Mini DC Generator

DISCLAIMER: This DIY DC generator is for education purposes only and is not a reliable way to generate energy for practical uses.

The intended purpose of this design is for educating youth. It is an excellent way to introduce aspiring future engineers to the ideas of motors and generators, light emitting diodes, pulleys and gear reductions, soldering, and power generation.

In the original design, the body of the generator was built using laser-cut carboard, however a makeshift model could be made to achieve the same purposes quite easily if no access to advanced tools are available. Furthermore, a 3D printed pulley is used to connect the DC motor to the belt, this could probably be improvised with a thick piece of cardboard or plastic if necessary. If you do have access to a laser cutter and wish to use these files, a modifiable .f3d file and all of the .dxf files can be found here (the STL for the 3D printed pulley can also be found there).

Materials

• ≈5mm thick cardboard
• Two DVDs
• Elastic Band
• Wooden Dowel
• Small DC motor
• LED
• Small length of Wire
• 220 Ω resistor (optional)

Tools

• Hot Glue Gun
• Soldering Iron
• 3D Printer (optional)
• Laser Cutter (optional)

Note: In the following instructions, the part labels corresponding to the filenames on Thingiverse are italicized

• Cut one of every part and 3 of the MidLayer
• Measure a length of dowel that is slightly longer than 5 widths thickness of the carboard you are using (i.e. 28-30mm should be plenty)
• Put a MidLayer piece on the end of the dowel and glue it in place
• Put one DVD on top of this, followed by the CenterDisk, then another DVD
• Put another MidLayer on top of that, then push the entire assembly through the Upright
• Put another Midlayer on the dowel on the other side of the Upright, and glue it to the dowel
• Glue the Upright into the Base
• Glue the SupportArm into the Base and Upright as shown in the in the Rear-View image above
• Solder the wires and LED to the motor (You could add a 220 ohm resistor in series to prevent burning out the LED over time, but the motor generates such a small current when being turned by hand it is unlikely this will occur)
• Install the pulley onto the motor shaft (can use a soldering iron or the bed of the 3D printer to heat up the pulley so it slides on the shaft easier
• Position and Glue the motor so the pulley lines up with the DVDs
• Run an elastic band between the pulley and the DVDs
• Glue a small section of Dowel to the side of the outside DVD to serve as a handle