Bike headlight displays speed

My friend Matt Richardson made a system for his bike that projects a spotlight with data onto the street. It's currently set up to display speed, but it can also be used to project other kinds of information (like turn-by-turn directions). He's going to write about it for MAKE so you can build one, too.


  1. That is fantastic.  The pi could probably even overlay a map on the road and do realtime directions.  I’ve always thought that those little battery driven projectors were useless, I’m glad to be proven wrong.  

          1. Yeah, these days they gotta be better than the one I had in the early 90s.  That sucker was heavy, noisy, and sucked a lot of pedalpower considering how little wattage it put out.

          2.  Dunno, I had probably the same thing in the ’70s (and a MUCH heavier bike), but my kid-size legs did ok with it. But aye, it should be considerably lighter & more efficient.

    1. Since it uses one of those little battery powered projectors, no.  I’m a little surprised it works as well as it does on lit city streets.  Those projectors are really crap. 

  2. They already have handlebar mounted GPS for bikes, and handlebar mounts for smartphones. I mean, I get that this guy wanted to build it himself, but this seems strictly less practical.

    1. Everyone, stop making things!  It’s much more practical to just consume!

      Whew, close one there.  Someone almost taught themselves something.

      1. While this is a pretty cool project, the pico-projectors I’ve seen cost as much as a bike GPS all by themselves.  There’s a whole lot of consuming going on there.

    2.  His project is cool, and all, but I don’t see an advantage over a regular speedometer. Other than maybe not having to re-focus your eyes as much.

      1. How about the advantage of having made something and having become smarter about making along the way? Seems pretty practical to me.

  3. If he can make it so that it throws a hologram about 5-10 feet in front of the bike of someone frantically running away while looking over their shoulder, I’m in.

    1. The Pi is more than capable of playing videos, so that’s not too hard to do.  Making it not look bad by keeping the video synced with the ground passing underneath would be pretty tricky, but the basic mode should work fine. 

    1. seriously though. after watching the video it looks like he’s having a hard time operating the bike because he’s watching the display. this would be cooler if it were on some sort of HUD on a helmet or glasses so you don’t have to take your eyes off of your environment.

  4. This makes me want to have a rear camera and have this thing show me blinking red squares of cars approaching from behind.  It could detect the headlights at night (and the shape of them during the day).

    It could also figure out the speed in which the car is approaching and put that number beside it.I guess it’d look something like this…  take my money.

    1. I know, right?

      Hand signals for turns?  Sissy stuff.  Hand signals for lane changes?  Faugh.  Shoulder checking before merging?  Where’s that at?

      At least all the traffic, including the bike, were going nice and slow.

        1.  I live in England, where we have a MUCH harder driving test, and I check my six constantly, cos people are still idiots.

      1. How did you know he wasn’t doing shoulder checks? Judging by the angle the 1st person shot was taken at the camera was mounted on a shoulder or to his top somehow. Also the weaving seemed mainly to do with getting out of the way of the car behind.

        1. Anyone riding like that is not shoulder checking.

          Given how slowly the cars were moving, there was no need to get out of their way anyway – just move at the same speed as other traffic…

    2.  I wouldn’t insult him like that, but I thought this was weird too. He seemed to be weaving back and forth into empty parking spaces and then back into the riding space between traffic and parked cars which is where he should just stay. If something blocks his way or it gets to tight then he needs to “take the lane”.

  5. What a cool use of a raspberry pi! It seems like once something like Google Glass becomes more mainstream though, this will be obsolete as Glass works in daylight and is directly in your field of vision so you don’t have to look down at the street to see it.

    1. Google glasses have obsoleted an invention before it’s even invented?

      I feel like I just put instant coffee in the microwave and went back in time a little. 

    2. One of these days, Google Glass will display the potholes and roadkill and drainage grates and other assorted road hazards in my path, so I never need glance down at the road again!

      Until then, I’d like to hook my Kindle to this projector, so I might catch up on my latest issue of Asimov’s on the ride home.

      1. Make sure to get the Semen Stain ID app so that you know where not to put your foot.

        1. I can’t help but wonder if there’s an almost too-subtle dig about putting your foot in your mouth?

  6.  Ouch – wearing a black jacket and dark jeans while biking at night?  Dodging traffic up close?  Gives this urban cyclist the heebies.  Or maybe the jeebies…

      What I’d like to see (and would be a delight if Matt could create) is a wearable vest that displays big bright messages using a matrix of leds.  I imagine programmable flashing bars, stars, letters, or a message for the car behind me.  Make the vest orange so it’s visible in the day, and interwoven with 3M reflective material, so it’ll show up in headlights even when its batteries are dead.

      Hmmm – maybe I’ll hack something together…

    1. Yeah! Cycling is too dangerous to be enjoyed by the masses! Let’s force people to wear absurd safety gear or make them feel like they’re engaging in something akin to snowboarding off a cliff.

      Seriously, cycling in most cities, day or night simply isn’t that dangerous, this idea that all cyclists must wear reflective vests, etc. does nothing but reenforces the idea that cycling is a fringe activity not worthy of serious consideration by governments or the general public. If you’ve got lights on, you’re doing ok.

      1. He just needs to get a blinking white front light and blinking red rear light. Giving him the benefit of the doubt perhaps he has them and didn’t want to distract from his demonstration. Lights are very necessary even in bright cities. As a cyclist I’ve almost hit other people on bikes I couldn’t see who didn’t have lights. Lights are kind of a no-brainer. As far as covering yourself in reflective material, I agree that’s not as necessary.

  7. This is very cool – I’d think it would be fun to implement in software on an iDevice or Android phone rather than hauling an additional processor and battery around. Of course, I may be biased as I already use my iPhone as a bike computer for speed/cadence/HR…

    Are there any ruggedized and wireless pico projectors out there?

  8. back-up with Solar power or use some sort of chargeable unit, so you are not having a high budget on battery usage.  

  9. So…what are the assembly/disassembly times associated with not wanting someone to steal your projector, etc every time you need to get off your bike and can’t take it inside with you?

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