Final Project: The Puzzle of How It All Ended...

Today, my partner Christina and I finished our final product and got to show it off in the science center.

For the most part, it worked very well. The user simply had to pedal the bike to create energy. The back wheel was raised off the ground using a bike stand. A permanent-magnet motor was braced against the back wheel and another smaller wheel was connect to the motor's axle. This second wheel was in contact with the bike wheel and transferred the mechanical energy from the spinning to the motor, where it was transformed into electrical energy to power the light bulbs and various other appliances.The board held the bulbs, wires, circuit and other appliances in place, as well as featured some fun facts about the country's energy consumption and how the Energy Bike's output compares the average household's needs.

At the Presentation!

We even made a video of how the energy bike works so that, should anything go wrong, users would still be able to see what our project outlines and how it functions.

Overall, we were very pleased with the outcome of our Energy Bike Project, though the final days leading up to it were quite a scramble to check last minute details.

We had to paint the motor brace and stands for the board:

 

We also needed to find a creative way to attach the two legs to the back of the board, as simply nailing them directly on was not working. In the end, we nailed them to smaller pieces of wood and then screwed the wood flush against the back of the board. 

Because the wood was so thin, a few of the nails did stick out in places, we managed to hammer enough directly into it to keep it stable.We also added a simple voltmeter, so the user could see how much energy they were producing and be able to keep their output between 12 and 15 volts (that is the range that the inverter could handle).

Voltmeter

Finally, all that was left to do was glue our fact sheets on and make the front of the board aesthetically pleasing. We carefully planned how it would look prior to permanently gluing everything into place.

Organizing Information

Making Everything Fit Nicely

Final Taped version

Final Product

We managed to finish the entire project early the night before the presentation. We even found a hairdryer with a low enough power requirement to be powered by our bike.

Finally, we had to test everything to make sure it worked properly.

Testing

Then, after a good night's sleep, it was time to show the world what we had made.

Overall, the presentation went well. Unfortunately, about twenty minutes in, the small wheel attached to the motor fell off and never quite stayed on correctly. Originally, we had thought that the glue was melting under the heat caused by the friction and resistance between the motor wheel and the bike wheel. However, the glue we had used the night before was heat resistant. That meant it was the tape that could not endure the heat. We tried fixing the problem with aluminum tape, but the glue did not have sufficient time to dry before we used it. In the end, we used duct tape and a small object to brace a small piece of wood to the other side of the brace to keep the wheel from falling off. It worked for a while. The wood pushed back against the wheel as it tried to fall off and kept it in place. Eventually, though, the glue and tape between the axle and the wheel could not withstand the heat and stopped holding the two together. Though the wheel was staying in place, it was not turning the axle, so nothing was powering the lights. If we had more time, I would have liked to explore other wheel options. Though it may have worn down, perhaps if we had made a Delrin wheel and directly glued it to the axle, the motor wheel might not have fallen off.

Overall, though, we had fun and our users did learn about the importance of energy efficiency. The ones that got a chance to pedal felt the difference between powering the incandescent and powering the fluorescent lights. I think we really delivered our message to our users, and I am very proud of what we accomplished in such a short amount of time, whether or not it worked perfectly every time.

I had a lot of fun working on this project. I was extremely difficult, and though I went into it nervous, I ended up learning a lot about circuitry that I never knew before. Christina and I got along quite well, and I think I will always remember our late nights together in the lab. 

Here ends the story of the construction of the Wellesley Energy Bike. We hope you've enjoyed the ride as much as we have.

Team Wellesley Energy Bike! (Christina left, Kat right)

For our references about the country's energy consumption, please see:

 

https://www.dosomething.org/facts/11-facts-about-energy

http://www.eia.gov/tools/faqs/faq.cfm?id=97&t=3

For the Wellesley Energy Bike Official Site, see

<http://wellesleyenergybike.blogspot.com/>

For Christina's Blog, see

<http://christinaholman-engrportfolio.blogspot.com/>

Final Project: The Puzzle of Editing the Prototype

Today, my partner Christina and I worked to improve our first model of the Energy Bike set up. We had a lot to do.

We started by addressing several of the problems we noticed from our previous work day. The motor tended to bob up and down when the bike wheel was pressed flush against its axle. I built an arch onto the motor stand and brace to counteract the force of the bike wheel and keep the motor steady and in place.

Brace with Attached Arch

This held the motor quite well, and the friction between the wood and the motor itself was an unexpected bonus that kept the bike wheel from accidentally turning the motor itself if the wheel happened to brush it.

Next, we turned our attention to the wheel. The wheel we had originally attached to the motor axle was too big, and the user could not generate the needed RPM to reach 12 volts (without being Lance Armstrong, that is). We needed a smaller wheel or the Energy Bike would be too difficult for an ordinary user to manage. 

