Hi all !! It's very important to me the following questions to be answered, if possible,I need them for my degree project urgently .
Well I'm using tinyos-1.x and telosb motes of moteiv. I'm decoding the sensing measurements from the Osciilloscope application and I'm converting them to enginnering units.. I'm using the conversion formulas that I have found in the equivalent datasheets. After all these I have the following questions:* 1)* As far as the TSR and PAR measurements is concerned, I have found that they depend on the internal voltage of the mote.But how can this happen as this value remains the same but the light conditions do not remain the same. To be more specific I have found this in moteiv's datasheets *PAR/TSR Light Photodiodes* The TSR and PAR sensors are also measured using the microcontrollers 12-bit ADC with Vref=1.5V. The photodiodes create a current through a 100kOhm resistor. By calculating the raw voltage using equation (1) above, convert the voltage into a current using V=IR: (2) I = Vsensor / 100,000 where Vsensor is the voltage calculated with the raw value and converted using equation (1). The Moteiv datasheet includes curves for converting the photodiode's current into light values (Lux). Based on the graphs available in the Hamamatsu S1087 datasheet<http://sales.hamamatsu.com/assets/pdf/parts_S/S1087_etc.pdf> (*http://sales.hamamatsu.com/assets/pdf/parts_S/S1087_etc.pdf*), the current of the sensor, I, may be converted to Lux. S1087 lx = 0.625 * 1e6 * I * 1000 S1087-01 lx = 0.769 * 1e5 * I * 1000 *2)* On the other hand I'm trying to get internal temperature .It is calculated as follows depending on the voltage but I must be getting a huge erros because I calculate values such as 144 in Celsius that does not seem logic..How can I achieve calibration?? Internal Temperature Similar to the internal voltage, the internal temperature sensor is an uncalibrated thermistor that is sampled using the microcontroller's 12-bit ADC. Note that the sensor is not calibrated, although the following formula works well for most applications: T = (Vtemp - 0.986)/0.00355 Temperature is specified for degrees Celcius. I would be so grateful for your prompt answer!
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