Workshop build · in progress

The Xylophone
Robot

A machine that plays a row of glass bottles like a xylophone. The bottles hang from the frame. A belt-driven carriage runs along steel rails beneath them, stops at the right bottle, and a solenoid flicks a striker against it.

Tap a bottle, or press keys A–K. The carriage travels, then strikes.
How it plays a note

Move, stop, strike

  1. 01 · home

    Find zero

    On power-up the carriage creeps toward the motor end until the inductive sensor sees it. That point becomes position zero.

  2. 02 · travel

    Drive to the bottle

    The stepper turns the timing-belt pulley a counted number of steps, which puts the carriage at the bottle for the next note.

  3. 03 · strike

    Fire the solenoid

    A short pulse snaps the striker against the glass and lets it fall back. Hanging free, the bottle rings on instead of being damped.

Video

On the bench

Assembling the carriage on the rails, with the gantry already up and the first bottles on the bench.

What it's made of

Parts on the bench

Instrument
Glass bottles, one per note, hanging in a row from the gantry
Frame
Aluminum extrusion base on a plywood bench, with an aluminum-tube gantry above
Guides
Two parallel ground-steel rods with linear bearings
Drive
NEMA 17 stepper motor and a toothed timing belt
Belt return
Idler pulley on a shaft held in split clamp blocks
Striker
Push-pull solenoid JF-1039B on the carriage
Homing
Inductive proximity sensor LJ12A3 (12 mm barrel)
The carriage plate with a blue-labelled solenoid mounted under a vertical striker rod, riding on two steel rails beside a white timing belt
The carriage: solenoid underneath, striker rod pointing up.
Build log

From the workshop

The full rig on a workbench: a rectangular aluminum gantry over the rail assembly, with two wine bottles standing underneath
The whole rig. The bottles will hang from the top bar of the gantry.
Black stepper motor bolted to an aluminum plate, driving the timing belt, with a proximity sensor below
Motor end: stepper, pulley and homing sensor.
Idler pulley on a vertical shaft between split clamp blocks at the end of the rails
Idler end, where the belt turns around.
Low view along the two steel rails and white belt toward the carriage and its solenoid
Looking down the rails.
The builder at the workbench in front of a pegboard wall full of hand tools
At the bench.
Status

The mechanics are assembled and the carriage moves. Next: a full row of tuned bottles, firmware that turns a melody into positions and strikes, and the first full song.