There are two other sensors used in this application mainly light sensors and smoke detection. The light sensor is used to display the colour that falls on the LDR surface and to display colour information on the LCD. And the other sensor smoke sensor is used to detect the smoke and the microcontroller will set the alarm.
The LDR colour sensor can interact directly with the microcontroller. If this colour sensor is irradiated with any colour, it produces 3 different frequency outputs to the microcontroller by selecting the respective RGB filters present in it. The microcontroller then calculates the value of HUE% with these three composition values. According to this calculated HUE value, the microcontroller shows that colour name.