Proposal:

A frustrating experience I have identified for my housemates (and myself) is that sometimes we stayed at the school library/studio or hung out with friends until late in the midnight and forgot to tell others in advance, which sometimes resulted in one of us got accidentally locked outside when we went back. (We have the habit of locking the house gate from the inner side using a knob before going to bed for safety concerns, in which way the door could not be opened with a key from outside.) 

To solve this problem, I plan to develop an IoT device that can send a text message notification to everyone once someone locks the gate from the inner side, therefore we can react to it quickly.  To realize this function, I plan to put a tilt sensor on the lock (knob) and connect it to a Photon. The Phonton will then integrate with Twilio API to text messages.