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.

Final Project: The Puzzle of a Works-Like Model

Today, my partner Christina and I worked on creating a mock-up of what we wanted our final project to work like. Using Legos, foam board, a breadboard and bulbs from the Physics Lab, we managed to created a miniature of the energy bike set up. All the bulbs we attached in series, so that as each switch was flipped, they would become a little dimmer as the resistance increased. Because we did not have access to a generator, we improvised a 9 volt battery. Our Lego bike and chain configuration represents the user and how the bike motion will provide power to the generator, which in turn will provide current to the circuit.

Works-Like Model Energy Bike

 Our model includes an (optional) outlet. If we have time before the due date, we have thought about adding an appliance option, so that the user could see how much power a basic piece of technology, like a hairdryer, requires to run.

Energy Bike Circuit Diagram (Iteration 3)

Our circuit puts the two types of bulb (incandescent and fluorescent) in series, but each series is then connected in parallel, such that all eight can be on at once without more effort than it takes to power one series.

Our Completed Circuit Based on Iteration 3

For this model, the switches were required to be on the breadboard, which is attached to the back of the foam-board. However, if we use switches in our final version, they will either have to be on the front where another user could manually activate them on on the handlebars of the bike so a single user could operate the entire display without dismounting. To avoid the user having to do anything, we could simply user a timer-program to turn on the lights at different points. This way, the user would only have to focus on pedaling and overcoming the steadily increasing resistance.

We ended up having to recreate our entire circuit from our original design (see previous post) because the parallel set up would not increase the resistance as more bulbs were added to the system. Fail fast and frequently...

Once the circuit was built, we had to test it to be sure it worked to our specifications.

To our great relief, the circuit worked perfectly. Each time a new bulb was added to the circuit via a switch, the previous bulb(s) became slightly dimmer. Though we can not directly experience it on this model, the increased resistance will be evident to the user on the cyclist. They will have to pedal harder in order to keep the bulbs (mostly, the incandescent ones) lit.

Stand-In with Functioning Gear Train

Overall, our model represents what we expect to happen during our final demonstration. Though we did not have access to a generator, our Lego stand-in's gear chain does work, and can visually simulate the task. As we built our model, and found we had trouble doing so, we realized just how difficult this project is going to be.

In the first place, we will need to calculate what kind of generator and bulbs we will want. All this will depend on the range of the user's pedaling ability. We do not want bulbs that cannot be powered by the generator, or worse, bulbs that burn out to easily. Safety is also a concern. The generator could overheat, or the bulbs could become very hot, or even the circuit board could reach dangerous temperatures. This project will require careful wiring and calculations prior to experimentation. However, while the bulbs can easily be tested until a usable combination is found, the generator is a one time shot. We cannot simply buy a bunch of generators or motors to test at random: that would consume our entire budget. To solve the issue of the varied/too little/ too much current, we may have to include an inverter on our list of supplies. Beyond the initial set-up and look, what our mock-up really demonstrates is just how tedious and detail-oriented our road to the final product is going to be.

Final Project: The Puzzle of Testing Critical Elements...

Today in class, mt final project partner Christina and I worked on developing our pedal powered light board, as well as testing our a circuit that could potentially power it.

Our project will require mostly custom -made parts, but the circuits and light will be the most difficult aspect.

We stared by designing two options for our circuit. One incorporates user activated switches to add more bulbs to the circuit, the other uses an Arduino program to time when the lights are added to the circuit.

 Design 1 used switches, which the user would have to manually flip in order to add more bulbs to the circuit. Wells within the circuit would allow the current to flow from point A to B no matter how many bulbs were activated, not what their configuration to each other was.

Design 2 used Arduino programming instead of manual switches to add bulbs to the circuit. This was the user could focus on pedaling and physically observing the difference in resistance as the amount of bulbs (and type) in the circuit changed.

Finally, to test this configuration, we assembled a mock circuit using the Design 1 schematic (to an extent) using a 9 volt battery, five 270 ohm resistors and five LEDs to test the switches and configuration. Our mock up did not include a well,  so the negative end of the 9 volt battery served that purpose.

The mock up worked exactly as planned, and the LEDs could be lit up in any configuration simply by flipping the needed switches. This means that either Design for the circuit will work, so if we cannot make the Arduino program fit our needs in time, the switch design will work just as well.

Additionally, we spent part of our time gathering resources and researching previous Energy Bike designs.

Instructables:

http://www.instructables.com/id/Turn-an-exercise-bike-into-an-energy-bike/step6/Build-a-meter-and-light-display/

http://topmagneticgenerator.com/Blog/magnetic-generator-videos.html

http://www.instructables.com/id/How-To-Build-A-Bicycle-Generator/

https://www.youtube.com/watch?v=8XzqytSwJYk