MaxBotix MB7389-100 HRXL-MaxSonar-WRMT Outdoor Ultrasonic Sensor - PVC Housing, IP67, 30-500cm Range

The MB7389-100 provides Analog Voltage, Serial (TTL), and Pulse Width outputs simultaneously. The analog output provides a voltage scaled to distance (Vcc/512 per cm). The serial output transmits ASCII characters (e.g., 'R1234\r' for 1234 mm) via a TTL UART interface. The pulse width pin outputs a pulse with a period proportional to the measured distance. You can select the most convenient output for your microcontroller (Arduino, Raspberry Pi, PLC) without configuring the sensor.

The sensor's advanced firmware analyzes the return echo waveform and selects the largest amplitude signal within its detection zone. It ignores smaller, closer clutter, making it ideal for measuring the level of a bulk material in a bin where dust or internal structures might cause smaller echoes. If the largest target is removed, the sensor automatically switches to the next largest detectable return, ensuring continuous operation.

The sensor housing is designed with a 3/4-inch National Pipe Thread (NPT) straight thread. You can screw it directly into a compatible threaded hole or use a 3/4-inch NPT coupling or bushing for panel mounting. Ensure the O-ring seal is intact and the housing is tightened sufficiently to maintain the IP67 waterproof rating against dust and temporary immersion.

The sensor operates from a 2.7V to 5.5V DC supply. Its average current draw is very low at approximately 2.9 mA, making it suitable for battery-powered or low-power embedded systems. Ensure your power source is clean and stable, especially for the analog voltage output, which scales directly with the supply voltage (Vcc).

It features internal temperature compensation and real-time automatic calibration that adjusts for changes in temperature, humidity, supply voltage, and ambient acoustic noise. Combined with its firmware-based noise rejection algorithms, this ensures stable and accurate distance readings even in electrically noisy industrial environments or across its full -40°C to +70°C operating temperature range.