HO Scale TurnTable

thingiverse

HO scale turntable. Parts: 28BYJ-48 stepper motor Longrunner A4988 motor controller Raspberry pi screws 1/4" ball bearings Adafruit 736 Slip Ring with Flange, 22 mm Diameter, 6 Wire The bowl measures 323mm in diameter. The longrunner requires a 12V power source to operate, but can function adequately at 5.5V when paired with the 5V stepper motor I'm using. You may opt for a 12V version if desired. To connect a longrunner A4988 to the 28BYJ-48 stepper motor, research is necessary; modifications to the motor are also needed to convert it from unipolar to bipolar operation. The Raspberry pi controls the motor by sending pulses to the longrunner motor controller. An on-off-on switch on the pi regulates the direction of the rail bed, and I added 0.1uf capacitors across the switch contacts to eliminate bounce issues. Alternatively, you can control it with a joystick; I chose the yaw axis on a flight stick. I incorporated a sigmoid curve equation for smooth acceleration during ramp up and ramp down movement in turntableswitchcontrol.py.