Alarmclock puzzle

Robin Paulson robin.paulson at gmail.com
Wed May 14 09:28:37 CEST 2008


2008/5/14 Sven Klomp <sven at klomp.de>:
>  I had the same idea and bought two 1W LEDs. I can dim them with PWM from a
>  microcontroller. The microcontroller has its own power supply and will be
>  connected via USB to the Freerunner. Thus, the Freerunner can control the
>  LEDs in the morning and is also charged during the night (I belive the
>  Freerunner can be charged in host mode).
>
>  Maybe I don't need a wake-up sound since the LEDs are VERY bright :-)

yes, that would all work, but it reduces the neo to a bit-part in the
process - i might as well have a separate alarm clock if i have to
faff about with external components in that way.

maybe if the neo itself could do the pwm, hacking a couple of leds
into a modified case would not be so difficult?

on the wiki i see the neo screen can emit 220 cd/m^2

which is ~0.0819 lumens (guessing at a 25deg cone for the light emittance)

and from this http://en.wikipedia.org/wiki/Lumen_%28unit%29 ,

a 100W incandescent bulb emits about 1700lumens

=>a 12W bulb (as in the soleil alarm clock) emits about 200 lumens

a lot more than the neo screen, so i guess i'm out of luck




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