Building a multiple device charger


Picture of the device charger

In this walkthrough I will describe how we build our device charger and what to be aware of when assembling it.

WARNING

Before you start making your own device charger, remember that this project requires you to work with mains power. Mains power is dangerous. You could burn down your house or kill a kitten and remember that you will be connecting your valuable USB device to it. If you are new at building electronics or unsure of how it works, consider waiting with making this project.

Also if you are planning to use the device charger with Apple products then you will need to do some additional work for it to work. You can find information about this here: Device charger improvements.

To build your own you will need the following

The most important parts to this build is the power supply. The power supply needs to be a 5v power supply with enough amperage to simultaneously charge 8 devices. We decided on this 5v/10A Switching power supply which should be more then enough to charge 8 devices even if a couple of devices should be tablets.

You will also need the following components:

  • 8 x USB Cables
  • 8 x USB Breakout boards
  • 1 x Power socket
  • 1 x IEC 320 C13 Power cable
  • 1 x Fuse for the power socket, 0.5 A should be enough.
  • 1 x Volt meter
  • 1 x 5 pin terminal block
  • 16 x 3 mm spacers OR a piece of 3 mm acrylic
  • 16 x M3 Bolts
  • 16 x M3 Nuts
  • A large piece of 4mm plywood
  • A role of masking tape
  • Some shrink tubing
  • Small piece of 3 x ~1.5 mm² wire
  • Some black and red ~0.5 mm² wire

You will also need access to the following tools:

  • A laser cutter capable of cutting the 4mm plywood
  • A hot glue gun
  • A utility knife
  • Lighter/Blowtorch
  • Soldering iron
  • Multimeter

Preparing the parts and cutting files

Most of the parts that you need to make are designed to be cut on a laser cutter, all the files needed can be found on Thingiverse

You need to adapt the cutting files to match your laser cutter, but other then that you do not need to modify the files in any way. You can of course make your own design changes to the files e.g. engravings. Just remember that the cuts made on the front plate must not be altered in order for it to bend properly.

Also if you made any changes in the parts list, make sure that you take this in to account an make the appropriate changes.

Laser Cutting

Start out by making a test cut of the plywood. Due to the way plywood is made the power need to make a clean cut with a laser cutter can vary and you need to have this dialed in for this to work.

After the laser cutter has been calibrated cover the surface of the plywood with masking tape, this will prevent fumes and small flames from damaging the surface of your charger. If you decided to add an engraving, then remember that you may need to use a little more power when engraving to compensate for the masking tape.

For the device charger you will need to make:

  • 1 x Right plate
  • 1 x Left plate
  • 1 x Back plate
  • 1 x Bottom plate
  • 1 x Front plate
  • 1 x USB Breakout board
  • 2 x Power supply support
  • 5 x Support

If you did not find some 3mm spacers then you will also need to cut 8 x 3mm spacers.

Cutting process

Charger assembly

Assembling the charger can be a bit difficult as it needs to be assembled in a specific order and manner.

First step is to add the supports to the front plate. This can be a bit of a pain, so if you have friend at your disposal you might want to enlist a little help. The most important part is to bend the front plate and then tape it together using masking tape. This is important as the force from the bended front plate will break the supports if you do not have almost all of them mounted.

Adding charger support

Before adding the two power supply supports make sure that the power supply fits through the mounting holes. Then add the power supply supports in the center towards the left plate (The side with the holes for the display and power socket). However make sure to have space on one side to maneuver the power supply in to place before adding the rest of the support pieces. Finally add the right plate.

After adding the right plate, supports and the power supply, you should start to glue the charger together. Start by gluing the front of the charger front plate to the supports. Make sure that the supports a aligned correctly (You can use the top and bottom plate to help align them). Do NOT glue the top of the front plate yet! (The last bend with the holes for the USB Breakouts).

The next step is adding the USB breakouts. Start by soldering the wires to the breakout as these will be hard to work with after mounting. I used small pieces of shrink tubing to make it easier to work with the wires after mounting. After soldering the breakouts, slide in the USB Breakout mount through the holes in the top of the supports, remember to turn it the right way. (The holes should face down).

Now bolt the breakout boards to the mount adding the 3 mm spacer in between the breakout board and the wood mount. Pull the wires from the USB breakouts so that they all end up near the connections of the power supply. Start by mounting one breakout board and confirm that the breakout fits in the holes on top of the front plate, before you start adding the rest.

Wiring the USB breakouts

Now it is time to connect the display and power socket. You should start by confirming that the display and the power socket fits into the left plate, this may require a little rework of the holes and/or sockets to make them fit together. Once the parts fits, solder thick wire to the power socket and remember to use shrink tubing so that you don’t risk a short on the main wires. Confirm you wiring using a multimeter before connecting anything

Glue the terminal block to the charger and start connecting the wires according to this diagram. Start by connecting the power socket to the power supply and confirm that the power supply’s output is correct. Then add the volt meter and confirm that it displays the correct values. Finally add the USB breakouts and once again confirm the values. You do not want to risk you smart device being fried because you were to lazy to test 8 USB sockets.

NB. Your parts might be different than the ones we used. Please validate that the diagram is works with your parts

Wiring diagram

The device charger is now almost done just add the bottom plate and glue it to the rest of the charger. Finally add the back plate, we did not use anything to keep the back plate in place, but you may need to.

Now just relax and enjoy your new device charger.



By: Rune Haugaard