FIRE FLYS

ACE37918 · Post by **ACE37918** » Tue Oct 07, 2003 9:39 pm

I need a circuit that will blink 5 green leds, at ramdom , and have it turn on and off like a fire fly would do. Also it would be nice if I could use 555 or 558 timers, I have some in stock. Thanks,
Rick

sundancer87 · Post by **sundancer87** » Wed Oct 08, 2003 1:58 pm

I'm trying to visualize your project, you want these green LEDs to look like a jar full of fireflies, correct.
If this is what you want I think you would be better served using a 4017 decade counter. The 4017 has ten outputs and is clocked by a 555 so your flash rate can be varied.
The 555s alone can't do what you need them to do. Unless, you used one 555 per two LEDs in a 50% duty cycle.

josmith · Post by **josmith** » Wed Oct 08, 2003 4:29 pm

my favorite broken recordbasic stamp click basic stamp click basic stampAll you would need would be the stamp,five resistors and your led'syou could keep changing the pattern in software until you're happy with it.since firefly blinking is set,not random pattern you could research the type of firefly you want and simulate it's pattern

k7elp60 · Post by **k7elp60** » Wed Oct 08, 2003 5:52 pm

Rick,
I have been working on a random display for LED's
for several days. The circuit is worked out just have to finish up the timing. The circuit uses one 74AC14(hex schmitt triggers,inverting) as three seperate oscillators feeding the three inputs A,B,C of a 74AC138(3 line to 8 line decoder) I have two of the oscillators working,just have to get the third oscillator to work at about 1 HZ. The circuit uses up to 8 LED's and they pretty much flash in a random state. Since the IC's are AC version the circut will work from 3 to 5.5 VDC, and the 74AC138 will sink up to 24Ma so most LED's will work. Soon as I get the timing of the third oscillator where I want it I will post a reply.
Ned

dacflyer · Post by **dacflyer** » Thu Oct 09, 2003 9:56 am

also note....fire flies do not blink on/off
they turn on then have a fast fade off
there was a circuit once i saw somewhere,,,this circuit actually mimmicked fire flies really good it even attracted them....
just giving my 2 cents worth

ACE37918 · Post by **ACE37918** » Thu Oct 09, 2003 5:33 pm

K7elp60,Thanks please e-mail me if you have a circuit that I could use , This project is for a out door pond , I well be hanging the leds from a small tree next to the pond. Thanks,Ned And I would like to thank all of you for your time.
Thank again, Rick[ October 09, 2003: Message edited by: ACE37918 ][ October 09, 2003: Message edited by: ACE37918 ]

frhrwa · Post by **frhrwa** » Fri Oct 10, 2003 7:34 am

yep.. Disneyland... Pirates of the Carribean.. fireflys, we call them lightning bugs... everywhere.. pop a muscadine out and put the firefly in and you have a flashing purple grape..

Tommy volts · Post by **Tommy volts** » Fri Oct 10, 2003 11:02 am

<blockquote>quote:<hr> <hr></blockquote>The bs2 is $49, would the $24 carrier board also be required or can I use my boe-bot carrier board to program the bs2, pull the bs2 off and then solder up the pins to some make shift perfboard? Is there a socket available for the stamp? I would rather not have to purchase a carrier board.I have a similar project and need to keep the size and $$ to a minimum.thank you.

Tommy volts · Post by **Tommy volts** » Fri Oct 10, 2003 11:05 am

please see my post above, how do I get a quote from josmiths post, I tried to quote his "basic stamp click basic stamp click etc." but it came out blank.

k7elp60 · Post by **k7elp60** » Fri Oct 10, 2003 3:38 pm

This is the circuit I worked out. It didn't as good as I wanted, but thought maybe someone else might like to try it. The circuit uses a 74AC14 as three seperate oscillators driving a 74AC138 decoder. In my breadboard circuit I used film capacitors and when I built it in a small translucent pumkin with orange LED's I use multilayer ceramic capacitors so I had to juggle on resistor in an oscillator. As it turns out the frequency = 1/(2.0RC).
Here are the connectionsConnections for 74AC14:
Pin 14 to VCC(3.0 to 5 Volts Plus) Pin 7 to Ground
Pin 2 tied to Pin 3. 2.2Mohm resistor from Pin 1 to Pin 2
0.1uf capacitor from Pin 1 to Pin 4. Pin 4 connected to Pin 3 of 74AC138Pin 6 tied to Pin 9. 6.8Mohm resistor from Pin 5 to Pin 6
0.1uf capacitor from Pin 5 to Pin 8. Pin 8 connected to Pin 2 of 74AC138Pin 11 tied to Pin 12. 3.9Mohm resistor from Pin 12 to Pin 13
0.1uf capacitor from Pin 10 to Pin 13. Pin 10 connectd to Pin 1 of 74AC138Connections for 74AC138
Pins 6 and 16 to VCC(3.0 to 5 Volts Plus)
Pins 4,5, and 8 to Ground.
Pin 1 connected to Pin 10 of 74AC138
Pin 2 connected to Pin 8 of 74AC138
Pin 3 connected to Pin 4 of 74AC138
Pins 7,9 thru 15 connect to cathode of LED's
If all LED are Red,Yellow, Green or Orange tie anodes together and connect 1 resistor
from the anodes to VCC.
Resistor is found by R=((VCC-VLED)/10Ma))
In my circuit I used a 78L05 and a 9 Volt Battery. The 78L05 drops the 9V battery to
5V for the circuit
Ned

dacflyer · Post by **dacflyer** » Thu Oct 16, 2003 2:44 pm

heres another idea... use a quad 555 timer..and set your timing there...and then use a large cap on each output so that then the firefly fires,,it will fade out like a natural fire fly...but you know its a fast fade out..
try it...with a single 555 to see what i mean...
might have to use a dioad to keep the 555 from reversing the current on the cap....forcing it to a hard discharge...
let me know what you think,,,

ACE37918 · Post by **ACE37918** » Tue Oct 28, 2003 5:09 pm

Dacflyer,
I put the 555 together and installed a diode right after the resistor on pin 3 ,I put the cap.(470uF) between diode and l.e.d. with - lead to ground and it will not fade.
What would you do next?
I tried 3 or 4 other ways and fryed 2 555's
thats the price of a good education I guess.

desterline · Post by **desterline** » Wed Oct 29, 2003 1:06 am

This might be more hardware than you want, but why not just hook up a five 555 circuits? Since they would all have differnt frequencies, they would blink randomly. Any other method is going to produce some kind of pattern. -Denny

Bernius1 · Post by **Bernius1** » Wed Oct 29, 2003 4:51 am

I was working on a variant of a 1-trans. oscillator (no DC to base, just a cap chge/dischge, & a PNP in reverse as a push/pull). Well, th osc. failed, but the LED's (1-from base to gnd, 1- from emitter to gnd.) would glow; the 'base' LED came on fast, & faded, & as it faded, the emitter LED faded on. About 2-sec for the x-fer, with a small cap. Both ,when ON, were full bright. So, maybe a series/parallel arrgt of cap's in the gnd.ckt. of your LED's will cause each to fast-fade. Look at 'design briefs' on [URL=http://www.elecdesign.com]elec.design.com, there's a PIC 1-wire, 3-color controller.

dacflyer · Post by **dacflyer** » Thu Oct 30, 2003 7:41 pm

Hmmmm only thing i can think of,,is if the led does not go out,,maybe the cap is too high capacity?...does it fade out after a while...??
i might make one on my bench and test it...
and then work on the plans for the quad 555...
will respond in a few days...

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