HC-SR04 Ultrasonic Distance Sensor Module (Pack of 20)

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HC-SR04 ULTRASONIC DISTANCE SENSOR
(Pack of 20)
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MODEL: HC-SR04
TYPE: Ultrasonic distance sensor
MEASUREMENT RANGE: 2 cm – 400 cm
ACCURACY: ±3 mm
OPERATING VOLTAGE: 5 V DC
CURRENT CONSUMPTION: ~15 mA
OUTPUT: Digital pulse (pulse width proportional to distance)
INTERFACE: 4 pins (VCC, Trig, Echo, GND)
PACK QUANTITY: 20 units

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🔹 HOW IT WORKS:
1. **Trigger Pulse:** Microcontroller sends a 10 µs HIGH pulse to the Trig pin.
2. **Ultrasonic Burst:** Sensor emits 8-cycle 40 kHz ultrasonic burst.
3. **Echo Received:** Reflected wave returns to Echo pin.
4. **Distance Calculation:** Pulse width of Echo pin = time of flight → Distance = (Time × Speed of Sound)/2

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📌 PINOUT:
• VCC → 5 V DC supply
• Trig → Trigger input (digital output from MCU)
• Echo → Echo output (pulse width proportional to distance)
• GND → Ground

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📊 TECHNICAL SPECIFICATIONS:
• Operating Temp: -15 °C to +70 °C
• Sensing Angle: ~15° cone
• Resolution: ~0.3 cm
• Response Time: ~50 ms
• Signal Type: Digital (pulse width in microseconds)

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⚙️ MICROCONTROLLER CONNECTION:
• Works with Arduino, ESP32, Raspberry Pi, STM32
• Requires reading the Echo pulse using digital input
• Distance in cm = (pulse duration in µs) / 58
• Distance in inches = (pulse duration in µs) / 148

Example (Arduino formula):
distance_cm = pulseWidth(EchoPin) / 58.0;

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🛠️ APPLICATIONS:
• Obstacle detection for robots
• Water level measurement
• Proximity sensing
• Industrial automation
• Parking sensors
• DIY smart projects

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💡 TIPS:
• Avoid soft or angled surfaces — may reduce echo reflection
• Keep sensor perpendicular to target for best results
• Multiple sensors can be used with different Trig/Echo pins
• Ensure proper timing between consecutive measurements (~60 ms)