Haptolin is my Arduino-based, microtonal instrument/MIDI controller. The project is mainly inspired by:

• Theremin

• Modulin

• Haptx Glove

• Power Glove

Haptolin produces a theremin-like sound while providing an analog haptic feedback allowing for a precise pitch control. Whereas Haptx glove relies on complex, actuator-based feedback system, haptolin uses simple braided elastic bands. The higher the pitch the stronger the response. The left key controls the pitch, the right one controls the dynamics.

Unlike most of the microtonal MIDI instruments, Haptolin uses native MIDI and implements the microtonality through pitch shifts in between the notes. Thanks to this solution Haptolin is compatible with most of the MIDI synthesizers without any drivers needed.

You can check my haptolin cover of Wintergatan's "All Was Well" here:

You need a 3D printer to make the elements. The haptolin was photogrametrically fitted to my hand, so your experience may vary depending on the palm size.

During assembly, you should slide the potentiometers in the holes and use a nut to fix them in place. The elastic bands are hooked on one side to the keys attachements, and on the other side to m3 bolts that hold the 2 pieces of the case together (it's visible on one of the close-up pictures).The belt is a 30mm-wide elastic strap. On one side (next to the power bank) you glue it to the case, on the other side it is held with an m3 nut, which makes it sort of adjustable. (you only need to ajdust it once - you can just slide your palm in when the strap is mounted properly).

The project is also available on Thingiverse:

https://www.thingiverse.com/thing:4190495

EXPANDED TECHNICAL DETAILS

Tactile String Instrument Synthesis

Haptolin is an experimental digital violin that replaces traditional physical strings with high-sensitivity haptic and capacitive sensors.

• Touch-Sensitive Fingerboard Matrix: Uses a series of capacitive touch strips along the "Neck" of the instrument. The Arduino identifies the exact finger position and maps it to a musical pitch using an 8-bit chroma table.
• Haptic Feedback Resonator: Includes a small vibration motor or a piezo actuator in the body. The Arduino modulates the vibration intensity based on the "Bowing" speed, providing the player with a tactile sensation of a vibrating string.

Performance

• Low-Latency Audio Triggering: Optimized for sub-10ms response times, ensuring that the student can perform complex musical passages with real-time digital sound generation.