Firmata Weather Station

weather.py

import http.client
import time

from pyfirmata import Arduino, util

# Parameters
COM_PORT = 'COM37'
API_KEY = 'BMZ44FSBTE8JANSU'
HOSTNAME = 'api.thingspeak.com'
AREF = 5.0
SLEEP = 10							# seconds

# Connect to firmata
print('Connecting to Arduino')
board = Arduino(COM_PORT)

# Define pins
a0 = board.get_pin('a:0:i')
d3 = board.get_pin('d:3:o')

# Start thread to sample analog pin values
it = util.Iterator(board)
it.start()
time.sleep(0.1)

# Do forever
while True:

	# Turn on LED to show that we are sampling
	d3.write(1)

	# Read temperature
	voltage = a0.read() * AREF
	temp_val = (voltage - 0.5) * 100
	temp_str = '%.1f'%temp_val
	print("Temperature: " + temp_str + " C")

	# Construct GET request
	get_str = '/update?api_key=' + API_KEY + '&field1=' + temp_str
	print(HOSTNAME + get_str)

	# Send request (update channel)
	conn = http.client.HTTPSConnection(HOSTNAME)
	conn.request('GET', get_str)
	resp = conn.getresponse()
	print(resp.status, resp.reason)
	
	# Turn off LED to show that we are done
	d3.write(0)
	
	# Wait before next request
	time.sleep(SLEEP)