The useless box is a fun and innovative way to learn and understand systems and controls. While making the useless box you will learn how to laser cut, how to make connect circuit, and how to solder. When switched on a lever will come out of the box switching it off. I hope you have as much fun as I did while making this box!

Supplies

Tools:

Soldering Iron
Laser Cutter

Parts:

DPDT Switch x1
Gearbox x1
Motor x1
Wires x7
Battery Pack x1
Micro switch x1
PVA Glue (I used Gorrila Glue)
Heat Protectant x1

Step 1: Learning How It Works.

Inside the box, in the circuit, there are 2 switches, a momentary switch which is a micro switch, and a toggle switch. The toggle switch is on the top of the box and what you switch. The microswitch is what opens and closes your circuit. There is a motor, which moves the lever to the toggle switch. A battery pack, which you need to make the motor work. Plus wires which you need to solder to connect the circuit. The microswitch has 2 states - normally open and normally closed. When you flip the toggle switch the micro switch closes entering a state of normally closed causing the current to flow through the circuit, making the motor move the lever to extend out of the box flipping the toggle switch. After the toggle switch is hit by the lever the current starts to flow in an opposite direction making the lever go back down to hit the micro switch, opening the circuit back to how it was at the start which is in a state of normally open.

Step 2: Laser Cutting

Using the file attached below, the first step will be to laser-cut all your parts for this project.

uselessbox.ai
Download

Step 3: Assembling Your Parts

In this step, you will not assemble all your parts, only a few pieces. Using PVA glue, attach both the sides to the bottom part then glue on your back bit on. In the end, it should look like how it does in the second photo.

Step 4: Soldering

Using the diagram in the first photo drawn by Mr. Walker, you should solder the circuit using 7 wires (the colour does not matter).

Above are real-life photos of the diagram for extra guidance on what to do. It is a photo of my DPDT toggle switch, microcontroller switch, and battery pack being soldered together. It is a good idea to check and see if the circuit works by connecting it to the motor before soldering it to the motor.

The first step is to solder the DPDT toggle switch, following the diagram get all the wires soldered to this switch before soldering them to anything else.

The next step is to solder any of the 2 wires in the top left corner and bottom right corner to the microcontroller switch. It does matter which wire connects to where so be sure to really look at the diagram. Connect the top left wire to the 'Con' pole, and the bottom right wire to the 'No' pole (Not the middle one).

Now, we can connect the battery pack. Using the top right wire and the top left wire that is not connected to the microcontroller solder you can solder them to the battery pack. However, for this one, it is important to have a wire heat protectant on. The way to solder with a wire heat protectant is you cut a little bit of your heat protectant and slide it over one of the wires, then you proceed to solder the wire from the toggle switch with the wire from the battery pack. After this is done you slide the heat protectant over the bit of exposed wires and then you tap the soldering iron on the heat protectant so it scrunches up and does not move. It is important to note that the top right wire should go into the positive, and the top left into the negative.

Lastly, we will check the motor connection before soldering it to the motor. Ensuring that there are batteries in the battery holder, hold the 2 wires in the middle of the toggle switch to the 2 metal bits sticking out of the motor (It should not matter which wire you connect to the motor bits, but if it doesn't work it is a good idea to switch the wires). If your motor moves, you can proceed to remove the batteries from the pack and solder the wires to the motor, also remembering to check it again once it is soldered. If your motor does not work look at the key things down below to see if there is anything wrong with your circuit, or try and switch out the motor.

Some key things to note about soldering/problems which could arise:

Be careful not to overheat your DPDT toggle switch
Make sure the wires are neat if the individual exposed from one pole wires touched another from another pole the circuit can short circuit. Some ways to fix this problem are twirling the wires together before soldering them or cutting wires that touch one another.
Dry joints happen when there is not enough solder, however, this was a quick fix by adding more solder to the circuit. A way to check whether or not you have dry joints is by moving the wire, if it can move that is a sign you have dry joints.

Step 5: Testing

Testing to see if it works is a crucial step before finishing the product, this is because it will allow you to see if you want to change anything before finalising it. Before glueing the top bit on, I put masking tape on it to see if everything fits, and if the product as a whole works. If the product works you should see that when you flick the switch the lever will come up and flick the switch back.

A problem that could arise is that the switch is too strong for the lever… This would be because the spring in the switch is too strong for the lever to push back. A way to fix this issue is to uncap the switch using pliers and GENTLY take out the parts, you will then remove the spring which is at an original length of 1cm and cut no more than 0.3 cm off the spring, then making sure to use pliers and expand it back to the original length of 1cm, and put all the part back.

Step 6: Put Finishing Touches

If all is fine in the testing step you can finalise your product by using the 5 remaining laser-cutting parts left . You need to use PVA glue to glue the 2 bits that are coming out of the rectangular-looking figure to the circle in both the other bits, and you will need to connect the male tabs with the female tabs, the rectangular-looking figure being in the middle of the other parts. Then connect the other smaller rectangles (shown in the photo labelled 3) bottom with the big rectangle (not the one you have already used), and attach it to the front of you box. Lastly, attach the male tab with the female tab.

All done!