Implementation

Workflow:

• The force resister sensor determines how much weight is in a certain area.
• Then it will calculate how many members are in that area.
• If there's one, the tree will trigger only yellow lights.
• If there're two, the tree will trigger yellow and orange lights.
• If all the three family members gather together, the tree will trigger yellow, orange and red lights.
• When there is no one in that area, the light will be turned off.

List of parts:

• Argon Particle with WIFI connector
• Breadboard
• Force resister sensor
  
• Three 1k-ohm resistors
• One 10k-ohm resistor
• Yellow LED
  
• Red LED
• Green LED

Demonstration video, completed code, circuit diagram, photos of the prototype are below.