pulsing led circuit?

[snyper1982]

i was wondering how i would build an adjustable pulsing led circuit, so i could adjust how fast it flashes. what kind of parts would i need?

[Black_Ops]

pulsating or blinking?

pulsating being it goes from off to dim to bright gradually an back again.

[snyper1982]

ohh, i didnt realize there is a difference, i guess blinking then, lol.

[Comrade]

Pulsating would look cooler--like the computer was alive and breathing.

Blinking makes me think of obnoxious Christmas decorations. I love them--my brother and I ran around a friend's neighborhood on Christmas Eve and replaced random bulbs on others' Christmas lights with blinking bulbs. It was hilarious to watch the reindeer decorations blink incessantly.

[Captain Slug]

This is a pulser circuit in action.
4_pulse.avi (http://www.captainslug.com/modding/4_pulse.avi)

[Black_Ops]

here you go, one quick blinker for 1 or more led's

The schematic (pdf) (http://blackops.shacknet.nu/led1.pdf)

[snyper1982]

ok i was looking at that, and, well its been a few years since i have read any circuit diagrams, and im not sure what all of it means lol. if you could explain it to me a little, i would really appreciate it. oh yeah, and how exactly could i go about testing how many hz it is flashing at?

[chkptcharlie]

did you build a circuit yourself from a 555, or are you talking about a blinking led, that comes as an independant component?

[Black_Ops]

Well ok here i go at explaining this.

the 555 timer is a generic timer integrated circuit its been arround forever an a half.

ok R1, R2, and C1 form the resistor capacitor timing constat.
because i made R2 adjustabe it allows you to adjust your flash rate from 0.0065455 Khz or about 7hz to 0.072 Khz or about 72 hz.

Frequency = 1.44 / ( (R1+R2+R2) * C)

so if you have a target frequency you could just plug in a fixed value for R2

anyways

the 555 is capable of driving 200 mA on its output pin.

i chose to drive a transistor so you could put as many led's as you wanted on it. you could also put pnp transistor on it in addition to the npn and have the pnp drive a different set of led's durring the first sets off time.

the part list is:

U1 - 555 timer (NE555)
Q1 - any sutiable npn transistor capable of handling the current you want.
R1 - 1K ohm 5% 1/4 watt
R2 - 10K potentiometer (any will work)
R3 - 1K ohm 5% 1/4 watt (different value might be required to trigger your transistor)
R4 - Based on your led (use a led calculator to figure it out)
R5 - 500 ohm 5% 1/4 watt
C1 - 10 uF electrolitic (greater than or equal to 16volt)
C2 - 0.1 uF ceramic (greater than or equal to 16volt)

all pin numbers are labeled. shouldent be a problem hookin it up.

[chkptcharlie]

ok.... sorry i didnt see that pdf attatch up there