Fire-Fighting Robot Using Arduino: Flame Detection, Approach and Water Suppression

Small fires are easiest to put out in their first few minutes, but that is exactly when nobody may be nearby. This project presents a low-cost mobile robot that finds a flame on its own, drives up to it and sprays water on it, completing the full detect-approach-extinguish cycle without human input. The primary objective is to respond to small, localized flames quickly and at their source, using commonly available hobby components. The robot detects fire with three infrared (IR) flame-sensor modules (YG1006 phototransistor with LM393 comparator) mounted in a divergent array facing left, centre and right. An Arduino Uno reads the three outputs and decides which way to move. Locomotion uses differential drive: an L298N dual H-bridge drives four BO gear motors, so the chassis can turn on the spot. When the flame is close enough, the robot stops at a safe distance, switches on a 3-6 V mini submersible pump through a transistor driver and sweeps the water nozzle across 180 degrees with an SG90 servo. Two 18650 lithium-ion cells (7.4 V nominal) power the system. In indoor trials with small open flames, the robot detected flames from 10 cm to 65 cm away, covered approximately 120 degrees in front of the chassis, reacted to a change in flame direction in under 50 ms, stopped about 22 cm from the source and extinguished the flame in 4.5 s to 6.0 s. The main limitation found was false triggering by strong sunlight, which emits in the same near-infrared band as the sensors. The project demonstrates that inexpensive, widely available components are sufficient for early-stage, localized fire suppression in indoor spaces. It is a demonstrator, not a replacement for certified fire-detection and suppression systems.