Hi!
I'm trying to use the XO-1.5 as an oscilloscope, using xoscope (*) [1].
I thought that should be easy to do given that the audio input seems to
be specifically designed to do something like this. However my experiences
so far are strange at best...
For a start there always is a bias voltage.
On Wed, Nov 17, 2010 at 1:38 PM, Sascha Silbe
wrote:
> Hi!
>
> I'm trying to use the XO-1.5 as an oscilloscope, using xoscope (*) [1].
> I thought that should be easy to do given that the audio input seems to
> be specifically designed to do something like this. However my experiences
> so far are
As a wild stab at a first guess, it sounds like a software problem to
me -- seems like xoscope is not successfully turning off either the
bias voltage or the decoupling capacitor (high pass filter). Perhaps
a silent failure of some sort?
--scott
--
( http://cscott.net/
On Wed, Nov 17, 2010 at 2:46 PM, C. Scott Ananian wrote:
> As a wild stab at a first guess, it sounds like a software problem to
> me -- seems like xoscope is not successfully turning off either the
> bias voltage or the decoupling capacitor (high pass filter). Perhaps
> a silent failure of some
Sascha
This matches what Walter and I are observing with TurtleArt 103.
TA uses commands issued to amixer, amixer seems to be behaving inconsistently.
Biases of 5k and 15k have been observed but unpredictably. The amixer commands
that should switch the bias off just change the gain. With 0dB ga
Excerpts from Sascha Silbe's message of Wed Nov 17 19:38:20 +0100 2010:
> I'm trying to use the XO-1.5 as an oscilloscope, using xoscope (*) [1].
[...]
Thanks to everybody who replied and helped me figure this out. I still
haven't succeeded using the XO-1.5 as an oscilloscope, but made some
progr
On 11/24/2010 06:52 AM, Sascha Silbe wrote:
> 2. The voltage I see with bias off is probably generated internally by
> the codec chip. I don't think the chip designers envisioned it to be
> used without a decoupling capacitor. I've been told the (non-public)
> data sheet is rather spar
On Wed, Nov 24, 2010 at 6:52 AM, Sascha Silbe
wrote:
> 2. The voltage I see with bias off is probably generated internally by
> the codec chip. [...]
> Unless someone finds a magic way to disable this from the digital
> side of the chip (which I doubt), we'll have to cope with it. This
> m
I see a problem recording sound in the Distance activity, but I don't
know if it is related.
You can see more information in OLPC #10122 http://dev.laptop.org/ticket/10122
The sound was recorded with the internal mic, at the start there are a
negative max
and a curve before you can get values to pr
On Thu, Nov 25, 2010 at 02:54:33AM -0300, Gonzalo Odiard wrote:
> The sound was recorded with the internal mic, at the start there are a
> negative max
> and a curve before you can get values to process
> (http://dev.laptop.org/attachment/ticket/10122/Screenshot.png)
Vague memory this is privacy r
This sounds like the problem with TurtleArt
The bias is present in voltage mode.
The version for sensors on the xo1.5 is
http://bugs.sugarlabs.org/attachment/ticket/2506/TurtleArt-104.xo
The bias is not leakage and capacitance, 15k ohms at the socket halves the bias
voltage at the socket.
It is
11 matches
Mail list logo
