This magnet powered car (skateboard figure) is one of many moving devices to be found in Christmas Display 2016. This figure will be joined by elves, Santa, and unusual toys to perform an electromechanical show.
The small wheeled car has a bar magnet glued on top. This magnet is pulled along the track by sequentially activated electromagnets.
Required parts include:
12 2n3904 transistors
12 1n4007 diodes
12 100 ohm resistors
12 volt dc, 500 milliamp power supply
9 volt dc power supply
Tiny skating figure
Bar magnet (one inch by 1/4 inch)
- left track high.stl
- long track.stl
- magnet base.stl
- track right end.stl
- wire pusher.stl
Remove the solar cell and motor from the tiny car. Glue the bar magnet lengthwise along the top of the car. Glue the skateboarding figure atop the magnet.
Apply 12 volts to each electromagnet. If the car is above the magnet, it will be pulled or pushed. When pulled, note which lead is attached to "plus" from the dc power supply. Mark this lead--it will be attached to positive in the operational configuration.
Using a 3d printer or print service, print three magnet holders and glue them together.
Lengthen the leads of the electromagnets, taking care to tape or heat shrink any connections so that they are not exposed or in a position to short against one another. Use the printed "wire pushers" to hold the wires in the wire tray.
Tape the track to the magnetic base and test the system using the Arduino sketch provided in step number one.
Glue (or melt with a soldering iron) the track to the magnet base.
The figure will "jerk" from position to position. Without feedback, it's difficult to smooth the motion. If the magnets are set in the pushing (repel) direction, the distance between magnets can be increased to 3 or 4 inches--but issues arise. If the car is directly above a magnet when it "repels," the car will flip or leave the track. If the car is stopped between magnets, the force from the nearest magnet will not restart it.
So, the next step in the evolution of this system will require feedback so that the magnets can be "fired" at the right time.