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Old 10-01-07, 07:57 AM   #1
HandsomeRyan
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LED blinker circuit diagrams that work?

I know there is already a thread for homebrew lighting but it appears to be focused on headlights. I am trying to find a reasonable design for a rear blinker for my bike. I have found several links with pretty diagrams but with my limited knowledge of electronics, I'm not sure i trust some of them to be accurate. It is easy to post a diagram on the internet and say it will work, but i was unable to find pictures of the lights below accually constructed and in use.

For example: http://www.redcircuits.com/Page24.htm

I like the compactness and the pattern these lights blink at but the resistors for the led's (10Ω) appear to me that they would turn most light emitting diodes into smoke emmiting diodes.

another example is http://ourworld.compuserve.com/homep...tm#555leds.gif

the 40LED flasher looks really neat but I do not understand how the second batch of lights flashes. When pin 3 (output) of the 555 goes high, it will trigger the upper transistor (2N3053) to complete the circuit and light the top segment of LED's. when the output current goes low, it seems that the second transistor (2N2905) would be unaffected and the lower set of lights will never come on? admittedly i do not know much about transistors and how they opperate.

the 10 LED sequencer at http://ourworld.compuserve.com/homep...htm#4017-2.gif
looks like a pretty good design that could be expanded to light multiple LED's for each output of the 4017IC. I have not built it yet, but I believe it has lots of possibilities for running various patterns in a simple compact circuit design.

If anyone else has links or pictures of wiring diagrams for use in building LED tail lights I'd love to see them.
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Old 10-01-07, 09:50 AM   #2
jeff-o
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Originally Posted by HandsomeRyan View Post
I know there is already a thread for homebrew lighting but it appears to be focused on headlights. I am trying to find a reasonable design for a rear blinker for my bike. I have found several links with pretty diagrams but with my limited knowledge of electronics, I'm not sure i trust some of them to be accurate. It is easy to post a diagram on the internet and say it will work, but i was unable to find pictures of the lights below accually constructed and in use.

For example: http://www.redcircuits.com/Page24.htm

I like the compactness and the pattern these lights blink at but the resistors for the led's (10Ω) appear to me that they would turn most light emitting diodes into smoke emmiting diodes.

another example is http://ourworld.compuserve.com/homep...tm#555leds.gif

the 40LED flasher looks really neat but I do not understand how the second batch of lights flashes. When pin 3 (output) of the 555 goes high, it will trigger the upper transistor (2N3053) to complete the circuit and light the top segment of LED's. when the output current goes low, it seems that the second transistor (2N2905) would be unaffected and the lower set of lights will never come on? admittedly i do not know much about transistors and how they opperate.

the 10 LED sequencer at http://ourworld.compuserve.com/homep...htm#4017-2.gif
looks like a pretty good design that could be expanded to light multiple LED's for each output of the 4017IC. I have not built it yet, but I believe it has lots of possibilities for running various patterns in a simple compact circuit design.

If anyone else has links or pictures of wiring diagrams for use in building LED tail lights I'd love to see them.
I can confirm that the 40LED flasher works - I've built one myself!
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Old 10-01-07, 10:31 AM   #3
HandsomeRyan
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I can confirm that the 40LED flasher works - I've built one myself!
good to know that it works. did you incorperate any changes to the design such as # of LED's or values of the resistors? I'm about to place an order with Mouser but I guess i have to commit to one design first.
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Old 10-01-07, 10:45 AM   #4
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good to know that it works. did you incorperate any changes to the design such as # of LED's or values of the resistors? I'm about to place an order with Mouser but I guess i have to commit to one design first.
Yeah, I changed the voltage and increased the LEDs. The 555 timer will work with up to 15V. Make sure that you choose the right values for the current-limiting resistors, based on the forward voltage of the LEDs, the current they're operating at, the voltage of the power supply, and the voltage drop of the transistor.

Oh, also be sure to decide on the blink frequency you want, and calculate the values of the resistors and capacitors.
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Old 10-03-07, 05:15 AM   #5
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And how well does your 40 LED taillight work?
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