DIY Synth

Modulino™ Buttons

Arduino® UNO™ Q DIY synth bundle

Arduino® UNO™ Q 2GB

Modulino™ Knob

Arduino App Lab

Modulino™ Distance

Modulino™ Movement

<html><body>This project turns an Arduino UNO Q into a live musical instrument you can play using four Modulino nodes. The Modulino Buttons, Knob, Distance and Movement. Plug them in, press Run in Arduino App Lab, open Pure Data, and you have a working drum machine and polyphonic synthesizer that responds to your gestures in real time. The UNO Q acts as both the microcontroller reading the sensors and the computer running the audio software. <h3>Hardware Setup</h3>For the next steps we need to use the UNO Q as a single-board computer, which means that you will need a USB Type-C hub that can connect a monitor, keyboard and mouse to the UNO Q. Connect your monitor, mouse and keyboard to a USB-C Hub. Power the UNO Q by connecting the USB Type-C power source to your USB-C hub; connect it all to the UNO Q using the output Type-C cable of your hub. <figure><img src="https://projects.arduinocontent.cc/8f9e6ecd-f2df-4972-81fd-b8285bef6655.png"/><figcaption></figcaption></figure>Connect the Modulino Movement, Modulino Buttons, Modulino Knob and Modulino Distance to the UNO Q via the qwiic connector. <figure><img src="https://projects.arduinocontent.cc/f82ded4c-291b-4c0b-96dc-e740f93d0521.png"/><figcaption></figcaption></figure>The UNO Q will be powered through the USB hub, make sure to power the monitor individually. For more information on how to run the UNO Q as a single-board computer have a look at the <a href="https://docs.arduino.cc/tutorials/uno-q/single-board-computer/">documentation here. </a><h3>Downloading and importing the project into Arduino App Lab</h3><ol><li>Open a browser on the UNO Q and navigate to this project page on Arduino Project Hub . </li><li>Download the project ZIP file from the Arduino App Lab section and save it. For example, in the Downloads folder. </li><li>Find the Arduino App Lab icon on the desktop or in the application menu and double-click it. </li><li>In App Lab, click Create new app , then choose Import app . In the file picker, navigate to your Downloads folder, select the ZIP you just downloaded, and click Open . </li><li>App Lab extracts the project into <code class="code">~/ArduinoApps/modulino-udp-pure-data-bridge/ </code>and opens it automatically. </li><li>With the project open, click the Run button. App Lab compiles and uploads the sketch to the microcontroller and starts the Python bridge at the same time. When the status indicator turns green or if you see the sine wave animation on the boards led matrix, both parts are running. </li></ol><h3>The different components of the project</h3>The Arduino sketch This sections looks at the <code class="code">sketch/sketch.ino </code>file. At startup the sketch scans the I²C bus and identifies every Modulino module by its address. It polls all connected modules every 16 ms and sends a typed event to the Python bridge whenever a value changes. Here you can see each Modulino event and the information it contains: <ol><li><code class="code">btn_event </code>- Address, button 0, button 1, button 2 </li><li><code class="code">knob_event </code>- Address, rotation direction (−1 / 0 / +1), pressed </li><li><code class="code">dist_event </code>- Address, distance in mm </li><li><code class="code">imu_event </code>- Address, acceleration X/Y/Z, roll, pitch, yaw </li></ol>The sketch also drives the built-in 13×8 LED matrix on the board with a looping animation that runs independently of the sensors. <figure><img src="https://projects.arduinocontent.cc/d678da63-aa63-44a8-aed5-bea596e41d95.gif"/><figcaption></figcaption></figure>The Python bridge This sections looks at the <code class="code">python/main.py </code>file. The bridge receives each event from the sketch, formats it as a space-separated text message, and sends it over UDP to <code class="code">localhost:7400 </code>. It also serves a web dashboard at <code class="code">http://IP_ADDRESS:7000 </code>showing live values for every connected module. <figure><img src="https://projects.arduinocontent.cc/3e36dadb-d208-427f-8aed-08219f8e6752.png"/><figcaption></figcaption></figure>The Pure Data file This sections looks at the <code class="code">pd/main.pd </code>file. Open <code class="code">main.pd </code>in Pure Data, this is the main instrument patch you interact with. The other <code class="code">.pd </code>files in the <code class="code">pd/ </code>folder are supporting abstractions used internally, you do not need to open them directly. A quick explanation of all the files: <ol><li><code class="code">main.pd </code>- Main patch, open this one </li><li><code class="code">udp_io.pd </code>- Receives UDP messages and routes them by sensor type </li><li><code class="code">transport.pd </code>- Manages tempo, play/stop, and the beat grid </li><li><code class="code">drum.pd </code>- Drum machine engine </li><li><code