Shane

Intro

My name is Shane, and I am a senior at Archbishop Riordan High School. My starter project is the light sensing robot, which helped me learn some basic skills, such as soldering. My main project is the micro wind turbine. It has three vertical aluminum sails at the top, which catch wind to accumulate kinetic energy. The sails spin the aluminum shaft that supports the whole turbine, which connects through two gears to a motor. The motor then converts the energy into electrical energy and connects to a circuit. When the circuit is powered, it lights up an LED. In a fundamental sense, the goal of this project is to generate energy from nature, and harness it as electrical energy. I chose this project because it allowed me to work with both mechanical and electrical components, and because it makes use of natural energy.

Here is a link to the bill of materials I used :

https://docs.google.com/spreadsheet/ccc?key=0AkWz2KhdTpL4dFhZU203Z3RtTnFSY0Q4NUVabzhzZlE&usp=sharing

And the inspiration for my project came from Dustyn’s instructable.

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Shane

Main Project: Wind Turbine

Final Thoughts and Modification #2: Put Circuit onto Perfboard

For my second modification, I remade my circuit on a perfboard. I remade both the original circuit, and the modified circuit (with two LEDs replacing two of the diodes). A perfboard is basically a grid of holes to solder into, and is even more customizable than a breadboard in that nothing is pre-connected for you; any connection that you want to make you must make yourself through soldering. There are a few things that make using a perfboard challenging though, mostly related to soldering. First of all, soldering can take a lot of time, even for a small circuit, and fixing mistakes can be frustrating and even more time consuming. Also, while I had built this circuit before on a breadboard, I had never used a perfboard before, which meant that I was learning as I went. Because of this, I made a lot of mistakes, and my circuit is a bit ugly, but I learned from my mistake and my modified circuit, which I made next, is much prettier. I definitely learned a lot from using the perfboard, and it was rewarding in that the circuit on the perfboard seems more final than the breadboard circuit. However, before making a circuit on a perfboard I would definitely recommend building it first on a breadboard and understanding exactly where each connection in the circuit is.

Since this is my last post in regard to this project, I will also say a bit about my overall experience at Bluestamp. I applied for Bluestamp because I was very interested in studying engineering in the future, but I did not really have any experience with it. Before Bluestamp, the only thing close to engineering experience that I had was taking a physics class in the first semester in my junior year. I had a great time in that class, but it was also a lot of hard work, and at the end of my junior year I was very happy to receive a school award for my work in this class. That experience definitely amplified my interest in engineering, and considering that my school will not be offering an AP physics class in my senior year, I was open to any opportunity learn more about physics or engineering.

Bluestamp has definitely given me a taste of what engineering is about. Not only have I learned a lot, but I got to do it in a totally hands-on way. It is amazing to me when I think back to my first week that I didn’t know how to solder, couldn’t read resistor bands, didn’t know what a breadboard is (let alone how one works), didn’t know the difference between alternating and direct current, and so much more. That puts in perspective for me just how much I have learned in my five weeks at bluestamp, and I am very glad to have learned it all from experience. Learning out of a book is fine, but because I learned about resistor bands only after making a huge mistake in my starter project and having to realize for myself where I had messed up makes that knowledge even more memorable and personal to me. I feel like I have accomplished and learned so much here, but at the same time it feels like just the tip of the iceberg.

Coming into the program, mechanical engineering was what interested me the most. There are a lot of reasons that mechanical engineering intrigues me, but most basically because it involves very clear manipulation of the physical world. While I am still very interested in mechanical engineering, working with some circuitry has sparked an interest in me for electrical engineering. Furthermore, after seeing some of the other awesome projects that other students were working on has made me realize that there are lots of fields within the world of engineering and that the possibilities are practically endless.

I am very glad that I chose the wind turbine project because it allowed me to work with plenty of mechanical elements, it exposed me to the world of electrical engineering, and also because it allowed me to make something that generated energy. Generating energy efficiently from natural sources is becoming increasingly important, and it is an area that I am definitely interested in working in in the future. While my wind turbine is a very small scale energy generating mechanism, it has definitely inspired me to pursue innovation in this field.

I am very thankful to all of the Bluestamp staff who helped make this summer great!

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Modification #1: Using LEDs as Diodes 

After completing the wind turbine, I decided that it would be interesting to mess around with it a bit. Mechanically, I did not see much room to change things without disassembling what I had just completed, so instead I focused on my circuit. First I thought I might redo the circuit to power the LED with AC to see how that changed how it worked. So I expanded on this idea, realizing that LEDs are, in the most basic sense, diodes, and decided to replace some diodes in my circuit with LEDs. The cool thing about this is that it allows me to see the AC powering the LEDs working in the diode bridge, and the DC powering the LED at the end of the circuit. When the turbine is spinning rapidly, all of the LEDs glow brightly, but when the turbine spins more slowly, the DC powered LED will fade to a less intense, but still constant glow, while the AC powered LEDs flicker. I was actually able to replace all of the diodes in the circuit with LEDs and see the AC working. The only issue is that because the LEDs provide more resistance than the diodes, the LED at the end of the circuit was extremely difficult to power with any more than two extra LEDs in the circuit.

