Thrift & Print

This week in CEP811 we had to pursue a “thrifting” project. Thrifting is essentially taking junk and making it into something useful. Fortunately, this is already something I do on a fairly regular basis (I’m a cheap, cheap, person), so I already had a bunch of junk lying around that I could use for inspiration. The kicker here, was that we had to combine our junk with our maker tool, which in my case is a 3d printer.

I got to looking around at my junk piles here and there, and came across a box of old computer fans that one of my classes pulled out of a bunch of ancient computers we junked last year. I don’t know a whole lot about electric motors, but they interest me, and I find it hard to throw one away. I thought to myself, there has to be something fun that I could do with these, and they are small, so it shouldn’t take a lot of material to 3d print something to go with them (with 3d printing time and material are big factors in decided what to print). I set out to do some research on the net of what other people have done with old computer fans. Out of all the projects I came across, two interested me most. The first was a computer fan generator, and the second was a computer fan boat. Here are the videos that caught my eye:

Because I lacked the little electronic pieces necessary to complete the generator, I decided to go with the boat, but ordered the parts I needed for the generator, so I can experiment with that later.

Now, looking at the video, you can see that a 3d printer isn’t necessarily needed to complete the project, however, my goal isn’t just to build a boat, it is to learn something about physics in the process. My thought process was to have the students design their boats from the ground up, using the 3d printer when needed to tweak the aerodynamics (aquadynamics?) and their propeller design. Looking through the new middle school science standards, here are some that I thought this project could address:

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I began to gather all of my materials. Here is what I needed to complete one boat (this could change depending on your boat design, and what kind of cutting / grinding tools you have available):

  • 1 9v battery
  • 1 9v battery receptacle
  • mini-toggle switch
  • plastic bottle
  • computer fan
  • 3d printer
  • pair of scissors
  • shoe goo
  • wood clamp
  • razor
  • high speed cutting tool (dremel)
  • bench grinder
  • all purpose snippers
  • duct tape

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My first step was to separate the fan from its enclosure. I did this using my high speed cutting tool. A dremel would work just as well.
My first step was to separate the fan from its enclosure. I did this using my high speed cutting tool. A dremel would work just as well.

 

Then, using my all purpose snippers, I roughly cut all of the blades off the fan.
Then, using my all purpose snippers, I roughly cut all of the blades off the fan.

 

Next, I used my bench grinder to grind off what was left of the original blades.
Next, I used my bench grinder to grind off what was left of the original blades.

 

I needed a power source. I thought I would try a 9v battery. I cut this one out of little dog whistle thing that is suppose to keep our neighbor's dog from barking, but doesn't work.
I needed a power source. I thought I would try a 9v battery. I cut this one out of little dog whistle thing that is suppose to keep our neighbor’s dog from barking, but doesn’t work.

 

Using a small pair of scissors, I cut and stripped the wires from the fan and battery. Then, twisted them together. It worked, the fan started spinning!
Using a small pair of scissors, I cut and stripped the wires from the fan and battery. Then, twisted them together. It worked, the fan started spinning!

 

I need to see how to go about designing my new propeller system. I decided to try and remove the entire original blade assembly, which was a bad idea, as it the fan inoperable. Lesson learned, I repeated all the earlier steps and go back to a usable base fan.
I needed to see how to go about designing my new propeller system. I decided to try and remove the entire original blade assembly, which was a bad idea, as it left the fan inoperable. Lesson learned, I repeated all the earlier steps with a new fan, and got back to a usable base motor.

 

So, I would have to build my new blade system to attached to the old one. This is what I came up with for a first design. I chose three blades, because I recently watched a video about why wind generators have three blades, and figured it was as good a place to start as any.
So, I would have to build my new blade system to attach to the old one. This is what I came up with for a first design. I chose three blades, because I recently watched a video about why wind generators have three blades, and figured it was as good a place to start as any. For my 3d design work, I use Autodesk Inventor, because I was trained in it for my PLTW class. Also, it is free for educators. It is extremely powerful software, but can be kind of daunting at first. Another, simpler option would be Tinkercad, also made by Autodesk, but geared more towards young people.

 

My school purchased an Ultimaker 2 for our 3d printer, and I use their Cura software to ready my designs for printing.
My school purchased an Ultimaker 2 for our 3d printer, and I use their Cura software to ready my designs for printing.

 

Next up was securing the new propeller system to the old. I did this using one of my favorite fix-all, Shoe Goo. Hot glue would be quicker, and probably better, but I didn't have a hot glue gun handy.
Next up was securing the new propeller system to the old. I did this using one of my favorite fix-alls, Shoe Goo. Hot glue would be quicker, and probably better, but I didn’t have a hot glue gun handy.

 

I put on a glob of Goo, and clamped it together.
I put on a glob of Goo, and clamped it together.

 

I also prepped the bottle that would serve as my initial vessel. I simply took a water bottle and cut the top off of it.
I also prepped the bottle that would serve as my initial vessel. I simply took a water bottle and cut the top off of it.

 

I also designed a prototype boat in Inventor, so I could have something to compare to the bottle.
I also designed a prototype boat in Inventor, so I could have something to compare to the bottle.

 

I hooked up a simple little mini-toggle switch to my getting and cutting power to the fan a little simpler.
I hooked up a simple little mini-toggle switch to make getting and cutting power to the fan a little simpler.

 

Lastly, I used our good old friend, duct tape, to secure everything to the bottle. I positioned the battery towards the front, hoping it would offset the weight. Next up, trail run!
Lastly, I used our good old friend, duct tape, to secure everything to the bottle. I positioned the battery towards the front, hoping it would offset the weight. Next up, trail run!

 


So, the bottle boats were a failure for me. that is not to say a bottle boat couldn’t work. I just didn’t have mine designed correctly. If you had the propeller high enough out of the water, I think it would be fine. Or, like I state in the second video, maybe a paddle boat would be a better design with the fan motor.

My next step was to try out my 3d printed boat model.

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As you can see, it actually fared worse than the plastic bottle. The major issue with each of these designs is the weight of the motor, which I obviously didn’t account for enough in my designs.

What lessons did a learn from this whole process? It isn’t as easy as you think to make a fan powered boat. A lot of thought needs to go into the design of the boat as well as propeller. This means that students would mostly likely need time to go through several different iterations of their boat in order to come up with something that works, let alone works good. I’ve found that 3d printing in general takes a lot of trial and error, and lots (and LOTS) of time. This is something that educators need to be painfully aware of when planning their lessons around 3d printing student work. My boat model took over five hours to print; take that times seventy students and…. It’s just something you need to keep in mind.

Personally, I think I would utilize groups for the project, and probably have students build their vessels out of something other than 3d printed plastic. I would save the printing for propeller design, and small pieces needed to attach everything together; pieces that wouldn’t take a lot of time to print. There are lots of lessons to be learned here in the STEM realm, but you would need to allow an appropriate amount of time for students to really work through the problems.

That being said, I feel like a project like this really has some legs. If you took the time to really flesh out all of the mechanics at work here, you could easily cover half a dozen science standards. If you add in the measuring and number work, and have students write about their experiences, I’m sure you could get quite a few math and language arts standards in as well. Throw in some background research on different historical designs of boats in various cultures, and you could very easily run the cross curricular gamut. Bottom line: there is a lot of learning to be had from an experience like this. You just need to make sure that you are leading the students to all of those connections.

Tracking my project with images and videos also allows for some unique learning experiences. It takes the pressure off of my memory, and allows me to elaborate on specific parts of the project that would most likely get lost without some sort of media. I also believe it helps with the transfer of my experience to others, making it a more valuable learning experience for people visiting the blog.

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