Introduction: Computerized Wheelo--Santa's Shop 2016
Did you ever get tired of operating your Wheelo by hand? I know I did, so I automated the process using a servo motor to raise and lower the wheel, a ping ultrasonic transducer to detect location and an Arduino to manage the feedback.
Mount the parts and wire according to the schematic. The Arduino sketch I provided will cause the mechanism to lower for two seconds then rise. It will remain in the upper position until the ultrasonic detector recognizes that the wheel is closest to the mechanism--then the cycle repeats.
It is necessary to power the servo motor from its own 5 volt supply. The Arduino supply can't handle the motor load and weird things will occur if you attempt this (says the voice of experience).
Actually, I am using this as an automated toy in my Christmas Display, Santa's Shop 2016.