LightSpeed Pedals

Cycling is an exhilarating, speed‑fueled sport, but when bikes are on the road, cars create a danger for riders. In my own riding and in the research I gathered, it became clear that many close calls and accidents happen because drivers don’t see cyclists soon enough. Talking to other cyclists, it stood out to me that many road cyclists often reduce or remove visibility features to save weight and improve aerodynamics. I admit, I have done this myself, and it creates a tradeoff between performance and safety that shouldn’t have to exist. In 2021 alone, the National Highway Traffic Safety Administration (NHTSA) found that 41,615 cyclists were injured by motor vehicles in 2021. Cyclists also represent 2.2% of all traffic fatalities in 2021

I started by looking for research on visibility, reflectance and light systems on bikes. From this I found a Clemson University study in funded by Trek Bicycles covering just this. Its primary finding where that cyclists are perceived at much greater rates when they contrast their environment (Hi-Vis), have running day lights, and most notably when light or reflective material is placed on moving parts of the bike, such as the pedals (biomotion).

After knowing this, I wanted to see what I could buy to make myself a safer cyclist. I could get taillights, headlights, and reflective clothing. I then stumbled across something that I thought was special. It was a bike pedal that featured a tail and headlight. This combined the elements of running daylights, biomotion, and general contrast from the environment. These pedals were designed and created by Redshift sports, called Arclight Pedals. These where really interesting to me, but they would not work for me. I ride my bike using clipless pedals, spd-sl. Many cyclists use these pedals because they improve comfort and power transfer from the rider to the cranks. They are also light weight and aerodynamic. These Arclight pedals were not. coming in at 756g for a set, these are almost twice the weight as my spd-sl pedals, 356g. Additionally, they did not sell a version compatible with spd-sl bike cleats. From this I wanted to create a cost-effective system that would work for cyclists wanting a light weight, aerodynamic solution to safety.

That led me to create LightSpeed Pedals, a research‑backed visibility system that uses biomotion to help drivers recognize cyclists earlier and more reliably. By integrating lighting into the natural movement of the pedals, the design improves safety while staying true to the priorities of performance‑oriented riders. This design combines both speed with safety, and here is how you can build it at home yourself!

Additional Sources:

Tyrrell, R. A., Fekety, D. K., and Edewaard, D. E. "The Conspicuity Benefits of Bicycle Taillights in Daylight." Technical Report delivered to Trek Bicycle Corp. on January 13, 2016.

"Improving Safety for Walking, Biking, and Rolling." *US Department of Transportation*, https://www.trekbikes.com/us/en_US/abcs_of_awareness/.

"Daytime Running Lights for Cyclists Reduce Accidents." *PubMed*, 2020, https://pubmed.ncbi.nlm.nih.gov/32408145/.

Edewaard, Darlene Elise. The Nighttime Conspicuity Benefits of Static and Dynamic Bicycle Taillights. Clemson University, Master’s thesis, 2017. TigerPrints, https://open.clemson.edu/cgi/viewcontent.cgi?article=3627&context=all_theses. .

Bill of Materials (LightSpeed Pedals)

1. Red LEDs — $0.60 total (10 × $0.06)

Color: Red (620–625 nm), Forward Voltage: 2.0–2.2 V, Forward Current: 20 mA

Link: https://www.amazon.com/dp/B01N0XQO4A

2. CR2025 Batteries — $0.50 total (2 × $0.25)

Voltage: 3.0 V, Capacity: 160 mAh

Link: https://www.amazon.com/dp/B0002DSV3G

3. CR2025 Battery Holders — $0.56 total (2 × $0.28)

Through‑hole coin cell holder

Link: https://www.amazon.com/dp/B07Q6VZ8ZC

4. Acrylic Sheeting — $0.04 total (4 in² × $0.01)

Thickness: 0.04", Transparent

Link: https://www.amazon.com/dp/B07KXQJ7ZC

5. Machine Screws — $0.36 total (12 × $0.03)

4 × M4×8 mm, 8 × M2×8 mm

Link (M4×8): https://www.amazon.com/dp/B07QKQ8Z8C

Link (M2×8): https://www.amazon.com/dp/B07QKQ8Z8C

6. Prototype Board — $0.20 (1 × $0.20)

39×17 mm section cut from standard PCB

Link: https://www.amazon.com/dp/B07B4F7W1N

7. Lockable Push‑Button Switch (KAN‑28) — $1.40 total (2 × $0.70)

Self‑locking push button

Link: https://www.amazon.com/dp/B07Q6VZ8ZC

8. Threaded Inserts — $0.42 total (14 × $0.03)

M2 and M4 heat‑set inserts

Link (M2): https://www.amazon.com/dp/B07G2Q7Z8C

Link (M4): https://www.amazon.com/dp/B07G2Q7Z8C

9. 3D Printer Filament — $2.00

Standard PLA filament used for housing and battery cover

Link: https://www.amazon.com/dp/B01N0XQO4A

Total Cost (Pedal Set): $6.24

Also attached here are the 3d print files device. I will go over printing instructions in a bit.

The LightSpeed pedal attachment mounts on your existing pedal by securing two bolts to the "clip" of the pedal.

To create a lens, I used some thin acrylic sheet that I sanded the surface of to make a diffuse lens. After trimming it to size, 9.45*34mm, it would be ready to embed in the print.

Yes! I said embed. When designing this I wanted to avoid using glues or adhesives, and I wanted to make it as few pieces as possible. To do this, I designed a channel in the body print that you can insert the lens it at a pre-programmed stop in the g-code! I found that this worked well to create a rigid part.

To slice the file, I found it best to print at an angle with a raft using supports. I made sure that supports where excluded from areas that would inhibit the lens cut out. After this I set a stop in the print just before the lens is fully sealed, for .2mm layer height, this was layer 59.

Once the parts are printed, I started on assembling the electronics.

I used prototype board as the base. The LEDs get soldered to 9.45x34mm piece of board, and the battery holder gets soldered to a 20x20mm piece.

Finally, use a soldering iron to press the brass inserts into the holes in print. Now, put in the bolts and your done!