Glow in the Dark Double Pendulum

When I asked my oldest friend if he had a birthday wish, he told me that he would like to get something with the logo of the non-profit association he had found.

After a bit of brainstorming I decided to build a double pendulum, since I always found them fascinating.

Things you need

• 48x48x0,4 cm plywood (or a bit bigger for tolerances)
• 48x48x0,6 cm plywood
• 48x48 cm glow in the dark self-adhesive vinyl film
• 6 mm acrylic for the pendulum
• M8 screw 20 cm
• M8 screw 35 cm
• Four M8 washers
• Three 608 bearings
• Five M8 nuts
• CR2032 battery holder + battery
• UV LED

• wood primer, paint

I made the base plate from plywood. Cut a 48 mm circle with a 8 mm clircle in the middle from 4 mm plywood and the two files attached to this step according to their name.

Glue the 4 mm disc to the 6 mm ring and the other 4 mm ring to the other side of the 6 mm ring. Afterwards coat everything in primer and paint it.

I laser cut the glow in the dark self-adhesive vinyl film at a very low setting, because my vinyl cutter is too small. Don't forget the small circle in the middle.

You of course don't have to add a logo.

I used my vinyl cutter to cut the different parts of the logo. Aligning the logo was quite tricky. I found the best way is to hang it on a wall.

Afterwards I spray painted over it and removed the stencil.

Start by cleaning the bearing with brake cleaner and cut the pendulum pieces from 6 mm plywood.

The best way I found to clean the bearing was to just let them sit in the break cleaner for about twenty minutes and aftwards place them on a paper towel to let them dry.

Start by soldering the UV LED to the battery holder and press it into the bottom part of the pendulum.

Afterward connect the two pendulums, as shown in the second picture.

Now you can attach the pendulum to the disk. Use a 35 mm screw, add a washer, then the wooden disc, two nuts, two washers, the pendulum and another not. You can of course also use a distant holder.

Enjoy the fun!