Pushing existing body of work.

main.py

@@ -0,0 +1,55 @@
+#!/usr/bin/env python3
+
+import RPi.GPIO as GPIO
+import adafruit_dht
+import time
+from datetime import datetime
+import pytz
+
+from writer import get_db_creds, connect_db, insert_data
+
+def get_sensor_data(dht22):
+    try:
+        temperature = 9./5. * dht22.temperature + 32.
+        humidity = dht22.humidity
+        return temperature, humidity
+    except RuntimeError as e:
+        print("Reading from DHT failure: ", e.args)
+        return None    
+
+if __name__ == "__main__":
+
+    # Setup for Hardware
+    DHT22_PIN = 4
+    dht_device = adafruit_dht.DHT22(4)
+    file = '/home/pi/code/dht22/log.csv'
+    
+    with open(file,'a') as f:
+
+        try:
+            while True:
+                data = get_sensor_data(dht22=dht_device)
+                if data:
+                    temperature, humidity = get_sensor_data(dht22=dht_device)
+#                    current_time = datetime.now().strftime("%D %H:%M:%S")
+                    current_time = datetime.now(pytz.timezone('UTC')).strftime("%D %H:%M:%S")
+                    print(f'{humidity:.2f}%    {temperature:.2f}degF')
+                    f.write(f'{current_time},{temperature:.2f},{humidity:.2f}\n') 
+                    try:
+                         data_dict = {
+                         "datetime": current_time,
+                         "temperature": temperature,
+                         "humidity": humidity,
+                         "location": "basement"
+			}
+                         creds = get_db_creds("./.creds.json")
+                         conn = connect_db(creds["db"], creds["host"], creds["user"], creds["passwd"])
+                         insert_data(conn, data_dict)
+                    except (Exception, psycopg2.Error) as err:
+                         print ("\npsycopg2 connect error:", err)
+                    time.sleep(14.9)
+                else:
+                    time.sleep(0.1)
+
+        finally:
+            GPIO.cleanup()

setup.sh

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+# Install base OS (Debian) packages.
+apt update && apt upgrade -y && apt install python3-dev python3-pip python3-psycopg2 libgpiod2 -y
+
+# Install Python modules.
+pip3 install RPi.GPIO psycopg2 adafruit-circuitpython-dht
+
+# Start the python script.
+/usr/bin/python3 main.py

writer.py

@@ -0,0 +1,62 @@
+#! env/bin/python3
+
+# import the psycopg2 database adapter for PostgreSQL
+import psycopg2
+from psycopg2.extras import Json
+import json
+import sys
+
+def connect_db(db: str,host: str,user: str,passwd: str):
+    try:
+        # declare a new PostgreSQL connection object
+        conn = psycopg2.connect(
+            dbname = db,
+            user = user,
+            host = host,
+            password = passwd,
+            # attempt to connect for 3 seconds then raise exception
+            connect_timeout = 3
+        )
+
+    except (Exception, psycopg2.Error) as err:
+#        print ("\npsycopg2 connect error:", err)
+        conn = None
+    return conn
+
+def get_db_creds(file: str):
+    with open(file) as cred_file:
+        creds = json.load(cred_file)
+    return creds
+
+def insert_data(conn, data):
+    
+    # insert a new vendor into the vendors table
+    sql = """  
+    INSERT INTO
+        air(datetime, temperature, humidity, location) 
+    VALUES
+        (%s, %s, %s, %s)
+    """
+    
+    try:
+        # open cursor on our db connection
+        cur = conn.cursor()
+
+        # execute the INSERT statement
+        data = (data["datetime"], data["temperature"], data["humidity"], data["location"])
+        cur.execute(sql,data)
+
+        # commit the changes to the database
+        conn.commit()
+
+        # close communication with the database
+        cur.close()
+
+    except (Exception, psycopg2.DatabaseError) as error:
+ #       print(error)
+        pass
+
+    finally:
+        if conn is not None:
+            conn.close()
+