We were tasked with creating a device using communication between two Particle Photons to make our lives better. As we both live in apartments and enjoy playing video games, we decided to address our inability to hear. Living in an apartment means there are often two doors and a number of yards between a visitor knocking at the front door and those able to let them in. This coupled with gaming headphones at high volume makes knowing when a visitor comes knocking nearly impossible. We solved this problem by making a doorbell that uses a visual signal rather than an audible one. The operation of this device is very simple. The doorbell photon, placed on the outside of the front door, is constantly outputting a signal on pin A0 and reading on pin A1. A0 and A1 are wired to a toggle switch. When the switch is open, the doorbell photon publishes an event with data, "SILENCE". When the switch is closed, the doorbell photon publishes the same event with data, "DING DONG". The receiver photon, placed in plain view in the occupant's room, subscribes to the doorbell photon's event. When the receiver photon reads "SILENCE", it turns the light wired to D7 off and publishes an event with data, "GOODBYE". When the receiver photon reads "DING DONG", it turns the light wired to D7 on and publishes the same event with data, "HELLO". The doorbell photon is in turn subscribed to the receiver photon's event. When the doorbell photon reads "GOODBYE", it turns the light wired to D7 off. When the doorbell photon reads "HELLO", it turns the light wired to D7 on. This way the occupant sees the visitor's arrival and the visitor's light confirms that the receiver is indeed lit. All of this means that when a visitor flips the switch and sees the light, the occupant will see their light too.
Live Data: https://docs.google.com/spreadsheets/d/1xhV4qqL3JErlXlj2pcfrKUo4lvCA_l4zqCE6fWd9tss/edit#gid=0