CL1B power distribution

John Watlington wad at
Tue Apr 28 20:09:19 EDT 2009

On Apr 28, 2009, at 7:31 PM, david at wrote:

> On Wed, 29 Apr 2009, James Cameron wrote:
>> On Tue, Apr 28, 2009 at 10:15:47AM -0400, C. Scott Ananian wrote:
>>> I wonder if one could easily support running an LED backwards as an
>>> ambient light monitor in Gen 1.5 - it seems that automatically
>>> powering off the backlight in bright sunlight would lead to a lot of
>>> power savings for most young users.
>> I agree that an ambient light detector and automatic adjustment of
>> backlight would save power.  It would happen transparently,  
>> magically.
>> But I don't think the LEDs are often specified in terms of their  
>> ambient
>> light detection properties.
>> Perhaps it would be better to use a photodiode, or light dependent
>> resistor.
>> Then there's the spectrum of light being received.
>> Then there's reflection from the laptop display itself to consider.
>> I recall we also once had a discussion on whether the camera could be
>> used as an ambient light detector.
> you don't want to have to run the camera to detect the light (this  
> will
> eat far more power than you would save)
> the LED trick has the advantage of not requiring a change to the case,
> just a single additional drive pin to be able to run it as a detector.

And where would you place said detector LED, without modifying the  
case ?

(I have the pin...)


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