

Edrumulus
Open Source E-Drum Trigger Module
- Size
- 65 × 56.5 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 67
- Nets
- 75
- Pads
- 223
- Tracks, vias
- 481, 19
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 6 (file 20211014)
- Created
- 15 Dec 2020
- Updated
- 12 Sep 2026
Overview
Edrumulus is an open-source printed circuit board by corrados, from the corrados/edrumulus repository on GitHub, published under the GPL-2.0 licence. It is a 2-layer board of 65 × 56.5 mm with 67 parts on 75 nets, routed with 481 tracks and 19 vias.
It is built around the BAT85. Its parts include 38 resistors, 26 diodes, 2 connectors and 1 IC. It belongs with the ESP32 boards of this library.
Main components
1README
hardware/prototype_3hhh/kicad/README.mdedrumulus 3hhh prototype with a Teensy 4.1
PCBA design of the edrumulus circuit with modifications by 3hhh to be used with a Teensy 4.1 with soldered pins.
Features
- size: 12x7cm
- price: ~30 EUR plus shipping and tariffs (~10 EUR to EU) at https://jlcpcb.com/ for 5 units (2025)
- little soldering required:
- female socket for the Teensy 4.1
- SMD components intended for assembly at the manufacturer
- all 18 Teensy 4.1 analog inputs are connected to respective edrumulus circuits
- female header as "breakout" connector to the drum hardware via DuPont jumper wires: Standard 6,3mm Jack stereo cables can relatively easily be soldered to three male-male jumper wires to connect the board to the drum kit (search "solder wires" on youtube). It may make sense to use short cables for soldering and connect them to longer 6,3mm cables as needed.
- 3hhh modifications:
- Rp=10k for higher sensitivity
- some pins (A1-A5) with Rs=100k for low sensitivity needs (kick, ...)
- some pins (A6-A17) with Rs=10k for high sensitivity needs (snare, hihat, ...)
- 1N5819WS Schottky diode: cheaper and lower forward voltage than BAT85
- M2 screw holes
- also see this image
JLCPCB manufacturing
Make sure to select:
- 2 layers
- Suface Finish: LeadFree HASL or ENIG
- Mark on PCB: Order Number(Specify Position)
- PCB Assembly
Manufacturing incl. assembly (PCBA) can be done elsewhere as well, but was optimized for JLCPCB.
Used software
KiCad 9 with the JLCPCB plugin.
Useful presets: https://github.com/sethhillbrand/kicad_templates
Helpful KiCad tutorial: https://www.youtube.com/playlist?list=PLUOaI24LpvQPls1Ru_qECJrENwzD7XImd
Known issues
- edrumulus currently maxes out at ~15 used analog inputs
- the used female headers tend to run out of stock and may have to be replaced with others
- GND needs to be expanded with a small breadboard
Parts
67| Qty | Value | Footprint | References |
|---|---|---|---|
| 26 | BAT85 | Diode_SMD:D_MiniMELF | D1, D2, D10, D11, D12, D13, D14, D15, D16, D17, D18, D19, D20, D21, D22, D23 +10 |
| 24 | 22 kOhm | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22, R23, R24, R29 +8 |
| 12 | 100 kOhm | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | R1, R2, R3, R4, R5, R6, R7, R8, R25, R26, R27, R28 |
| 2 | 10 kOhm | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | R37, R38 |
| 1 | ESP32-DEVKIT-V1 | edrumulus:esp32_devkit_v1 | U1 |
| 1 | Raspberry Pi GPIO pins | Connector_PinHeader_2.54mm:PinHeader_2x20_P2.54mm_Vertical | J2 |
| 1 | Trigger Connector | Connector_Dsub:DSUB-25_Female_Vertical_P2.77x2.84mm | J1 |
Questions
How big is the Edrumulus PCB?
It measures 65 × 56.5 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Edrumulus use?
67 parts, built around the BAT85. 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 Edrumulus KiCad files?
From the corrados/edrumulus repository on GitHub, at the commit this page was made from: the board is hardware/prototype4/edrumulus.kicad_pcb and its schematic hardware/prototype4/edrumulus.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Edrumulus design in my own project?
Its repository publishes it under the GPL-2.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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