Tim's Piezoelectric Crystal Experiment [Noise Maker]

🎸 Piezo-Powered String Experiment

This is an experiment to see if I could use a Piezoelectric Crystal to amplify sound from a stringed instrument. 🎶🔍

All that is required is:

1. 🧿 A Piezoelectric Crystal
2. 🔊 An amplifier
3. 🔈 A speaker
4. 🔌 Some wires to connect them all together

You will need some sort of stringed instrument that has a bridge to transfer sound from the strings. 🎻🪕

I just wanted to see how easy it would be to make something based on the Steel Guitar. 🎼

As it was experimental, I went for something small. 🧪📏

1. I wanted something I could make quickly on my laser cutter. ⚡🪚

🔍 What Is a Piezoelectric Crystal?

Piezoelectric crystals (like the ones in buzzers or contact mics) generate voltage when they’re physically deformed — squeezed, bent, or vibrated. In this project, the vibrations from the string travel through the bridge and press against the crystal, creating a small electrical signal that can be amplified and played through a speaker.

⚙️ Key Properties:

1. Material: Usually ceramic (like PZT) bonded to a brass disc
2. Size: Common discs are 27 mm diameter, but they come in many shapes
3. Sensitivity: Best when mounted under pressure — not too loose, not too tight
4. Signal type: High-impedance, low-voltage AC — needs amplification
5. Durability: Fragile if bent too much, but long-lasting when mounted properly

🎶 Why It Works for Instruments:

1. Converts mechanical vibration into electrical signal
2. Picks up direct contact vibrations (not airborne sound)
3. Works well with stringed instruments, especially if mounted under the bridge or saddle

Supplies You'll Need

If you already have an acoustic stringed instrument you'd like to electrify, the parts list is refreshingly minimal:

1. Piezoelectric disk – the heart of the pickup system
2. Mono amplifier – any small amp module will do
3. Speaker – for bringing your vibrations to life
4. Cables – to connect everything together
5. ⚡ Power supply – 5V from a USB wall-wart (charger) works perfectly

If you're testing this on a precious instrument (like a guitar or violin), I recommend placing a thin layer of linen or soft cloth under the piezo disk to protect the enamel or lacquer finish.

If you'd like to build the instrument I made — a compact, laser-cut steel-style prototype — here's what you'll need:

1. 3mm plywood – for the frame and top plate
2. Laser cutter – to shape the parts quickly and precisely
3. Drawings – all files are attached for easy cutting
4. 3mm diameter rod – used for the nut and bridge supports
5. Cutting wire – ultra-thin and high-tensile, often sold as wire for removing phone screens
6. This wire is surprisingly strong and works well for short-scale stringing — just be gentle when tensioning, and let the piezo do the listening.

I’ve done a Fritzing diagram to show how it’s all wired together. 🧠📈

If you’re trying this with your own acoustic instrument, you’ll need a long cable from the Piezoelectric disc to the amplifier. 🎻➡️🧿📶

🎼 I suspect that if you're electrifying an acoustic instrument, the instrument itself will be louder than this little amplifier — but that’s okay!

1. 🔊 This little amp can still be used as a pre-amplifier, feeding into a larger amplifier if needed. It’s a great way to test the concept before scaling up. ⚡🔈➡️🔉

The following steps show how I assembled my experimental stringed instrument, using laser-cut plywood, stainless rods, and a piezo-powered sound system. 🎶🧪

Each image highlights how the separate parts fit together — from the top plate and string supports to the piezo disc and amplifier wiring. 📸🔧

🧴 For construction, I’ve just used everyday PVA glue to hold everything together — simple, accessible, and strong enough for this lightweight build.

This is a hands-on build, so feel free to adapt the layout, materials, or string configuration to suit your own experiments. Let’s get building! 🪚🎸

This step uses the following parts:

1. 🦴 2× Spine.dxf
2. 🧩 1× Neck_Support.dxf
3. 🪚 3× Bracing.dxf
4. 🪵 1× Top_Plate.dxf

🧠 Place the 3 bracing pieces and the Neck Support in between the 2 Spines, forming the internal structure.

