Keyboards & Input Devices


An open source rotary encoder with a 1.27" TFT customizable display

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of $12,700 goal

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RoenDi is a visually adaptable rotary encoder capable of displaying customized graphics. Having a built-in screen allows it to provide visual feedback unlike any other encoder we’ve seen. RoenDi is designed with simplicity and versatility in mind. Just connect a MicroUSB cable or ST-LINK connector, upload your code to the MCU, and you’re ready to go!

An Innovative & Versatile Platform

The potential uses for RoenDi are up to your imagination, and we’d love to see the unique applications you come up with. Some examples of potential uses are:

With RoenDi, you can create unique custom interfaces that stand out from the rest and provide responsive visual feedback to the user.

Open Source Software

RoenDi uses a powerful STM32L433 MCU, which can be programmed with the Arduino IDE. This makes it easier for novice makers to get involved, while allowing experts to enjoy the benefits of ST’s inline debugging tools. The code base from ST and Arduino is robust, which means there is plenty of sample code to work with.

To help get you started customizing your RoenDi, we have provided sample code using several well documented code libraries. For Arduino lovers, we have provided examples using the Adafruit GFX library, which means you can add text, images, and other graphical objects to the screen with just a few lines of code. If you prefer STM32CubeIDE, we have provided examples using the robust TouchGFX library, which is designed specifically for interactive display interfaces like RoenDi.

Below is an demonstration of RoenDi being used as a combination lock:

Open Source & Fully Customizable Hardware

RoenDi hardware and software are open source, so you can modify and customize its components as you wish. We also worked to build RoenDi with readily available off-the-shelf parts, so you can modify and repair your RoenDi if you ever need to.

The encoder-and-displays MCU also contain a multitude of available IO pins to work with. They are broken out to pads on the side of the PCB so you can easily connect to the UART, CAN, I²C, PWM, DAC, and SAI peripherals. These interfaces can be used to communicate with a large variety of third-party ICs, including LED drivers, speakers, motors, and sensors that detect temperature, humidity, and light, to name just a few examples. One of the great things about the STM32L4 MCU is that all pins tolerate 5 V for easy interfacing.

RoenDi can also be used in conjunction with other connected devices, such as Wi-Fi and Bluetooth modules, which makes RoenDi great for wireless interfaces and IoT applications.

RoenDi pinout diagram

Features & Specifications


RoenDiGrayhill TE-M32M1-A11CSLB-10-40-0
Material Aluminum & PLA Stainless & Plastic Aluminum & Plastic
Power supply 3.3 V DC to 5 V DC 4.75 V DC to 18 V DC 3.3 V DC
Resolution 240 x 240 320 x 300 240 x 204
Display colors 4 K / 65 K / 262 K unknown 262 K
MCU + on board memoryyes yes no
Open source & open hardwareyes no no
Customizable encoder bodyyes no no
Breakout for GPIOyes no no
Capable for standalone applicationsyes yes no
Touch sensorno yes no
Brightness400 Cd/m2 200 Cd/m2 unknown
Arduino compatibleyes no yes
Boot timeless then 1 second 5 seconds to O.S. N/A (display only, no processor)
USByes yes no
CANyes yes no
SAI, PWM, I²C, DAC, RTCyes no no
Price$135 $212 $131

Support & Documentation

All hardware and software documentation for RoenDi will be published and openly maintained in our GitHub repositories.

We will also be releasing a series of tutorials that will walk you through the process of using RoenDi for various applications.

In the Press


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Produced by Xtech in Rousse, Bulgaria.

Sold and shipped by Crowd Supply.

RoenDi Ready to Go

Everything you need! Parts included: Main encoder board, Display board with connection cable, Matte black aluminum body, ST-LINK adaptor board + cable

$135 $8 US Shipping / $18 Worldwide

About the Team


Rousse, Bulgaria  ·   xtech.bg

I am software engineer who likes to develop embedded systems. I am passionate about aviation and everything flying.

Dimitar Dyakov

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