OVERVIEW – DESIGN PROBLEM – BRAINSTORMING – DESIGNING THE PROTOTYPE – DEVELOPING AND IMPROVEMENTS – FINAL PRODUCT- THE SMART PEDAL – TEAM MEMBERS
Team Das PedalHaüs designed and developed a self-aligning bike pedal for clipless pedal systems. When riders are first learning how to use clipless pedals they often struggle with manually aligning the pedal when they are trying to clip in. This distracts the rider and can cause a safety hazard, especially at dangerous intersections. To fix this problem, the design uses a motor, circuit board and accelerometer to rotate the pedal into the aligned position whenever the rider steps out of the pedal. The system disengages the system once the rider is clipped in and they are ready to ride. In addition, the 3D-printed enclosure protects the electronics from the environment and a rechargeable battery allows the system to run with daily charging at night. The smart pedal has been manufactured and tested, and is ready for further development with clipless pedal manufacturers.
In the fall of 2012, Team Das Pedal Haüs recognized that there was an inherent flaw in today’s available clipless pedal systems in that they are often rotated out of alignment when the rider is attempting to clip into their pedals. This causes frustration for many beginning riders and also divides the attention of all riders because they must manually align their pedals while balancing on their bike. Since many riders stop, clip out, and attempt to clip back in at busy intersections and along roadways the alignment issue also poses a potential safety threat. As a result, the team decided to create a product that would automatically rotate their pedals to be horizontal to the ground so that they may clip in more easily and without having to pay attention to the alignment of the pedal.
Team Das Pedal Haüs spent several days brainstorming ideas to solve the problem of clipless pedal alignment. The first and most obvious potential solution was to develop a counterweight system that would balance the forces of gravity acting on the pedal so that when the rider clipped out of the system an uneven distribution of weight would force the pedal to rotate into alignment. However, a quick patent search revealed that this system already existed and that it would have to be heavily modified and balanced for every different pedal.
Image of patented “Counterweight” design
In addition, a magnetic system that would attract the pedal into alignment with the cleat was investigated but was also found to be previously patented. In addition, reviews of this product demonstrated that riders were unsatisfied with this solution because the magnet often disengaged inappropriately.
Several other potential solutions were analyzed
- Power screw and motor assembly that would actively move a counterweight to set the pedal to the desired orientation.
- A cylindrical pedal and cleat which would allow the rider to clip in regardless of the rotation of the pedal.
- A ratcheting system which would leave the pedal in alignment when the rider clipped out, but allow the pedal to freely rotate while riding.
However, the potential solution that seemed to be the most unique and provide the best opportunity to solve the problem was an active “smart pedal” that contained a microcontroller, accelerometer, and motor to rotate the pedal into alignment when the rider clipped out.
Having the solution selected the team set forth in developing the system.
Basic Design Concept
To ensure that whatever product they made actually solved the pedal alignment problem, the team created a set of specifications which, if all were met, would demonstrate that the product was a success. The specifications the team set out to meet with their product were the following:
DESIGNING THE PROTOTYPE
With a clear set of specifications now developed, the team began the process of designing and building a “proof-of-concept” prototype.
The prototype was first designed using Solid Works® 3D drafting software to outline the dimensions of the different product components and determine the most efficient way to manufacture the prototype. In addition, circuit analysis was used to determine the power requirements of the system and how to provide enough power to each of the components.
SolidWorks Drawing of Prototype
Once the design was completed, the team set forth in building the prototype. The microcontroller, an Arduino® Uno R3 micro contoller, was used as the “brains” of the prototype. The microcontroller took in a signal from the accelerometer which correlated to the pedal’s current rotation position and then sent out a signal to the motor to rotate the pedal back into alignment. The programming required to accomplish this was completed using if/then logic and the prototype was powered up.
Prototype in Action
The prototype worked well within specifications, demonstrating that the design solution had some real potential! Following the success of the prototype, the team tested the product using varying degrees of alignment and rotation scenarios to determine where any design issues may lie, and how to improve upon them for a final product.
DEVELOPING AND IMPROVEMENTS
Improving the Prototype:
In addition, to meet the remaining specifications that the team set out to accomplish, the team would have to develop an enclosure to protect the system from the environmental conditions experienced by pedals in day to day use, as well as integrate a switch to turn the system off and on when the rider was clipped in and out.
One of the biggest improvements that the team sought to make on the prototype was decreasing the overall footprint of the device to minimize the weight and loss of clearance provided by the system.
FINAL PRODUCT- THE SMART PEDAL
With all of the pieces in place, the final product was ready to be tested. First the team ensured that the system worked in a lab setting by testing that the components all worked individually.
Internal Components of the Final Design
The first test was to determine if the product could withstand the common forces experienced by clipless pedals during use. The product was placed on a bicycle and tested.
The rider was able to clip in and out of the pedal with ease and the enclosure was unaffected by the forces of pedaling.
Once this was complete, the final product was attached to a testing crankshaft. The pedal was placed out of alignment, switched on, and the results were recorded.
The pedal rotated into alignment within 5 degrees.
It rotated into alignment from the “worst case scenario” (180 degrees out of alignment) within 5 seconds.
And the enclosure protected the internal components while being held under water.
With all of the specifications met. It was time to take the product to the streets…
One group member was already an avid clipless pedal user so she was selected as the test subject to test the product in real world situations. Rachel rode her bike with the self aligning pedal for several days around the streets of Reno, NV, stopping and taking her foot on and off the pedal to test the alignment. After reviewing her experience, it was shown that not only did the pedal operate as specified; it maintained operation while working in the actual environment.
Hence, Team Das Pedal Haüs’ “Smart Pedal” was a success. The pedal system offers a real solution to the pedal alignment problem, fulfills the specifications set out by the team, and can be expected to operate in real world environments.
Team Das PedalHaüs would like to thank Dr. Emil J Geiger for his advice, direction, and tireless patience with our group as we developed this product. In addition, the team would like to thank C.J. Dudley for donating pedals to the final product and Milan Heninger for assistance with 3D printing.