CODEWITHSUNDEEP
pythonsensorsraspberry-pi2
Layric Xu
Layric Xu

Reputation: 21

How to connect two sensors into Raspberry Pi?

I am trying to use Raspberry Pi 2 to connect two sensors and let them work. They are a DFROBOT analog light sensor and a DFROBOT analog sound sensor.

I am also using a AD converter, and the converter connect to SCL and SDA pins on Raspberry Pi.

The converter has four Ains, so I can use two of them, one connect to light sensor, one connect to sound sensor.

Could somebody help me with the Python code? I want to let my Pi receive 1 second for Ain1(Light sensor) and 1 second for Ain2(Sound sensor), alternately.

Here is my code, but It seems that it doesn't work well.

import time

import datetime

from smbus import SMBus

bus = SMBus(1)

def readSoundSensor():

    return bus.read_byte(0x48)

def runSoundSensor():

    bus.write_byte(0x48,0x00)
    last_reading = -1
    sound = readSoundSensor()
    timestamp= datetime.datetime.utcnow()
    record = str(timestamp) + ":" +str(sound)
    print "Sound: "+record

def readLightSensor():

    return bus.read_byte(0x48)

def runLightSensor():

    bus.write_byte(0x48,0x01)
    last_reading = -1
    light = readLightSensor()
    timestamp= datetime.datetime.utcnow()
    record = str(timestamp) + ":" +str(light)
    print "Light: "+record

while(Ture):

   runSoundSensor()

   time.sleep(1)

   runLightSensor()

   time.sleep(1)

My Pi has some data, but I data is not what I want, and is not as when I connect just a single sound/light sensor.

I am totally new in Raspberry Pi, and I don't know anything about address 0x48, etc, I just learn from some guide. Could someone help me where I was wrong?

Upvotes: 0

Views: 1011

Answers (1)

SiHa
SiHa

Reputation: 8410

Your while(Ture): is obviously wrong.

You are writing the same command - 0x48 0x00 to the A/D for both the sensors - that can't be correct, unless it samples all inputs on each read?

Are you sure you have the correct SMBUS address - 0x48?
What is this command 0x00 meant to do?

To clarify, SMBUS commands will consist of address in hex, command byte(s) in hex. You might want to read up on SMBUS / I2C addressing: This article is quite good.

I would imagine that at the very least you need to send a command to select one of the Ain inputs and then another to sample it. 0x00 looks more like a reset.

Have you read the documentation for the A/D?

Upvotes: 2

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