Leg Mounted Personal Air Conditioner
During the wedding of a good friend, I noticed his new bride was in tears due being too hot in her wedding dress. I felt terrible and didn’t want my wife to experience the same issues, so I got to work designing some sort of system to keep her cool during our wedding (which was in August!).
This simple project is effective, cheap, and doesn’t require any fancy electrical engineering or soldering skills!
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Note: The below items are not exactly the items utilized in this build. However, they are either very similar or better than what was actually used. Each of the items contain an affiliated link to Amazon.
Approximate cost for project using below materials = ~$32. You likely have some of these items lying around and can save – the original design was based completely on parts on hand (So it effectively costs $0.00).
- 5.0V USB Portable Charger
- Rocker Power Switch
- 5V USB Blower Brushless Cooling Fan
- Cellphone Armband Case
- Electrical Tape
- Hole Punch
- Hot Glue Gun
You don’t HAVE to stick to the exact products listed above, but the following instructions will work best if what you acquire is fairly similar.
Lets start with the 5V USB Blower Brushless Cooling Fan. If you purchased the recommended fan, this will be easier due to the attached USB cord. If you pulled a fan out of an e-waste dump(no judgments), you will need to attach a USB plug to connect to the battery.
Wherever the fan was acquired, you need to ensure it fits inside of the Cellphone Armband Case. If it does not, you may need to remove some material so it fits.
In the image, you can see the various parts assorted to the device. First step is to splice the switch into the wire from the fan. Do this by carefully cutting open the rubber shielding exposing the two wires inside (One red, one black). Cut the red wire and strip each end and connect an end to each blade of the switch (See below photo). This can be attached by either soldering the terminals or routing the end of the wire through the tiny holes in the blade, twist the wire to secure, then wrap in electrical tape.
Nest step is to affix the switch to the rounded edge of the fan using hot glue. Route the USB cable from the fan up the side of the fan as shown in the above image. Secure all the wires with electrical tape.
The next bit could be a little tricky. My goal was to have all the parts in a self contained unit, and to achieve this, the 5.0V USB Portable Charger plug must be turned 90 degrees from the position it was supplied. Remove the battery from the supplied plastic/metal case, the plug in is typically not secured to the actual battery and you should have enough play to gently rotate it 90 degrees. Once successful, affix in place using hot glue and wrap in electrical tape.
Now that your fan is assembled and battery is modified, attach the battery to the fan and flip the switch! If everything is correct, the fan should turn on!
Time to prep the Cellphone Armband Case – it is important you test fitted the fan and battery before purchasing your case. The fan must fit inside the case. First step is to identify the end of the case opposite the zipper and cut this side out. This will be the fan discharge (Where the air exits). To ensure the fabric didn’t tear, I sewed a small seam around the outside edge; can’t say this step is necessary, but it doesn’t hurt.
If your armband case came with a plastic sheath, then insert your fan assembly into the case(Battery end first) and mark the location of the switch and fan inlet. Using the hole punch, cut a series of holes in the plastic cover where the air inlet was – this will allow sufficient air to enter the fan. We’re using the hole punch here for create small holes (We wouldn’t want anything going in the fan… like a dress or finger… awkward…)
If your armband did not come with a plastic cover, like mine did not, then find a thin and firm plastic sheet (I pulled mine from a piece of packaging material in the trash), cut the plastic to fit over the fan inlet and punch holes using the hole punch. Affix this cover to the fan inlet using hot glue.
The last step is to insert all of your components into the armband and close up the zipper! Slip this up your soon-to-be wife’s leg and prepare for tender embrace- unless of course you are the wife-to-be and in that case you’re awesome!
The fan is fixed speed, but you could likely modify the plans by substituting a potentiometer in place of the switch to vary the fan speed.
You’re Done! (I Hope)
Congratulations, you’ve created you’re own personal AC! The 5.0V USB Portable Charger enables the recharging of the battery for reuse and no need to change out and throw away batteries. This device is great for non-wedding use too! We’ve used ours attached to a stroller to keep a baby cool, and general walking around on a hot day. Its rather convenient!