The AJ-SR04M is commonly used in:
Distance (cm) = (Echo pulse width in µs) / 58.0 Distance (mm) = (Echo pulse width in µs) / 5.8
The is a rugged, waterproof ultrasonic ranging module often used as a more durable alternative to the popular HC-SR04. It features a separate waterproof probe connected by a cable, allowing the main control board to stay dry while the sensor works in harsh or wet environments. Core Specifications aj sr04m datasheet
The AJ-SR04M has a . This means the effective detection area is a cone:
// Add 1kΩ resistor from Echo to ESP32 pin, and 2kΩ from pin to GND. // Then code same as Arduino but use pulseIn() or interrupts. The AJ-SR04M is commonly used in: Distance (cm)
| Parameter | Conditions | Value | |-----------|------------|-------| | Supply voltage | Absolute max | 5.5V | | Supply voltage | Operating | 4.5V – 5.5V | | Logic input low | Trig, EN | < 0.8V | | Logic input high | Trig, EN | > 2.0V (3.3V compatible) | | Echo output low | IOL = 2mA | < 0.4V | | Echo output high | IOH = 2mA | > 4.0V (5V logic) | | Output impedance | - | 100 Ω |
This concludes the expanded technical reference for the AJ-SR04M. For the exact manufacturer's datasheet, please search the web for the PDF using the model number. Always refer to the official document for production designs. This means the effective detection area is a
The datasheet specifies ±1% accuracy at 20°C. However, sound speed changes with temperature: