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Brake-powered brake light

Mate a brake shoe with a dynamo
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You're wondering why those automobilists don't respect you? That's because your vehicle is missing a lot to make it impressive. A brake light might help.

There are of course brake handles with switches which may be used to power a brake light. But with Murphy's law the battery is always down when you really need it.

With today's LED technology, we need only very small electric power to produce quite a light show. Modify one brake shoe of the rear brake (in right-lane driving countries, the left one) so that there is a miniature dynamo and an LED attached to it. When the brake is activated, the dynamo gets in contact with the rim and powers the LED.

Maybe someone can marry this idea to the contactless Magnic bike light?

Toto Anders, Dec 04 2014

Rim Magnet Lights http://www.bikerumo...iy-tire-studs-more/
[bs0u0155, Dec 09 2014]

[link]






       I like this, but would use the energy to power my horn. How dare someone make me brake?
bungston, Dec 06 2014
  

       Why not a shower of sparks, from a flint and a striker?
rcarty, Dec 06 2014
  

       Why not just have a tiny hub or rim dynamo and a small photovoltaic panel, that recharge a battery? Harvest small amounts of energy in daylight or while riding, then use that to power front and rear lights after dark.
8th of 7, Dec 06 2014
  

       I like the idea that the harder you brake, the brighter the light. So, why not dispense with the brake pads entirely (or keep them as a backup, if you're a wimp) and use the back-EMF to do the stopping.   

       Just a hub dynamo and a resistive load to dump it in (the brake lights). The brake lever would be replaced with a variac.
mitxela, Dec 07 2014
  

       Brake shoe? What is this, the 50s?
DIYMatt, Dec 07 2014
  

       //Brake shoe? What is this, the 50s?//   

       Hey! my drum brake is from the mid 60's thank you very much.
bs0u0155, Dec 07 2014
  

       Why does your drum need a brake ? You can just stop hitting it with the sticks, shirley ?
8th of 7, Dec 07 2014
  

       Praps it's an electric drumkit.
pocmloc, Dec 08 2014
  

       Yes, that would make sense.
8th of 7, Dec 08 2014
  

       // //Brake shoe? What is this, the 50s?// Hey! my drum brake is from the mid 60's thank you very much. //   

       You know, they still make cars with rear drum brakes. Ford Focus and Toyota Corolla are two that I know of.   

       They're cheaper and last longer, and are completely adequate on the light rear end of a compact car. I've got an old 1998 Corolla with 150K miles. The original rear brake shoes are still good. I suppose I should check them again sometime since it's been a while, but they performed well during a panic stop on the freeway last month.
scad mientist, Dec 08 2014
  

       //completely adequate// words that make me die a little on the inside.   

       My 1978 daily driver has 4 wheel discs.
DIYMatt, Dec 09 2014
  

       //They're cheaper and last longer, and are completely adequate on the light rear end of a compact car. //   

       Ah, but wait, the cast iron drum brakes are heavier. Now, that means the overall mass of the car is greater. Now, if we're going to have the same braking performance, then we need bigger brakes. That's OK, we put bigger disks up front, and bigger drums at the rear. We might need a bigger pair of master/slave cylinders and the wishbone arrangement might need to be beefed up a little, the lines might need to be larger. OK, so a little more mass, that's fine, some slightly bigger disks and drums, maybe bigger wheels to fit them in....   

       I've come to the logical conclusion that fitting drum brakes at the rear leads to an out of control mass cycle. Although they work great on bikes, as long as you don't mind them weighing 2lb.
bs0u0155, Dec 09 2014
  

       // they still make cars with rear drum brakes //   

       I hope you realize that this idea is about bicycles. And brake shoes are standard equipment with the rim brakes which most bicycles come with.
Toto Anders, Dec 09 2014
  

       You wouldn't even need a dynamo; a permanent magnet alternator would work fine.   

       Or glue some very small magnets to the inside of the rim, and mount a solenoid beneath the brake shoe (there are rear lights that work on this principle; the magnet(s) are mounted on the spokes). Set up properly, it would give you a rear light - brake light combo; that is, the light would get brighter when you applied the brakes.
spidermother, Dec 09 2014
  

       // permanent magnet alternator //   

       The old-fashioned bottle-shaped rim "dynamos" are in fact just that; a permanent magnet rotating within the pole pieces of a coil. Since the lamps were incandescent filaments, no rectification is needed.   

       However, lacking any sort of regulation, lamp brightness is a function of wheel speed.
8th of 7, Dec 09 2014
  

       //Or glue some very small magnets to the inside of the rim, and mount a solenoid beneath the brake shoe //   

       Baked <link>
bs0u0155, Dec 09 2014
  
      
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