Lean Rack
The Challenge
Design an easier, more secure way to lock a bike in urban environments
The result
A smart bike rack that locks any bike with the swipe of an ID card
The details
Timeline: 6 weeks
Budget: $500
Course: Making It, Spring 2019 (Senior Project)
Team Members: Lauren Chapey, Eli Swab, Sida Tang
My Responsibilities: form design and calculations, CAD, electronics, and coding; collaborated on fabrication and all design decisions
Roll into an open rack, fold the rack closed, and lock your bike by swiping an RFID-enabled ID card.
Swipe-Activated
Our prototype uses RFID technology, but NFC- and app-based activation can be applied to our flexible platform.
Neat and Tidy
Lean Rack hugs bicycle frames to prevent bikes from falling over. All bikes rest at the same 17-degree angle lean, providing an organized aesthetic to a cluster of bikes.
Secure
Thick metal pins secure both the front wheel and frame of the bike.
Universal
Lean Rack’s novel geometry accommodates all adult-sized bicycles.
How it Works
When a user swipes their ID card to lock their bike, an RFID reader sends ID data to a Raspberry Pi microcomputer. A Python Script on the Raspberry Pi saves the user’s RFID number and actuates a solenoid to mechanically lock the rack. The rack will only unlock when the same user swipes their card again.
Design Process
Examining pain points in urban and campus bike use
We saw an opportunity to increase both convenience and security with an innovative rack.
Racks are often overcrowded, making it difficult to maneuver your bike into an open position.
On traditional racks, bikes have a tendency to flop over, giving the rack an untidy look and making it harder for other people to lock their bikes.
Many people forgo the time-consuming precaution of locking the front wheel, leaving quick release wheels as easy targets for thieves.
Identifying stakeholders and project goals
We identified and interviewed different stakeholders in urban and campus bike use, including bike users, pedestrians, business owners, universities, city planners, and bike share companies.
We used this information to create a set of priorities for our project. We aimed for our solution to be:
Secure (for both frame and front wheel)
More time-efficient than existing methods
Space-efficient
Durable
Inclusive (usable by all types of bike users)
Universal (usable for all bikes)
Ideation, Prototyping, and Iteration
In order to achieve universality, we determined a universal locking geometry by compiling and analyzing standard adult bike models. Our two locking points are above the diagonal down tube and through the bottom of the front wheel.
We considered an on-bike attachment that locked into an electromagnetic docking station, but decided that this solution required too much user buy-in
After initial testing, rolling the bike up our ramp-based rack proved too strenuous to be included in the final prototype
A few of our physical prototypes that we employed for user testing
A very small sample of the geometry calculations that I completed over the course of this project. Once I established key parameters, I wrote a MATLAB script to do the calculations for me.
I would calculate the key dimensions of the next iteration using our universal locking geometry data and user testing feedback, and then make a simple CAD model. My teammates would then laser cut and construct a prototype (using minimum viable product principles). For each prototype, we tested three bikes that varied greatly in size and structure (a women’s cruiser, a unisex mountain bike, and a men’s road bike) and evaluated each model based on our project goals and priorities. For these low-fidelity prototypes, we looked for functionality, ease of use, smoothness, and consistency of results.
Final Prototype
Lean Rack’s eponymous 17-degree lean allows for a hands-free resting surface for the bike while the user closes the rack and swipes their card.
Our prototype was constructed from welded steel square tubing and 1/4-inch plate. Based on SolidWorks analyses, Lean Rack is extremely durable and minimally susceptible to human-inflicted damage. The structural gussets also provide a space for logos or advertisements.
After testing, Lean Rack proved faster to use than a U-Lock, and more secure than any combination of U-Lock and cable locks.
By shifting ownership from users to institutions, Lean Rack allows companies, universities, and cities to incentivize green alternative transportation by enhancing convenience and eliminating a bicyclists’s financial burden of purchasing a lock, or worse, replacing a stolen bike.
Next Steps
Potential improvements to future iterations of Lean Rack include:
Adding U-Lock and cable lock compatibility, so that those without an RFID card can still use Lean Rack
Migrating electronics to the inside of the arm
Connecting multiple racks to a central ID-authentication server