Rotating Miniature London Eye

My niece, aged 10 (almost 11) asked me to make something "cool" for an assignment. She has to make a "Show and Tell box" about England. She has to cover the outside with pictures of England and she also has to put things in the box that she can take out when asked and tell something about it. She imagined a rotating London Eye on the outside. We did some thinking and came up with this, easy to make, solution.

Materials:

• Plywood (I used 4 mm poplar plywood from our schools scrap box)
• Dc gear motor (Sparkfun) for example or aliexpres)
• Toggle switch (aliexpres, Sparkfun)
• Battery holder for AA batteries (aliexpres, Sparkfun)
• Some wire (I used the wire of the battery holder)
• Glue (wood glue, superglue and hot glue)
• Two m3 nuts and bolts
• Some solder

Tools:

• Drawing program (I used CorelDraw)
• Laser cutter (optional)
• Soldering iron
• Hot glue gun
• Screw driver
• Sanding paper

First I designed the London Eye wheel. I downloaded a photo from wikipedia and used that as a template. Of course I had to give in on the details somewhat. The number of capsules in this model is the same as in the real thing. And also the structure of the wheel itself is the same. The number of spokes is less and they are much wider in my model. I also designed a center where the axis of the motor can be attached. That is also not on the real wheel, which is driven from the ground.

You can download the design files I made. The original CorelDraw file is not included. It is not supported here. Send me a message if you want to have it.

I then cutted the wheel with the laser cutter at my school. It took some iterations. I was happy with the final wheel, which is 150% of the original design (so the diameter is about 150 mm). Smaller was too fragile.

It is of course also very possible to print out a picture of the London Eye and glue it on a piece of wood or cardboard.

My niece and I settled on the idea to have the motor on the inside with the axis sticking out. The wheel is in the box and can be attached to the axis. So we had to design a structure to hold the motor. I used makercase.com to design the first basic box. Then I made some iterations to have the box fit in the shoe box, to attach the motor to the box and a switch sticking out.

As ever the first cut on the laser cutter was not good. The third one came out great.

The files are attached here.

Here it is also possible to make the box without the laser cutter.

The circuit is quite simple. The battery, the motor and the switch in series. My niece had her first soldering experience! She enjoyed it very much.

The it was time to assemble the whole thing. I glued the box together with wood glue and (on hard to glue places) superglue. We attach the motor with the nuts and bolts and glued the battery holder in with hot glue. Then we put it in a test shoe box (the real one is at my nieces place). We put some tape around the edges to hold it in place and made a hole for the axis.

Time to test it all out. It worked like a charm. Maybe the hole for the axis could be filed to the perfect shape but that is a small detail.