switch.py

# Based on the example code on http://razzpisampler.oreilly.com/ch07.html
import RPi.GPIO as GPIO
import urllib
import time

GPIO.setmode(GPIO.BCM)

GPIO.setup(18, GPIO.IN, pull_up_down=GPIO.PUD_UP)

def button_pressed():
    print('button pressed')
    data = urllib.urlencode({'text': 'hello!'})
    print(data)
    urllib.urlopen('http://beam.soracom.io:8888/', data)

while True:
    input_state = GPIO.input(18)
    if input_state == False:
        button_pressed()
        time.sleep(0.5)