This project uses a 555 bistable circuit.
Parts Required -->
- resistors: 1k ×2, 33k ×2
- capacitors: 220µF
- 1N4001 diode
- 1N4148 diode
- red LED (3mm best)
- green LED (3mm best)
- 555 timer IC
- 8-pin DIL socket for IC
- push-switch ×2
- reed switch ×2
- relay SPCO 12V coil
- miniature magnet - each locomotive needs one
- stripboard 11 rows × 24 holes
Stripboard layout -->
Track connections -->
- Connect the reed switches to push-switches A and B (see the stripboard layout).
- The switches can be held in place between the rails with a small piece of blu tac.
- Connect the track wires to the COM and NC contacts of the relay.
- When soldering to the track make sure you solder to the outside of the rail.
- Each locomotive will need a miniature magnet glued to its underside - test first with blu tac, but superglue is probably best once you are sure it is in the correct position.
- Note that railway signals have red at the bottom, unlike road traffic lights where red is at the top.
Circuit diagram -->