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]> 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]>> > 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]>> 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 > > > > > ------------------------------------------------------------------------ > > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
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