009 or N gauge Turntable Servo drive 100mm UPDATED

thingiverse

UPDATE File turntableNM.txt added. This is an Arduino sketch. Copy and paste into a completely blank sketch. Three libraries are required: stepper.h, EEPROM.h, and encoder.h. The stepper motor is 28BYJ-48 with a driver board, while the rotary encoder is a popular cheap one found on auction sites. The motor requires a 1 amp power supply at 5V DC, which can also power VCC on Arduino, but this is not recommended when used with USB connected. Note that this sketch has not been tested or debugged yet and will be completed in mid-August 2020. This project is still under development. This is a stepper motor-controlled model turntable designed for 009 but compatible with short N gauge locos (loose the fences). The bed is 100mm long, and the Arduino code will follow in the coming weeks. Primarily designed for DCC++ JMRI CMRI control, I also plan to include manual button control for up to six tracks (with forward and reverse positions for each). A prototype has been working manually but not as part of a layout. It rotates smoothly and has very little backlash, so it's just a matter of software. Other materials required: * 009/N track (100mm) * 28BYJ48 Servo & Driver * Three or three-point-five millimeter screws and nuts * Copper foil (guitar scratch-plate hum screening type or thin copper sheet) thirty by thirty millimeters * Two electric guitar strings (top and bottom E) * A short piece of two-point-five millimeter solid copper wire (UK socket cable) fifty millimeters long * Arduino * C/MRI library for Arduino (for JMRI control) * Rotary * Handfuls of push switches, LEDs, resistors, etc. * Ultra mini microswitch 125V five amps * Five-volt power supply * Hook-up cable, tools, and accessories * Two axles six millimeters 009/N gauge wheels (solid metal type but others may work) Printing: Print three spacers, two handrails, and one of everything else. I used ABS with supports no raft on Acetone sprayed, ABS wiped, Kapton covered glass in an old covered CTC dual head. Assembly: Remove all the supports Prep the tub Paint before assembly and handrails Countersink the three holes in the base to suit your screws. Screws need to be long enough to pass through the tub, spacer, and mount with nut. Stick a piece of copper foil over center, knife round the edges, and push through the holes to make two semi-circle tracks. Add more tape strips from each track to the back and solder connection wires, one to each semi-circle. Glue down wires as strain relief Fill the rest of the holes with CA gel glue and kicker spray. Get the foil and glue as smooth as possible. Check that the two semi-circle tracks are not shorted. Use grid covers to mask screw heads. Assemble Bridge: Strip approximately thirty millimeters two-point-five millimeter solid copper cable straighten it Using a file or Dremel form shoulder in the wire stepping down to approximately one millimeter diameter forming a step taper. There should be about four millimeters of close-wound spring pull it out to about fifteen millimeters long, trim, and make another. Glue outer track bed to bridge on one side. Drill three small holes from under the bridge to mount the other side. This will be obvious. Get this exact or the turntable won't line up. Use a length of track to get the sleeper spacing right. Don't fit the center bed yet. The four small holes in the bridge should be directly under the rails and the large hole center. Pull off four wheels from the axles and fit flanges innermost using thick wire as axles Drop the tapered copper pins taper down through the top face of two diagonal small holes Three-point-five millimeter screw through the center of the bridge tighten a lock nut behind, trim to twenty millimeters long protruding from the underside of the bridge. Add another locknut. Clean out coupling. Insert three-point-five millimeter nut into square radial hole align with axial hole Ensure motor spindle is a snug fit in coupling then assemble the motor and mount. Screw the bridge assembly through the tub into the motor mount until wheels run smoothly on rail. Tighten locknut, add handrails. The timber boards relief in decking will be concealed by squish.