Making a Party Lights Gondola Lift With the Kids

When my youngest daughter's godmother was giving a big garden party, I threw a workshop for the kids. To contribute to the decoration in an original way, we made a 25 m long gondola lift with 18 Joule thief party lights. We had a great time and the result looked really festive. It is hard to photograph small moving lights at night, but this video gives an impression:


At the party the lift was hung between two trees and served till the next morning. After the party, the children were allowed to take their gondola lights home (always important for kids). Back home we hung the lift between my oldest daughter's bedroom window and her tree-house in the garden. Some of her friends came over, bringing their light gondolas from the party, and attached them again, making the fun last even longer.

There seem to be not many instructables on gondola lifts or cable cars. A nice one is https://www.instructables.com/id/Miniature-Moving-Gondola/. However, in this instructable I show how you can make simple and cheap pulley wheels out of plastic dinner plates, that allow for an easy, yet stable attachment of the gondolas. I illustrate the gondolas we made with a kind of joule thief flashlights shining down on reflective aluminium foil shapes, but of course you can make your own. You can use led throwies as even simpler party lights or go for gondolas transporting messages, small toys or modelled after the real thing. The gondolas we made weighed a good 50g each, but I guess the construction is suitable for gondola's up to about 100g or more, depending on the number of gondolas and the span of the lift.

Of course you will need two safely accessible endpoints for your lift, in a clear line of sight from each other.

This the parts list for the gondola lift:
- a windscreen wiper motor salvaged from a car (or a similar very low rpm geared motor, around 50 rpm)
- a power source suitable for the motor, either battery or a power supply (I found a 12 V switching power supply rating 1200mA just coping with the motor at its lowest speed).
- two matching pairs of plastic camping dinner plates (not the high end hard plastic types, but the cheap, slightly flexible ones. I tried both dinner plates and deep soup plates, but the deep plates do not work on the motor side, as their high rim touches the motor).
- some small screws
- hot melt glue (or a lot more small screws)
- a “side wheel” (see picture, I used 35 mm diameter pvc furniture wheel)
- a couple of washers large enough to fit over the axle of the drive shaft
- a nail 2-2,5 mm diameter
- tie wraps or an alternative to attach the motor to a support
- some scrap wood and larger screws to make two supports (this will depend on what you want to attach the lift to)
- some rope, two times the length the lift has to span, + some extra to make the knot (I used kite rope, about 2 mm in diameter)
- 1 to 2 mm steel wire, I used about 50 cm length for each gondola
- some sturdy tape (e.g. duct tape)

To this you add the materials of your choice for the gondola’s (see last step for inspiration).

Of course, you will need some tools:
- a hot melt glue gun
- a drill and drill bits for steel (diameter 2,5, 4 mm and 10 mm)
- screwdrivers for the screws used
- scissors
 

Start making the wheels supporting and driving the cable/rope biy drilling a 10 mm whole in the middle of the plate. You can use the markings left by the production of the plate (injection moulding) to find the middle. Next, each pair of plates is glued together bottom side to bottom side to form a pulley wheel. Apply hot melt glue to the bottom of one of the plates as shown in the picture) and without hesitation put the other plate on, using the center hole to align. Check the alignment of the sides before the glue sets completely and press. 

One wheel is driven by the geared motor. On a windscreen wiper motor the connection to whatever is driven is usually made pressing it on the axle with the bolt. But with plastic plates/wheels that does not work well. Instead, with the bolt screwed on completely I drilled a 2,5 mm hole through bolt and axle, in order to be able to insert a nail. Nail and bolt are removed and before the wheel is put on one or two washers are added to make the wheel fit tightly but not being squeezed under the bolt screwed to the end. Some small screws in the wheel catch on to the nail put through the hole again. Some hot melt glue put on top removes any slack and prevents the nail of falling out.

For the non-driven wheel the center hole only serves as a guide to position the “side wheel” in the middle. Mark it out  the small “side wheel” on the pulley wheel and drill 4 holes in each in the same pattern. Some small misalignment is no problem.

Now, first attach the “side wheel” on a piece of wood and than attach the pulley wheel on it with 4 small screws (If you would try to do it the other way around, it would be nearly impossible to reach the holes of the side wheel mounting plate). Make sure the screws do not hinder the turning of the wheel assembly.

Attach a piece of wood to the motor with tie-wraps or any other way you prefer. Make sure it can not slide of. A screw here or there can help prevent that. I also advise to attach a “safety rope” to the motor independently. Later, you first attach this safety rope to whatever endpoint you have chosen (e.g. tree, furniture…) to avoid the heavy motor falling whenever anything goes wrong when mounting or in use.

Obviously both wheels are mounted horizontally, each at one endpoint, with the supports on the top side and the bottom side free. Also make sure there will be enough space for the gondola’s to pass easily. How you start out of the first piece of wood to make a make a construction to mount each of the two wheel assemblies will completely depend on where you put them. Therefore I while not go into that. Use your own insight and make sure it withstand some force (you should not be able to pull it apart with your bare hands (unless you are into power training or something).

Knot the rope into a long loop running over both wheels. You should put quite some tension on it. I make a first loop fitting on rather loose and then remove it and make a knot to make it fit a little tighter. I repeat this in couple of small steps till I can just pull it over both pulley wheels.

When building the lift outside, take care with any mains connection that might come into contact with water. A simple approach is making the mains connection indoors and from there go outside to the motor with 12V.

The basis of each gondola is formed by a piece of steel wire allowing for it to run “in” the wheels. It starts with a short end (about 1,5 cm) to be attached in parallel to the rope. Then follows a bend bringing it outside the wheel’s rim. Some more bends are made as a counterweight. The latter is not necessary if the gondola itself forms a counterweight.
Take care none of the inwards bends measure further than half of the wheel diameter, as otherwise the gondolas will hit when passing each other.

In the picture you see how the small “connection” piece is slightly bent "out of the plane" to bring equilibrium in tha direction too.

A small piece of tape put on the steel wire end is rolled tightly over the steel wire and looped rope together. Check how it fits in the pulley in the last picture. One kid operating the motor till the desired spot of attachment passes and stopping it so another can attach his or her gondola proved to be a great little game of collaboration.

We made a kind of joule thief flashlights, based on a construction derived from my cyborg zombies https://www.instructables.com/id/Cyborg-zombie-feeding-on-quotdeadquot-batterie/

The battery holders were made of cardboard, but that proved to be a lot of work. I do advise to pick up some ready made battery holders or make your own following any of the Ibles available on that subject. We used high yield 5mm LEDs in different colours (3 000-10 000 mcd depending on the colour) and let them shine down on shapes made from aluminium foil. Actually letting the LED light shine one the ground also gives a nice effect of traveling spots, but it tends to get lost when people are walking under the lift. So we stuck to catching the light on reflective shapes.

When we put the lift back up at home, soon a gondola able to carry a message or a small freight came soon to mind. A simple way to make one with a little cardboard box we had lying around is shown in the third picture. The end of the steel wire was bent perpendicular and inserted in a blob of hot melt glue on the bottom.

As said earlier LED-throwies would work to, but it would be less ecological. In contrast, a greener possibility is using solar garden lights (se last picture). The clear plastic part can even double as a cargo or play figure passenger space. For the 18 lights at the party that would however have been to expensive.