HC-SR04 Ultrasonic Distance Sensor Module for Precision Measurement and Obstacle Detection
The HC-SR04 ultrasonic sensor uses sonar to determine distance to an object – just like bats or dolphins do. This module offers excellent range accuracy and stable readings in an easy-to-use package. It operation is not affected by sunlight or black material (although acoustically soft materials like cloth can be difficult to detect). It is similar in performance to the SRF05 but with the low-price of a Sharp infrared sensor. Perfect for collision avoidance on your next robotics or multi-rotor project!
Features:
- HC-SR04 ultrasonic module can offer non-contact distance sensing function, the range of which is 2cm-400cm and the range accuracy is up to 2mm; the module includes ultrasonic transmitter, receiver and control circuit.
- Working Voltage: 5V(DC)
- Static current: Less than 2mA.
- Output signal: DC3.3-5V
- Sensor angle: Not more than 15 degrees.
- Detection distance: 2cm-450cm.
- High precision: Up to 0.3cm
- Input trigger signal: 10us TTL impulse
- Echo signal: output TTL PWL signal
Specification | Value |
|---|
Working Voltage | 3.3V to 5V DC |
Measurement Range | 2cm to 400cm (4m) |
I/O Pins Needed | 4 |
Operating Current | 15mA (typical) |
Dimensions | 45mm x 20mm x 15mm |
Frequency | 40kHz |
Accuracy | ±3mm |
Compatibility | Arduino, Raspberry Pi, Microcontrollers |
Pin Out:
Pin Number | Pin Name | Description |
1 | Vcc | The Vcc pin powers the sensor, DC3.3-5V |
2 | Trigger | Trigger pin is an Input pin. This pin has to be kept high for 10us to initialize measurement by sending US wave. |
3 | Echo | Echo pin is an Output pin. This pin goes high for a period of time which will be equal to the time taken for the US wave to return back to the sensor. |
4 | Ground | This pin is connected to the Ground of the system. |
Interfaces for HC-SR04 Ultrasonic Sensor:
| Interface | M1 | M2 | |
|---|
| GPIO (General Purpose I/O) | NC | NC | |
| I2C (Inter-Integrated Circuit) | NC | R8 | |
| UART (Universal Asynchronous Receiver-Transmitter) | R7 | NC | |
| 1-WIRE | R7 | R8 | |
| Interface | Usage | Connection | Description |
|---|
| GPIO (General Purpose I/O) | Digital signal output for distance measurement. | Connect Trigger Pin to a digital output pin and Echo Pin to a digital input pin of the microcontroller. | Used for triggering the sensor and reading the echo for distance calculation. |
| I2C (Inter-Integrated Circuit) | Allows communication with multiple devices over two wires (SDA and SCL). | Connect SDA and SCL to the respective pins on your microcontroller with pull-up resistors (typically 4.7kΩ). | Enables communication with multiple devices on the same bus using just two wires. |
| UART (Universal Asynchronous Receiver-Transmitter) | Serial communication for sending and receiving data. | Connect TX to RX and RX to TX of the microcontroller (with voltage level shifting if necessary). | Used for serial communication to transmit or receive data to/from the sensor. |
| 1-WIRE | A single-wire interface for multiple device communication. | Connect the data line to the Trigger Pin with a pull-up resistor (typically 4.7kΩ) to the supply voltage. | Allows communication between multiple devices over a single wire. |
Wiring and Resistor Configuration:
| Interface | Resistor Configuration | Description |
|---|
| GPIO (General Purpose I/O) | Echo Pin: 1kΩ resistor in series with the Echo Pin (if interfacing with a 3.3V system). | Ensures safe voltage level for the microcontroller (e.g., Arduino with 5V logic). |
| I2C (Inter-Integrated Circuit) | SDA/SCL Lines: 4.7kΩ pull-up resistors on both the SDA and SCL lines. | Required for proper I2C communication to ensure signal integrity. |
| UART (Universal Asynchronous Receiver-Transmitter) | TX/RX Lines: Level shifting may be required if interfacing with a 3.3V system. Use a voltage divider (typically 1kΩ and 2kΩ resistors). | Ensures the voltage levels between the HC-SR04 and microcontroller are compatible (for UART communication). |
| 1-WIRE Interface | Data Line: 4.7kΩ pull-up resistor between data line and supply voltage. | Required to ensure reliable communication over the 1-WIRE data line. |
Functionality of HC-SR04 Ultrasonic Sensor:
Distance Measurement: The HC-SR04 sensor uses ultrasonic sound waves to measure the distance to an object. The sensor emits a pulse via the Trigger Pin. The pulse travels, hits an object, and returns to the sensor, which detects it through the Echo Pin. The time taken for the echo to return is proportional to the distance.
Applications:
- Robotics: Used for obstacle avoidance and navigation in robots.
- Automation: Implemented for liquid level sensing and distance measurement in industrial systems.
- Security Systems: Ideal for motion detection and intruder alerts.
- Parking Sensors: Commonly used in automated parking systems for distance measurements.
- Measuring and Mapping: Helpful in 3D mapping and geolocation systems.
Drawing:
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