Use the TRIG port to trigger telemetry. The module requires at least 10 µs high-level TTL trigger signals. It automatically outputs an 8-cycle, 40 kHz square wave and detects any returned echo signal. If an echo is detected, a high-level TTL signal is output via the ECHO port. The duration of this high-level signal corresponds to the time between transmission and reception of the ultrasonic pulse. Measured distance = (high-level pulse duration × speed of sound (340 m/s)) / 2. Static current (max): 2 mA Output voltage level: 5 V (high), 0 V (low) Detection range: 2 cm – 450 cm Accuracy: ±2 mm Operating voltage: 5 V DC Output signal: TTL-compatible frequency signal Sensor beam angle: ≤15° Trigger input signal: 10 µs TTL pulse Echo output signal: TTL pulse-width output Pin configuration: VCC (5 V power supply), TRIG (trigger input), ECHO (echo output), GND (ground) Package includes: 5 × HC-SR04 Ultrasonic Distance Sensor Modules for Arduino Note: Measurements are manually obtained; a tolerance of ±1–3 cm may occur. Slight color variations may exist due to lighting and display differences.