I have always wanted to play drums, but there were practical obstacles. After I bought an acoustic kit, the neighbours objected to the noise, which pushed me towards an electronic alternative I could play silently with headphones.

The whole project is really an exercise in understanding MIDI (Musical Instrument Digital Interface). I first tried infrared sensors to trigger MIDI signals, but the latency was too high, so I switched to analog comparators with piezo sensors instead. The kit has four main parts.

Part 1: Drum rack

The structure is built from GI pipes and aluminium pipes:

• Elbows: 6
• T-joints: 7
• 1 ft pipes: 5
• 2 ft pipe: 1
• 2.5 ft pipe: 1
• Miscellaneous nuts, bolts, and welded angles

Part 2: Drum pads

The pads use piezoelectric sensors sandwiched between sponge and 6mm MDF. The kit includes three toms, plus splash, ride, and crash cymbals. A Roland PDX-6 serves as the snare and a CY-5 as the hi-hat.

The bass-drum trigger modifies a Pluto acoustic drum pedal by adding a piezoelectric sensor mounted on an L-shaped plywood platform with sponge cushioning. The hi-hat pedal uses a basic potentiometer (volume) pedal with an LDR-LED setup to control the open and closed positions.

Part 3: Trigger-to-MIDI converter

For this component I relied on Admir Salahovic’s open-source drum-trigger converter project at edrum.info as the primary resource.

Part 4: MIDI-to-sound conversion

There are three options:

1. Feed the MIDI signals to a PC running software like Propellerhead Reason, Ableton Live, Sonar LE, or GarageBand. This needs a MIDI-to-USB converter and a good sound card to keep latency low.
2. Use a sound module with MIDI input, including DIY options like SamplerBox or Zynthian, or a drum machine like the Alesis SR16/SR18.
3. Connect to an iPhone or iPad running GarageBand, via a MIDI-to-USB converter or BLE MIDI (Bluetooth Low Energy MIDI) using a Zivix PUC+ converter.

I went with GarageBand on iOS, which lets me practise on headphones with studio-quality sounds and zero complaints from the neighbours.

Originally published on sslabs.in.