"Vactrol” is the trade name for an optoisolator or optocoupler. A simple vactrol is a lightproof packet containing an LED and a photoresistor, usually a Cadmium Sulfide (CdS) cell. Practically any material can be used as the vactrol’s casing – as long as it is lightproof (electrician’s tape, gaffer’s tape, heat shrink tubing, opaque epoxy, wood, etc.) Optoisolators are a convenient way to control trigger points within a circuit bent toy. Controlled by a homemade sequencer circuit and various devices can be triggered in predictable (and sometimes unpredictable!) patterns. Though not a prerequisite, participants will benefit from having basic soldering and Circuit Bending skills, a basic understanding of electronics components, and a basic understanding of oscillators. Participants are encouraged to bring a Circuit Bent device to the workshop.