fading red eyes

If it is simpler, all I really do is for the LEDs to illuminate slowly when turned on and fade away slowly when switched off. By putting the resiter and LED in series across a 1000 uF cap but I can't get them to illuminate slowly,

What is this " fading red eyes circuit " ?

Graham

You'll need a resistor between the power supply and the cap/LED/resistor combo -- there has to be something to drop the voltage across while the capacitor charges.

Macros

any suggestions for value, I tried that but it just stopped it working completely, or perhaps charging toooo slow.

I'm using a 1000uF cap and a super bright blue 5mm LED with 9v supply.

Thanks for the help.

Macros

We can't see what you have done. Post a picture of what you built. Also, replace the blue LED with red leds, at least until you get the thing working as per the Bowden design.

Next: if you followed the schematic, either the transistor is always turned on, or is mis-wired, or is shorted. You can disconnect the wire from pin 1 of the 1458 to the base of the transistor - if the leds still glow, your transistor is shorted or wired wrong. Do you have a DMM?

Ed

How can a "super bright blue 5mm LED " make fading RED eyes?

What is the forward drop of those LEDs?

Tom

I've gone off the fading red eyes idea as it pulses continuously. All I want is for it to come on slowly when I switch it on and fade away when I switch it off. It is for a stage prop, goes in the top of an ornate staff.

I think the simple circuit across a cap is what I need, just gotta figure out the resistor combinations.

Not sure what the drop over the LED is and what is a DMM?

Thanks for the help, will play around with some resistor combos today and see how I go.

I still want the fading red eyes for something else, but best get this one done first ;)

Macros

Tom Biasi wrote: