555 Pulsing or Breathing led need help

333

05:21:46

Hello, I am new to every circuit and the community. I could use some help. Could someone show me how to adjust the transistors and diodes in my simulation to match the ones in this schematic? http://pcbheaven.com/circuitpages/555_Breathing_Pulsing_LED/ 

This is a circuit that will create an adjustable triangle wave voltage source to drive an led, capable of simulating a "breathing" pattern. The two pots adjust the up and down ramp speed of the wave voltage. I have built it on a physical breadboard with success. 

I will also need to figure out how to reverse mirror the led with another led so I can instead use two optocouplers working opposite each other to simulate both sides of the wiper in a pot. I hope that makes sense. My end goal is to use this circuit and optocouplers (led and photoresistor combined) to modulate the resistance of external circuits such as guitar effect pedals and circuit bent kids toys. I hope this makes sense. Any help would be greatly appreciated. 

published 11 years ago

bobbyrsd

11 years ago

You must connect all open pins from voltage sources to ground (or other pins)

bobbyrsd

11 years ago

And you must correct the polarity of all voltage sources

bobbyrsd

11 years ago

And 1 voltage source is enough

b1llygo4t

11 years ago

Ahh I see. I have my voltage source and ground worked out now. I can see my wave in the osciloscope, but the led wont light up. The circuit uses two different npn transistors. How do I find the correct setting to emulate them?

gwbop

11 years ago

Besure to set diode and trans values

lmccoig

11 years ago

I removed right most transistor changed above 47 k ohm resistor to 100 ohms thn conn

lmccoig

11 years ago

Sorry, wrong button. Remove right most resistor. Change above resistor to 100 ohms. Connect this resistor to output pin #3 on 555. Connect light diode to this resistor.

b1llygo4t

11 years ago

The rightmost resistor is the 47 k ohm resistor. Removing it seems to do the trick on the scope but the led has a burn symbol on it. And qhat exactly do I connect to pin #3? On my breadboard that pin is unused. Is there any chance you could make the changes to show me?

Sine_eyed

11 years ago

Hey Billy! I gotcha- it took me a minute to find what was wrong, because you did a pretty good job of building this just like the schematic lol! So, good job at least on that. Here's your solution= Put that 47R back where it belongs, and reduce the value of the 1st transistor R.c to 3.3K.... that's it lol! You're welcome.. =^)

Sine_eyed

11 years ago

Edit: when I said reduce the collector resistor "down", I meant from the original value given in the schem of 4.7K- so bring that one "up" from 100R and you're good..

lmccoig

11 years ago

On EveryCircuit when you zoom in on the 555 the pins show numbers. #3 is also labeled out. Outer Span

lmccoig

11 years ago

I keep hitting send button at wrong time. Outer Space music has volume growing or pulsing louder at times as a star twinkling- as in Space Odessey 2001. Breathing pattern on volume control may sound good?

Sine_eyed

11 years ago

lmccoig- it's already been done. I.e. phase shifters, swell, etc..

Sine_eyed

11 years ago

You haven't fixed it yet billy?..

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