Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Electronic Fireflys

  1. Sep 5, 2006 #1
    I am the Lighting Designer for a production of 'As You Like It' and have been asked to find a way to create a realistic firefly effect.

    From my research, Fireflys have a dominant wavelength of 570 nanometers. They fade on quickly, pulse (a very fast fade on and off) at a rate between 2.5 and 3.5 Hz (varying from firefly to firefly), and then fade out. The on cycle should last between 1.5 and 3 seconds, and the off cycle should be 4 to 7 seconds.

    They make LEDs with a dominant wavelength of 570 nanometers and I was considering using (2) 555 IC Timer chips, one to control the flicker within the on cycle, and one to control the on and off cycle itself.

    My question is, is this the most effective way to achieve this effect? If not, what would you recommend?

    If so, how can I make the pulses fast-fade instead of blink? How do I determine the values of the resistors and capacitors to get the desired rates? And finally, how do I get the 'firefly' to fade out at the end of it's on cycle instead of blinking off?

    I would greatly appreciate any insight you could offer on this project.

    Thanks,

    Nick
     
  2. jcsd
  3. Sep 5, 2006 #2

    NoTime

    User Avatar
    Science Advisor
    Homework Helper

    Try looking up sawtooth wave generator.
    So called because the output waveform resemble the teeth of a saw.
    If set up properly it will produce a quick on with slow decay to off.

    If you set up a 555 to produce narrow pulses, then you can charge a capacitor with the pulse. The decay to 0 time is dependent on the value of the cap and resistance of the led. Set the cap/led to decay in your 1.5 to three seconds and the repetition time of the 555 to be your 4 to 7 seconds.

    If you want variable times, like sometimes 4 and sometimes 7 sec and/or decay times then i would look into using a PIC (a small single chip computer)
     
  4. Dec 11, 2007 #3
    This post is probably too late for your production. However, we are the leader in the design & manufacture of realistic firefly reproductions for stage, screen, zoos, natural history museums, commercial locations, and home backyards. We even design units that Universities utilize to lure-in real fireflies for research.

    Through the use of our patented microprocessor technology and accurate LED selections we can mimic virtually any of hundreds of species of firefly from around the world. We are alway happy to discuss the specific needs of any project in order to determine if our 'Firefly Magic' fireflies will work. http://www.ledsfx.com or http://www.fireflymagic.com
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Electronic Fireflys
  1. Basic Electronics (Replies: 3)

  2. New to Electronics (Replies: 87)

  3. Electronics books? (Replies: 4)

Loading...