JSN-SR04T Waterproof Ultrasonic Distance Sensor, 25cm-4.5m, with Separate Probe

The standard HC-SR04 ultrasonic sensor works well indoors but its exposed transducers have no real protection against moisture, rain, or submersion, ruling it out for outdoor or liquid-level sensing applications. The JSN-SR04T solves exactly this problem with a fully waterproof probe connected to the main control board by a 2.5 meter cable, letting the sensing element itself be mounted in a wet or outdoor location - over a water tank, outside a building, in a humid enclosure - while the control electronics stay in a drier, more protected location.

Measurement range extends from 25cm at the near end out to 4.5 meters at the far end, a genuinely useful range for tank-level monitoring, outdoor obstacle detection, or any medium-range distance sensing task, with resolution down to 0.5cm and a detection angle under 70 degrees for reasonably focused sensing rather than a very wide, imprecise cone. Like the standard HC-SR04, it works on the same basic principle - a 10 microsecond trigger pulse sends out eight 40kHz ultrasonic pulses, and the sensor measures the time until the echo returns, converting that into distance using the known speed of sound (340 m/s).

Wiring is a simple four-connection interface (+5V, Trig, Echo, GND), matching the familiar HC-SR04 pin-out closely enough that existing HC-SR04 code and libraries often work with minimal modification. Operating current is a modest 30mA active, dropping to 5mA static, making it reasonable to run even from a lightly battery-powered outdoor monitoring setup. The probe and its full cable run are enclosed for genuine moisture resistance, not just a splash-resistant coating.

Builders working on an outdoor water tank level monitor, a weatherproof obstacle or parking sensor, or any distance-sensing application exposed to rain, humidity, or occasional submersion will find the JSN-SR04T a practical, purpose-built alternative to the common indoor-only HC-SR04.