2 layers132.1 × 45.7 mm
IPoS
peterheinrich/InternetOverSpaghetti
Transmitting IP packages over a pair of spaghetti thus demonstrating how media independent IP really is.
42 parts342
2 layers50.8 × 50.8 mm
Theremin
ryan-racer/mini-thereminMini-Theremin PCB designed in KiCad - a capacitive touch musical device using a Schmitt Trigger oscillator
- Size
- 50.8 × 50.8 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 17
- Nets
- 11
- Pads
- 40
- Tracks, vias
- 93, 0
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 15 Apr 2026
- Updated
- 15 Apr 2026
Overview
Theremin is an open-source printed circuit board by ryan-racer, from the ryan-racer/mini-theremin repository on GitHub. It is a 2-layer board of 50.8 × 50.8 mm with 17 parts on 11 nets, routed with 93 tracks and 0 vias.
It is built around the LM358. Its parts include 4 resistors, 1 IC, 1 transistor and 1 connector.
Main components
1README
README.mdMini-Theremin
A Mini-Theremin PCB designed as part of an electronics course project. A theremin is a musical instrument played without physical contact — this compact version uses a capacitive touch pad to control audio frequency through a Schmitt Trigger oscillator.
How It Works
The Mini-Theremin uses a copper touch pad as one half of a capacitor. When you bring your hand near or touch the pad, you change the system's capacitance, which alters the oscillation frequency of a Schmitt Trigger oscillator built around an LM358 op-amp. The oscillator output drives a 2N7000 MOSFET that switches a speaker on and off at the oscillation frequency, producing an audible tone. Moving your hand closer to the pad lowers the pitch; moving it away raises it.
3D Board View
Completed Build
| Front | Back |
|---|---|
 |  |
Bill of Materials
| Reference | Qty | Value | Component |
|---|---|---|---|
| Cbase1 | 1 | 220 pF | Base capacitor |
| Cbulk1 | 1 | 10 uF | Bulk decoupling capacitor |
| Cdec1, Cref1 | 2 | 0.1 uF | Decoupling/reference capacitors |
| J1 | 1 | Conn_01x02 | 2-pin power connector |
| LS1 | 1 | Speaker | Piezo speaker |
| Q1 | 1 | 2N7000 | N-channel MOSFET |
| R3, R4, Rg1, Rpd1 | 4 | 100 kOhm | Resistors |
| Rf1 | 1 | 200 kOhm | Feedback resistor |
| Rgate1, RLS1 | 2 | 100 Ohm | Gate/load resistors |
| Rosc1 | 1 | 2.2 MOhm | Oscillation resistor |
| TOUCH_PAD1 | 1 | TOUCH_PAD | 30x30mm capacitive touch pad |
| U1 | 1 | LM358 | Dual op-amp (Schmitt trigger) |
Files
Theremin.kicad_sch- KiCad schematicTheremin.kicad_pcb- KiCad PCB layoutTheremin.kicad_pro- KiCad project file240Library/- Custom component library (footprints and symbols)Therminim.pretty/- Custom touch pad footprintPCB_Lab_Report.pdf- Lab report with design documentation*.gbr/*.drl- Gerber files and drill files for manufacturing
Software
Designed in KiCad 9.0.
Parts
17| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | 100 kΩ | 240Library:K104K10X7RF5UH5_VIS | R3, R4, Rg1, Rpd1 |
| 2 | 0.1 µF | 240Library:CAP_YX_6P3X11_RUB | Cdec1, Cref1 |
| 2 | 100 Ω | 240Library:K104K10X7RF5UH5_VIS | Rgate1, RLS1 |
| 1 | 10 µF | 240Library:CAP_YX_6P3X11_RUB | Cbulk1 |
| 1 | 2.2 MΩ | 240Library:K104K10X7RF5UH5_VIS | Rosc1 |
| 1 | 200 kΩ | 240Library:K104K10X7RF5UH5_VIS | Rf1 |
| 1 | 220 pF | 240Library:CAP_YX_6P3X11_RUB | Cbase1 |
| 1 | 2N7000 | 240Library:TO220AB_VIS | Q1 |
| 1 | Conn_01x02 | 240Library:HARWIN_M20-9990246 | J1 |
| 1 | LM358 | 240Library:DIP794W45P254L959H508Q8 | U1 |
| 1 | Speaker | 240Library:XDCR_AT-1224-TWT-5V-2-R | LS1 |
| 1 | TOUCH_PAD | Therminim:Touch_Pad_30x30mm | TOUCH_PAD1 |
Questions
How big is the Theremin PCB?
It measures 50.8 × 50.8 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Theremin use?
17 parts, built around the LM358. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Theremin KiCad files?
From the ryan-racer/mini-theremin repository on GitHub, at the commit this page was made from: the board is Theremin.kicad_pcb and its schematic Theremin.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Theremin design in my own project?
Its repository states no licence, so its author keeps all rights: ask ryan-racer before reusing the design.
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