Attention flashers from LED flashlights ?

Luka

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I like the idea of using LED flashlights on the front of the bike.

I have been planning on using two of them.

But a couple of other threads here have gotten me to thinking further.

I'll assume that it is possible to pull the battery packs out of the flashlights, and run a wire from a single 4.5 volt source, to power both lights.

Not beyond my capabilities.

But what I am wondering is, is there a way to do this so that one light is on, the other is off... Then the other is on and the first is off. Continuously flashing back and forth, like that ?

Without having to build some huge/complicated electrical 'project'. (Diodes and rectifiers and bridges, oh my !)
 
Here is the simplest of simple turn signal circuits. Just change the battery to a 4.5v source and whatever LEDs compatible with 4.5V you have.
 

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Here is the simplest of simple turn signal circuits. Just change the battery to a 4.5v source and whatever LEDs compatible with 4.5V you have.

Thank you, but I know how to wire a turn signal circuit.

I am not talking about turn signals. I want continuously flashing lights, for attention sake. And not both on, both off. (I could easily do that, as well, with a simple flasher unit.) I want them to flash on one side, then the other, then the first, etc... Constantly, with no effort on my part other than turning it on in the first place.

I don't want to have to keep a hand on a turn signal switch, switching it back and forth, back and forth, all the time... LOL (Besides, if I were going to do it that way, I wouldn't even need the flasher unit. Just a SPDT switch.)
 
Ask an Auto Electrician....their must be a really simple way of doing it with minimal electronics.
Google it to & please post your results.
 
Ask an Auto Electrician....their must be a really simple way of doing it with minimal electronics.
Google it to & please post your results.

Well, I have done about an hour and a half research, and this is what I have found...

These are sites which contain circuit diagrams for several different ways to build this yourself:

http://www.sentex.ca/~mec1995/circ/flash2.htm

http://www.bit-tech.net/modding/2002/06/22/knight_rider/1

http://www.sentex.net/~mec1995/gadgets/bfflash.htm

http://www.attiny.com/knightrider.htm

http://www.mrollins.com/flash3.html

http://www.edn.com/ednmag/archives/1998/032698/07di.htm#Alternating LED

This last site is my favorite. The link there, will download a PDF file, with several diagrams for different things.

Here is the diagram out of that PDF, for the led alternating flasher. (I have done a screen capture, then saved it in paint shop pro.)

This cannot be adapted to two flashlights, because it is the particular LEDs in the diagram and instructions, that make it possible. But it would at least put alternating flashing LEDs at both side of your handlebars , or somewhere on the back.

attachment.php


Here is a factory made flasher. It flashes back and forth, as I had hoped. But it is only 6 inches across.

I am thinking this could be taken apart, and the guts used to power two led flashlights, instead. Or... Maybe the flashlights could just be tied into this, and have all three lights flashing...

http://www.columbussupply.com/products/?productid=761

Here is a different idea. These are pretty cheap. You could get three of these, spread them across some sort of mount. Set the outside two, to flash fast, and the middle one to flash slow, or versey-visey. Etc...

http://www.columbussupply.com/products/?productid=765

I am including this one simply because I think it is worth mentioning. This is just a light. Again, about 6 inches across. But it has 28 super bright LED's in it. Can be seen from a long way away. And fast flashes or steady on.

http://www.columbussupply.com/products/?productid=485
 

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Something like the circuit below should work.

When power is applied, current flows through the normally closed relay contact through R2 to charge the capacitor. Once the capacitor voltage reaches the relay pull-in voltage (about 3.4V) the relay contacts switch state.

Now, the capacitor discharges through the relay coil until the voltage drops to the drop-out voltage (about .5V) Then, the relay opens, and the cycle begins again.

The trim-pot variable resistor was added to 'balance' the time between charge and discharge cycles. by providing a small amount of 'make-up' current to the capacitor, it will act to 'stretch' the discharge time a bit. It should initially be set to about 2500 ohms. (about half way.)

The diode is present to absorb any reverse voltage spike when the magnetic field in the coil collapses, to protect the capacitor and the relay contacts.

Note - I haven't bread-boarded this exact circuit. (I have done so with virtually the same circuit, but with different voltages/relays, though.) Some experimentation will be needed. If the timer flashes too fast, you'll need to add some capacitance in parallel with C1. If it's too slow, replace C1 with a smaller cap. With these values of R and C, it should switch at about a 1.5 cycles per second rate. It might turn out that R1 and R2 wouldn't be needed at all. (In which case, remove R1 entirely, and run a wire in place of R2.)

The only critical part in this circuit is the relay. It's about $3.50 (unit price) from digikey.
Code:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=255-1769-5-ND

The flasher circuit will draw about 20 ma from the battery pack, plus the current to power the LEDs. Obviously, you'll also want a switch between the battery positive terminal and the circuit.

Just about everything else you could find at radio shack. Of course, you could order them at the same time as the relay, too.
 

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Thank you, but I know how to wire a turn signal circuit.

I am not talking about turn signals. I want continuously flashing lights, for attention sake. And not both on, both off. (I could easily do that, as well, with a simple flasher unit.) I want them to flash on one side, then the other, then the first, etc... Constantly, with no effort on my part other than turning it on in the first place.

I don't want to have to keep a hand on a turn signal switch, switching it back and forth, back and forth, all the time... LOL (Besides, if I were going to do it that way, I wouldn't even need the flasher unit. Just a SPDT switch.)

what you are describing, in any colored or even clear lense is called "wig-wag" and illegal ( i think ) in our state for other than police and emergency response.

is that correct Houghmade ?

steve
 
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