Archive | April 2019

How to make a Mini Wind Turbine from a Dollar Store Pinwheel

I’m teaching a Renewable Energy venture this quarter, and I wanted to make activities for the students involving wind, solar, and hydroelectric power. Purchasing mini-wind farm kits online is really expensive, so I experimented with making my own wind farm. After a few experiments I found a fairly easy way to make a wind turbine! Here’s how to do it.

 

Supplies:

  • Pinwheels from the Dollar Tree
  • DC Motors (preferably with a motor mount. We have THIS PACK that was sitting around school, so we repurposed them for our wind farm. The motor mounts work perfectly.)
  • Gears. I modified some gears found Here , changed the hole diameter and made an .svg file for laser cutting. Use this .svg file if you have access to a laser cutter. Otherwise you will need one large gear with a 7mm hole and one wee little gear with a 2mm hole.
  • Wire cutters, alligator clips, and a hot glue gun.

 

Step 1: Clip the end off the pinwheel hub with your wire cutters. You need to remove the pinwheel.

 

Step 2: Hot-glue the big gear to the pinwheel so it’s centered over the hole. Depending on the thickness of your material, consider hot-gluing the medium gear to the pinwheel and then the big gear to the medium gear. The medium gear will just be a spacer so the motor doesn’t rub against the pinwheel petals.

 

Step 3: Hot-glue the small gear to the shaft of your DC motor.

 

Step 4: Insert the motor into the motor mount and place the pinwheel on the hub with the gears facing in. Find the spot where the motor gear meshes with the pinwheel gears. Hot-glue the motor mount to the pinwheel shaft so it stays in place.

Step 5. The pinwheel now has nothing keeping it from falling off the hub, so what worked best for me was adding a TINY dot of hot glue to the end of the hub and then when that dried, add a little more and then a little more until I had a button of hot glue preventing the pinwheel from falling off. The pinwheel should still spin freely. If not, scrape off the hot glue and try again.

 

That’s it! I clipped a multimeter to my DC motor and was able to get 0.75 volts in a stiff breeze. If you chain several together in series, you can get enough voltage to charge a battery, perhaps. A little lubricant on the pinwheel hub seemed to help.

A student and I chained several together and ran around the parking lot with them. We got up to 5 volts. We clipped a USB charger to the circuit but it did not seem to be enough to charge a phone. For students, phone charging seems to be the gold standard of “is it a good circuit”, so that feels like a good goal. Stay tuned. Let me know if you are able to stitch together a wind-powered phone charger or you find something more efficient than these Dollar Tree pinwheels.