Process

I started with the installation of PIR sensor, which was easy. The hardest part is to install the message notification. I searched online and found the guide here : https://www.twilio.com/docs/guides/sms-mms-messages-particle-photon#sign-into-or-sign-up-for-a-twilio-account. But it failed to work on my photon, and it turned out later that my Particle Dev had some errors. Finally problem solved after I changed to use build.particle.io. I also find a similar project online that used PIR sensor (http://ideate.xsead.cmu.edu/uploads/contents/8028/original/homehack.pdf?1486020771), and learned how he coded PIR and switch button, I also learned from http://diotlabs.daraghbyrne.me/5-getting-input/switches/. I was struggling between using a LED as a sign or a text message, I finally choose using text messages because it is more mobile that people don't need to stay beside the LED. A challenge I met was that it kept sending messages to my phones when there is a detection, and the sensor is quite sensitive so my phone kept ringing. I later added "delay(600000)" to solve the problem.