Marble ball release mechanism cylinder version

thingiverse

**Safety Alert: Finger Injury Risk** The servo's strength is not sufficient to cause a serious injury, but it can still nip young children with small fingers. To prevent accidents, it's recommended to glue the tube at least as long as a finger on each entrance of the device. #Marble Release Mechanism 2# Revisiting the marble release problem, I'm introducing a new mechanism that replaces my previous "beam engine" style device. This design is more reliable and allows only one 21mm diameter ball to drop at a time without fail. ##Instructions:## Attach a SG90 micro servo using an M2.5 nut and bolt to the mounting points, as shown in the photographs. Mount the round hub gear to the servo horn by cutting off the tips so they don't interfere with the meshing of the gear teeth. The cylinder rotates 120 degrees to release the ball from a 30-degree feed tube (25mm electrical conduit) into a vertical drop at the bottom. The 25mm electrical conduit should fit snugly into the holes. Use a washer superglued to the shaft, but only on the shaft itself, to keep the cylinder in place. Glue it hard against the face so there's no lateral movement, or the gears may loose mesh. Place the open cone side of the washer against the face for less surface area (less friction) and use the gap between the shaft and washer to prevent super glue from getting onto the face. Keep moving the shaft while drying to ensure it doesn't get stuck. The square of the other gear cog should push onto the cylinder with a firm friction fit. Glue if required for extra security. If a clean print has been made, the cylinder should move smoothly and freely in its position before attaching the motor. Before screwing on the servo horn, find the mid-position of the servo and set it as the mid-position of the cylinder movement, so when manually moving the servo, it covers the range needed to release the ball. **Enjoy and Share!** If you make this mechanism, please comment and post photos. It motivates me to share more projects! https://youtu.be/5PLN1OL_mF0 https://youtu.be/kqvsuGK7beo https://youtu.be/cNvKvMjKVTQ https://youtu.be/tcLlVTGSCCc **Updated 2018-03-10** Changed spur gears to 40 from 48 teeth for ease of printing.