Matt Richardson and the world’s smartest bike light

Our friend Matt from Make (whom I totally failed to hook up with for drinks when we were in NYC last month – sorry Matt! We’ll see you at Maker Faire San Mateo) has been busy. This demo is absolutely superb. He’s rigged up a light on the front of his bike that works as a headlight and as a projector to show what speed the bike’s travelling at – Matt has plans to add some more features and make the whole thing rather more beautiful, and we’ll be putting video of the finished article up here as soon as he’s ready.

Matt’s book, Getting Started with Raspberry Pi is published by Make – check it out!


Jim Manley avatar

Extreme coolness! Being one of what seems many cyclists here (not to be confused with “biker” despite the “style” of my beard :) ) I am just going to have to do this on my bike!

Andy Willo avatar

I see the makings of a game – a spot of object detection and rather than your speed a score achieved for staying alive on that ride is dispalyed

Rich Kavanagh avatar

I never cease to be blown away by the ingenuity of Raspberry Pi owners!

Yet another truly amazing project :)

Homer Hazel avatar

Matt, that’s very cool. And you don’t have to take your eyes off the road to see how fast you are going. You’ve got more guts than I do. I would not dream about riding a bicycle in New York. For me, it would be a nightmare.

Have you considered some sort of proximity sensor and alarms when cars come too close?

Splendid idea though.

Stephen avatar

Extreme coolness indeed! I can see a few iterations down the line of this to be used indoors on a turbo trainer which is synced to a cycling video so you can join in on the ride (tour de France etc) and the speed of the video playback linked to the speed of your cycling. If you could link the pi to some way to control resistance of your turbo trainer, and elevation maps/GPX data then you could very quickly have a system comparable to the very expensive virtual reality esque trainers :-)

Simon D avatar

This what I thought. Two parts to a project: 1) collect data from turbo 2) do something with it.

Cheap turbos are adjusted by a lever. But if you know the lever position and your turbo flywheel speed then the power + roadspeed are an easy calculation. You could read your bike speedo and eyeball a lookup table, but I can’t be bothered with that.

Writing a VR output system isn’t that hard. So long as you have elevation data and video then the rest is “trivial”. Your power/speed log will allow the computer to calculate your ground-speed for the gradient. Note that your aerodynamic drag power is cubic. Then numerically integrate this to give your current position on the course.

The output is really just a computer controlled video player. Normally the human controls the display. Here the VR machine controls the framerate.

Of course you could just ride on your own, or ride in a virtual peloton. Or do timetrials where you can’t be online together.

Stephen avatar

Now you’re talking. Online multiplayer indoor cycling against your mates when the weather is terrible. You could have a Mariokart like onscreen map with your and your friends locations plotted on top.

Andrew Scheller avatar

Yeah, I made a similar suggestion in the comments on

iledip avatar

Looking dangerous staring light against the moving car. Did you get people pointing finger and laughing at you saying “Hahahah. Look at that Nerd bike”?

Sigh*… Next day you won’t ride again.

Dec avatar

This is very cool, I love the concept, I think the coolest thing I can think of here is linking this to turn by turn directions from google maps and having it project the turn signs. not sure how this would work at day, maybe some cool led colour lights or something, There is so much potential here!!!

silverfox0786 avatar

what would be cool is to add a dymo or something that charges the battery as you ride

JBeale avatar

Only if they work a lot better than the wheel-powered bike light I remember trying briefly about 30 years ago, the stiff load made it almost impossible to pedal. It was like having the brake almost fully on… but I guess LED lights are a lot more efficient now.

Andy avatar

When I were a kid, we all had dynamo-driven lights – it was cooler than batteries. The major problem was when you stopped, the light went off. More than once a car mashed my bike.

liz avatar

I had a bike with a dynamo when I was at university – it was a heavy great bike, and if you weren’t going as fast as your little legs would move, the light was thready, weedy and fluttered on and off. (And, as Andy says, it was a bit rubbish if you were stopped in traffic, ‘cos it went out.) I hope dynamo technology has improved since then, but the lights on my bike now are LED ones driven by a battery!

silverfox0786 avatar

I dunno

I think its possible I got a wind up torch and its pretty good and real easy to wind

and all you want really is for when the back wheel turn during riding to wind the dynamo and send power to the battery to keep it maintained and charged

its possible as I have made a solar charger that keeps my pi running so the concept is same just replace the solar panel with a dynamo system

yakko TDI avatar

Modern technology to the rescue!*

*I did not do any research so this may not work.

gordon77 avatar

Interesting idea. Maybe work as a head up display for cars etc ?.

Didn’t look like balsa wood to me :)

Matthew avatar

This is, to be fair, a bit silly.

Because the projector is designed to project precisely in one direction with as little overspill as possible, it’s not going to help oncoming drivers see you.

Much of the bulb’s power is wasted by the dark areas. The remaining light isn’t bright enough to see where you’re going.

The small spot won’t help you spot obstacles in the road, like potholes.

You will have to have some other way to see your speed in sunlight.

I could go on…

JamesH avatar

You could go on, but it’s seems that you have rather missed the point….

stocker avatar

Interesting project. At work we have a lot of projectors and they blind you when you look into it…how does it wor here? im concerned that ppl going towards you on bike,car and so on wont be blinded by the light.

Neil avatar

I’d have started with a cheap projection alarm clock (something like this: ) and re-purpose the projection bit. A bit of GPIO twiddling later and you have a four digit 7-segment readout on the road.

Andrew Scheller avatar

Would that be bright enough to be seen on a street-lit road though, rather than just a perfectly-dark bedroom ceiling?

Neil avatar

Maybe – you can just about make out the one I have during the day. By early evening it is clearly visible.

Raphael Kopfmann Switzerland avatar

Congratulation and Jubilation for this “Bike-light” on the streetfloor. Many Greetings from Raphael kopfmann, Switzerland, Europe

gaming grandma avatar

I’d love to have my grandchildren built one of these for their grandpa. Are any instructions available?

Helen Lynn avatar

There don’t seem to be any further videos in this series, nor any build notes or instructions, sadly. If alternative cycle projects are of any interest, I found that a search for “Raspberry Pi bike […]” turns up quite a few helmet camera/speedo/bike computer projects, although I haven’t dug in to see whether anyone has written a tutorial/instructions – could be worth a poke around.

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