Barrel Organ – AKA MIDI Crank

In the same manar as a barrel organ, this is a box with a crank connected to a rotational sensor.

Playing a hackedup drumbeat via MIDI. ie. rotating backwards will play the drum backwards.

Presently, one idée explored, is using a rotary potentiometer to try to make a simple 360-degrees sensor to mount the crank on.

We scraped the potentiometer solution and went for a twin diod, intermittent transparent rotating disc solution. The LED‘s trigger LDR‘s on the other side of the disc and their offset positioning makes it possible to detect the rotational direction.

Here are some pictures of the first testrigg.

Olle trying to simulate the darkness of the box with a cloth

The crank has showed to deliver LDR-values that are not completely stable. This have forced us to construct a continuously-auto-calibration of the sensors.Using this setup we seem to be able to make the crank run at an acceptable level. The fact that the triggers are coming in a uneven fashion is yet to resolve.