Showing posts with label Project. Show all posts
Showing posts with label Project. Show all posts
Model Railway Signal Project
A magnet under the train operates reed switches positioned on the track. The first reed switch changes the signal to red as the train passes, then further along the track a second reed switch changes the signal back to green ready for the next train. The isolated section of track just in front of the signal is switched off by the relay when the signal is red so a train will stop automatically at the red signal.
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
Simple Electronic Lock Project
There are six (or more) push switches. To 'unlock' you must press all the correct ones at the same time, but not press any of the cancel switches. Pressing just one cancel switch will prevent the circuit unlocking. When the circuit unlocks it actually just turns on an LED for about one second, but it is intended to be adapted to turn on a relay which could be used to switch on another circuit.
Please Note: This circuit just turns on an LED for about one second when the correct switches are pressed. It does not actually lock or unlock anything!
This project uses a 555 monostable circuit.
Parts Required
- resistors: 470, 100k ×2, 1M
- capacitors: 0.1µF, 1µF 16V radial
- red LED
- 555 timer IC
- 8-pin DIL socket for IC
- on/off switch
- push-switch ×6 (or more)
- battery clip for 9V PP3
- stripboard 12 rows × 25 holes
Stripboard Layout
Circuit diagram
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