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Post date: May 18, 2018 11:05:40 PM
This project has taken a good amount of time, but I have created a design concept. This project started as a project intending on slowing down a shaft to the speed that grass grows. This goal has altered, and my new goal is to create a windmill. With the correct materials, including arduino circuits, breadboards and specialized motors, I could have finished this project long ago. However, projects like this aren't useful unless they have some sort of application. This project could become a future fab lab design project, and for this reason, I have decided to use a cheap toy motor. This has made my project slightly harder, as the average RPM of the toy motors I am using is into the thousands.
I started this project by learning how to create and laser cut gears. I settled on a 10:1 gear ratio to reduce the speed of the shaft. After doing so, I tirelessly experimented in how to make two gears spin together well. I tried one gear, numerous spaced out gears and finally settled on many of the same size gear glued together. This increases the probability of the gears meshing together. This was a relatively simple model, and I was able to witness the speed reduction by manually spinning the shafts connected to the gears. One problem, the gears continuously moved side to side and caused the gears to slip. After brainstorming, I implemented several redundancies to prevent this from happening. I placed straws around the shafts, which held the gears in place. Then, I used supports from the base of the structure to hold the shafts down. After this, I really thought I was done. But my teacher, Mr. Moss urged me to keep going.
I was able to create a new structure which was a scaled down version of the original structure. The only difference was one last change that I made. I moved the gears closer together so that they would be really tight together. This prevented the gears from shifting sideways and this change made the gears mesh perfectly with each other. After this, I thought that I should tinker with motorization concepts. I used a slow lego motor as where I wanted to be an endpoint, and I experimented with a toy motor. I kept on thinking how the motor was going to stay in place next to the initial shaft and how the motor was going to connect with the gear shaft. The first problem had an easy fix. I 3D printed a motor stand which kept the motor level with the gear shaft. The second problem took me a little longer to figure out. At the inception of this effort, I was using a glue stick to connect the motor shaft and the gear shaft. This was not a very reliable method of connection but worked most of the time. Then, my classmates and mentors introduced me to heat shrink tubing, which shrinks after exposed to extreme heat. This was a very efficient and effective solution. My gear system was motorized and incredibly reliable within 5 minutes. After this, I had a working prototype of a speed reducer. This utilized a 10:1 gear ratio, which reduced a motor speed of roughly 3500 RPM to 350 RPM. Though this may have taken a long time, my work has numerous application both in and out of the fab lab as gears are used universally.
Link to Speed Reducer Material List
Original Gears. As you can see, there are multiple gears spaced out.
My first structure.
How to make Gears
The first structure complete with gears, supports and the straws. But there is still slight rotation.
The newer version of the speed reducer. It was smaller, and the gears meshed together better. It was being run by a lego motor, which is my ideal end speed at the end of this speed reducer.
The motor stand I created to hold the motor.
The motor stand and the heat shrink tubing in action. As you can see, it was "beautiful". They are a very effective combo and work well together. The black tubing connecting the motor and the shaft is the heat shrink tubing. This heat shrink tubing works very well as it compresses perfectly around the motor shaft and the gear shaft.
Look how fast the windmill goes.
Executive Summary and Future
I stand committed towards my goal of creating a speed reducer that can take a shaft powered by a very fast toy motor and reduce the speed enough to become a windmill. Right not, I am in the process of slowing down the speed reducer even more. Instead of a 10:1 ratio that consists of two gears, my new speed reducer will be a 10:5:1, and will consists of three gears. I believe this will reduce the speed by up to 5 times more. This will bring the speed into much more manageable conditions. If this change does it, I will be done with this project. If not, I can properly adjust the middle gear or add more gears. Nonetheless, I am close to the finish line. This project has many application to the fab lab. There are many other projects that use gears, and my expertise in creating gears and manipulating gear speeds can be used in many other projects in the fab lab. This project is not meant to be perfect but is meant to be experimental. Though I could have used an expensive motor and coded slow speeds but I decided to use a small, cheap toy motor for the purpose that the knowledge i have garnered regarding gears can be used in the future and that the materials I have used are accessible.
The adobe illustrator file of the new structure I am creating.
All of the materials I need for my new structure. I have my base, walls, 3 sizes of gears, shafts and a motor.
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