My bicycle break light idea

[deathkenli]

Few days ago I came up with an idea to make a bicycle break light that would suprise drivers behind me.

At first, I thought about a break light mounted on my bike with a dozen of red LEDs. That wasn't really creative and I kept thinking for something better. So when I saw that 3.5mm to 1/4'' converter came with my Sony headphone, I immediately got this excellent(well, I think it is..) idea...

Those wires between the plug and the switch will be reinforce with fishing line(shorter than wires), so there won't be any problems if I forgot to pull it out before I get off my bike.

I have ordered 20 red LEDs from DX. However, I know nothing about their forward voltage except it's lower than white LEDs. If anyone is familiar with these red LEDs please tell me. Advice on power source would be nice too!

Thanks in advance!

 

[slvoid]

You can also get a small normal closed limit switch and zip-tie it (or tape or whatever) it to the handlebar next to the stop for the brake lever. As you open the brakes, this releases the actuator and closes the circuit, turning the brake lights on.

But since I ride a fixed gear track bike around, a better idea would be to make a unit with an accelerometer to detect when I'm actually slowing down.

 

[Nubo]

I've never been enthusiastic about attaching lights to my backpack, or back of helmet, because very often the lights will not be pointing where you want them due to changes in position, bending, etc. The light would have to be nearly omnidirectional to be effective.

In my opinion you're better off mounting the light in a rigid position on the bike, where they can be aimed properly and you can be assured the light is going where it should.

On the other hand, a forward-pointing helmet light can be a useful addition because it allows you to aim the light precisely at a target while riding. Maybe your plug idea would facilitate this.

 

[TorchBoy]

Re: My bicycle BRAKE (?) light idea

Those "10 LEDs" are two parallel strings, each of five in series, right? (When I first saw it I thought you might be trying to drive them with an audio signal. That would have been very interesting.)

Um... which red LEDs from DX have you ordered?

 

[Darell]

How about using an accelerometer for automatic light activation?

BTW, I don't mean to be snotty... and would like to point out that we're talking about BRAKES here. I'm the worst speller you'll know, but I do know what brakes are!

 

[deathkenli]

5mm red LEDs.
I think it's easier to make if all LEDs are in parellel.

 

[TorchBoy]

Re: My bicycle brayk light idea

I think it's easier to make if all LEDs are in parellel.

Ah, I see. You're talking of 10 LEDs in parallel and 5 LEDs in parallel, with a low voltage (~1.7V) supply.

 

[deathkenli]

So the vF of red leds is about 1.7v?:thumbsup:
Thanks!
Maybe two alkaline cells with a resistor would be ok.

 

[TorchBoy]

Re: My bicycle breyk light idea

Maybe two alkaline cells with a resistor would be ok.

A separate resistor for each LED is best, so you don't risk current-hogging or cascade meltdown.