The HC-SR04 Ultrasonic Sensor: A Comprehensive Guide
The HC-SR04 ultrasonic sensor is a cutting-edge technology that utilizes sonar principles to accurately measure distances, much like how bats and dolphins navigate their surroundings. This sensor offers precise non-contact distance measurements ranging from 2 cm to 400 cm (approximately 1″ to 13 feet), making it a versatile tool for various applications.
Key Module Specifications:
- Working Voltage: 5V (DC)
- Static Current: Less than 2mA
- Output Signal: Electric frequency signal, high level 5V, low level 0V
- Sensor Angle: Not more than 15 degrees
- Detection Distance: 2cm to 450cm
- High Precision: Up to 0.3cm
- Input Trigger Signal: 10µs TTL pulse
- Echo Signal: Output TTL Pulse Width Level (PWL) signal
Connection Mode:
- VCC
- Trig (T)
- Echo (R)
- GND
How to Use the HC-SR04 Ultrasonic Sensor:
To operate the sensor, supply it with 5V. The output will switch to 5V when an obstacle is detected within the specified range, and it will remain at 0V if no obstacle is present. The output pin serves as a switching output for anti-theft systems and ranging modules.
Note: Always insert the module into the circuit before powering it on to prevent malfunctions. Sequential power supply is crucial to avoid system restarts.
Understanding the Working Principle:
- Initiate the module with a minimum 10µs high-level signal.
- The module emits eight 40kHz square waves and awaits the echo signal.
- Upon detecting the reflected signal, the module generates a high-level signal, with the duration indicating the ultrasonic wave’s round-trip travel time. Calculate the distance using the formula: Distance = (High-Level Duration * Speed of Sound (340 m/s)) / 2.
Important: Avoid direct connection to an electric power supply. When integrating with an electronic system, connect the GND terminal first to ensure proper functionality.
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