I got this LED from Radio shack and when you apply power it goes through a "power up" cycle of a bunch of color flashing and then goes to sleep mode. When the switch lead is grounded it changes to red, then grounded again off, then again green, then off, plus other colors, always with an off mode in between. Finally it has a fade into/out of all colors before a final sleep mode. Also the switch doesn't do anything during power up.
So to control this LED with no physical switching I figure I can use something like This.
And What I need is square wave that stays Low for 12 sec (enough to get through the power up cycle) and then has a 50ms High, then 50ms Low, then 50ms High. This is made more difficult since the LED is in sleep mode after power up.
But! If the switch lead is grounded while power up is going on, then It will go straight to Red.
So I need From power up:
12sL 50msH 50msL 50msH 12sL 50msH 50msL 50msH 12sL
The highs will be lows and lows high with a NPN transistor.
I figure I can keep the power up cycle low by having a power-on reset circuit on the 555. But to do 12 sec all these capacitors are getting big....
Does anyone see anything obviously wrong? I'm in the process of calculating the C's and R's and putting it on the breadboard.
Any better ways of building this?
Thanks!
(my next thread will be about fading a RGB led to produce all the colors with minimal components.)
So to control this LED with no physical switching I figure I can use something like This.
And What I need is square wave that stays Low for 12 sec (enough to get through the power up cycle) and then has a 50ms High, then 50ms Low, then 50ms High. This is made more difficult since the LED is in sleep mode after power up.
But! If the switch lead is grounded while power up is going on, then It will go straight to Red.
So I need From power up:
12sL 50msH 50msL 50msH 12sL 50msH 50msL 50msH 12sL
The highs will be lows and lows high with a NPN transistor.
I figure I can keep the power up cycle low by having a power-on reset circuit on the 555. But to do 12 sec all these capacitors are getting big....
Does anyone see anything obviously wrong? I'm in the process of calculating the C's and R's and putting it on the breadboard.
Any better ways of building this?
Thanks!
(my next thread will be about fading a RGB led to produce all the colors with minimal components.)
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