This project uses a rotary encoder connected to an Arduino Leonardo to control the audio volume of a computer.

The computer runs a Volume.exe program, compiled by AutoHotkey which enables a set of key combinations to increase/decrease the volume.

Let's start with getting all the supplies.

Supplies:

For this project, you will need:

• A USB HID microcontroller(Leonardo, Micro, Pro Micro)
• A rotary encoder(Here, a stepper motor is being used)
• A suitable USB data cable for the microcontroller board

Step 1: Program the Microcontroller

You can get the Arduino code from here.

Step 2: Install the Volume.exe program on your computer

Find the Volume.exe file in the downloaded folder and copy it. Press Windows+R to open the Run window and type in shell:startup. Paste the file in the opened folder and double click on it to run it, you will only need to run it once. Since this program is now in the startup folder, it will run every time, the computer is started.

Step 3: Connect the Stepper Motor to the Rotary Encoder Board

You can skip this step if you are using a regular rotary encoder instead of a stepper motor.

If you are using a stepper motor, you can take help from here.

Step 4: Connect the Rotary Encoder to the Microcontroller

Connect the +ve of the input power of the encoder to the +5-volt header of the Arduino board and the -ve of the encoder to the GND header.

Connect the digital outputs of the encoder to the headers A0 and A1 of the Arduino board in any order. If you swap the order of the output wires, the direction of the encoder registered by the microcontroller will get reversed.

Step 5: Connect the Microcontroller to the Computer and Test the Controls

Make sure the Volume.exe program is running and check it by pressing the buttons on the keyboard as shown in the video. After that, check if rotating the encoder in either direction changes the volume.

Step 6: Do more With the Project

Since the microcontroller can control the computer as a keyboard and even mouse, you can try a large range of control applications with just a rotary encoder like scrolling a page, changing the windows, adjusting the brightness, and a lot more. You can modify the given Volume.ahk script to change the buttons or add different functions, compile it and replace the Volume.exe program with the one you made. There is a lot that you can do, all the best!