I don't understand how to convert voltage in temperature. My sensor is a IR temperature sensor with 5 V DC power supply (http://it.tinypic.com/r/dqfx37/9). My beaglebone cannot support an output (0-5V) so I've used this voltage divider. I've calculated the resistor R1=634 Ohm (5% so it's not so good but it's what I have now) and R2=324 Ohm (5%), considering an output max of 5.3V to scale to 1.8V. So the conversion factor is (R2/(R1+R2))=0.34. So 1/0.34=2.94. All it seems working. I can read with multimeter a voltage of 49/50mV in my room. My running instead produces fluctuanting values between 20 to 65. I read in python analog in this way:
import Adafruit_BBIO.ADC as ADC import time sensor_pin = 'P9_40' ADC.setup() while True: reading = ADC.read(sensor_pin) millivolts = 2.94*(reading) #to obtain original voltage temp_c = (millivolts) #here I've to obtain the correct slope to convert volts in degree time.sleep(1) Is it correct my code? Thanks. -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