However, once we attached a smaller wheel, made of PCB pipe, pedaling was far too easy, and the user could easily outdo 12 volts (in one instance, we managed 21) and drive the inverter wild. We needed to find a wheel size in between the two that made pedaling a chore, but not an impossible one.

Original Wheel on Left, Smaller Wheel on Right

     

Final Wheel Upper Right

In addition to being the middle ground between our two original wheels, the new wheel also solved the pedaling problem: it is much easier to maintain a constant current with this sized wheel. Because pedaling is simpler with this size wheel and a constant current is easy to maintain, an extra battery pack may no longer be necessary.

Next, we moved onto the switches. Our store-bought switches were designed to turn a circuit one or off, not switch between two different circuits. In other words, we could not put our bulbs in series with these switches. After much deliberation, we decided to edit the switches ourselves rather than return them and locate the right ones to purchase. We simply turned the ground prong (green) into another option within the switch to allow the current to flow in one of two directions depending on what direction the switch was flipped.

 

New Circuit Diagram for In Series Design

Getting it In Series...

We Had to Break into the Switches to Edit Them

An Edited Switch, Ground is Now an Alternate Route

Now that the switches are all fixed, we can put the circuit in series and test as to whether or not it works in this manner.

Finally, we began to decorate our board and attach safety instructions and fun facts. We still need to figure out how we are going to qualify the concept of kilowatt-hours to the user in layman's terms, but our first priority is to make sure the user understands how the Energy Bike works so they do not get hurt while using it.

Decoration Plans

Testing

Despite all our progress, there is still a lot that needs to be done.

1.) The board needs to be decorated for real
2.) The switches need to be covered slightly so that only the switch part is visible to the user
3.) The NEW circuit needs to be tested with the bike
4.) We need to get a more permanent bike for the display - Christina needs hers back for the summer

However, for the moment, we are ready for the final week of preparations and we can not wait to see how our project is going to turn out.

One bulb down...seven to go.

Final Project: The Puzzle of the Prototype

Today, Christina and I began constructing our first version of the Energy Bike.

We had to gather our materials, first, but after some shopping on Amazon, eBay and a trip to Lowes, we were all set to go.

Putting Together the Supply List

Our Adventures at Lowes

Our Shipped Inverter and Motor

All the supplies came in on time and we were able to start building. First, I set out to construct a brace to hold the motor against the back tire of the bicycle. I mounted some rubber Lego wheels on the axle of the motor to act as a gear with the bike tire. It had to be sturdy enough to stay in place as the user pedaled, so around the stand I constructed a frame that used the bike stand to stay in place.

Bike and Bike Stand

Preparations

Motor Wheel

Completed Motor Stand and Brace

Bike and Motor

Though crude, the first iteration of the motor stand and brace worked fairly well. We then tested it to make sure the set up would allow the user to generate power by pedaling.

Success! Though, it did not produce as much power as we were hoping it would.

With our energy source working properly, we turned our attention to the physical board. I began cutting holes for the switches and lights while Christina worked on the circuit that would attach to the back.

Holes for Lights and First Switch

Switches and Holes Completed

Soldering the Bulb-Holders

The bulb-holders all came with hook attached to them, so all we had to do was drill holes large enough to accommodate the hooks and hang the bulbs from them. Christina soldered copper wire to the bulb-holders so they could reach the circuit no matter where we placed them. We placed the bulb-holders on the board and began connecting the circuit on the back.

Bulb-Holders on the Front

Front with Bulbs

Completed Circuit

 As it turned out, our circuit was incapable of being an in series circuit, as the switches were only on/off in set up. We will have to make another trip to Lowes or find a way to wire the circuit to work around this issue. Additionally, we had to change the placement of the first switch(s) to accommodate for this and allow the user to only have one string of lights on at a time.

Meanwhile, our motor stand and brace began to have problems. The bike tire eventually began to tear up the tiny Lego tire, and no amount of duct tape could prevent this. We are now planning on using PCB piping to create the otter layer of the wheel to prevent this from happening. Additionally, the user has to pedal an inordinate amount to light just a few bulbs. We think that this is due to the size of the wheel attached to the motor: it is too big and thus not allowing the user to reach the optimum number of rotations per minute. Hopefully, a smaller wheel will solve this problem. The stand and brace itself began to fall apart, so I designed an new version and sealed all the edges with hot glue to keep it sturdy.

Stand and Brace Iteration 2

The new stand works much better than its predecessor, but the motor has a tendency to dip under the pressure of the bike wheel, s it lifts off the stand after and certain amount of time passes. I plan on adding a brace on top of it to fix this problem.

Finally, after all this, we tested our product to see how well it worked over-all.

