analog sensors give the same value

Products & Technology Raspberry Pi
#1

I have the grovepi light sensor on A0 and the sound sensor on A2. When I read the sensors and print I get the same value for both.



this seems … odd…

#2

Hi there, please provide the code and we can talk a look. thanks.



Seeed techsupport team

Bill

#3

it turns out I was reading the analog sensors after reading a temperature/humidity sensor on D4. putting the codeto read the analog sensors BEFORE the temp/humidity sensor solved the problem.



this specific order for accessing analog/digital sensors should possibly be mentioned somewhere in the documentation.



The complete code can be found here: <LINK_TEXT text=“https://github.com/nosarious/curiousity … sensors.py”>https://github.com/nosarious/curiousity-exploration/blob/master/file-save-sensors.py</LINK_TEXT>



The specific code for the sensor values is here:



this code works, giving distinct values for analog sensors:
[code]
 sensor_value0 = grovepi.analogRead(sensor0)
sensor_value1 = grovepi.analogRead(sensor1)
sensor_value2 = grovepi.analogRead(sensor2)
#these analog sensor values will be distinct

        #temperature sensor data
        temperatureV = 0
        humidityV = 0            

        [temp,humidity] = grovepi.dht(temp_hum_sensor,0)
        if math.isnan(temp) == False and math.isnan(humidity) == False:
            #print("temp = %.02f C humidity = %.02f%%" %(temp, humidity))
            temperatureV = temp
            humidityV = humidity<e>[/code]</e></CODE>

what doesn’t work:
[code]
 #temperature sensor data
temperatureV = 0
humidityV = 0

        [temp,humidity] = grovepi.dht(temp_hum_sensor,blue)

        if math.isnan(temp) == False and math.isnan(humidity) == False:
            #print("temp = %.02f C humidity = %.02f%%" %(temp, humidity))
            temperatureV = temp
            humidityV = humidity
                          
        sensor_value0 = grovepi.analogRead(sensor0)
        sensor_value1 = grovepi.analogRead(sensor1)
        sensor_value2 = grovepi.analogRead(sensor2)
        
        #these analog sensor values will be the same
        <e>[/code]</e></CODE>

I am still having trouble getting information from the GPS, but I shall post that problem in a different post.

#4

Hi, thanks for the sharing. please post GPS as another issue. thanks.

Bill

#5

Hu, You are Using the Analog sensor directly with Raspberry Pi…?

#6

Hi there,



it uses the Grovepi+, it includes the atmel chip to turn the analog signal to I2C signal. thanks.