Schematics / Percussion Ribbon Controller
Percussion Ribbon Controller by Electronic Peasant ,for more details on the construction of this controller visit http://www.electronicpeasant.com/projects/ribbon/controller.html from there the brief description on the circuit and it's functionality :
A 2 foot long piece of 1 1/2 inch diameter wooden dowel was mounted horizontally on the top of an old lamp stand with some angle brackets and wood screws. Along the top of this dowel a length of 1/2 inch mylar adhesive tape was applied. Then graphite powder (the type for lock and key lubrication) was rubbed into the mylar tape until the total resistance from end to end was about 100K ohms. Next, a belt was trimmed to the same length as the dowel. Then a 1/2 inch wide strip of brass shimstock was glued down along the center of one side of the belt. The belt was then attached to the top of the dowel at either end with washers underneath, so that it was suspended over top of the mylar/graphite tape with the brass strip facing down. Electrical connections were made using ring lugs on one side of the assembly.
Next, a basic sample and hold was built for the controller using a FET and a few op amps. The circuit is similar to that which Eric Barbour uses for his keyboard controllers, with a few mods and additions. The electronics was installed in a nifty little plastic box and attached it to the stand just under the ribbon controller. It has three controls; pitch, which offsets the CV output; width, which increases or decreases the CV output range; and glide, which is a basic portamento. There is one LED for power and another to indicate triggering (bright flash) and key down (dimmer steady light). As the whole circuit is just running on a single 15 volt supply, CV output range is from about 1 to 14 volts, which works well with my tube oscillators but which could also be adapted to solid state oscillators if required