Making Your First Instrument

The project: a painted paper keyboard

We’re building a one-octave keyboard (six notes) on card, playable by anyone who picks it up. No previous experience required, no coding needed — just the Touch Board in its default mode, some paint, and a speaker.

Materials

• A4 or Letter card (not too thin — at least 200gsm)
• Electric Paint pen or pot + brush
• Ruler and pencil
• 6 crocodile clip cables
• Touch Board with SD card
• Speaker or headphones
• 6 MP3 files (musical notes — see below)

Step 1: Prepare the audio files

You need six MP3 files — the notes C, D, E, F, G, A (a major hexatonic scale). Several options:

Option A: Record them yourself Play each note on a real instrument and record on your phone. Export as MP3.

Option B: Download from Freesound.org Search for “piano C4”, “piano D4” etc. Most are CC licensed. Download and rename.

Option C: Generate with GarageBand or LMMS Set a MIDI piano to the note, record a 2-second clip, export as MP3.

Rename them:

• C → TRACK000.mp3
• D → TRACK001.mp3
• E → TRACK002.mp3
• F → TRACK003.mp3
• G → TRACK004.mp3
• A → TRACK005.mp3

Copy to the SD card. Insert card into Touch Board.

Step 2: Design the keyboard layout

With pencil, lightly sketch the keyboard on card:

┌─────────────────────────────────────────┐
│                                         │
│  C    D    E    F    G    A             │
│  ┌──┐ ┌──┐ ┌──┐ ┌──┐ ┌──┐ ┌──┐        │
│  │  │ │  │ │  │ │  │ │  │ │  │        │
│  │  │ │  │ │  │ │  │ │  │ │  │        │
│  │  │ │  │ │  │ │  │ │  │ │  │        │
│  └──┘ └──┘ └──┘ └──┘ └──┘ └──┘        │
│                                         │
│  ←lines to right edge→  ─ ─ ─ ─ ─ ─   │
└─────────────────────────────────────────┘

Draw the six key rectangles (about 3cm wide, 8cm tall) across the card. Label each with a note name.

Then draw a thin line from each key down to the right edge of the card — this is where you’ll clip the crocodile cables.

Step 3: Paint the keys and traces

Using the Electric Paint pen (or brush):

1. Fill each key — paint within the pencil-sketched rectangles, aim for solid coverage
2. Paint the connecting traces — thin lines from each key rectangle down to the right edge
3. At the right edge, paint a small connection pad (about 1cm × 0.5cm) at the end of each trace
4. Let everything dry completely (30 minutes minimum)

Tips:

• Keep the key areas dense and well-covered — this is what you touch, so good conductivity matters
• Traces can be thinner (5mm minimum) as long as they’re unbroken
• Check for gaps with a magnifying glass if available

Step 4: Test conductivity

Before connecting anything, check your paint with a multimeter:

• Probe one point within a key and the connection pad at the end of its trace
• You should read under 100 kΩ per key
• If higher, add another layer of paint and dry again

Step 5: Connect and play

1. Clip crocodile cable 1 → electrode E0 on Touch Board ↔ connection pad for key C
2. Clip crocodile cable 2 → E1 ↔ connection pad for key D
3. Continue for E2–E5 and keys E–A
4. Connect headphones or speaker to the Touch Board
5. Power the Touch Board via USB
6. Play your keyboard

You should hear the corresponding note whenever you touch each painted key.

Making it more playable

Add a backing: Glue the painted card to a piece of foam board or MDF. This prevents the card flexing (which can crack the paint) and makes it feel more like an instrument.

Label clearly: Write the note names on the keys in permanent marker after the paint has dried. Add decorative elements without covering the painted areas.

Reduce noise between keys: If touching one key occasionally triggers an adjacent one, the traces may be running too close together. Leave at least 5mm of unpainted card between traces.

Going further

Once this basic keyboard works, you can extend it:

• Add the remaining 6 electrodes (E6–E11) for a full chromatic scale or two octaves
• Replace paper with card and mount it vertically as a wall piece
• Paint directly onto a wooden board for durability
• Use a power bank so the instrument is completely wireless

Key takeaways

• A complete painted paper instrument requires: painted key areas, connecting traces, connection pads, crocodile clips, MP3 files, and the Touch Board in default mode
• Fill key areas densely; traces can be thinner as long as unbroken
• Measure resistance to verify paint quality before connecting
• Mount on a rigid backing to prevent paint cracking from flexing
• Start with six keys — you can always extend to all 12 electrodes later