The assembly of the smart system for the feral cat shelter is shown below in Fig. 1. Considering the Arduino Mega as the core central microcontroller, the other sensors were connected to it. The LCD was used for monitoring the working condition and was connected to I2C, SDL and SDA pins. The Fans and heating pad were also connected through the relay modules which connected to the 5V and GND pins. The DHT22, HC-SR04, ESP8266, and Gikfun Liquid sensors were all connected to different analog and digital pins. The Wyze Camera was connected outside of the Arduino through a power outlet.