Cat Pantry IoT Detector
Smart Home Sensor Network
The Objective
My roommate's cats figured out how to open the pantry and eat our bread, so I engineered a custom IoT security system. I paired a PIR motion sensor with an Arduino and an NRF24 radio module to transmit activity alerts to a Raspberry Pi base station. The Pi parses the radio packets and triggers a custom Discord bot to immediately ping me when motion is detected. It's a scalable architecture that could easily be adapted into a larger home security network.
The soldered circuit.
The soldered circuit (back).
The discord bot
Technical Stack & Optimizations
The overall idea was to have a low-power node that is in my pantry at all times. This node has an Arduino Nano (which I regret using—I will explain why), a passive infrared sensor, and an NRF24 radio module. When a cat walks in, its heat activates the PIR sensor and triggers the interrupt in the Arduino. The Arduino then sends a packet over the NRF24 module and just broadcasts this packet. The Raspberry Pi in my room listens for this packet and as soon as a packet is detected, the Pi reads it and sends the message over Discord into my Discord server. Now the reason I regret the Nano is because even in sleep mode it was still consuming 5mA of current (If I destroy/remove the power indication LED on the Nano I could make it consume less current, but it's still over 1mA). I should've gotten the Arduino Pro Mini which would consume 1uA (micro Amps) instead, which would increase the battery life by orders of magnitude.