Comments on: Bike brake light senses you slowing down

By: Joel

Joel — Mon, 07 Dec 2009 15:05:56 +0000

I’ve used non-contact infrared temperature sensing parts on a lot of projects. If inflating the price of the project $10 is acceptable, it seems you could solve a lot of the problems mentioned here by having a clip on part near the wheel rim (or brake disc if so equipped). The mass of the wheel is small enough that if you tap the brakes there will be a very sudden increase in temperature, well within the precision of most low cost sensors. It seems a fairly generic solution to detect _braking_ (not only deceleration, which is important as previously mentioned). Illuminating the LEDs at a positive temperature gradient of say, 1 degree per second would probably do the trick.

By: Haku

Haku — Wed, 11 Nov 2009 02:56:55 +0000

@Slacker: it’s in development, ETA: when ALL car drivers actually take notice of you and don’t cut you up etc. when you’re riding correctly.
I feel safer on pavements late at night (past 1-2am) especially Friday/Saturday when the boy racer chavs are racing around like they own the roads because there’s hardly anyone around.
I don’t run red lights though, that’s just asking for a hospital/morgue visit.

By: Slacker

Slacker — Tue, 10 Nov 2009 18:48:33 +0000

Brilliant, now we just need a hack that stops these tossers riding on the pavements, through light on red etc. etc.

By: tantris

tantris — Tue, 10 Nov 2009 17:40:37 +0000

@Samuel:
not just drifting, it could also warn you against sudden loss of gravity.
50 cents more in parts (a piezo) and a low quality voice sample later: “warning, loss in gravity. if you are not in space, you might be falling down a cliff”

By: Samuel

Samuel — Tue, 10 Nov 2009 15:57:05 +0000

@Haku

…kinda like a low-pass filter, which can be implemented with a capacitor. Yeah, yeah. Shame on us.

And all that stuff about uneven terrain just shows us how easier it would be to use RPM… unless of course one want’s the functionality while drifting.

By: Tim Snaith

Tim Snaith — Tue, 10 Nov 2009 11:01:32 +0000

There’s something on the market that uses an accelerometer as a rear cycle brake light. It also wireless left/right indicator LED clusters and it can be used as a power bank to recharge your ipod, psp, etc via USB.

It’s called the Spooklight. Ah right, previous poster beat me to it.

By: nubu

nubu — Tue, 10 Nov 2009 07:46:22 +0000

Nice, also it’s a good idea to use a female subject in hack videos. Hackers should do this more often.

By: rasz

rasz — Tue, 10 Nov 2009 07:29:54 +0000

Dont be hating just because author cant drive two independent leds with >12MHz microcontroller :)

By: Haku

Haku — Tue, 10 Nov 2009 01:55:48 +0000

@tantris: ahh, nice! so it’s designed to only react to sudden & long deceleration, kinda like motion sensing CCTV that only records large movements and can ignore things like the sun/shadows moving over time and analogue clock faces.

And people say a microcontroller is overkill for this kind of thing. Shame on them.

By: tantris

tantris — Tue, 10 Nov 2009 01:46:19 +0000

@Haku:
uphill/downhill: the author added some code to compensate for uneven terrain and the shifting g-vector. (at least a linear approximation that works for small changes). have a look at the loop at the end of his source code.
above i also pointed out some other problems with hills: basically, it probably doesn’t behave like people (behind you) are expecting brake lights to behave.

By: inportb

inportb — Tue, 10 Nov 2009 01:42:20 +0000

… which you can’t do now because it’s common knowledge =p

By: JB

JB — Tue, 10 Nov 2009 01:03:43 +0000

@therian: different solutions to the same problem. That’s how you come up with ideas you can patent ;)

By: Haku

Haku — Tue, 10 Nov 2009 00:52:29 +0000

@Jamie: putting reliable, waterproof switches on brake levers is a job in itself, why not get hold of brake levers used on electric bikes, they have a switch built-in to tell the motor controller to cut power to the motor so it doesn’t try and ‘drive’ with the brakes on.

I’ve often wondered about tapping into the brake sensor lines on my electric bike so I can have a working brake light that’s driven from the levers, but resisted against it so far because I don’t want to accidentally damage the motor controller during the initial investigation/testing phase (those controllers aren’t cheap).

I really do like this approach to making a brake light, except how well does it cope when you’re going downhill at a steady speed with the brakes on? or even not using the brakes? or even uphill?

I’ve already got an accelerometer from http://www.dimensionengineering.com on the way for a different project but I might have a little play with it on my bike :)

By: vicx

vicx — Tue, 10 Nov 2009 00:43:58 +0000

The idea of it is great. This belongs in cars and motorcycles too because they de-celerate on down shifts and some people in cars only watch for brakelights.

In this day and age I would have thought a tiny micro and g sensor is the cheapest/tiniest way to do it. A chinese factory could make these for less than a buck.

By: Doug

Doug — Mon, 09 Nov 2009 23:43:08 +0000

@ therian Its not that people forget how to think, it’s that people just think differently. The first person who posts what they are thinking doesn’t stand a chance. Anyway; Mr. Szczys, “I” approve of this post.
D-