Several days ago on this site, AC published “Model Railroad: Backing Automobile Animation.” This article described a way to liven up your layout by creating an animated scene where a VW Beetle backed from its garage, down to the bottom of a driveway, and then returned again to the top. This small scene is in a glass encased coffee table part of which you can see in Picture 1. Needed were the following.
1. One – Tamiya Motor and Gearbox – You might find this at a regular hobby storewww.pololu.com/catalog/product/69
2. Two – Dpdt relays – Radio Shack – 1 3pole dt relay would be sufficient but Radio Shack does not carry this item. It is just as easy to wire two of them.
3. One – 12 volt DC transformer from Radio Shack
4. One – on/off switch
5. Wires of different colors to make wiring easier
A diagram for the mechanism that moves the Beetle can be seen in Picture 2. The two items you will need are very simple contacts. I made mine from those small paper connectors you see in Picture 3. You can use any type of metal that is springy enough to move a very short distance (1/8″) or less and then spring back without staying bent. If you look closely in Picture 1, the Beetle is just about to push down one of these contacts. It is hard to see because I painted the top of it to match the driveway.
I imbedded one short strip of metal into the roadway at the bottom of the hill. The second piece I also imbedded in such a way that when the Beetle’s bumper hits it, it moves down a fraction of an inch and touches the other strip. Picture 4 shows that the top contact should be mounted so it is normally closed. The bottom contact should be open.
Picture 5 shows the complete wiring diagram. When I mounted the two relays, I simply used a hot glue gun and mounted them upside down to make soldering that much easier. I did not use the relay sockets. The 12 volt DC transformer was just a wee bit bulky. I mounted a black plastic project box I got from Radio Shack to my layout bottom, and then placed the transformer inside. Obviously, you will have to notch the project box so the transformer can be wired.
When you first turn on the small system, if the car is moving down, close the bottom contact with your finger. If the car does not reverse, don’t wait for it to reach the bottom. Reverse the two wires leading to the motor. If the car is traveling up, before it reaches the top, open the top contact with your finger. If the car does not reverse, don’t wait for it to reach the top. Reverse the contacts leading to the motor. See E and F in Picture 5.
If you have any problems, you can contact me here: firstname.lastname@example.org.
Here are some adaptive possibilities:
1. A tractor trailor that stalls before reaching the top of a steep grade
2. A single car incline that travels between an upper and lower station
3. An automobile that cannot climb a roadway because of ice and snow
4. An ore car that carries minerals to the top of a steel mill furnace
5. An outside elevator that carries supplies to a building under construction