The computer controlled
Vertical Lift-bridge.
In 1998 I started afresh with Meccano. At that time I did not have too many parts so I had to keep it simple. The model should be controlled from a computer by means of a interface connected to the parallel port. Just moving the bridge up and down was a bit too simple, so I added a couple of traffic lights in the form of two-colored LED's. It is pity that these traffic lights almost invisible in the pictures. The controlling program starts when the bridge is in its lower position and the traffic lights are green. After a few seconds these lights change to red and a moment later the bridge is slowly raised. After an operator-adjustable time the bridge is lowered again and when the bridge is back in its lower position the traffic lights change to green. Then the whole sequence is started again.
Here, at the right, you can see the old AT-286 computer that I used to command the interface. The program displays the in- and outputs from the interface cart on screen.
On the picture at the left you can see a part of the hoisting mechanism. To obtain a realistic slow movement of the bridge a substantial reduction was needed to compensate for the high speed of the motor.
The bridge in my Meccano room just after it had been finished. In this picture you can see the traffic lights.