Real-Time Guitar DSP on the UNO Q

Arduino USB-C Hub (8 in 1)

Arduino App Lab

Arduino® UNO™ Q 4GB

<html><body><h3>Creating a magic "pedal" (it is not really a pedal)</h3>I love guitar pedals, but I hate spending 100-500$ for new gear, particularly when I don't know what I am looking for. So I had an idea: why not hook up my guitar to a UNO Q via an USB Audio Interface (Behringer UM2), and generate whatever effects I want to programatically. Sounds pretty straightforward right? And it was, very straightforward! The total BOM came in around 120$, which included the following material: <ol><li><a href="https://store.arduino.cc/products/uno-q-4gb">Arduino UNO Q 4GB </a>version (probably works with 2GB version, not a very demanding application) </li><li><a href="https://store.arduino.cc/products/usb-c-hub-8-in-1?srsltid=AfmBOoq5VS6Nx5vvoQS1WPZDD48A6Kk05-nxeTJ22i-H4Ywlr0pjouPt">USB-C Hub </a>+ USB-C cable (to power the USB hub) </li><li><a href="https://www.behringer.com/en/products/0805-AAL">Behringer UM2 </a>(includes a USB cable to connect to UNO Q) </li><li><a href="https://www.gear4music.se/sv/Inspelning-and-datorer/Adam-Hall-3-STAR-Unbalanced-Twin-1-4-Jack-to-RCA-Cable-3m/6R9I">1/4" to RCA cable </a></li><li>A 1/4" cable </li></ol><blockquote>Please note that the audio quality is what it is: this is a very cheap setup, but it is a lot of fun! </blockquote><h3>Wiring the Project</h3>All circuitry is just plug and play, no complicated circuits or anything. You can see the beautiful wiring diagram below: <ol><li>Connect the guitar to the Behringer UM2 (INST2 jack) using a 1/4" cable </li><li>Connect USB-C hub to the Arduino UNO Q* and power the USB hub via e.g. phone charger, laptop charger, using a USB-C cable. </li><li>Connect the UM2 to the USB-C hub via the provided USB-B to USB-A cable. </li><li>Connect the RIGHT channel of the Behringer UM2 (red jack) with an RCA cable, and the other end plugs in to the amp. </li><li>Done! </li></ol>*If it is the first time using the UNO Q, you need to first configure and update the board. See <a href="https://docs.arduino.cc/tutorials/uno-q/user-manual/">https://docs.arduino.cc/tutorials/uno-q/user-manual/ </a> <figure><img src="https://projects.arduinocontent.cc/45355aca-7722-4d4e-beda-e722fa9a71ee.png"/><figcaption></figcaption></figure> <h3>Software Setup</h3>The whole setup is built around programmatically altering the guitar's signal on its way to the amplifier. This is done by writing Python scripts that run directly on the board. So how do we do this? It's pretty simple. <ol><li>First, connect to your board using <code class="code">ssh </code>. The easiest way is to use the <a href="https://www.arduino.cc/en/software/#app-lab-section">Arduino App Lab </a>, where you can access your board over the local network. Inside App Lab, there's a button you can click, which will open a terminal on the board. </li></ol> <figure><img src="https://projects.arduinocontent.cc/64ede271-d204-4c03-96ae-25d386046049.png"/><figcaption></figcaption></figure><ol><li>Then, on your main computer, we need to transfer a zip file (available in this tutorial). The IP is obtained via the Arduino App Lab next to the button we just clicked. </li></ol><blockquote>Project Hub did not allow to upload a .tar.gz file, so it is now contained in pedal.zip in downloadable resources. Just unzip it on your computer before continuing with the steps below.</blockquote><pre>scp -R pedal.tar.gz arduino@&lt;YOUR_IP_ADDRESS&gt;:/home/arduino </pre><ol><li>Switch to the terminal of your board (the window that opened when we clicked the button). Unzip the package we just transferred: </li></ol><pre>tar xzf pedal.tar.gz &amp;&amp; cd pedal </pre><ol><li>Then we need to install libasound2-dev, done by running the following command: </li></ol><pre>sudo apt install -y libasound2-dev </pre>1. On the board, create a virtual environment (venv) by running <pre>python3 -m venv .venv </pre>2. Install the needed python packages: <pre>pip install pyalsaaudio numpy </pre>3. We should at this point be inside the "pedal" directory, which looks like this: <figure><img src="https://projects.arduinocontent.cc/ea8d8df2-7d1b-4def-bdd3-899a2ee38076.png"/><figcaption></figcaption></figure>4. We can now run a script to see if it works. To do so, we use: <pre>python3 pedal.py fuzz </pre>This will enable the "fuzz" effect. If you write <code class="code">python3 pedal.py --list </code>you will get a list of all available effects. You can also pass additional parameters. <figure><img src="https://projects.arduinocontent.cc/66de6ada-c146-4af2-8eb2-cb363d92809e.png"/><figcaption></figcaption></figure> Try it out, and see if it works! <h3>Using AI to generate effects</h3>As a little bonus to this workflow: I installed <a href="https://code.claude.com/docs/en/quickstart">Claude Code </a>on the board, where the AI can generate a new effect in just a minute or so. Since I have little to no music theory knowledge, this is a great way. Installing claude code is really quick and easy, just follow the official docs linked above.So far, I have prompted: <ol><li>Create a "Tame Impala" inspired effect </li><li>Create a desert rock / QOTSA effect that rocks hard </li><li>Combine every pink floyd effect ever into a single one (this was an interesting disaster). </li></ol> For any questions please leave comments! </body></html>

Real-Time Guitar DSP on the UNO Q

Create any effects you want to with this UNO Q + USB audio interface setup