The JSN-SR04T is an industrial-grade, waterproof ultrasonic rangefinder designed for stable and accurate distance sensing in demanding environments. Unlike standard indoor sensors, it features a detached, sealed probe with a 2.5m cable, allowing the control electronics to remain protected while the sensor is exposed to moisture or outdoor conditions.

Specifications

• Operating Voltage: DC 3.0V – 5.5V
• Operating Current: < 8mA>
• Frequency: 40kHz
• Measurement Range: 20cm – 600cm
• Accuracy: ± 1cm
• Resolution: 1mm
• Measuring Angle: 75°
• Operating Temperature: -20°C to +70°C

Operating Modes (Configurable via R27 Resistor)

• Mode 1: Pulse Width Output (Default)
  • Configuration: R27 is open (not welded).
  • Operation: Functions exactly like an HC-SR04. Triggered by a 10μs high pulse on the Trig pin. The Echo pin outputs a high level for a duration proportional to the distance.
• Mode 2: Automatic Serial Output
  • Configuration: 47kΩ resistor welded at R27.
  • Operation: The module automatically performs a measurement every 100ms and transmits the data via the TX pin at 9600 baud. Data is sent in a 4-byte frame: 0xFF + High Data + Low Data + Sum.
• Mode 3: Triggered Serial Output
  • Configuration: 120kΩ resistor welded at R27.
  • Operation: The module enters standby and waits for the serial command 0x55 on the RX pin. Once received, it triggers a single measurement and returns the 4-byte data frame via the TX pin.

Features

• Industrial-Grade Probe: The integrated piezoelectric transducer is housed in a waterproof casing, making it ideal for tank level sensing and outdoor weather stations.
• Small Blind Zone: Features a detection range starting as close as 20cm with consistent stability and a long-range reach of up to 6m.
• Output Diversification: Supports both standard Pulse Width Modulation (PWM) and TTL Serial (UART) communication for compatibility with all major MCUs.
• Low Power Consumption: Drawing less than 8mA, it is highly suitable for battery-powered IoT devices and remote monitoring.
• Integrated Processing: The blue PCB control board handles the complex 40kHz signal generation and echo detection, providing simplified data to the user.

Wiring Guide

• 5V/3.3V: Positive Power Supply
• Trig (RX): Trigger Input (Mode 1) or Serial Receive (Mode 3)
• Echo (TX): Pulse Output (Mode 1) or Serial Transmit (Modes 2 & 3)
• GND: Power Ground

Common Applications

• Water Level Monitoring: Measuring levels in tanks, wells, or reservoirs.
• Automotive Sensors: Obstacle avoidance and parking assistance systems.
• Industrial Automation: Detecting object presence or height on production lines.
• Outdoor Sensing: Liquid or solid level measurement in environments exposed to moisture.

Usage Tips

• Distance Calculation (Mode 1): Distance (cm) = High Time (μs) / 58.
• Submersion Warning: The probe is waterproof for splashes and rain but is not designed to be submerged in water.
• Mounting: For accurate readings, ensure the probe is mounted perpendicular to the target surface to minimize signal loss from the 75° beam angle.