class="code">synth.pd </code>- Polyphonic synthesizer </li></ol><h3>Running the project</h3><h3>Install Pure Data</h3>Pure Data is the software we use to produce the sound and provide the interface to control it. Our Arduino App Lab application connects to it and shares the Modulino data. We use Pd Vanilla — no extra externals or libraries are needed, as the patches use only vanilla objects. To install it, open a terminal on the UNO Q and run: <pre>sudo apt-get update </pre><pre>sudo apt-get install -y puredata </pre><h3>Install PipeWire (first-time setup)</h3>The Pure Data launcher uses PipeWire to route audio to your bluetooth speaker. On a fresh UNO Q setup we need to install PipeWire. Open a terminal on the UNO Q and run: <pre>sudo apt-get update </pre><pre>sudo apt-get install -y pipewire pipewire-jack pipewire-audio-client-libraries wireplumber </pre>After installation, reboot the board, which can be done with this command: <pre>sudo reboot </pre><h3>Connecting a Bluetooth speaker</h3>Connect your Bluetooth speaker before launching the Pure Data patch. The launcher automatically picks up the first already-connected Bluetooth device, no extra steps are needed after the initial pairing. Step-by-step <ol><li>Make sure the Bluetooth speaker is powered on and in pairing mode. </li><li>Click the Bluetooth icon in the system tray (bottom-right of the screen). </li><figure><img src="https://projects.arduinocontent.cc/182ef6b6-a99b-4923-b4cb-cea207dcc51c.jpg"/><figcaption></figcaption></figure></ol><ol><li>Choose Devices (or Connect new device ) from the menu. </li></ol><ol><li>The Bluetooth manager window will open. Click Search (or Scan ) to discover nearby devices. </li></ol><figure><img src="https://projects.arduinocontent.cc/b4ae8c8e-3133-4009-b5c3-7c74f5388896.png"/><figcaption></figcaption></figure> <ol><li>Double-click your speaker in the device list. When the status changes to Connected , you can close the window. </li></ol><figure><img src="https://projects.arduinocontent.cc/6c525c7b-09b9-484d-9ae2-3af0b3ffa2cf.png"/><figcaption></figcaption></figure> <blockquote>The speaker stays connected across reboots once paired. You only need to repeat this step if you switch to a different speaker. </blockquote> <h3>Run the Pure Data patch</h3>Open the file manager and navigate to <code class="code">~/ArduinoApps/modulino-udp-pure-data-bridge/ </code>. Double-click the start-pd.desktop file in the project folder. A terminal window opens, it shows the audio connection status, and Pure Data launches with <code class="code">main.pd </code>loaded automatically. <figure><img src="https://projects.arduinocontent.cc/892c85b8-013b-4aad-a5cb-b3155b9678d7.png"/><figcaption></figcaption></figure>The launcher detects the already-connected Bluetooth device automatically. It also waits for PipeWire to register the audio sink. Pure Data starts with <code class="code">main.pd </code>and the <code class="code">pd/ </code>folder as the search path. It then connects Pure Data's audio outputs to the Bluetooth speaker and falls back to the built-in audio output if no Bluetooth device is found. The terminal shows a confirmation line like: <pre>✓ Audio → Bluetooth: bluez_output.78_2B_64_36_BB_E8.playback_FL </pre>You can minimize the terminal, do not close it , as it keeps Pure Data running. <h3>Playing the instrument</h3>When <code class="code">main.pd </code>opens, it starts silently. Do two things: <ol><li>Enable audio : click the AUDIO ON toggle in the top-left corner of the patch. The toggle turns orange. </li><li>Press play : click the PLAY button in the Transport section. The beat grid starts cycling and you hear the default drum pattern. </li></ol> <figure><img src="https://projects.arduinocontent.cc/979399bc-e615-48e2-a0d7-b0e618ee3cfe.png"/><figcaption></figcaption></figure> <h3>Hardware controls</h3><ol><li>Rotating the Knob controls the tempo (BPM) . Clockwise = faster, anti-clockwise = slower. </li><li>Pressing the Knob toggles Play and Stop . </li><li>Pressing Button 1 (B0) enables or disable the kick channel in the drum machine. </li><li>Pressing Button 2 (B1) enables or disables the snare channel in the drum. </li><li>Pressing Button 3 (B2) enables or disables the hi-hat channel in the drum machine. </li><li>Using the Distance sensor changes the synths pitch . Move your hand closer to raise the pitch, further away to lower it. </li><li>Tilting the Movement sensor (X-axis tilt) controls a user-selectable effect (wah frequency, wah Q, master filter, synth level or off) - default: wah frequency. </li><li>Tilting the Movement sensor (Y-axis tilt) controls another user-selectable effect - default: wah Q. </li></ol><h3>Manual additional controls</h3>Additionally, other parameters can be adjusted using the mouse. <ol><li>Audio ON : Enables Pure Data’s audio output. </li><li>Master volume : Control the full audio output level. </li><li>Drum machine : Modify the pattern of the drum by clicking on each cell. </li></ol>Modulino