Making the Incline
We wanted the incline to have sound effects for loading and unloading. We akso wanted the truck to appear empty on the way up and loaded on the way down. The video below show the incline before the final tweaks. The way it was developed is decribed afterwards.
The initial design concentrated on how to make an object move up and then down repeatedly. The spec required there should be a stationary period at each end during which it should be possible to make sounds and noises.
The electronics compised an Arduino which controls:
1. A small MP3 player and amplifier
2. A relay to switch the sound between the top and bottom speakers
3. IR sensors at the top and bottom of the track to know when the truck is at these places
4. A motor and reversing relays to wind the truck up and down.
The image below shows the circuit board that was designed and the video on the right shows the original vertical model.
The next task was to find a way of making the trucks look empty on the way up the slope and loaded on the way down. There were a number of blind alleys but eventually it was decided to have the truck contain a platform that could be turned upside down magnetically. One side of the platform looks empty, the other looks to have slate. The pivot needs to be high enough to give room for the platform to spin. The first model is shown in the video below.
Two slab magets are under the track where the platform turns over. These are arranged with opposite polarity. The small magnet on the platform is then pushed over when the truck is above the magnet.
This is initial model was unsatisfactory because when flipped the platform was not in a stable position. This was fixed with a small pin, set almost invisibly, to stop the turn at the horizontal position. The sideways oscillations do not happen when the truck is towed up the incline with a pulley.
The places where the platform flips are in the shed at the bottom and the slate cavern at the top and so cannot be seen.
The video at the top of this page shows the solution after further refinements, which is moderately effective.