Last Updated: 24/09/2021
JSN-SR04T Waterproof Ultrasonic Module
Components >> JSN-SR04T Waterproof Ultrasonic Module
JSN-SR04T Waterproof Ultrasonic Sensor
The JSN-SR04T Ultrasonic sensor is a sensor that measures distance from an object by sending out a high frequency sound that is reflected and it's return timed. A bit like timing the echo from someone clapping under a bridge.
From a coding point of view it works like the more common HC-SR04 Ultrasonic sensor but has a combined transmitter and receiver and has a seperate processing board.
The Transmitter/reveiver unit is waterproof (the circuit board it plugs into is not waterproof)., this means it can be used for measuring liquids and powders.
Please see the
HC-SR04 Ultrasonic sensor tutorial for more details on how the unit works.
JSN-SR04T Range and Issues to consider
TheJSN-SR04T is supposed to have a range of between 250mm and 4000mm (4 metres). However, certain factors need to be taken into account at both ends of this range.
Close range: In my experiemnts I managed to get the sensor to read down to about 245mm but below that it enters a sort of blind spot and will give readings of 2000 - 2500mm.
Long Range: The maximum range is quoted as 4000mm, I had no problems with readings of 2800mm but as the distance increases there are issues caused by the angle that the sensor works at as it has a much wider angle, this means the signal can bounce off objects either side of the object you are pointing the sensor at. This means positioning is important. I also noticed when looking online that there are Ultrasonic sensors that look similar that are mounted on a tube, I wonder if this is to reduce refelections from items to the side?
JSN-SR04T Ultrasonic Distance Sensor pins
The sensor has 4 pins:
VCC: 5v DC to power the sensor
Trig: (Marked RX on my Unit). The trigger pin causes a set of pulses to be sent when it is held HIGH (5v) for 10 microseconds ( a microsecond is millionth of a second), this is a very short period of time. When we blink it takes approx 350,000 microseconds ( about 1/3 of a second).
Echo: (Marked TX on my unit). This is the pin that gives us the received pulse.
Gnd: The common ground for the unit.
JSN-SR04T Ultrasonic Distance Sensor Connections
These are the pin outs for the examples
VCC: to Arduino 5V
Trig: Arduino digital pin 7
Echo: Arduino digital pin 6
Gnd: To Arduino Ground (Gnd).
JSN-SR04T Ultrasonic Distance Sensor Arduino Tutorial (Same code as HC-SR04)
All examples for the HC-SR04 work on the JSN-SR04T
Example 1: HCSR04UltrasonicDistanceSensorv1.ino
Click to Download code:HCSR04UltrasonicDistanceSensorv1.ino
New items learnt in this lesson:
pulsein() function
This code uses lessons learnt in:
Lesson2 "Hello World"
Lesson 6: Basic Numeric variables, boolean, byte, int, unsigned int, long, unsigned long
Lesson 7: delay();
Functions 1: digitalWrite();
/* HCSR04UltrasonicDistanceSensorv1
*
* Basic sketch to learn how the HC-SR04 sensor works
* The sketch works but because it uses delay() would be harder to integrate with other components or sensors.
*
* pins used
* pin 7 to Trig Pin
* pin 6 to Echo pin
*/
//const int is a constant integer that cannot have it's value changed.
const int triggerPin = 7;
const int echoPin = 6;
//An unsigned long is needed because the numbers produced can be much larger
//than an int can hold (max value 32,767)
unsigned long duration; //time taken for echo
int distance; //in mm
void setup() {
Serial.begin(9600);
Serial.println("HCSR04UltrasonicDistanceSensorv1...");
Serial.println(" ");//Blank line
//pinMode set for OUTPUT...sending HIGH of LOW
pinMode(triggerPin, OUTPUT); //sends signal
//pinMode set for INPUT, we will receive an incoming HIGH or LOW on this pin
pinMode(echoPin, INPUT); //receives signal
}
void loop() {
// Clears the trigPin condition, just in case it had been left HIGH
//Same as turing the LED off in the blink sketch
digitalWrite(triggerPin, LOW);
//A tiny delay 2 millionths of a second
delayMicroseconds(2);
// Sets the trigPin HIGH (ACTIVE) for 10 microseconds
//same as turing the LED on in the blink sketch
digitalWrite(triggerPin, HIGH);
//pin stays HIGH (5v) for 10 microseconds to trigger a pulse
delayMicroseconds(10);
//Pin taken LOW (0v) after pulse triggered ready for next pulse
digitalWrite(triggerPin, LOW);
// Reads the echoPin, returns the sound wave travel time in microseconds
//Pulse in HIGH waits for the echoPin to go HIGH (5v) and then starts a timer until it goes LOW
//At that point the HC-SR04 has received it's set of echos
duration = pulseIn(echoPin, HIGH);
// Calculating the distance
// Speed of sound wave divided by 2 as the sound travels to and from the object
distance = duration * 0.34 / 2;
// Displays the distance on the Serial Monitor
Serial.print("Distance: ");
Serial.print(distance);
Serial.println(" mm");
//wait 1 second before runing the code again
delay(1000);
}
Example 2: HCSR04UltrasonicDistanceSensorv2Function.ino
Click to Download code:HCSR04UltrasonicDistanceSensorv2Function.ino
New items learnt in this lesson:
Declaring a Local variable in a function
This sketch uses the code from example 1 and turns it into a function called by a millis() timer.
