The sun's pretty hot, but with the help of scrapped together components, you can beat the heat with some alkaline strapped to your forehead and a 5-volt computer fan!

Things you'll need

  • Baseball Cap
  • 5V Computer Fan
  • 4xAA Battery Pack (Supplies 6V)
  • On/Off Switch (Recommended)
  • Velcro Strips (Anything to attach battery pack to cap)
  • Electrical Tape or Heat Shrink (Recommended)
  • Box Cutter (Something sharp enough to cut out a hole for the fan)
  • Soldering Iron (for soldering)(Recommended)
  • Solder (I mean what else do you solder with?)
  • Wire Strippers/Cutters (Recommended)
  • Permanent Marker (Recommended)
  • Hot Glue (Recommended)
Circuit Diagram made with


  1. Come to terms with the fact that you're going to make a baseball cap look at least 10x worse.
  2. Use your permanent marker to outline the shape of the computer fan in the bill of the cap.
  3. Cut a hole in the bill of the cap to make room for the fan.
  4. Hot glue the fan to the hole so it doesn't fall out
  5. With your wire strippers/cutters, expose the red and black wires of the computer fan and battery pack. If your battery pack doesn't have wires attached, you'll need to solder the power and ground of the battery pack according to however it's designed.
  6. Solder the black (ground) wires of the fan and the battery pack together.
  7. Cover the exposed soldered joint with electrical tape or heat shrink. (If you were going to use heat shrink but didn't put it on the wires before soldering I bet you feel real inconvenienced right now don't you. I could've put an instruction to prepare the heat shrink before the soldering instruction but I didn't because I wanted to make fun of you for forgetting that step. Looks like you gotta unsolder that joint or dig up some electrical tape! Or use hot glue but please don't use hot glue are you crazy?)
  8. Solder the red wire of the fan to one end of the on/off switch.
  9. Solder the red wire of the battery pack to the other end of the of the on/off switch.
  10. Cover those exposed joints! It might be tricky depending on your on/off switch, but I believe in you!
  11. Now that the circuit is complete, attach the battery pack to the cap using velcro. I attached mine to the forehead, but you may choose to attach it to the back or on the top.
  12. The switch might be able to dangle freely depending on how tight it sits on your cap, otherwise I would suggest taping it, hot glue-ing it, or cutting out a small velcro piece to the hat to secure the switch.
  13. Plug in the batteries and enjoy the breeze!

Given that I made this a few years ago and gave it away as a gift, I do not have an image of the original make to show you. But luckily, through the magic of GIMP ("GNU Image Manipulation Tool" or "Photoshop but Free"), you can envision the Fan Baseball Cap for yourself on this webpage! (See the envisioning below this paragraph.)

Shabby Mock-Up of the Fan Baseball made with GIMP using images from DuckDuckGo's Image Search

Thank you so much for reading!

Image Sources of Images I Edited Together

For your safety, please don't click these links unless you absolutely need to. Included to give credit to sources.