Interested in helping an MIT student design ultimate rear bike light?

Discussion in 'Cycling Equipment' started by pekap, Apr 5, 2013.

  1. pekap

    pekap New Member

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    Hi Everyone,

    I'm a graduate student at MIT taking an entrepreneurship class. I'm working with a local Cambridge start-up and we're working on a new rear bike light. It will be anti-theft and very cool designed (in "afterburners" style). We talked with a lot of customer trying to undesrstand how ultimate rear bike light should look like. And currently we are trying to decide upon 2 things:

    1. metal housing VS. plastic housing (both of course with high quality material) . The trade-off here is about price premium - how much more are you honestly ready to pay for metal housing?
    2. flashing patterns and how to control them - how many buttons, blinking options and which blinking options are the best. The trade-off here is about easiness of usage vs. bunch of blinking options.

    We would love to hear what you think about this. It would be great if you could specify how much more are you ready to pay for metal housing and if you could tell what are the best blinking options.
    I appreciate any feedback that I can get. So excited to hear from you,guys!


    Regards,
    Petr
     
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  2. alienator

    alienator Well-Known Member

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    In my mind the perfect rear light has at least two bulbs: one that can stay constant and one that flashes randomly or quasi randomly with a period less or much less than 1 second. Flashing lights impair judgement of distance at night, so having at least one bulb stay constant will improve a driver's ability to correctly judge the distance to a bike. A number of lights come like this and have a single button which controls flash patterns (quite often though, one or several of the patterns involve both lights flashing). I think a single button is about the best option since it simplifies the entire assembly, can be used to cycle the light on and off and trough the different flash patterns. It also decreases the number of places the light could be possibly leak in wet conditions. Output is critical in power and luminous exitance (lm/m^2 or similar units). As you might guess, the more of both, the better. The light should be designed such that it provides significant visibility from the side as well as to the rear since at night bicycles are especially at risk to side collisions because they are typically not as visible from the side at night. I see no reason to have a light designed with a metal enclosure as it will only drive the price up. The light should be able adjustable in tilt so that depending on its mounting location, it can be positioned to provide maximum visibility from the rear. Good luck.
     
  3. dhk2

    dhk2 Active Member

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    I never ride at night, but use a bright flashing Dinotte rear taillight for daytime visibility. Their latest taillights have dual LEDs and a self-contained battery, as well as the various flash modes and reduced-power setting for nighttime use. Advise you study the Dinotte and other high-performance taillights to see how you could improve their design and function.

    Metal housings mean nothing to me; I'm interested in daytime performance, battery life and price. Can the light last for 8 hours in slow-flash daytime mode, and how behind me will the driver see it on a sunny day? The $30 AAA battery lights aren't very visible in the daytime, but the price of an effective light (eg, Dinotte) may keep a lot of potential buyers away.
     
  4. jpr95

    jpr95 Active Member

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    USB rechargeable
    Visible from at least 500' in bright daylight
    Side visibility
    Period-adjustable flash mode
     
  5. pekap

    pekap New Member

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    The thing is that start-up has already design its own front light and it had huge success. The price is premium - around $ 50-60. That is why they decided to get into rear-lights market too.
    And for the rear light the price will be premium too (so we are closer to Dinotte than to cheap lights).
     
  6. vspa

    vspa Active Member

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  7. dabac

    dabac Well-Known Member

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    I rteally don't care about metal vs plastic as such, they can both be made either sucky or good. It's more about the design than about the material.

    What I do like is good waterproofness, and either a fairly theft proof mount or easy removal together with good retention.

    Don't care much for flashing.
    As a cyclist, intense flashes annoy me, they create halos and make bikes harder to position.
    As a motorist I see reflective, hi-viz clothing much better than just about any light.

    But maybe a limp-home flashing pattern would be nice. It could do a double duty to both indicate time to recharge/replace batteries, and to extend working time enough to get home.

    Another feature I like is auto-on. A motion sensor together with a light sensor turns the light on automatically when needed.

    And as others have already mentioned, a good sideways spread, preferably with limited vertical beam width.
     
  8. bobqzzi

    bobqzzi New Member

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    As for flashing patterns: None. Flashing lights on the back of bike are just dumb.
    Should be dynamo and battery powered- runs on dynamo when present, otherwise runs on 2 AA batteries. Rechargable batteries aren't a great idea. If you forget to charge it, you have no options until you get home.
    2 separate circuits/LEDs would be nice in case one failed.

    Along the same vein- something that would allow the rider to know if the light was functioning while he/she was riding. Maybe a (very) small forward facing reflector that a rider could see by turning his/her head.

    Theft proof- that seems kind of tough. Perhaps a quick release that would allow it to be removed.
     
  9. jpr95

    jpr95 Active Member

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    Dynamos add weight, complexity and cost to the overall system. Flashing prolongs battery life (an LED light that's on 50% of the time due to the flashing pattern nearly doubles the battery life). It's a tradeoff, not "dumb". Designing a product for market also has to include the consideration of price point. We could list features here until we are blue in the face and the guy designs a $2000 whiz-bang light, but I guarantee you that he wouldn't be able to cover the cost of tooling at that price point. It just isn't going to sell. I thought I was splurging a bit for a $40 rear light (not as much as my wife thought I was, though!)
     
