How it works
- Same wheel as the windmill arpeggio machine, but the fixed pick is replaced by a striker: a lever on a fulcrum with a mallet on the far end. Each passing blade trips the lever, and the mallet hits whatever is set up: a bell, a drum, a block, a pipe.
- Old precedent: the trip hammer, where a rotating cam lifts a hammer and drops it.
Two ways to strike
- Direct lever. The blade drives the mallet straight into the target. Strike force rises with wheel speed, so tempo and loudness are linked. Simple, and the coupling is musically interesting.
- Cock and release. The blade lifts a spring-loaded or weighted mallet and slips off, letting it fall. Every strike is the same force regardless of speed. Spring tension or drop height sets the dynamic.
Selecting notes
Same toolkit as the string version:
- Hinged blades: a folded blade misses the lever and is a rest.
- Tilting axis: blades or tabs at different depths engage different levers side by side, each with its own target. Tilt chooses the instrument instead of the chord.
- Several strike stations around the circle (bell at 12 o’clock, drum at 3): one wheel plays several instruments with fixed phase offsets, so the geometry writes the rhythm.
Things to watch
- The mallet must rebound off the target, not rest on it, or it chokes the note. Use a stop or check so it strikes and lifts clear.
- Each strike briefly slows the wheel. Give the spin motor headroom, or add a flywheel.
- The blade hitting the lever is audible. Pad it with leather or felt, or keep the clack as part of the sound.
Build order
- No strings to tune, so this may be the simplest instrument in the windmill family and a strong candidate for a first build.
References
- Trip hammer. A rotating cam lifts a hammer and drops it. Model for the percussive windmill.
- Kick drum pedal. Converts a downward push into a forward beater swing, with return spring and rebound built in.