[Tinyos-help] Problems with MDA300 and Micaz using ECHO5

[Daniel Villón]

Hi,

I'm currently using a Micaz with a MDA300 board to get moisture samples. I'm
using Sample interface to access SamplerC as in the example in
Xsensormda300M.nc. I think that I have already set correctly the MDA300
sensorboard to take the samples from Channel 6. I'm using:

call Sample.getSample(6,ANALOG,150,SAMPLER_DEFAULT | EXCITATION_25);
......
event result_t Sample.dataReady(uint8_t channel,uint8_t channelType,uint16_t
data) {

         atomic{
            data1 = data;
            }

My question is that I'm not sure if this is working in the way that it
should be. It sends a sample every 15 seconds which I think it's correct but
when I use a multimeter to measure the voltage in the excitation 2.5V pin I
always get -2.8V and it never turns off. Then I tried to change the argument
and put EXCITATION_ALWAYS_ON instead of EXCITATION_25 and nothing happens,
the weirdest thing is the the voltage is negative. Correct me please if I'm
wrong but isn't this supposed to turn on the excitation for a moment, take a
measure and then turn the excitation off? the other question that I have is
that I need to know how to regulate the time the excitation stays on because
it needs to be at least 10ms. I'm using ECHO5 soil moisture sensor. If
anybody around knows how to help me or had used a ECHO sensor before it will
be very helpful.

Thanks

-- 
Daniel Villón V.
-----------------------------------------------------------
Departamento de Ingeniería Telemática.
Universitat Politècnica de Catalunya
-----------------------------------------------------------
C/. Jordi Girona 1-3
Modulo C3 Laboratorio 003
Barcelona CP 08034, España
Teléfono: +34 93 289 36 71
Celular:   +34 697 91 43 53
e-mail: dvil1541 at alu-etsetb.upc.edu
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