Fading LEDs connected to alarm clock

Thread Starter


Joined May 26, 2006
Hello everybody! I stumbled onto this formu while searching the internet, and figured I might be able to give it a try.
My name is Nathan. My entire life has been devoted to figuring out how things work, why they sometimes don't work, and how to make things work better.
I have an idea for an alarm clock. I love being awoken slowly by light. During the summer, this is no problem, because the sun does that. But, during the winter, I'm stuck with the annoying buzzing sound of the normal alarm clock. Is there any way that I could hook up or invent from scratch an alarm clock connected to a panel of LEDs aimed at my pillow, that would slowly fade on over about 20-30 minutes, ending at full blaze, then have a beeping sound at the desired time? I have been researching other sites, and they seem to be able to make clocks and other whatnots seemingly easily, and so I would imagine this would be possible for me. I have had a lifetime of working with electronics, but have never really studied practical application and or circuit creation. I don't necessarily need a step to step from you guys, I would just like to know how much something like that would cost, and how hard it would be to make. I thank all of you in advance!

-Nathan Gold


Joined May 16, 2005
The brightness of LEDs can be vaired using a pulse-width modulator. There are one or two old threads on this board that discuss such - the search function should turn them up.

Your pulse-width modulator would have to be controlled by a ramp of some kind. The ramp in turn would be triggered by the alarm clock.


Joined May 10, 2006
A pulsewidth modulated switching converter would be an efficient solution. The SG1524 PWM chip has a softstart that could be set to be really long! I think RadioShack sells the chip; and www.boostbuck.com shows a viable converter.
Hey nathan, im not exactly a whizz at electronics, but i am a designer. A couple of years back one of my mates on my degree was looking into how light awakens you in a more natural way than an abrupt alarm starting up.
With the help of our uni electronics guru he wired up a load of different rigs to wake you up slowly in the morning. They all used a cheap £1 alarm clock, with the alarm trigger setng off a secondary circuit that slowly increased the voltage and hence the light emmitted from his chosen device.

He experimented with lots of different light sources, LED's, Bulbs, Florescent tubes, and even the flourescent paper like material that lights up with a voltage (sorry - forgot what its called off the top of my head).

His final project was a pillow made with memory foam and that illuminating paper stuff, i tryed it out and it was pretty damn successful (well it woke me up anyways!)

I have seen many different variations on this now, light up duvets, pillows and the clocks you discussed. I am curently experimenting with solar powered Super Bright LED's and have been contemplating fitting a series to my celing in a simular manner as to you described. Although this may not be very techincal for you i thought it may be a bit of fuel for the imagination.