====== Installing DH22 Temp / Humidity Software ======

Make sure you are updated:\\

<code>
sudo apt upgrade
</code>

Install the required packages:\\

<code>
sudo apt install python3-pip python3-rrdtool librrd-dev 

sudo pip3 install adafruit-circuitpython-dht rrdtool --break-system-packages
</code>

Test Script:\\

<code>
# Complete Project Details: https://RandomNerdTutorials.com/raspberry-pi-dht11-dht22-python/
# Based on Adafruit_CircuitPython_DHT Library Example

import time
import board
import adafruit_dht

# Sensor data pin is connected to GPIO 4
sensor = adafruit_dht.DHT22(board.D4)
# Uncomment for DHT11
#sensor = adafruit_dht.DHT11(board.D4)

while True:
    try:
        # Print the values to the serial port
        temperature_c = sensor.temperature
        temperature_f = temperature_c * (9 / 5) + 32
        humidity = sensor.humidity
        print("Temp={0:0.1f}ºC, Temp={1:0.1f}ºF, Humidity={2:0.1f}%".format(temperature_c, temperature_f, humidity))

    except RuntimeError as error:
        # Errors happen fairly often, DHT's are hard to read, just keep going
        print(error.args[0])
        time.sleep(2.0)
        continue
    except Exception as error:
        sensor.exit()
        raise error
    
    #Sleep 5 Min
    time.sleep(300.0)
</code>

Test it:\\

<code>
python3 bin/temp-2.py
</code>

Working Script:\\

<code>
sudo vi bin/temperature.py
</code>

<code>

import adafruit_dht
import board
import time
import rrdtool

# Set up the DHT22 sensor
dht_device = adafruit_dht.DHT22(board.D4)

while True:
    # Read the temperature and humidity data
    temperature = dht_device.temperature
    temperature_f = temperature * (9 / 5) + 32
    humidity = dht_device.humidity

    # Update the RRD database
    rrdtool.update('/etc/temperature/test.rrd', 'N:%s:%s' % (temperature_f, humidity))

    # Sleep for 1 minute
    time.sleep(60.0)
    
</code>

Move to location:\\
<code>
sudo cp bin/temperature.py /usr/local/bin/

sudo chmod 755 /usr/local/bin/temperature.py

</code>

Setup RRD:\\

<code>
sudo mkdir /etc/temperature
</code>

Make Database:\\

<code>
sudo rrdtool create /etc/temperature/test.rrd --step 300 \
  DS:temperature_f:GAUGE:600:-40:80 \
  DS:humidity:GAUGE:600:0:100 \
  RRA:AVERAGE:0.5:1:288
</code>

Add it to Startup:\\

Create file /etc/systemd/system/temperature.service\\

<code>
[Unit]
Description=Script to start taking temperarures

[Service]
ExecStart=/usr/local/bin/temperature.py
Restart=always
RestartSec=3

[Install]
WantedBy=multi-user.target
</code>

Enable Script:

<code>
sudo systemctl daemon-reload

sudo systemctl enable temperature.service

sudo systemctl start temperature.service
</code>

Graph it:\\

<code>
sudo rrdtool graph temperature.png --start -1d --end now \
  DEF:temperature=/etc/temperature/test.rrd:temperature_f:AVERAGE \
  LINE2:temperature#FF0000

sudo rrdtool graph humidity.png --start -1d --end now \
  DEF:humidity=/etc/temperature/test.rrd:humidity:AVERAGE \
  LINE2:humidity#0000FF
</code>

Graph it in Cron:

<code>
sudo crontab -e

*/5 *   *   *   *    /usr/local/bin/graph_test.sh > /dev/null 2>&1
</code>

<code>
sudo cp bin/graph_printmon.sh /usr/local/bin/

sudo chmod 750 /usr/local/bin/graph_printmon.sh
</code>


https://randomnerdtutorials.com/raspberry-pi-dht11-dht22-python/