# Ultrasonic sensor module, JSN-SR04T, v3.3, waterproof, 3-5V

> Ultrasonic sensor module JSN-SR04T v3.3, waterproof, for contactless distance measurement, DC 3.0-5.5V supply, current

- Page: https://sigmanortec.ro/en/ultrasonic-sensor-module-jsn-sr04t-v33-waterproof-3-5v
- Price: 56.07 RON
- Availability: In stock; 1-2 zile
- Reference: 9381 · EAN: 5946649856880
- Category: Mechatronics and IoT > Sensors and Modules > Distance and Presence Sensors
- Specifications: Supply Voltage: 3; Maximum Input Voltage: 5; Input Voltage Type: “DC” in Romanian can mean **“de ce”**, which translates to **“why”** in English.
- Package (shipping data): 0.047 kg
- Updated: 2026-09-14
- Shop: [Sigmanortec.ro](https://sigmanortec.ro/en/llms.txt)
- Prices: RON, VAT included; prices and stock as of 2026-10-22 05:21 (Europe/Bucharest)

## Description

Waterproof ultrasonic module for non-contact distance measurement, ideal for automation, level monitoring and object detection in wet or dusty environments. It operates at 3-5V, offers stable measurement between 21 and 500 cm with fine resolution, has temperature compensation and improved filtering for better accuracy. Easily compatible with Arduino, ESP32, STM32 via TRIG and ECHO.
JSN-SR04T V3.3 is an ultrasonic module for contactless distance measurement, designed for industrial applications, automation, level monitoring, object detection, and microcontroller projects. Version V3.3 brings significant improvements such as temperature compensation for increased accuracy, filtering of same-frequency interference for a cleaner and more stable signal, optimization of interference generated by the flyback DCDC source, and the possibility to adjust the measurement angle for different scenarios.
The product is equipped with an integrated, sealed, and waterproof ultrasonic probe, making it suitable for wet or challenging environments. The module offers stable measurement, low power consumption, compact size, and good compatibility with most microcontrollers on the market. The detection range is approximately 21 to 500 cm, with 1 mm resolution and high accuracy when used correctly.
From the factory, the module is set to Mode 0, which means pulse width output, and in this mode it is used very similarly to a classic HC-SR04. A pulse is sent on the TRIG pin, and the duration of the returned pulse is read on the ECHO pin. Distance is calculated in the same way, making integration very simple in Arduino, ESP32, STM32, or other embedded platform projects. The main difference from a classic HC-SR04 is that this model is waterproof, has a larger minimum measurement zone of about 20-21 cm, and can also operate in UART or switch modes.
It is a very good choice for liquid level measurement applications, smart systems, presence detection, industrial automation, robotics, and monitoring in humid or dusty spaces.
Specifications:
Power supply voltage: DC 3.0-5.5 V
Operating current: <8 mA
Probe frequency: 40 kHz
Measurement range: 21-500 cm
Minimum distance: 20 cm
Maximum distance: 500 cm
Accuracy at long distance: ±1 cm
Declared accuracy for version V3.3: up to 3 mm under certain conditions
Resolution: 1 mm
Measurement angle: 75 degrees
Trigger signal: TTL pulse over 10 us or serial command 0x55
Output signal: pulse width, TTL, UART, or switch output depending on mode
Connections: VCC, TRIG/RX, ECHO/TX, GND
Operating temperature: -20°C to +70°C
Probe type: integrated, sealed, waterproof
Module dimensions: 42 x 29 x 12 mm
Operating modes:
Jumpers are made directly on the board, in the area marked M1 / M2 / M3, by closing the contact between the common pad and the desired mode pad. The MODE jumper is soldered to set the M1, M2, and M3 modes which have 47K, 120K, and 470K resistors inserted on the PCB. For example, for M2, the MODE jumper and M2 jumper are soldered.
Mode
Mode selection
Output
Notes
Mode 0
Mode floating
Pulse width output
Default factory mode, similar to HC-SR04
Mode 1
M1 short or 47K
UART automatic output
Automatic periodic transmission on TX
Mode 2
M2 short or 120K
UART controlled output
Triggered by 0x55 command on RX
Mode 3
M3 short or 470K
Switch output
Digital output based on preset threshold
Connection:
Module Pin
Connection
Role in Mode 0
Role in UART modes
VCC
3.0-5.5 V
Module power supply
GND
Common ground
TRIG / RX
Digital output pin from microcontroller
Receives trigger pulse of minimum 10 us
Receives serial data or 0x55 command in Mode 2
ECHO / TX
Digital input pin to microcontroller
Sends ECHO pulse proportional to distance
Sends serial data with measured distance
MODE
Common mode selection pad
Left open for Mode 0
Connected by jumper to M1, M2, or M3 to select mode
M1
Selection pad
Not used in Mode 0
MODE-M1 jumper for automatic UART
M2
Selection pad
Not used in Mode 0
MODE-M2 jumper for controlled UART
M3
Selection pad
Not used in Mode 0
MODE-M3 jumper for switch output
Usage:
The module is used for contactless distance measurement in automation applications, liquid level monitoring, object detection, robotics, and embedded systems. In the factory configuration, the sensor operates in Mode 0 with pulse width output, similar to a classic HC-SR04. It is powered at 3.0-5.5 V, a pulse of at least 10 us is applied on the TRIG pin, and the duration of the returned pulse is read on the ECHO pin, proportional to the measured distance. Distance calculation can be done with the formula time (us) / 58 = cm. For stable measurements, an interval greater than 60 ms between two consecutive readings is recommended.
The selection of operating modes is done directly on the PCB, in the area marked MODE, M1, M2, and M3. For the default Mode 0, the MODE pad remains open. For the other modes, a solder jumper is made between the common MODE pad and the desired mode pad. Thus, MODE-M1 activates automatic UART output, MODE-M2 activates controlled UART output, and MODE-M3 activates switch output mode. The board also has series resistors for mode selection, with M1 corresponding to 47K, M2 to 120K, and M3 to 470K. Only one mode can be selected at a time.
In automatic UART mode, the sensor measures periodically and automatically transmits the distance value on the TX pin. In controlled UART mode, each measurement is initiated by sending the 0x55 command on the RX pin, and the result is subsequently sent on TX. In switch mode, the ECHO output changes state depending on the preset threshold, useful for simple presence or proximity detection. To control a relay, an external transistor stage is necessary since the output does not have direct driving capability.
For correct results, the sensor must be mounted stably, properly oriented towards the measurement surface, and used outside the minimum zone of approximately 20-21 cm. The waterproof design and improved interference filtering make the module suitable for wet or challenging environments.
Arduino Example:
Test code in the adjacent section.
JSN-SR04T V3.3 Module Pin
Arduino Uno Pin
Role
VCC
5V
Module power supply
GND
Common ground
TRIG
D9
Measurement trigger
ECHO
D8
ECHO pulse reading
MODE
open
No jumper in factory mode
M1
open
Not connected
M2
open
Not connected
M3
open
Not connected