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3D Printing Design Engineering

Magnetic Induction Flashlight

My most recent project has been designing and creating a magnetic induction flashlight. A magnetic induction flashlight is a magnet / human powered circuit. It is also known as a “linear induction”, “shake light”, or a “Faraday flashlight”.

The parts are 3D printed, which include an inner housing, a outer shell, and an end cap. The inner housing is where the coil of wire, magnet, PCB board, electrical components, and LED reside. The shell holds the switch, and the end cap is what holds the inner housing in.

The inner housing was modeled from an induction flashlight in which I disassembled to learn how it worked. I modified the design, changing over 30% of it such as the size, a completely new shell, and minute details, including the length of the coil – which gives it more charge. I also designed a new circuit and circuit board, and included a rechargeable battery.

Parts list:

  • LED Super bright 10mm (Jameco: 2205341)
  • NiMH 3.6v (Jameco: 2137473)
  • Diodes (x4)
  • SPST Mini rocker switch (Jameco: 2208198)
  • Neodymium magnet 9/16″ x 3/4″ (K&J: D9C)
  • 30 AWG Magnet wire (Jameco: 2119363)
  • M2 (x4-6) – Female threaded heat sinks.
  • M2 (x4-6) – Screws

To create one, first print the shell, cap, and inner housing, either yourself (if you have a 3D printer) or from a 3D printing service such as makexyz or through thingiverse. The print material is PLA. Download the 3D artwork here.

With the the zipped PCB artwork included here, order a circuit board through Osh Park or from a prototype circuit board making company. Alternatively, you could get a prototyping board from Jameco or Sparkfun, and design the board yourself.

Wind the coil.

I think I drew the schematic correctly, however, make sure to check your polarities before soldering.

When the prototype arrives, solder your electrical components to your board.

Because screws don’t work so well with PLA, heat sink the female threaded inserts into the holes.

Next, assemble the flashlight and it should be complete.

More info on how this flashlight works: K&J Magnetics or How Shake Flashlights Work

Note: This information, project, the flashlight, and designs are for educational purposes only.