Stepper motor, gear and number of CD have to match. For example: Stepper motor 1.8° per step: 200 steps/turn. small gear wheel with 12 cogs. Large one with 120.
In this case the stepper has 2000 steps per turn, because of the 12:120 gearbox. So a revolver with 50 CDs would be possible, because you can divide 2000 by 50 or 40 steps per CD.A revolver with 48 CDs won't work.
Use wooden sticks in different sizes to create the magazine.
There is a velvet ribbon between the sticks to protect the CDs. The sticks are peaked for en easy insertion of the CDs. A 2 rings of thick wire prevent the CDs from rolling away.
Stepper motor, gear wheels & shaft are available at conrad.com.I've used an old stepper motor from a 5 1/4" floppy disk drive The stepper must be an unipolar motor.
By switching on the jukebox, a reference sequence is initiated. The revolver need a small photo sensor to detect the reference point.
The CD arm ismounted on a wooden block. The two RC servos are fixed with Tesa Power-Strips
The "hand" is made of aluminium which is deflected. The finger is a piece of FR4 and driven by a third RC servo
Insert 2 nails on the top of the "finger" to carry the CD.
The small hole of the CD is used to hold it.
The electronic works as a teachable infrared control unit. It can open and close the CD drive, select a track and play it.
An additional piece of wood with brass works as a guide and helps inserting the CD.
The exact positions of the arm can be teached in.