Temperature and Humidity Measuring Using Raspberry Pi

Measuring and monitoring temperature and humidity using raspberry pi and DHT11

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Temperature and Humidity Measuring Using Raspberry Pi

Things used in this project

Hardware components

Raspberry Pi 2 Model B

Bitcraze Micro SD card deck

OpenBuilds Cable Ties (10 Pack)

USB-A to Micro-USB Cable

Itead Nextion NX8048T070 - Generic 7.0" HMI TFT LCD Touch Display

Story

People without an air conditioner should be prepared to control the atmosphere indoors manually. In this post, I’m describing themodern way to measure the most important parameters for human comfort: temperature and humidity.

I am using a Raspberry Pi 2 board and the DHT11 sensor. You can do the same on any computer that has the Internet, GPIO, and Python. The cheaper DHT11 sensor also works fine.

from time import sleep
import sys
import cloud4rpi


# these functions will be called by device when sending data
def room_temp():
    return 25


def outside_temp():
    return 4

# Put your device token here. To get the token,
# sign up at https://cloud4rpi.io and create a device.
DEVICE_TOKEN = '__YOUR_DEVICE_TOKEN__'

# Constants
DATA_SENDING_INTERVAL = 30  # secs
DIAG_SENDING_INTERVAL = 60  # secs
POLL_INTERVAL = 0.5  # secs

def main():
    # Put variable declarations here
    variables = {
        'Room Temp': {
            'type': 'numeric',
            'bind': room_temp
        },
        'Outside Temp': {
            'type': 'numeric',
            'bind': outside_temp
        }
    }

    # Put system data declarations here
    diagnostics = {
        'CPU Temp': cpu_temp,
        'IP Address': ip_address,
        'Host Name': hostname,
        'Operating System': osname
    }

    device = cloud4rpi.connect(DEVICE_TOKEN)
    device.declare(variables)
    device.declare_diag(diagnostics)

    device.publish_config()

    # Adds a 1 second delay to ensure device variables are created
    sleep(1)

    try:
        diag_timer = 0
        data_timer = 0
        while True:
            if data_timer <= 0:
                device.publish_data()
                data_timer = DATA_SENDING_INTERVAL

            if diag_timer <= 0:
                device.publish_diag()
                diag_timer = DIAG_SENDING_INTERVAL

            diag_timer -= POLL_INTERVAL
            data_timer -= POLL_INTERVAL
            sleep(POLL_INTERVAL)

    except KeyboardInterrupt:
        cloud4rpi.log.info('Keyboard interrupt received. Stopping...')

    except Exception as e:
        error = cloud4rpi.get_error_message(e)
        cloud4rpi.log.error("ERROR! %s %s", error, sys.exc_info()[0])

    finally:
        sys.exit(0)


if __name__ == '__main__':
main()

from os import uname
from socket import gethostname
import subprocess
import re

def parse_output(pattern, args):
    try:
        out_str = subprocess.check_output(args)
        if isinstance(out_str, bytes):
            out_str = out_str.decode()
    except Exception:
        out_str = ''

    match = re.search(pattern, out_str)
    return match.group(1) if match else None

def cpu_temp():
    t_str = parse_output(r'temp=(\S*)\'C', ['vcgencmd', 'measure_temp'])
    return float(t_str) if t_str else None

def ip_address():
    return parse_output(r'(\S*)', ['hostname', '-I'])

def host_name():
    return gethostname()

def os_name():
return " ".join(uname())