Putting LEDs In Motorcyle Tail Light Shows How Trivial Becomes Tough

May 25, 2021 by Donald Papp 55 Comments

[Maarten Tromp]’s replacement of his motorcycle’s tail light with LED equivalents is a great example of something that every hacker learns sooner or later: interfacing to and working around existing parts can turn a trivial-seeming task into a much bigger job than expected. The more one has to work within the constraints of an existing system, the more opportunities there are for roadblocks and surprise issues to stall progress, and this project is a great example of that.

[Maarten]’s 1999 Honda ST1100 Pan European motorcycle had no aftermarket options for an LED rear light assembly, and he wasn’t too keen on just installing a generic module to replace the original. Instead, he resolved to purchase and disassemble a used factory assembly, and replace the incandescent lamps with some equivalent LEDs. Replacing bulbs with LEDs sounds easy, but doing the job right took [Maarten] almost two weeks in the end.

Problems started early with simple things like how to open up the light assembly itself. The unit isn’t user-serviceable and isn’t intended to be opened, and the parts are sealed shut with a waxy substance. Fortunately, heat does the trick. Another early hitch was the curved base of the light assembly, which made mounting flat perfboard or veroboard a challenge. In the end, [Maarten] settled on a triangular grid of high-brightness LEDs, driven with LM317 regulators configured as constant-current supplies, mounted on some protoboard cut to fit the unique curve of the assembly. The result accepts the wide voltage range of the motorcycle’s battery (from 10.5 V to 14.5 V) and can still function even if some individual LEDs stop working.

The project has one more example of how working around existing hardware can be a pain. [Maarten] had originally intended to swap out the turn signal lamps for LEDs as well, but there is a glitch. The motorcycle’s turn signal relay will do a fast blink pattern if burnt-out turn signal lamps are detected. Since LEDs consume considerably less current than the original bulbs, the relay will remain stuck in the fault condition. There are a few different ways around this, but it’s a problem for another day. For now, the tail light LED replacement is a success.

Working around existing hardware frequently brings unexpected challenges, but when safety systems (such as lights on a vehicle) are involved, it’s extra-important to make sure things are done right.

At Three Grand A Tail Light, There’s An Opportunity For A Hacker

December 29, 2019 by Jenny List 65 Comments

It can be amusing sometimes, to read an incredulous reaction from outside our community to something that would be bread-and-butter in most hackerspaces. Take the sorry saga of the Cadillac XLR tail light, as reported by Jalopnik. This car was a more-expensive Corvette with a bit of lard around its midriff, and could appear a tempting pick for a bit of inexpensive luxury rubber-burning were it not for the revelation that a replacement second-hand tail light for one of these roadsters can set you back as much as three grand. The trusty auto on the drive outside where this is being written cost around a tenth that sum, so what on earth is up? Is it because a Caddy carries some cachet, or is something else at play?

It appears that the problem lies in the light’s design. It’s an LED unit, with surface mount parts and a set of fragile internal PCBs that are coated in something that makes reworking them a challenge. On top of that, the unit is bonded together, and instead of being a traditional on-off tail light it’s a microprocessor-controlled device that gets its orders digitally. This is all too much for XLR owners and for the Jalopnik hacks, who castigate General Motors for woefully inadequate design and bemoan the lack of alternatives to the crazy-expensive lights, but can’t offer an alternative.

Reading about the problem from a hardware hacker perspective they are right to censure the motor manufacturer for an appalling product, but is there really nothing that can be done? Making off-the-shelf microcontroller boards light up LEDs is an elementary introduction project for our community, and having the same boards talk to a car’s computer via CAN is something of a done deal. Add in LED strips and 3D printing to create a new backing for the tail light lens, and instead of something impossibly futuristic, you’re doing nothing that couldn’t be found in hackerspaces five years ago.

So what’s to be learned from the Cadillac XLR tail light? First of all, there’s scope for an enterprising hacker to make a killing on a repair kit for owners faced with a three grand bill. Then, there’s another opportunity for us to be acquainted with the reality that the rest of the world hasn’t quite caught up with repair culture as we might imagine. And finally there’s the hope that a badly designed automotive component might just be the hook by which the issue of designed-in obsolescence moves up the agenda in the public consciousness. After all, there will be other similar stories to come, and only bad publicity is likely to produce a change in behavior.

Of course, to get it really right you need a car that’s hackable in the first place. Or better still, one designed by and for hackers.

Thanks [str-alorman] for the tip.

Cadillac XLR header image:Rudolf Stricker [CC BY-SA 3.0].

