Robert Schneider is a musician and record producer best known for his involvement in The Apples in Stereo. He is also a student of mathematics, occasional experimentalist, and a GetLoFi reader! The other day he shared this simple yet elegant mod for Mattel MindFlex.
This toy device is designed to read brain wave activity via a headset which allows the wearer to control a fan that levitates a small ball. The brain wave activity guides the fan and the ball around an obstacle course. The modification allows the wearer to use brain waves to control and change the pitch on a synthesizer via CV (control voltage). Schneider removed the DC power that goes to the internal fan and routed that to an added 1/4 inch output jack which he connected to a synthesizer.
In his own words Robert details the modification in the following video.