I believe the radio uses INT2 as an interrupt to the controller,
whereas it is used as an output to power the Temp sensor. The
Temp start/stop commands turn it on and off as an output, but
I don't know if it restores the radio function. I thought the
manual described the necessary procedure, but it may not have
dealt with the radio part.
If this is indeed the problem you may need to start and stop
the radio in between sensor readings, and there may be some
time involved in getting it going each time.
I don't use that sensor board nor even micaz's, so I'm afraid
that's about all I know...
MS
Hugo Sousa wrote:
Hi Michael, thank you for your answer
The photo and temp sensors use the same ADC, if INT2 is in fact used by
the radio (and so activating the temperature sensor while the
photosensor is also on), the ADC values become corrupt and meaningless,
according to the MTS-MDA series user's manual (by xbow). Looking at the
schematic, the activation of the most significant bit I wrote about was
just an unhappy coincidence with the room temperature being very near
the middle of the scale of the temperature sensor(the photo and
temperature resistors are in parallel and in total darkness the
resistance of the photoresistor is very high).
Do you know how the int2 is used by the radio? Could I change the
photosensor modules to clr() the INT2 pin, make a reading and re-set()
the pin without affecting the radio?
Cheers
Hugo
On 4/27/07, *Michael Schippling* <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>> wrote:
On the micaz the INT2 pin is shared between the radio receiver
and the Temp power on the micasb. This could be causing some grief...
Search back on this list for some discussion, and there's a bit
about it in the xbow User's Manual. The workaround is to make
sure you do Temp conversions when there are no radio messages,
and to start and stop the sensor on each sample. I don't know
how this could affect the Photo readings, but perhaps something
got crossed-up in T2...
MS
Hugo Sousa wrote:
> (using a mts300ca board on a crossbow micaz mote and tinyos 2.x)
>
> A did a simple experiment, I added one Timer to the Oscilloscope
> application, which is set periodic and samples the photosensor
(every
> 100ms), lighting the leds with the most significant bits of the
sensor
> reading; the other timer is used with a startOneShot(5000) (on
> Boot.booted() ) to start the radio when it is fired (just start the
> radio, do nothing else, no sending and no receiving).
>
> The light readings are ok before the radio starts, after that the
value
> always has the most significant bit on. It's not just that the
bit is
> on, the readings change on the other bits, but now the value is never
> lower than 512 (most significant bit). After turning off the radio,
> values go back to normal.
>
> Turning on the radio is affecting the adc voltage readings? The same
> happens with the TempC sensor, which has the same adc. The microphone
> doesn't seem to be affected by this.
>
> Any thoughts?
>
> Cheers,
> Hugo
>
> On 4/24/07, *Hugo Sousa* < [EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]> <mailto:[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>>>
> wrote:
>
> Forgot to mention, this only happens with the oscilloscope
> application. With Sense the readings are normal.
>
>
> On 4/24/07, *Hugo Sousa* < [EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>
> <mailto: [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>>> wrote:
>
> I never get light readings below a certain value (~500), not
> even in a closed box, why is that? Any kind of calibration is
> needed? Heat sensitivity? Also, while in the closed box, the
> readings slowly go up.
>
> Cheers,
> Hugo
>
>
>
>
>
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