Marble ball release mechanism cylinder version

thingiverse

**Danger of finger injury** *The servo is not strong enough to cause a serious injury (I don't think), but especially for very young children with small fingers it may nip them, so It is recommended to glue tube as least longer than a finger to each entrance of the device to prevent accidents with fingers being poked into the device while in operation.* #Marble release mechanism 2# Revisit of marble release problem, my previous "beam engine" style device that was not reliable enough at delivering a single ball every time. This is a very reliable mechanism allowing only one 21mm diameter ball to drop at a time, it does not fail! ##Instructions:## Attach a SG90 micro servo. Use M2.5 nut and bolt to mount the servo to the mounting points. See photographs for guide. Mount the round hub gear to the servo horn, cutting off the tips so they do not foul the meshing of the gear teeth. The cylinder rotates through 120 degrees to release the ball from a 30 degree feed tube (25mm electrical conduit) to a vertical drop out the bottom. 25mm electrical conduit should friction fit into the holes. Use the washer superglued to the shaft (only) to keep the cylinder in place. It should be glued hard against the face so there is no lateral movement, or the gears my loose mesh. The open cone side of the washer should be placed against the face as it has less surface area (less friction) and also the gap between shaft and washer should help prevent the super glue getting onto the face and gluing the shaft it in position. Keep moving the shaft while drying to ensure it does not 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, then the cylinder should move very smoothly and freely in its position before the motor is attached. Before screwing on the servo horn, thus meshing the gears, find the mid position of the servo and set this to be the mid position of the cylinder movement, so that when manually moving the servo it covers the range needed to release the ball. *Enjoy and do please comment and post photos if you make this, as it motivates me to post more!* 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 tooth for ease of printing.