Useless Box

Welcome to my guide on building a Useless box! This is a great project that is a fantastic challenge that produces a really eye-catching product at the end, and the code is endlessly customisable. It'll be sure to amaze your friends and family; it has received plaudits everywhere I've taken mine.

• Wooden box (approx 190mm x 125mm x 110mm)
• Arduino Uno
• Arduino 'kit' with cables, resistors, boards etc
• 2x male & female crimp wire plugs
• 2x MG990s Motor Servos
• 2x switches
• 1x P-clip
• A piece of aluminium (for the main arm) (110mm x 10mm)
• A piece of foamex (for the lid arm)
• Blocks of wood for
• 7.4v rechargeable battery
• Soldering iron, heatshrink rubber tubes, pliers, drill, screwdriver, screws, patience, whisky

The battery arrives with connectors designed for R/C projects, so we trim away the original plugs and crimp on the cable plugs. Then do the same with two regular jumper wires so that the battery can be easily disconnected from the circuit for safety, charging etc.

Although you can buy switches with cables attached, I bought a cheap multipack that needed cables.

Make sure you solder the correct terminals!

After soldering I added some heat-shrink rubber sheathes to protect the connections.

I used some old offcuts abou 25mm tall to raise the motors to about the correct height. It's not an exact science; the main arm can be bent to the right shape depending on its position, and the lid arm can be set easily as well.

Then it's just a matter of screwing the motors to the blocks, and lining them up inside the box. I screwed them in from underneath.

This piece of aluminium is what turns the main switch off when a user turns it on.

I cut a paw shape into one end of the arm but you could equally just cut a simple notch- this way the arm as able to flick the switch easily.

Bend the arm (you can do this by hand) until it's curved and the ends are about 70mm apart.

Then You need to twist it 45 degrees. I marked where I wanted the twist to be, and then using a vice and some pliers managed to get it right.

After that, it can be screwed to the star-shaped connector, which needs two of its arms cut off. You can then do a test-fit in situ, and adjust the arm to make sure it's the correct shape

I cut a piece of Foamex, which is a high density hard lightweight foam, about 90mm in length. You could equally use a piece of balsa wood for this.

I curved the ends so that it can raise the lid effectively.

Then, like with the other arm, screw it to a connector; this time I cut the two pronged connector down to one arm.

Mark a spot in the centre of the box, about 15mm down from the top of the box body. Then drill a hole about 5mm and chisel out the inside. This was a bit awkward with the box built, so I recommend doing it before you put the box together. Test fit the switch to make sure it fits and there you go!

After securing the arms in place, it's time to test everything to make sure it works.

I didn't shove everything in as cable management is important, so I left most things hanging out for now. You'll want to check that the main arm doesn't push too far, as it could damage the motor and fittings.

I unscrewed the arms to help organise the cables, after getting very frustrated trying to do it in place. Sometimes you have to think outside the box- literally!

I used tie-wraps to keep similar cables together and I was happy with the result. The on/off switch was held in place with a P-clip. You can put it wherever you like, somewhere hidden is best IMO.

And there you have it!

I hope you enjoy this project, and if you have any feedback then please get in touch.

Thanks!