Paddle Remote
A battery powered remote for triggering wireless electronic bicycle gear shifting.
Company: Archer Components, 2022
Background: This project began with Archer Components wanting a new remote to trigger their electronic gear shifting. The existing design was a remote with side by side tactile switch buttons. This design was not ergonomic and the short throw of the buttons felt unnatural compared to typical mechanical shifters.
Defining Architecture: My first task was to define the overall mechanical architecture of the new remote. Two designs stood out to me: one with trigger levers, and one with a rocker paddle. Most common bike shifters have trigger levers, with two separate levers rotating about a vertical axis. The rocker paddle design is a single piece of plastic that rotates about a horizontal axis. The benefit of the trigger design is that it is more familiar to cyclists, but the downsides are complex mechanisms with custom torsion springs, high bending moments on the long levers, and difficult servicing. I chose to proceed with the rocker paddle design because it can be made with off the shelf compression springs, it is more compact, and it is easier to assemble and service. The downside to the rocker paddle is the design is new to most cyclists so it would take more work for the user experience feel natural coming from a mechanical shifter.
Sketching & Ergonomics: I began by sketching various paddle and remote body shapes. I created rough designs of these sketches in CAD and 3D printed them. I mounted each design to a bicycle’s handlebars and sought feedback from friends with different hand sizes on these prototypes. I used anthropometry charts to further define the shape and orientation of the paddle. I learned form the charts I would need to design two separate mounting positions into the remote to accommodate thumb lengths from the 5th percentile female to the 95th percentile male. I also measured the stoke distance of conventional mechanical shifter levers to replicate their haptics in my design.
Mechanical Design: Due to the relatively low production volume of this product, Archer wanted to keep their tooling costs as low as possible. This guided me to design with mostly off the shelf components and to use Multi Jet Fusion (MJF) 3D Printing to produce both prototypes and the final product. I chose Nylon PA-12 as the material as it is the strongest MJF material, similar in strength to ABS. In my early designs I did not put enough material around the handlebar mount connection, making the remote susceptible to breaking as I found out in FEA simulations and testing. This is because the bending moments around the mount are the highest, which I corrected in later iterations.
A design challenge was keeping the number of holes in the plastic enclosure to a minimum to limit water ingress points. I eliminated two holes by designing embedded magnets in the rocker paddle which trigger hall effect sensors on the PCB when the paddle is pressed. I worked with an electrical engineer to layout the PCB, adjusting size of the board and position of the components to work with the enclosure shape. I used Finite Element Method Magnetics (FEMM) to model the magnetic field and select the appropriate strength hall effect sensors. External tactile switches are also embedded in the paddle to provide the user haptic feedback that they have triggered a shift. All external hardware is stainless steel to resist corrosion, and the USB charge port is IP-67 rated with a custom dust cover.
Prototyping: Though I modelled the magnetic field in FEMM, it was still necessary to make small PCB position adjustments to actuate shifting at the correct angle in the paddle’s stroke. Using MJF printing I created an enclosure with set screws on either side of the PCB to slide it left and right, moving the hall effect sensors closer to the magnets. I created a test fixture to quantify the exact angle of actuation and adjusted the board location until it matched the mechanical shifter. Pictured is the text fixture and remote with PCB-adjusting set screws.
Testing: The main failure modes for this product are water ingress or impact damage. The most significant water exposure occurs during bike washing or riding during a rainstorm, which align with the IP65 test rigor. I created this test by spraying the remote with a garden hose for 60 seconds on each side, and though this sounds crude, it is exactly what the professional testing machines do. Impact damage to the underside of the handlebar (where the remote will be located) would most likely occur during bike rack loading. I estimated this impact force to be 10 Joules, and created this test by dropping a 1kg mass down a 1m high tube onto the remote. As mentioned above the plastic initially cracked around the mount, so I added more material to increase the moment of inertia in this area.
Additionally, approximately 700 hours of test riding was logged on the prototype remotes before production. Archer has a small group of test riders, myself included, who live in various geographic locations and tested through the winter months. This ensured the remotes got exposure to rain, mud, and dust.
Production: Since this product is relatively low volume, the transition from prototype to production was less complex than high volume production. The manufacturing method was unchanged from prototyping, only the quantities increased. I worked with the assembly team throughout product development to ensure I was following Design for Assembly (DFA) principles, so they were already familiar with the assembly sequence.
The result of this project is a wireless remote that is more compact and half the weight of its market competitor. It has a rechargeable battery capable of lasting 50 hours, and is designed for repairability. The user can customize the stiffness of the rocker paddle by choosing from three different spring rates. The shifter has been in production since early 2023, and has been receiving great customer feedback.
If you are interested in seeing the shifter in action or buying on for yourself, please visit Archer’s website:
Skills: Full-Cycle Product Development, Ergonomics, Ideation, Sketching, Design for Assembly (DFA), PCB Design, Rapid Prototyping, MJF 3D Printing, Autodesk Fusion 360 CAD
Materials: Nylon PA-12, Neodymium Magnets, Stainless Steel, TPU, Cerakote
The second product I designed at Archer Components was this handlebar mounted remote to trigger the D1x wireless bicycle gear shifter (see here). Called the Paddle Remote, this product is aimed at mountain bikers. I was the sole engineer on this project and owned the entire development life cycle. My intent was to create a shifting experience that is quick and reliable, and feels natural transitioning from a traditional mechanical shifter. Through the grippy texture of the paddle, the slight resistance of the centering springs, and the haptic ‘click’ button feedback, the remote feels sturdy and is enjoyable to press. I focused heavily on the ergonomics of the remote so that a wide range of hand sizes with various cockpit setups can easily press the paddle.