Inverter

Plain Board

Final Decorated Version

Overall, it was successful. Though various aspects of the prototype would begin to have problems, for a few minutes after each fix, I was able to pedal fast enough to light all the fluorescent and three of the incandescent bulbs. Now, because we know the bike works, we only have to work out the kinks. 

1.) The motor needs something to hold it down and a smaller wheel

2.) The switches need to be exchanged for ones that allow an in series circuit

3.) The board needs to be decorated and the outlet added

4.) A nine volt battery pack may need to be added so the user does not have to pedal so hard to light just one or two bulbs

Despite its flaws, our prototype does work. This model has dramatically reduced our fears about the outcome of this project, as we were beginning to worry if we would be able to get Any of the bulbs to light with just pedal power, given how low the output was o the voltmeter when we first tested the motor. However, the electrical portion of the project is, for the most part, completed. All that is left to do is to make the physical components more stable, durable and attractive for our future users.

The future of the Wellesley Energy Bike looks rather....bright.

Final Project: The Puzzle of the Learns-Like-Model

Today, Christina and I had to make a presentation that demonstrated how the user will interact with our energy bike and learn from it. Below is a storyboard about each step in the process as well as some short descriptions about what each step teaches.

Final Project: The Puzzle of the Looks-Like-Model...

Today, my partner Christina and I built a model of what we wish our end product to look like. We want our energy bike display to be fun, inviting, aesthetically pleasing and easily understood. Needless to say, this took a lot of thought and visualization.

In the first place, we knew we would need a bike with the back wheel mounted up off the floor. A generator would need to be attached to this so that the wheel could power the generator. Finally, an inverter would need to be attached to the generator to keep the current in check for safety reasons.


We started by cutting all of our pieces out of foam and then using glue and markers to construct and decorate them. Originally, I had built a bike mount using bricks, wood, nails and a plastic pipe, however, it turned out that the engineering lab already owned a bike mount. Fail fast and frequently, fail fast and frequently...

Bike Mount Iteration 1

Bike Mount Iteration 2

Generator with Gear Representation

 

Bike to Generator Attachment Representation

Inverter Representation

Originally, Christina and I had planned on connecting the bike to the generator using a belt, however, after viewing several online generator and motor designs, we realized that the bike wheel could be placed flush against the generator gear and still work, so we updated our design.

Next, we got to work on the actual informational part of our project.  We knew we wanted four incandescent and four fluorescent bulbs to be in the display, so that the user could witness the resistive difference between each type of bulb as more were added in series.

We also included a voltmeter, so the user could see in units how much power they were producing by pedaling. Next, we added other electrical appliances, such as a hairdryer, radio and outlet to allow the user to power or charge their own items, like a cell phone.

 

Although we want to include as many applications as possible in our display, after talking with Professor Elaine Igo, we realized that we had a lot of calculations and careful circuit-board construction to do before we could begin building. In the first place, as 12 volt generator, which is what we originally planned on using, may not be enough to light even two bulbs at once, even with a large current. We may need to purchase a motor capable of producing up to 360 Watts. There will be more on this aspect once we begin our actual construction.

After we added all of our appliances to our board, we painted on a thermometer. We plan on using this (or some other similar system) to help the user keep the current within a safe parameter. based on the maximum current our appliances will be able to handle, the thermometer will tell the user when they are providing enough current and when they run the

risk of breaking something. This is simply another safety feature we are thinking about including. Though we want our final project to be as fun and interesting as possible, user safety is at the very top of our concern list.

 

Along the sides of the board, we will include 'Did You Know' facts and blurbs about energy consumptions and conservation so that the user will have a quantitative understanding of energy as well and the qualitative one (via their pedaling). 

 

Finally, we combined everything together using wires to represent our final appearance and paint 'Wellesley Energy Bike' across the top of our display.

Our Looks-Like model is both representative of what we hope our final version will look like as well as aesthetically pleasing in our eyes. We want our display to be attractive to potential users, so we used a variety of colors to make the board visually interesting. 

Our Looks-Like model is deceivingly simple, as the final model will have to incorporate an complex mechanical-to-electrical-energy conversion apparatus as well as a wiring system on the back of the board to transfer the power to our appliances in a specific way. Though the wiring may be difficult, it's the pre-planning that is proving the most difficult. Depending on our bulbs, we will need a certain generator/motor. We need to calculate how much the average person can pedal, how fast, how much energy they can produce, what is the range on energy human beings can produce by pedaling, etc. Overall, the actual build should be simple if we plan ahead properly. After our discussion with Professor Igo, we feel a little less daunted by the task and are ready to begin working on our complex pre-ordering process and the process of finding all the specific parts and devices we will need to make our vision a reality.