32-bit Cortex M0+ running at ~125 MHz, 3.3V logic
- 264KB RAM + 8MB Flash – Plenty of space for CircuitPython code, files, images, and fonts (~7MB usable with Python)
- STEMMA QT / Qwiic Port – Solderless I2C connector compatible with SparkFun Qwiic and hundreds of sensors and accessories
- Native USB – USB serial console, MIDI, keyboard/mouse HID, and USB mass storage
- CircuitPython & MicroPython – Ships ready for CircuitPython; also supports MicroPython and C/C++ via the Pico SDK
- Built-in RGB NeoPixel – Programmable status indicator
- Reset + Boot/User Button – Quick restarts and bootloader entry; boot button also usable in user code
- 3.3V Regulator – 600mA peak output
- Stackable Form Factor – 1.0" × 0.7" with M2.5 mounting holes matching most STEMMA QT boards
Ideal For
- Plug-and-play USB sensor devices
- Custom USB HID devices (keyboards, macros, MIDI controllers)
- Quick I2C sensor prototyping without a breadboard
- CircuitPython learning and experimentation
- Compact USB dongles and tools
Package Contents
- 1× Adafruit Trinkey QT2040 (with CircuitPython pre-loaded)
Resources
Jargon buster
Plain-language definitions for the technical terms used above.
- 3.3V regulator
- A 3.3V regulator is a power circuit that provides a steady 3.3 volts for parts that need that supply voltage. On a breakout board, it can let the sensor run safely even when the connected microcontroller or power source uses a higher voltage.
- Bootloader
- Small starter software on a microcontroller that lets new code be uploaded before the main program runs. Knowing how to enter bootloader mode matters when you need to program the board or recover it after a faulty sketch.
- CircuitPython
- A beginner-friendly version of Python designed to run directly on microcontroller boards. If a product supports CircuitPython, you can often program it by copying code files onto the board rather than setting up a more complex toolchain.
- HID
- Human Interface Device is a USB device class used for keyboards, mice, gamepads and similar controls. If a board supports HID over USB, it can act like an input device to a computer without needing a custom driver.
- I2C
- I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.
- M2.5
- A metric screw thread size with a 2.5 mm nominal diameter. It matters for mounting because screws, standoffs, and holes must use the same size to fit securely without damaging the board.
- microcontroller
- A microcontroller is a small computer on a single chip that runs a stored program and controls connected inputs and outputs such as buttons, sensors, displays and communication interfaces. In a device built around one, it is the part that executes the code and coordinates the device's behaviour.
- MicroPython
- A version of the Python programming language made to run on microcontrollers. It matters because it lets beginners write readable code to control LEDs, sensors, motors and displays without needing to start with lower-level languages.
- MIDI
- MIDI is a standard way for electronic instruments, controllers, and software to send musical control messages such as notes, velocity, and timing. If a board supports MIDI, it can be triggered from keyboards, drum pads, sequencers, or other music gear rather than only from buttons or code.
- native USB
- Native USB means the microcontroller itself handles USB communication, rather than using a separate USB-to-serial chip. This matters for programming, debugging, and projects that need the board to act directly as a USB device.
- NeoPixel
- A type of addressable LED system where colour data is sent along a single digital data line from one LED or controller to the next. Compatibility matters because the timing and signal format must match for the lights or driver board to respond correctly.
- PCB
- A printed circuit board (PCB) is a board, usually rigid, with etched copper tracks that connect electronic components together without loose wiring. Components are mounted on the board and signals route between them through the copper layout.
- Qwiic
- Qwiic is a plug-in connector system for I2C devices that uses small 4-pin cables, so you can connect compatible sensors without soldering. It matters because your controller or adapter also needs Qwiic, or you will need a cable or breakout to wire it up.
- RAM
- RAM (random-access memory) is fast, temporary memory a device uses for working data while it is running; in its common volatile form, its contents are lost when power is removed. Some devices offer a mode that applies settings to RAM only, which is handy for testing changes temporarily because they are not stored permanently and disappear at power-off.
- RGB
- Short for red, green and blue, the three primary colours of light that are mixed in varying amounts to make a wide range of colours. In electronics RGB can refer to an LED or pixel that blends these three colours, or to a colour signal or interface that carries separate red, green and blue channels.
- RP2040
- The RP2040 is a dual-core Arm Cortex-M0+ microcontroller chip from Raspberry Pi, used on many maker boards and offering programmable I/O, multiple GPIO pins and reasonable processing speed. Code and accessories built for that chip should work where RP2040 compatibility is listed, though demanding tasks such as reading a camera can require careful pin allocation and timing.
- STEMMA
- A plug-and-cable connection system used on some maker electronics boards to make wiring simpler. If a product uses STEMMA, you need the matching cable or connector type to plug it in without soldering.
- STEMMA QT
- A small plug-in connector system for I2C boards that lets you connect compatible sensors and controllers without soldering. It matters because it can make wiring faster and less error-prone, especially when adding several small modules to a project.
- USB mass storage
- USB mass storage is the standard USB device class used by many flash drives and external storage devices. If a board supports it, your project may be able to read and write files on compatible USB storage, provided the software library also supports the device.
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welcome to circuitpython
Circuit Diagram · 10.6 MB · Click any page to view full size
introducing adafruit stemma qt
Document · 1.5 MB · Click any page to view full size
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