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Homemade CD Changer Robot
The customized CD changer contains discs that are stacked 10 high on wooden pegs arranged in semi circles of six on seven shelves with the CD player drawer and an empty peg used to store the next disc to be played.
A maximum capacity of 400 discs is given by the left 40 pegs of ten discs. They are moved by a robotic arm with rubber suction cup on the end made out of toy dart. A stepper motor with a gear box moves the arm radially. This was attached to a trolley on steel rails which was moved vertically by a toothed timing belt driven by a large 12VDC motor with a gear box. The end of the arm has three micro switches where the left hand was used during initialization for finding the home position of the arm and the other two for safety. The limit switches was wired in series with the motors since the vertical motor is so powerful that it could easily snap the arm off.
The controller uses a Motorola MC6809 microprocessor with 32K battery backed RAM, 32K EPROM, timer, UART, and two PIAs, contained in a single chip.