I put a WiFi router into a phone charger (Final Post)

This is the fifth and final installment about designing a WiFi router into a phone charger for security, pentesting and red teaming; (part zero, part one, part two here, part three here). Feel free to join our community on Discord! Everything is open source: Github Here.

Up Until Now

The Build

I started by 3D printing the enclosure. The print was done in PLA with my Monoprice Mini.

It was then time to assemble the two boards. Board assembly usually follows this process.

  1. Solder paste is applied using a solder stencil.
  2. Tweezers are used to place all the parts on the boards.
  3. Boards are heated using a reflow oven or hotplate.
  4. The solder paste reflows in a molten state, creating permanent solder joints.
Compute Boards on the hotplate

Most of the board uses 0402 size passive components, which are 1mm x 0.5mm. These are some of the many components that are soldered on the board.

After the compute boards were finished, I built and tested the power boards.

Fire Extinguisher not pictured

Newer readers may not be aware, but the power board stacks above the compute board as pictured below. The power board is responsible for converting mains to 5V and creating all the other voltage rails required by the central processor. The compute board houses the microprocessor, RAM, WiFi radios etc. For lots of details on the electrical design, you might find Part 1 interesting.

I then glued the contacts into the enclosure; these parts will be over-moulded during the injection moulding process in the final design. It’s essential these contacts are secure in the device; if they come off in an outlet, someone would get hurt. I wouldn’t trust my glue job for anything other than a prototype handles by myself alone.

The mains blade contacts interface to the PCB through friction fit contacts are shown below.

Final Assembly

Proto 1

What’s next

I own and operate a small consulting company; if you or anyone else needs help with this type of engineering work, I would love to hear from you!

Ryan Walker
Interrupt Labs INC.

Building things.