Hi! The other option would be to use an IRIS mote to sample at 17 KHz and stream the data to a basestation. This is not going to be as fast as the soundcard, and can have dropped packets as well. You couls theoretically sample a single channel at 60 KHz with the mote, but there is not place to put all the data, not even the flash is fast enough.
Miklos On Mon, Sep 27, 2010 at 8:06 PM, Francesco Ficarola <[email protected]> wrote: > Urs Hunkeler ha scritto: >> I have not tried this yet, I am just thinking about it. >> >> Here is a link with a summary of different Oscilloscope replacements: >> http://opencircuits.com/Oscilloscope >> >> There is an open-source application called "xscope" for Linux: >> http://xoscope.sourceforge.net/ >> >> Apparently, sound cards have an input range on the line-in from -1V to >> 1V. Most sound cards should support a sampling rate of >40kHz and a >> sampling depth of 16 bits. The biggest unknown (to me) is whether the >> sound cards filter out the DC component (e.g. you cannot measure >> voltage, but only changes in voltage). If this is the case, I would need >> to find a different solution. Otherwise we can probably expect something >> like this: The sound card might have an antialiasing filter with a >> cut-off frequency of 20kHz, so we should get a temporal resolution of >> around (1s / 20'000 =) 50us (I think even 100us is good enough for me). >> We might have to amplify/attenuate the signal from the mote. If we make >> a simple input circuit to measure current in the range of 0-50mA (a >> typical MicaZ or Iris mote with the radio, CPU and all LEDs on and also >> writing to the Flash should not draw more current) and in order to keep >> the circuit simple map this to 0-1V (we loose half of the input range), >> we should get a resolution <2uV. Considering noise and imperfections in >> the circuit the accuracy is probably more around 10uV, but even 100uV >> are probably good enough for me. > > Wow. :) Your idea is amazing! Thank you very much for the project > description. If you realize it, keep me informed because I am very > concerned. > > Greetings and good luck, > -- > Francesco Ficarola <francesco.ficarola_at_gmail_dot_com> > Presidente LUG-PV (http://lugpv.netsons.org) > Mailing List: lugpv_at_lists.linux_dot_it > > [GPG KeyID: 0xDBA99D92] > http://lugpv.netsons.org/gpgkeys/francesco_ficarola.asc > > Il nuovo modo di fare ricerca: www.tradoogle.it > > > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
