Holiday decoration using LM555 timer and (possibly op amp)

Discussion in 'The Projects Forum' started by Hurt_it_Circuit, Dec 3, 2012.

  1. Hurt_it_Circuit

    Thread Starter Member

    Oct 2, 2012
    I need to create a circuit that is a holiday decoration that fullfils two basic components:

    1. A solid background consisting of LEDs that is "on" whenever your Power On/Off switch is on and "off" otherwise.

    2. A flashing foreground consisting of LEDs that are "on" for a period.

    Optional: Create a fade in/fade out feature to the flashing foreground.

    I have few questions about this:

    1. I initianlly just put an LED via pin 8 to give it the solid background. Is there any other way I can set up the background using an op amp?

    2. I am going to put LEDs in parallel (all same LEDs) so that they have the same brightness. Is this a bad practice if so is there any other way to set up the circuit so that I achieve the same brightness for the LEDs?

    3. Will a circuit like mine need a capacitor in pin 5? If so, why?

    4. Any hints on how to do the fade in fade out feature?
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
    Last edited: Dec 3, 2012
  3. Hurt_it_Circuit

    Thread Starter Member

    Oct 2, 2012
    That makes sense and by varying capacitor value I can dictate how fast or slow the LED flashes. What about for the background is there anyway for me to include an op amp? I am only given and allowed to use the one op amp and timer that I am given.