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Milestone 3: Completed Main Build of Wind Turbine

My third milestone is completing the main build of my project! This meant assembling the upper portion of my wind turbine. Essentially, there are three sails held in place on the rod by two sail holders. The sails are cut out of a roll of aluminum flashing. There were no dimensions suggested for the sail so it took a few tries to get them right. The sail holders are laser cut plastic pieces and have slots cut into them for tabs in the aluminum sails to fit through. The holders are held in place by shaft collars which are tightened onto the aluminum rod and pinch either side of the holders. I found that while the shaft collars would spin with the rod, the sail holders were not connected to the rod very well and would spin around it, so I added epoxy putty connect the holders and the shaft collars. This ensures that when the sails spin, they spin the rod too, rather than just spinning around it. Since making this adjustment, when the sails spin, the power is transferred smoothly throughout the build and the LED lights up.

Here is a mechanical drawing of my assembly of the upper portion of the turbine:

View post on imgur.com

Once again, any parts listed in the key correspond to a color on the diagram, and are listed as they appear from top to bottom.

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Milestone 2: Completed Base

My second milestone is completing the base for my wind turbine. The main portion of the base is the two plastic laser cut disks. One problem that I encountered was that the laser did not totally cut through the disks at every place it was supposed to, so I had to hand drill and file a few of the holes myself. The two disks are connected with three hex standoffs which are attached to each disk with a ¼ 20 screw, a flat washer, and a lock washer. The aluminum rod goes through the center of the two disks. It is held snugly in place by a sleeve bearing where it passes through each disk. On the bottom, it also has a thrust bearing sandwiched by two thrust washers, held in place by a shaft collar with an adjustable set screw. The other sleeve bearing is also held in place by a shaft collar, as is the gear halfway between the two disks.

The motor is mounted onto the upper plastic disk. To mount it, I removed the M3 screws holding the motor together, and then used longer M3 screws, along with a lock washer and a flat washer to screw it onto the upper disk. A gear is also attached to the shaft of the motor with a shaft collar. The other gear is attached to the aluminum rod, so when the aluminum rod spins, the gears mesh, the motor is powered, and the LED lights up. Getting the gears to mesh well was not difficult, but getting them to spin correctly, specifically to power the motor, was a bit of a challenge. The gears are held respectively to the aluminum rod and motor with epoxy putty. Applying the epoxy putty to the motor was difficult because there was not much space to work with. Also, I had to reapply it a couple of times to connect the gears well enough to spin instead of just sit idly while the aluminum rod spun.

Here is a mechanical drawing of my assembly of the base:

View post on imgur.com

Any parts listed in the key correspond to a color on the diagram, and are listed as they appear from top to bottom.

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Milestone 1: Completed Electronics

My first milestone is completing the electronic component of my project. Essentially this meant assembling a circuit to power the LED from the motor. Following the instructions to assemble the circuit was not super difficult, although I needed to learn a bit about how breadboards and different components work. The most difficult part of this milestone was trying to understand just how the circuit worked. The LED, capacitors, and jumper wires were not super complicated. The wires connect everything together, and also back to ground. The capacitors store energy to be released when the motor stops spinning, and the LED lights up when powered.

The most complicated part of the circuit involves the diodes. The motor is supplying alternating current to the circuit, which needs to be converted to direct current to power the LED correctly. If the LED was powered by alternating current, it would flash on and off as the direction of the current changed, while the direct current allows it to emit light continuously. The way the diodes are set up is called a diode bridge, which creates a full-wave rectifier, which is a fancy way of saying that it changes AC to DC. Diodes are essentially resistors that allow current to flow through one direction, and totally stop it from the other direction. The diode bridge makes it so that no matter which way the alternating current flows through the circuit, it comes out the same way, as direct current. There are four wires coming from the motor, and every two wires connect to a diode bridge, so there are actually two diode bridges on the circuit. Understanding how the diode bridges worked was difficult, but assembling them was not, and they allowed the circuit to work correctly.

Here is a schematic:

View post on imgur.com

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Starter Project

Hi, I’m Shane and for my starter project I made the light sensing microbug. It has two photoresistors on the front, and when the photoresistors are lit, their resistance lowers, allowing the motors to spin, and the LEDs to flash. In the dark, the microbug does not move or light up because the photoresistors apply more resistance. It has three trimmers, two of which adjust the sensitivity of the photoresistors, and the third of which adjusts the speed of the motors and flashing LEDs. The microbug also has two switches. Flipping the first switch will turn the microbug on, and the flipping the second switch puts it into a different mode where the LEDs flash less quickly, and the motors spin more slowly. Otherwise, there are assorted resistors, transistors,and capacitors on the circuit which allow the electricity to flow properly throughout.

Assembling the microbug was not without difficulty. The instructions have very few words, so sometimes it was challenging to interpret what some of the steps meant. For example, I got very confused when it came to putting the motors into the microbug, because they would not stay in place, despite my following of instructions. But I kept trying things, and I realized that the jumper wires were able to hold the motors in place. Later this would become an issue again, when one of the motors would totally stop when shifted at all, but after some inspection, I realized that the jumper wires were not taught enough, and tightening them fixed my problem. Another big problem that I had was that I did not realize from the instructions that the 10 resistors, which initially all looked identical to me, each had one of four different resistances, and that each resistor had a specific place on the circuit. I ended up having to move 7 resistors which I had already soldered to the circuit, but at least I learned how to read resistor bands.

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