A Bicycle Is Abandonware Now? Clever Hack Rescues Dead Light

April 24, 2025 by Jenny List 76 Comments

A bicycle is perhaps one of the most repairable pieces of equipment one can own — no matter what’s wrong with it, and wherever you are on the planet, you’ll be able to find somebody to fix your bike without too much trouble. Unfortunately as electric bikes become more popular, predatory manufacturers are doing everything they can to turn a bike into a closed machine, only serviceable by them.

That’s bad enough, but it’s even worse if the company happens to go under. As an example, [Fransisco] has a bike built by a company that has since gone bankrupt. He doesn’t name them, but it looks like a VanMoof to us. The bike features a light built into the front of the top tube of the frame, which if you can believe it, can only be operated by the company’s (now nonfunctional) cloud-based app.

The hack is relatively straightforward. The panel for the VanMoof electronics is removed and the works underneath are slid up the tube, leaving the connector to the front light. An off the shelf USB-C Li-Po charger and a small cell take the place of the original parts under a new 3D printed panel with a switch to run the light via a suitable resistor. If it wasn’t for the startling green color of the filament he used, you might not even know it wasn’t original.

We would advise anyone who will listen, that hardware which relies on an app and a cloud service should be avoided at all costs. We know most Hackaday readers will be on the same page as us on this one, but perhaps it’s time for a cycling manifesto to match our automotive one.

Thanks [cheetah_henry] for the tip.

Bike Wheel Light Flashes Just Right

February 4, 2021 by Kristina Panos 22 Comments

When it comes to safely riding a bike around cars, the more lights, the better. Ideally, these lights would come on by themselves, so you don’t have to remember to turn them on and off every time. That’s exactly the idea behind [Jeremy Cook]’s latest build — it’s an automatic bike light that detects vibration and lights up some LEDs in response.

The build is pretty simple — a coin cell-powered ATtiny85 reads input from a spring vibration sensor and flashes the LEDs. This is meant to complement [Jeremy]’s primary bike light, which is manually operated and always on. We especially like that form follows function here — the board shape is designed to be zip-tied to the spokes so it’s as close to the action as possible. He cleverly used cardboard and a laser cutter to mock up a prototype for a board that fits between the spokes. Pretty cool for your second professionally-fabbed PCB ever, if you ask us. Ride past the break to check out the build video.

If you don’t think fireflies on your spokes are enough to keep you safe, go full rainbow party bike.

Continue reading “Bike Wheel Light Flashes Just Right” →

Redesigned Bike Light Controller

November 6, 2014 by Bryan Cockfield 17 Comments

[JP] was looking for a bicycle light to do some night biking around his home. He found a reasonably priced light that suited his needs, but when he started using it he found that the controller was a little lackluster. To solve some of its problems, he ended up building his own lighting controller from scratch.

The original controller’s main problem was that the it didn’t debounce the input from the single pushbutton. This meant that a single press of the button might cause it to cycle through two or three different modes, which was inconvenient and annoying. The new controller took care of this along with implementing several new brightness modes and a “strobe” mode for commuting to work to help alert other drivers of [JP]’s presence on his bicycle.

While [JP] notes that an Arduino would have been very easy to use in this situation, it wouldn’t have fit in the original enclosure. He went with an 8-pin ATtiny45, which was perfectly sized for what he needed. Everything fit together perfectly and is much more useful than the original. Maybe next he could pair it with a light that is even brighter than the one he’s currently using.

Auto Bike Light: On When Moving Off When Not

October 2, 2014 by Mike Szczys 72 Comments

If you’re plagued by perpetually dead bike light batteries you’ll like this one. It’ll also fix the problem of remembering to turn the lights on in the first place. This hack uses an accelerometer to switch the light when the bike is in motion.

In this case the bike light was chosen for its ability to fit the control board inside the case. But with this proof-of-concept you can easily spin a tiny board with uC and accelerometer to replicate the functionality (the Bluetooth module shown above is going unused in this application). Many accelerometer chips have low-power mode that can be used to was a uC so we could easily see this having very little impact on the normally battery life of your light. The one caveat being the need to regulate the voltage as many of these lights take a 12V cell.

The other alternative is to make sure your battery is always charging during the day. This solar setup is one way, but then you won’t want to leave the thing unattended.

An Amazingly Professional LED Bike Light

May 7, 2009 by Caleb Kraft 15 Comments

light1

[Tom] sent us a link to this very professionally done project. He built a bike light that is a 540 lumen Luxeon light with a custom case. The LED, Lens, and driver were purchased first. Everything else was designed around it. The design is compact and good looking. You can download the CAD files on the site if you want to make your own. He is using an Atmel AVR ATTiny13 to control brightness.

AVR Light Controller

January 30, 2009 by Caleb Kraft 12 Comments

halogen

[Matthias] sent us this project where he builds an AVR light controller. He had a halogen bike light laying around, but was unsatisfied with its lead-acid battery. He wanted to use a lithium-polymer battery but found that they can’t be used directly with halogen lamps due to their voltage. His produced 8.5 volts at full charge and can’t be discharged to below 5 volts. He new a power controller would be necessary to try to flatten that out for his lamp, which needed to stay between 6-12 volts.

He used an ATtiny45 doing PWM to change the voltage. Some other cool features he added were the high and low settings and an LED status light for warnings. You can find pictures, schematics and source code on his page as well as tons of great information. Great job [Matthias].