Green Wu – Prototype II Final Report: Bicycle-powered Generator

Introduction:

This semester Green Wu team has been working with CPRF resident Marina who has a disability which prohibits her from using her lower body and prevents her from being able to sit down or lay on her back. Because of this disability she cannot use traditional workout equipment, which makes exercising a difficult task. Additionally, Marina has always wanted to be able to ride a bicycle, but currently there is no suitable bicycle design available to her. Our team has been working with Marina to help her overcome both of these obstacles. Our exercise stand will allow Marina to exercise her arms, and, at the same time, it will be able to gather valuable data to aid in construction of a road-safe bicycle for her in the future.
Besides helping Marina, our project also aims to accomplish another goal – green energy generation and environmental protection education. Because our bicycle-powered generator converts kinetic energy produced by the user to electrical current, it is also able to power household appliances. This allows us to demonstrate how much electrical energy can be generated through exercise and compare that to how much energy is needed to power common appliances, thereby raising awareness on energy conservation. 

Description:

To make the exercise stand, we started with a regular bicycle and removed the front wheel and steering column. Then we built a wooden stand to support the bicycle frame, and attached the frame to the stand. We reconnected the bicycle gears to allow user to change the difficulty of exercise. 

 

Currently the unmodified bicycle pedals are used to rotate the wheel, but we have already designed a more user-friendly handle system in CATIA. Due to the lack of an easily available metal shop we weren’t able to manufacture these parts yet, but they will be implemented in our next prototype.

Currently we are using a 24V DC 80 watt motor as a power generator. We used a 3D printer to manufacture a pulley which we attached to the motor axle and took the tire off of the back bicycle wheel. The rotational energy  is transferred from they bicycle wheel to the motor via a belt.

The outputs from the motor are connected to a voltage regulator circuit which prevents more than 12 volts from being sent to the battery. This protects battery from over-voltage,  which could damage it otherwise. The circuit uses a 133 Ohm resistor, MPN Transistor, Zener diode and a recovery diode.

On the output end of this circuit is a 12v Duracell 600 HD PowerPack. The PowerPack serves two important purposes – it serves as a DC to AC converter and stores the generated energy for future use. This allows common household appliances to  be plugged in directly into the PowerPack and operate much like they would if they were plugged into a regular AC outlet.

Arduino controller is used to measure the voltage generated by the DC generator. A simple AnalogReadDigital function reads the voltage input and sends it over a serial connection to the laptop. We are using SimpleVoltmeter application provided on cratel.wichita.edu for a visual display of the generated voltage.

Reflection:

Overall our project was a huge success. We all learned something new and we feel as if that reflects the spirit of the course. For instance, Alex and Stephen were both skilled in circuitry and were able to teach the other group members about the electrical engineering components of the project. Likewise, Alex and Eric were skilled in programming and were able to teach the other group members about some of the computer science aspects of the project. This helped with delegating the work to each group member. We focused on our individual strengths to accomplish our tasks.

For our project, we felt like we had a very late start before actually putting work into the bicycle. This was attributed to the first few weeks of unproductivity as we were deciding on a project. Additionally, we had issues obtaining components of our project, such as the bicycle. This inhibited us from putting work into the project as necessary. After we had all of the components in, it was much easier to implement a strategy for completing the project before open house. 

If we were to do a similar project in the future, we would prefer to have teams organized earlier in the semester, or perhaps during winter break. This would allow us to research and organize our project before the semester even started. Additionally, we would be able to acquire parts more quickly, which would allow us to put more work into the project.

For the second semester, we intend to further our project by developing a more user-friendly graphical user interface. Additionally, we would like to implement a sensor on the wheel which will then send information to our circuit for further analysis for distance traveled. Finally, we would like to design a environmental education stand around the exercise stand.

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