Does Nanonote give any signal when battery is near shutdown voltage?

Rubén Berenguel ruben at mostlymaths.net
Tue Apr 20 14:55:09 EDT 2010


Battery test undertaken. Started at 01:20 (AM) and the nano died at
17:12 (5:12 PM). That's 16 hours running (although the screen was not
on all times, of course, and it was doing nothing). Here is a link to
a jpg of the plot via gnuplot (sorry: I'm at Mac and have problems
with gnuplot...)
http://picasaweb.google.es/RBerenguel/MostlyMaths#5462294288966847058

On the x axis: minutes, on the vertical cat /sys/class/power_supply/capacity .

I'll try to extract more useful information of all these and condense
it someday in a useful script (one that does recording always and
such).

How are the debian things going?

Ruben

2010/4/20 Rubén Berenguel <ruben at mostlymaths.net>:
> I think the "correct" one to know about batery status is cat
> /sys/class/power_supply/battery/capacity. Not sure, but it gives a
> number I guess it is between (0) and 100 with the percentage (I guess,
> again) of remaining battery power. Yesterday I started a minute cron
> job outputting voltage_now, status and capacity, and will leave it
> running until battery depletes to see which of these numbers is more
> meaningful (and estimate times).
>
> After that I'll probably write something for every 5 minutes checking
> that value to be able to generate nice plots (in my main computer, not
> in the nano sadly) of power usage. Geek power :) Then it will be able
> to notify, somehow (what about it playing some sound file?) or
> whatever. By the way, I solved the problem with the mic: it was turned
> off and had to be turned on... Probably the same problem I had before.
> Thanks Marc!
>
> Btw, I don't have my cross-compiling computer here and can't check: is
> "at" (i.e. at 06:00 04212010 echo "Good morning!") in the instalable
> packages via menuconfig? I prefer at than cron, yesterday I got mad at
> it :/
>
> Ruben
>
> On Sun, Apr 18, 2010 at 07:19, Delbert Franz <ddf at sonic.net> wrote:
>> On Tuesday 13 April 2010, Ron K. Jeffries wrote:
>>> Don't forget that Nanonote has Lua, a very capable yet lightweight
>>> scripting language. My understanding is Lua has capability
>>> to interface with GTK
>>> ---
>>> Ron K. Jeffries
>>>
>>> >
>>> > When I get time, I want to investigate adding numpy to the python
>>> > already there--then I can do some interesting things on this little
>>> > jewel-even with its current limits:) Would also like the python-gtk
>>> > package as well.  Then this would be a really sweet little gizmo!
>>> > (I'm assuming we can reach the DirectFB from python-gtk.)
>>> >
>>
>> Thanks for the tip about Lua.  I did some research and then
>> translated a simple adaptive integration routine from Python to
>> Lua (rather simple but one has to declare all "local" variables as
>> local in the recursive functions in Lua-the are local by default
>> in Python).  Th syntatic differences for my simple case was small.
>>
>> Some simple timing tests on my Acer Aspire One showed about a factor
>> of two advantage for Lua.  However, the test was short so it might
>> not be valid.  Can't do a valid test on the Nanonote because Lua
>> is compiled there with single precision floating point whereas Python
>> only comes in double precision:)  When I set the tolerance to the same
>> value and run the Lua routine on both the Acer and the Nanonote I see
>> about a factor of 10 difference in time:  The Acer computes the results
>> in double precision in 1/10 the time that the Nanonote computes the
>> result in single precision.  The number of function evaluations agrees
>> exactly.  Not bad considering the Acer using IEEE hardware floating point
>> and the Nanonote uses some "unknown" OpenWRT software floating point:)
>>
>> Over the next few weeks I'll do some more simple numerical tests to see
>> how the Nanonote does.  I did not expect it to be fast but for many possible
>> applications it is fast enough-and that's all we need:)  In fact, considering
>> the electrical power drawn by the CPU, it does quite well on speed.
>>
>> There are bindings for Lua and gtk but I don't think they exist in the
>> OpenWRT list of packages.  The Python gtk bindings appear to be there
>> but are not in the Nanonote image--yet.  However, the Nanonote software
>> is in its infancy--we should see rather rapid changes over the next
>> few months.
>>
>>                             Delbert Franz
>>
>> _______________________________________________
>> discussion mailing list
>> discussion at lists.qi-hardware.com
>> http://en.qi-hardware.com/mailman/listinfo/discussion
>>
>
>
>
> --

-- 
====================================
* Rubén Berenguel
* http://www.mostlymaths.net
====================================




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