# Using the TRRS Trinkey as an Assistive Technology Device ## Introduction ![](https://cdn-learn.adafruit.com/assets/assets/000/130/910/medium800/customer___partner_projects_TRRS_Trinkey_5954-05.jpg?1719507566) Giving a disabled person the ability to use a mouse and keyboard on a PC is one of the most important pieces of assistive technology we can create. Many disabled people use pushbuttons or other devices known as an AT Switch. These devices have a 3.5 mm mono jack on the end. One of the easiest ways to connect multiple switches to an assistive technology device is using the TRRS plug and jack. This gives us four conductors that we can connect to the microcontroller. In this circumstance, we have three buttons plus a common ground. The TRRS Trinkey was specifically designed with assistive technology devices in mind. You can easily connect from 1 to 3 AT Switches to the device and use it for a variety of purposes. The great thing about this board is that it also has a STEMMA QT connector that allows us to connect other devices to the board. In this tutorial, we will connect a small OLED display that can be used as a virtual keyboard and mouse display. Using the AT Switches, a user can navigate a cursor around the display and type on a virtual keyboard. They can also move the mouse in any of eight directions, click any of the three mouse buttons, and operate the scroll wheel. The TRRS Trinkey can also be connected to a phone or tablet with an OTG adapter to allow switch control access to touchscreen devices on iOS and many Android devices. The original learning guide for the TRRS Trinkey has a simplified switch control application in both Circuit Python and Arduino versions. However, here we will present an advanced version of the application for Arduino that allows you to use multiple simultaneous keypresses to get even more capability out of the device. - [Next Page](https://learn.adafruit.com/using-the-trrs-trinkey-as-an-assistive-technology-device/parts-list.md) ## Guide Products ### Adafruit TRRS Trinkey - USB Key for Assistive Technology [Adafruit TRRS Trinkey - USB Key for Assistive Technology](https://www.adafruit.com/product/5954) It's half USB Key, half TRRS breakout_... _it's the  **Adafruit TRRS Trinkey**  specifically designed for Assistive Technology hackers and creators as a simple and low cost, but also flexible and extendable AT device.  Many AT interface... In Stock [Buy Now](https://www.adafruit.com/product/5954) [Related Guides to the Product](https://learn.adafruit.com/products/5954/guides) ### Monochrome 1.3" 128x64 OLED graphic display - STEMMA QT / Qwiic [Monochrome 1.3" 128x64 OLED graphic display - STEMMA QT / Qwiic](https://www.adafruit.com/product/938) These displays are small, only about 1.3" diagonal, but very readable due to the high contrast of an OLED display. This display is made of 128x64 individual white OLED pixels, each one is turned on or off by the controller chip. Because the display makes its own light, no backlight is... In Stock [Buy Now](https://www.adafruit.com/product/938) [Related Guides to the Product](https://learn.adafruit.com/products/938/guides) ### STEMMA QT / Qwiic JST SH 4-Pin Cable - 50mm Long [STEMMA QT / Qwiic JST SH 4-Pin Cable - 50mm Long](https://www.adafruit.com/product/4399) This 4-wire cable is 50mm / 1.9" long and fitted with JST SH female 4-pin connectors on both ends. Compared with the chunkier JST PH these are 1mm pitch instead of 2mm, but still have a nice latching feel, while being easy to insert and remove. In Stock [Buy Now](https://www.adafruit.com/product/4399) [Related Guides to the Product](https://learn.adafruit.com/products/4399/guides) ### Snap-on Enclosure for Adafruit TRRS Trinkey [Snap-on Enclosure for Adafruit TRRS Trinkey](https://www.adafruit.com/product/5981) Here is a cute and minimal enclosure for your [TRRS Trinkey](http://www.adafruit.com/product/5954) to keep it safe during use and transport. This case has been custom designed and 3D printed to accommodate the reset button and STEMMA QT connector. No screws or glue are... In Stock [Buy Now](https://www.adafruit.com/product/5981) [Related Guides to the Product](https://learn.adafruit.com/products/5981/guides) ### White Nylon Machine Screw and Stand-off Set – M2.5 Thread [White Nylon Machine Screw and Stand-off Set – M2.5 Thread](https://www.adafruit.com/product/3658) Totaling 420 pieces, this **White Nylon M2.5 Screw Set**  is a must-have smörgåsbord for your workstation. You'll have more than enough screws, nuts, and hex standoffs to construct your maker projects for days on end! M2.5 screws fit nearly... In Stock [Buy Now](https://www.adafruit.com/product/3658) [Related Guides to the Product](https://learn.adafruit.com/products/3658/guides) ## Related Guides - [Adafruit TRRS Trinkey](https://learn.adafruit.com/adafruit-trrs-trinkey.md) - [Adafruit QT Py ESP32-S2 and QT Py ESP32-S2 with uFL Antenna](https://learn.adafruit.com/adafruit-qt-py-esp32-s2.md) - [Adafruit Metro RP2040](https://learn.adafruit.com/adafruit-metro-rp2040.md) - [Toddler Timer](https://learn.adafruit.com/toddler-timer.md) - [Adafruit Feather RP2040 RFM69](https://learn.adafruit.com/feather-rp2040-rfm69.md) - [Trinkey True Random Number Generator](https://learn.adafruit.com/trinkey-qt2040-true-random-number-generator.md) - [Raspberry Pi Azure IoT Hub Dashboard with CircuitPython](https://learn.adafruit.com/raspberry-pi-iot-dashboard-with-azure-and-circuitpython.md) - [Tightrope Unicycle Bot](https://learn.adafruit.com/tightrope-unicycle-bot.md) - [Getting Started with Microsoft Azure and CircuitPython](https://learn.adafruit.com/getting-started-with-microsoft-azure-and-circuitpython.md) - [CircuitPython POV Bike Wheel](https://learn.adafruit.com/circuitpython-pov-bike-wheel.md) - [Adafruit RP2040 CAN Bus Feather](https://learn.adafruit.com/adafruit-rp2040-can-bus-feather.md) - [Arcade Fightstick](https://learn.adafruit.com/arcade-fightstick.md) - [ItsyBitsy ESP32 wFL case](https://learn.adafruit.com/itsybitsy-esp32-wfl-case.md) - [Adafruit Metro RP2350](https://learn.adafruit.com/adafruit-metro-rp2350.md) - [Adafruit IO IOT Hub with the Adafruit FunHouse](https://learn.adafruit.com/adafruit-io-hub-with-the-adafruit-funhouse.md) - [Monitor Your Greenhouse with a No-Code Environmental Sensor](https://learn.adafruit.com/monitor-your-greenhouse-with-a-no-code-environmental-sensor.md)