LED Tail Lights For Improved Motorcycle Visibility

May 10, 2017 by Lewin Day 32 Comments

Motorcycles are hard to see at the best of times, so riders are often concerned with making themselves as visible as possible at all times. [Josh] wanted to do this by creating a custom tail light for his Ducati 749.

The tail light is based around SMD LEDs, mounted in acrylic to diffuse the light. The construction is beautiful, using custom PCBs and carefully machined acrylic to match the lines of the bike.

As far as warning lights go, a brighter light will be more obvious in the day time, but could actually hinder visibility at night by blinding other road users. To this end, [Josh] built the tail light around an ATtiny 45, which could be programmed with various routines to optimise the light level depending on ambient conditions. Another feature is that the light’s brightness pulses at high frequency in an attempt to attract the eye. Many automakers have experimented with similar systems. The ATtiny controls the lights through a PCA9952 LED controller over I2C. This chip has plenty of channels for controlling a bunch of LEDs at once, making the job easy.

Overall, it’s a very tidy build that lends a very futuristic edge to the bike. We’ve seen [Josh]’s work in this space before, too – with this awesome instrument display on a Suzuki GSX-R.

Brake Light Blinker Does It With Three Fives

February 11, 2017 by Bryan Cockfield 35 Comments

Sometimes you use a Raspberry Pi when you really could have gotten by with an Arudino. Sometimes you use an Arduino when maybe an ATtiny45 would have been better. And sometimes, like [Bill]’s motorcycle tail light project, you use exactly the right tool for the job: a 555 timer.

One of the keys of motorcycle safety is visibility. People are often looking for other cars and often “miss” seeing motorcyclists for this reason. Headlight and tail light modulators (circuits that flash your lights continuously) are popular for this reason. Bill decided to roll out his own rather than buy a pre-made tail light flasher so he grabbed a trusty 555 timer and started soldering. His circuit flashes the tail light a specific number of times and then leaves it on (as long as one of the brake levers is depressed) which will definitely help alert other drivers to his presence.

[Bill] mentions that he likes the 555 timer because it’s simple and bulletproof, which is exactly what you’d need on something that will be attached to a motorcycle a be responsible for alerting drivers before they slam into you from behind.

We’d tend to agree with this assessment of the 555; we’ve featured entire 555 circuit contests before. His project also has all of the tools you’ll need to build your own, including the files to have your own PCB made. If you’d like inspiration for ways to improve motorcycle safety in other ways, though, we can suggest a pretty good starting point as well.

Hackaday Links: Sunday, June 9th, 2013

June 9, 2013 by Mike Szczys 25 Comments

This week we saw an interesting animated motorcycle tail light over on Reddit. But there wasn’t really enough background to get its own feature.

The NeuroKnitting project captures brainwaves by weaving them into a scarf.

On Semiconductor is showing off an 8x8x8 LED cube which they claim as 12,000 LEDs. We can’t figure out where all those LEDs are used in the design, but maybe you can. Here’s one that we know has 4096 LEDs in its matrix.

[Jeff] used hard drive platters as the disc section of his original Enterprise desk model.

Play around with an SNES controller and Arduino by following [Damon’s] guide.

Hackaday Alum [Jeremy Cook] posted an update of his laser graffiti project. His earlier effort used camera tricks to capture the image but this time around he’s exciting phosphorescent glow material to make a persistent display visible to the human eye.

This server hides in plain sight after being wrapped in a hard cover book binding. Hopefully this won’t cause heat dissipation problems.

[Trumpkin] built his own Nixie tube wristwatch which we think has the potential to be as neat as the one [Woz] wears.

Bike Alert Tells Drivers To Back Off

June 4, 2012 by Mike Szczys 79 Comments

Bicycle commuters are often in a battle with drivers for space on the road. [Hammock Boy] does all of his commuting on two human-powered wheels, and is quite interested in not getting hit by a car. He decided to ply his hobby skills to build a device that helps keep him safe. It’s not just a tail light, it’s a sensor that shines brighter the closer a car is to the back of the bike.

The sensor portion is the ultrasonic range finder seen in the center of the protoboard. Surrounding it is a set of LEDs. Each is individually addressable with the whole package controlled by an Arduino. The sketch measures the distance between the back of the bike and whatever’s behind it. If there’s nothing, one Red led is illuminated. If there is an object, the lights shine brighter, and in different patterns as the distance decreases.

Certainly the next iteration could use a standalone chip without the need for the whole Arduino. This could even work with two battery cells and no voltage regulator. We also think the use of any other color than Red LEDs is suspect but we do love the concept.