UDP IN: <ol><li>Print messages to console : Activate to see incoming values. Useful to debug. </li><li>Range : Adjust min and max values for X and Y tilt. </li><li>X fx and Y fy : Select which effect is assign to each axis of the modulino movement. </li></ol>Synth Lead: <ol><li>Wave : Select between different waveform (since, saw, square and noise). </li><li>Dist limit : set he farthest threshold for the modulino distance, after that threshold the synth will be silent. </li></ol><h3>Checking live sensor values</h3>Open a browser on the UNO Q and go to <code class="code">http://IP_ADDRESS:7000 </code>. The dashboard shows live readings from every connected Modulino, this can be useful for verifying that the modules are detected and sending data correctly. <h3>Assembly instructions for the 3D printed model</h3>The 3D files can be downloaded below or from our <a href="https://www.printables.com/model/1757623-arduino-uno-q-diy-synth-bundle-3d-printed-case">printables page here </a>. Required materials for the complete 3D model: Hardware <ol><li>Arduino UNO Q </li><li>Arduino Modulino Distance </li><li>Arduino Modulino Knob </li><li>Arduino Modulino Movement </li><li>Arduino Modulino Buttons </li><li>5 x 5cm Qwiic cables </li><li>10 x M3x6 screws </li><li>4 x M3x10 screws </li></ol> Tools and materials <ol><li>Screwdriver </li><li>FDM 3D printer (printbed size 160x90 mm minimum) </li><li>3D printing filament </li><li>(optional) small pliers </li></ol><h3>Printing tips</h3><figure><img src="https://projects.arduinocontent.cc/96311f62-db3f-4447-b027-9129af69f0bd.png"/><figcaption></figcaption></figure>The kit consists of 6 parts: <ol><li>Base </li><li>Cover </li><li>Buttons pad </li><li>Tilt Cross </li><li>Tilt Plane </li><li>Tilt Knob </li></ol>The .3mf print file is based on Prusa Slicer, and has been tested with a print layer of 0,2 mm both in PLA and PETG. In case another slicer is used it may require setting supports and parameters. Support is required only in 2 areas (green in the picture below): <ol><li>the power cable holes in the upper left corner of the Base; </li><li>the protruding joints of the Tilt Plane. </li></ol>The Tilt Cross .stl file is all round, but in the .3mf file it is slightly cut to lay flat without supports. It is suggested to assemble the cross with the flat surface facing downwards, as said in the following assembly guide. <figure><img src="https://projects.arduinocontent.cc/ceb8af55-dbce-469b-b131-26444370138a.png"/><figcaption></figcaption></figure><h3>Assembly steps</h3><ol><li>Connect the UnoQ and the Modulinos with the Qwiic cables, following this order: UnoQ -&gt; Movement -&gt; Buttons -&gt; Knob -&gt; Distance. </li></ol> <ol><li>Gently press the Tilt Cross (if printed with flat face, face it downwards) in the joint on the right side of the Base, until it clicks in place. </li></ol><figure><img src="https://projects.arduinocontent.cc/bcb85e1f-1f93-4bb4-8253-8dba485a6776.png"/><figcaption></figcaption></figure><li>Place the Modulino Movement on the Tilt Plane, the Knob on the Modulino Distance and screw them together with 2 M3x10 screws. </li><figure><img src="https://projects.arduinocontent.cc/13ab22e6-c974-4b2e-94e8-c3f2e00424ee.png"/><figcaption></figcaption></figure><li>Pass the cables in and out of the Modulino Distance around the hooks below the Tilt Plane. </li><figure><img src="https://projects.arduinocontent.cc/696b5a8f-ba3e-419b-b397-86d79b7fbfb6.png"/><figcaption></figcaption></figure><li>Gently press the resulting Tilt assembly on the Tilt Cross, until it clicks in place. </li><figure><img src="https://projects.arduinocontent.cc/f0320929-3f42-4f59-a6a3-b1adf569cbee.png"/><figcaption></figcaption></figure><li>Bend downwards the four Button Pad’s spacers along the weak lines. </li><figure><img src="https://projects.arduinocontent.cc/5db2c961-79eb-406d-a660-658138c18bc2.png"/><figcaption></figcaption></figure><li>Place the Button Pad over the Modulino Buttons, and then screw them both in the spot next to the Tilt module, using M3x10 screws. </li><figure><img src="https://projects.arduinocontent.cc/d4430439-b557-4244-bf7f-9b6d13e3cca0.png"/><figcaption></figcaption></figure><li>Screw the Modulino Knob on the spot right next to the Buttons, on the left. </li><figure><img src="https://projects.arduinocontent.cc/660ad4d8-411e-42e0-bbce-45ee4caeda4c.png"/><figcaption></figcaption></figure><li>Screw the Modulino Distance in the sloped seat on the left. </li><figure><img src="https://projects.arduinocontent.cc/d73bfd0b-5a8c-4699-8348-ca080ac67c9b.png"/><figcaption></figcaption></figure><li>Screw the Cover over the base. </li><figure><img src="https://projects.arduinocontent.cc/dce15ee1-d62d-4d89-92a9-b641f5b45d25.png"/><figcaption></figcaption></figure>Now you have a fully assembled 3D printed Arduino Modulino Synth. Have fun! </body></html>

DIY Synth

Turn your Arduino UNO Q into a live musical instrument, play a drum machine and polyphonic synthesizer in minutes!