# Hydraulic brake light?



## henry9419 (Nov 18, 2010)

Has anyone ever seen a hydraulic brake light set up on a mountain bike? Im thinking something like how its done on a motor cycle could work but i cant find a small enough pressure switch nor do i have any ideas how it would connect into the system.

Ive seen them set up on mechanical levers just not hydraulic


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## emu26 (Jun 23, 2008)

Why would it make a difference what the brake system was? It doesn't connect into the hose or cable does it?


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## henry9419 (Nov 18, 2010)

Well i know on a motorcycle theres a piece that has a switch that senses pressure that bolts onto the master cylinder and then the hydraulic line bolts onto that and two wires come out of it that you connect to the bulb and to ground


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## henry9419 (Nov 18, 2010)

Im thinking attaching an arm of sorts to the lever and having that pushing a switch


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## emu26 (Jun 23, 2008)

henry9419 said:


> Well i know on a motorcycle theres a piece that has a switch that senses pressure that bolts onto the master cylinder and then the hydraulic line bolts onto that and two wires come out of it that you connect to the bulb and to ground


way too complicated for a bike I would have thought

Why not just mount a small momentary switch to the face of the brake lever, as soon as you apply pressure to the lever the light turns on, rather than weighting until the lever has been depressed far enough to engage a switch behind it. Your way is kind of like people that change lanes and then turn the indicator on when they are half over the line.


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## yetibetty (Dec 24, 2007)

I don't think car drivers would notice a brake light on a bicycle. They are so used to our tail lights flashing on/off or pulsing bright/dim. The fact that it went bright for a bit when we hit the brakes would mean bugger all.


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## henry9419 (Nov 18, 2010)

Well i Intend it more for trail use and as more of a novelty, car drivers really dont seem to care about the bikers for the most part

I gotta see now where i would mount the switch and how, maybe drill a hole in the lever so when i pull the lever it activates the switch


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## henry9419 (Nov 18, 2010)

emu26 said:


> way too complicated for a bike I would have thought
> 
> Why not just mount a small momentary switch to the face of the brake lever, as soon as you apply pressure to the lever the light turns on, rather than weighting until the lever has been depressed far enough to engage a switch behind it. Your way is kind of like people that change lanes and then turn the indicator on when they are half over the line.


Yea i guess since the reservoir is smaller itd take longer to activate then on a bike, but on a bike they work almost instantly i know


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## MXRider72 (Aug 10, 2010)

henry9419 said:


> Well i know on a motorcycle theres a piece that has a switch that senses pressure that bolts onto the master cylinder and then the hydraulic line bolts onto that and two wires come out of it that you connect to the bulb and to ground


Very few motorcycles still use pressure switches due to their inconsistent nature. Almost everything uses a micro switch to actuate the light now a days.

Something like this might work: Microswitch - OEM type Radial Brake and RCS


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## henry9419 (Nov 18, 2010)

Oh wow i helped dad install a pressure swith on his wr250 around two years ago

I gotta get some pics of the lever mechanism to decide how i can mount it without interfering with the levers action


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## yetibetty (Dec 24, 2007)

henry9419 said:


> Well i Intend it more for trail use and as more of a novelty, car drivers really dont seem to care about the bikers for the most part
> 
> I gotta see now where i would mount the switch and how, maybe drill a hole in the lever so when i pull the lever it activates the switch


Nothing wrong with a bit of novelty, didn't mean to be too negative.

A limit swith as used in CNC mill conversions is the only thing that I can think off at the momment Motorized Products - Limits Switches


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## henry9419 (Nov 18, 2010)

yetibetty said:


> Nothing wrong with a bit of novelty, didn't mean to be too negative.
> 
> A limit swith as used in CNC mill conversions is the only thing that I can think off at the momment Motorized Products - Limits Switches


Didnt take it as negativity  im gonna look at the lever tomorrow to comeup with some ideas of how i can mount the switch


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## DIYtailight (Sep 14, 2009)

Another idea you might consider is putting a reed switch in the handlebars, or under the grips, and a small magnet in the hollow under the lever. When the lever is pulled the magnet closes the circuit and the light gets brighter. This could be simpler than rigging a standard switch onto the levers, however, reed switches (I've heard) can be fragile


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## Joules (Oct 12, 2005)

I'd look into a hall effect or some other non-contact proximity switch. Mechanical limit switches are not weather or corrosion resistant at all. (disclaimer: I work in boat/marine electronics, which probably makes me over cautious about corrosion and water)


If you were handy with electronics, you could probably rig something with a cyclometer's sensor. You'd probably need a relay to actually switch the light, but the reed switch is already designed for bike use, and are generally pretty tough.


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## MtbMacgyver (Jan 23, 2007)

henry9419 said:


> Well i Intend it more for trail use and as more of a novelty, car drivers really dont seem to care about the bikers for the most part


Among the groups I ride with, any kind of tail light for off road riding is considered a bad practice and discouraged. It doesn't serve any real purpose and it hinders the night vision of riders behind the person with the tail light. Having one that goes on and off with braking would be even more bothersome because of the inconsistent nature.


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## HEY HEY ITS HENDO (Feb 23, 2008)

MtbMacgyver said:


> Among the groups I ride with, any kind of tail light for off road riding is considered a bad practice and discouraged.
> It doesn't serve any real purpose and it hinders the night vision of riders behind the person with the tail light.
> Having one that goes on and off with braking would be even more bothersome because of the inconsistent nature.


yes i totally agree, and this is a rule of the groups that i ride with too!!
i have seen a bicycle rear light (Ebay) which uses an accelerometer to sense when you are braking


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## pimpbot (Dec 31, 2003)

henry9419 said:


> Well i Intend it more for trail use and as more of a novelty, car drivers really dont seem to care about the bikers for the most part


Neither do other cyclists. Cyclists aren't really trained to look for brake lights on other bikes.


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## C-Far (Oct 31, 2011)

Some sort of momentary switch on the lever should do the trick?


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## R+P+K (Oct 28, 2009)

You could probably modify a rear blinker light and mount it on or near the caliper. Attach a wire to each pad so they touch when you put the brake on.


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## brad72 (Jun 12, 2009)

A 2 pole NC switch wired to a 750mA buckpuck would do the job, wiring each pole of the switch to a different resistance value of the buckpuck brightness input. You would then only need a small actuator off the brake lever to activate the switch and work out what resistance values are needed to achieve the desire brightness

One of these would do the job Buy Tactile/Keyboard Switches Switch,pushbutton,2NO+2NC,momentary,PCB,silver contacts,IP54,unimec MEC 15501 online from RS for next day delivery.

Another option would be 2 of RS Components part # 320582 lever actuated switches mounted side by side as they are IP67 rated and very small. You would just use the common and NC wires, and cut off the NO wire.

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