Hi guys,
How can I help with this, I still teach electrical engineering at the
University of Nebraska, and before that I have about 25 years in
the field. Mostly embedded microcontrollers and stuff. I do have
several XOs to work with.
I would have jumped in earlier but the end of the semeste
On Sun, May 10, 2009 at 5:01 PM, Reinder de Haan wrote:
> C. Scott Ananian wrote:
>> On Wed, May 6, 2009 at 6:14 PM, Reinder de Haan wrote:
Absolutely not. The A/D is eight bits, with an input range spanning
0 - 3.3V, so the best you
can hope for is about 13 mV per LSB
C. Scott Ananian wrote:
> On Wed, May 6, 2009 at 6:14 PM, Reinder de Haan wrote:
>>> Absolutely not. The A/D is eight bits, with an input range spanning
>>> 0 - 3.3V, so the best you
>>> can hope for is about 13 mV per LSB. I would guess actual accuracy
>>> to be closer to 26 m
On Wed, May 6, 2009 at 6:14 PM, Reinder de Haan wrote:
>> Absolutely not. The A/D is eight bits, with an input range spanning
>> 0 - 3.3V, so the best you
>> can hope for is about 13 mV per LSB. I would guess actual accuracy
>> to be closer to 26 mV.
I think the actual A/D refer
Original Message
Subject: Re: Ambient light sensing via LED response
Date: Thu, 07 May 2009 00:02:49 +0200
From: Reinder de Haan
To: raf...@laptop.org
References: <200904290017.n3t0hl2v006...@new.toad.com>
<675d3c5c-95ed-4ee9-84bc-3b5164675...@laptop.org>
&l
Original Message
Subject: Re: Ambient light sensing via LED response
Date: Thu, 07 May 2009 00:02:49 +0200
From: Reinder de Haan
To: raf...@laptop.org
References: <200904290017.n3t0hl2v006...@new.toad.com>
<675d3c5c-95ed-4ee9-84bc-3b5164675...@laptop.org>
&l
> But why do you say you would need 1 mV accuracy ? Bright sunlight
> is far stronger than
> the light sources he used.
>
I am not an engineer so forgive me if I am saying something stupid, but
is not the goal to switch off the backlight if and only if there is no
difference between the s
On Tue, May 5, 2009 at 8:34 PM, John Watlington wrote:
>
> On May 5, 2009, at 6:44 PM, Rafael Enrique Ortiz Guerrero wrote:
>
> These measurements are really cool.
>>
>> But the question remains in whether the ADC could have a resolution of
>> 1mv?, i mean in light of these measurements is neces
On May 5, 2009, at 6:44 PM, Rafael Enrique Ortiz Guerrero wrote:
> These measurements are really cool.
>
> But the question remains in whether the ADC could have a resolution
> of 1mv?, i mean in light of these measurements is necessary to have
> an ADC that can reliable sense these variation
These measurements are really cool.
But the question remains in whether the ADC could have a resolution of 1mv?,
i mean in light of these measurements is necessary to have an ADC that can
reliable sense these variations and then with that basis have a transfer
function and add it to the algorithm
Hallo,
C. Scott Ananian wrote:
> A last resort would be hooking up a MOSFET as a simple amplifier --
> again, you're not worried about linearity or any such niceties, but
> you'd still need a good match for your MOSFET's threshold voltage...
> some real measurements to replace the WAGes would go
On Tue, 5 May 2009, C. Scott Ananian wrote:
On Fri, May 1, 2009 at 11:59 PM, John Watlington wrote:
Oh, yeah, you should be able to wire the top side of the LED directly to
the LED and measure the photovoltaic current directly; that's not patented:
battery voltage
On Fri, May 1, 2009 at 11:59 PM, John Watlington wrote:
>> Oh, yeah, you should be able to wire the top side of the LED directly to
>> the LED and measure the photovoltaic current directly; that's not patented:
>> battery voltage
>> Q1 |
>> ---from EC--|< _ t
On Sat, May 2, 2009 at 8:38 AM, wrote:
> > By the way, has anyone really thought about this feature ? I grok
> > the intent, but you have to make
> > sure that kids who happen to be in brightly lit rooms (glaring
> > fluourescents aren't uncommon)
> > don't loose their backlight, and wonder
> we had a dedicated light sensor on the last product i worked on
> (which, in retrospect, given that it had 15 watts (!) of
> backlight seems like maybe the wrong place to have started trying
> to save power ;-). i implemented a proof-of-concept algorithm
> for automatic control, but found it a l
john wrote:
>
> By the way, has anyone really thought about this feature ? I grok
> the intent, but you have to make
> sure that kids who happen to be in brightly lit rooms (glaring
> fluourescents aren't uncommon)
> don't loose their backlight, and wonder why ? The keyboard lighting
The back-bias voltage is a sensitive topic.
If you could guarantee periodic clearing of the integrator,
I could provide up to 10V or so. Otherwise, it should
probably be limited to +3.3V.
wad
On May 1, 2009, at 11:59 PM, John Watlington wrote:
> On May 1, 2009, at 2:28 PM, C. Scott Ananian wr
On May 1, 2009, at 2:28 PM, C. Scott Ananian wrote:
> On Tue, Apr 28, 2009 at 8:38 PM, John Watlington
> wrote:
> > I don't have time to take a look at this right now,
> > but we have a A/D input to dedicate to this, if it helps work around
> > the patent.
> >
> > We can talk to MERL if needed
On Fri, May 1, 2009 at 2:28 PM, C. Scott Ananian wrote:
> Oh, yeah, you should be able to wire the top side of the LED directly to
> the LED and measure the photovoltaic current directly; that's not patented:
> battery voltage
> Q1 |
> ---from EC--|< _ to
On Tue, Apr 28, 2009 at 8:38 PM, John Watlington wrote:
> I don't have time to take a look at this right now,
> but we have a A/D input to dedicate to this, if it helps work around
> the patent.
>
> We can talk to MERL if needed. I probably still know a handfull
> of people around there.
Oh, ye
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