1. 🪛 Then position the Top Plate on top — once in place, it should self-align and hold everything together neatly. 🎯

This step uses the following parts:

1. 🧾 1× Head.dxf
2. 🧷 1× Peg_Support.dxf

📐 The Peg_Support slots in from the end, forming the anchor for your string tensioners.

📦 The Head slots in from above, locking into place and completing the front structure.

This section sets up the tuning area — simple, sturdy, and ready for stringing. 🎸🔧

This step uses the following parts:

1. 📐 1× Top_String_Space.dxf
2. 🧷 1× Nut – made from a 3 mm diameter stainless steel rod, 30 mm long

🔼 The Top_String_Space is inserted from the top into the Head, acting as a guide for string spacing.

➡️ The Nut is inserted from one side, forming the contact point where the strings begin their vibrating length.

🧴 Apply PVA glue along the length between the Nut and the Neck Support to create a unified, stable piece. This helps maintain alignment and ensures smooth vibration transfer. 🎶🔧

This step uses the following parts:

1. 🧷 2× Stainless Steel Rods – 3 mm diameter, 30 mm long

🔽 The lower rod (Tail Rod) is used to tie off the strings — simply wrap and knot the wire around it to anchor each string securely.

🔼 The upper rod (Pre-Bridge Rod) lifts the strings and guides them toward the bridge, helping define the angle and tension before they reach the piezo pickup. 🎶📐

Together, these rods form a simple and effective tailpiece system — clean, minimal, and perfect for experimental builds.

This step uses the following parts:

1. 🧩 2× Peg_A.dxf
2. 🧩 2× Peg_B.dxf

These combine to form two tuning pegs — each peg is made by slotting Peg_A into Peg_B, creating a tapered, rotatable unit. 🔄🧷

🧠 The two tuning pegs fit into the Head and Peg_Support, forming the tensioning system for your strings.

1. 🎸 Once the strings are fitted, the pegs are rotated to tension and tune them. The tapered design creates a friction fit, so when the pegs are firmly inserted, they stay in place without slipping. 🎯🔧

This step uses the following parts:

1. 🧩 1× Bridge_Base.dxf
2. 🧩 2× Bridge_Side.dxf
3. 🧷 1× Stainless Steel Rod – 3 mm diameter, 38 mm long

📐 The rod sits on top of the Bridge_Base, and the two Bridge_Side pieces are fitted from either side to hold it in place.

🧿 This is also where the Piezoelectric disc is placed — it sits directly beneath the bridge to capture string vibrations.

🧴 The Bridge assembly and Piezo disc are not glued in place. Instead, they’re held securely by string tension once the instrument is strung. 🎶🔧

1. This floating setup allows for easy adjustment and experimentation — perfect for prototyping and sound testing.

This step uses the following parts:

1. 🧵 2× lengths of steel wire (I’ve used ultra-thin, high-tensile cutting wire — often sold for removing phone screens.)

🪝 String Path Overview:

1. 🔽 Tie off each string at the Tail Rod — wrap and knot securely
2. 🎯 Align the strings through the two slots in the Top_Plate
3. 🪜 Pass over the Pre-Bridge Rod
4. 🧿 Cross the Bridge — string tension will hold it in place
5. 🧷 Rest over the Nut (the rod at the neck)
6. 🕳️ Thread through the small holes in each Tuning Peg
7. 🔄 Wrap at least three rotations around the peg
8. 🎛️ Rotate the Tuning Peg to tension and tune the string
9. 🧲 The tapered peg forms a friction fit to stay securely in place

With the strings fitted and the Piezoelectric disc wired up to the amplifier, you're all set to experiment! 🎶⚡

🎥 Watch my video:

“Sounds like a cat with its balls nailed to a plank — or if you're old enough, the nostalgic tones of the Clangers and the Soup Dragon!” 🐉📡😹