  10. bobqzzi

    bobqzzi New Member

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    There is a small weight penalty. I'd say cost comes out about even or the dynamo ahead if a person is a regular commuter, randoneer, or nigh rider. A Sanyo dyno is about $30 and rock solid reliable- it also never goes dead. Battery life is not an issue with a dynamo. I did say it should run on batteries or a dynamo thus capturing both markets.
    The purpose of a taillight is to locate your position in the dark for other vehicles. A flashing light is much, much worse at that than a steady one which allows the other drivers to accurately calculate speed, distance and trajecotory.
    I believe he did say "ultimate" light. There are already dozens of cheap tailights on the market as well as some more expensive quality ones (nothing close to $2000 though) The B&M 4DToplight Senso Multi is only $53.00 and is feature packed. Going for the cheap market will get him exactly nowhere- it is saturated. Designing something that is practical, reliable, effective, and has features others don't may just produce something saleable.
     
  11. alienator

    alienator Well-Known Member

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    "Dumb" doesn't fit. A flashing tail light does make it more difficult for drivers to accurately judge distance to a rider, but a flashing light in combination with a steady light not only allows a driver to accurately judge distance, but also attracts the driver's attention via the flashing. The guy asked for input, very likely meaning constructive input. What you think is "dumb" isn't part of constructive input.
     
  12. An old Guy

    An old Guy Member

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    I don't use a rear light. I am cheap enough that at one time my bike headlight was a head lamp (a light you wear on your head) mounted on my bike with 4 D cells sitting in a water bottle cage powering it.

    I paid $26 for my LED flashlight (LiFeP04 battery) it comes with a metal housing. seems to be waterproof. Lasts a long time on a charge. Based on that I think $26 for a tail light with a metal housing would attract my attention.

    I don't like flashing. (I think lights mounted on the pedals would provide enough motion to attract attention without complaints. But that is not what you asked.)

    ---

    I have enough money that price is not an issue. I would only want the light to work for the purpose intended.

    Saying that I find most of the front lights available to be over priced. If I was going to buy a front light, I think I would buy parts and build one. The LED flash light above, a couple extra LIFePO4 batteries to run in series, and some brackets would get me all night long lights for $50 or so. Your price point needs to be very low.
     
  13. CAMPYBOB

    CAMPYBOB Well-Known Member

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    I like flashing just because it pisses people off.

    $10 at a LBS and has worked well for two winters.

    http://www.blackburndesign.com/click-rear.html

    Lifetime warranty. Steady state or flashing function. Easily removable. Lightweight. Dropping a hand behind it easily verifies function.
     
  14. dhk2

    dhk2 Active Member

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    I only ride in the daytime, so it's on/off flash mode for me, the brighter the better. Some riders use the Dinotte on the rapid bright/dim mode, but I think the simple, slow on/off is more attention-getting in the daytime from hundreds of meters back. One or two riders say the bright flashing is annoying (to them) when riding in a pack, but it doesn't bother me. The vast majority around here understand the importance of being seen from behind as far back as possible, even in sunny conditions. For darkness, I'd go with one of the bright/dim flashing modes rather than the on/off.

    Cost-wise, yeah, the Dinotte and other high-powered LED lights are expensive. I used a Planet Bike light for a couple of years, since I'm basically a cheapskate too. But since the risk of being hit from behind is all-too-real here, I decided the extra visibility was worth the price. Again, talking only about daytime visibility.
     
  15. rcrampton

    rcrampton New Member

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    As a start up competing against some large companies with massive distribution channels you need to differentiate your product so that it appeals to some segment of users in a compelling way. As you probably already know, you can't say "I just need to get 1% of this really big market to do well". You need to decide what market segment you've designed the product for and why they find it compelling. Part of the segment choice is probably picking one that will pay a premium for the benefits you'll offer so you don't have to compete on sell price.

    What is your target segment, what are you doing to make a compelling, differentiated product for them?

    To answer your question: I'd like auto-off, one half solid on and one half blinking, don't care about the pattern much but very low duty cycle blinking to conserve battery life, standard primary cells like AAA, a mount that I can use in multiple places (e.g. with and without panniers), don't care about housing material as long as it's good quality.

    Sounds like fun. I've been at two start-ups, the first one got to IPO (yay 2000 internet bubble!), the second one we just sold last year. Lots of work but lots of fun too.
     
  16. bartsie

    bartsie New Member

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    > I'm a graduate student at MIT

    Greetings from the other side of the Charles river.

    There is already (at least one) fancy rear light which I think covers everything: http://www.lightandmotion.com/bike/vis180.html

    How will the new one be different?...

    To answer your specific questions:
    (1) I personally don't care about metal vs plastic, but if you decide to go for metal and charge a premium, I think you should make it retro-looking and have a dynamo option (or version).
    (2) I don't care that much for blinking. In my car, I don't drive with emergency flashers on (except as part of a funeral procession). Bright does it for me. Many people like flashing but in any case having several patterns seems like a gimmick. What I'd like instead is being able to vary the brightness. On a bike path, I'd set it dimmer and when I get on the street I'd turn it up.

    I don't think there can be one ultimate light as I see at least two distinct usage patterns:
    (A, the one I prefer): The light is easily removable and is taken off and brought inside to recharge
    (B, the choice of some traditionalists): The light is permanently attached, dynamo-powered and doesn't need recharging/battery changes.
     
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