This code uses lessons learnt in:
Lesson 7: delay() v's millis(), controlling timing of programs
Lesson 9: Basics of creating and using functions
/* HCSR04UltrasonicDistanceSensorv2Function
*
* The goal of this sketch is to make the distance reading from the module into a function
* The function needs to be able to use multiple HC-SR04 modules if needed (front and rear)
* Basic sketch to learn how the HC-SR04 sensor works
*
* pins used
* pin 7 to Trig Pin
* pin 6 to Echo pin
*/
//const int is a constant integer that cannot have it's value changed.
const int triggerPin = 7;
const int echoPin = 6;
//Global Variable
unsigned long sensorTimer1;
//Function to trigger a sensor
//It receives the pins of the sensor and send back the distance
int getDistanceHCSSR04(int funcTriggerPin, int funcEchoPin){
//An unsigned long is needed because the numbers produced can be much larger
//than an int can hold (max value 32,767)
//Local variables
unsigned long duration; //time taken for echo
int myDistance;
digitalWrite(funcTriggerPin, LOW);
//A tiny delay 2 millionths of a second
delayMicroseconds(2);
// Sets the trigPin HIGH (ACTIVE) for 10 microseconds
//same as turing the LED on in the blink sketch
digitalWrite(funcTriggerPin, HIGH);
//pin stays HIGH (5v) for 10 microseconds to trigger a pulse
delayMicroseconds(10);
//Pin taken LOW (0v) after pulse triggered ready for next pulse
digitalWrite(funcTriggerPin, LOW);
duration = pulseIn(funcEchoPin, HIGH);
myDistance = duration * 0.34 / 2;
return myDistance;
}
void setup() {
Serial.begin(9600);
Serial.println("HCSR04UltrasonicDistanceSensorv2Function...");
Serial.println(" ");//Blank line
//pinMode set for OUTPUT...sending HIGH of LOW
pinMode(triggerPin, OUTPUT); //sends signal
//pinMode set for INPUT, we will receive an incoming HIGH or LOW on this pin
pinMode(echoPin, INPUT); //receives signal
}
void loop() {
//Local variable
int distance; //in mm
if(millis() > sensorTimer1){
sensorTimer1 = millis() + 1000;
distance = getDistanceHCSSR04(triggerPin,echoPin);
// Displays the distance on the Serial Monitor
Serial.print("Distance: ");
Serial.print(distance);
Serial.println(" mm");
}
}
Example 3: HCSR04UltrasonicDistanceSensorv3Function.ino
Click to Download code:HCSR04UltrasonicDistanceSensorv3Function.ino
This sketch shows how the function is called by three seperate HC-SR04 modules at independant times controlled by millis()
This code uses lessons learnt in:
Lesson 7: delay() v's millis(), controlling timing of programs
Lesson 9: Basics of creating and using functions
/* HCSR04UltrasonicDistanceSensorv3Function
*
* The goal of this sketch is to use multiple HC-SR04 modules triggering at independant intervals
*
* pins used
* pin 7 to Trig Pin...sensor 1
* pin 6 to Echo pin...sensor 1
* pin 5 Trig pin...sensor 2
* pin 4 Echo pin...sensor 2
* pin 3 Trig pin...sensor 3
* pin 2 Echo pin...sensor 3
*/
//Global Variables
//const int is a constant integer that cannot have it's value changed.
const int triggerPin = 7;
const int echoPin = 6;
const int triggerPin2 = 5;
const int echoPin2 = 4;
const int triggerPin3 = 3;
const int echoPin3 = 2;
//the three timers
unsigned long sensorTimer1;
unsigned long sensorTimer2;
unsigned long sensorTimer3;
//Function to trigger a sensor
//It receives the pins of the sensor and send back the distance
int getDistanceHCSSR04(int funcTriggerPin, int funcEchoPin){
//An unsigned long is needed because the numbers produced can be much larger
//than an int can hold (max value 32,767)
//Local Variables
unsigned long duration; //time taken for echo
int myDistance;
digitalWrite(funcTriggerPin, LOW);
//A tiny delay 2 millionths of a second
delayMicroseconds(2);
// Sets the trigPin HIGH (ACTIVE) for 10 microseconds
//same as turing the LED on in the blink sketch
digitalWrite(funcTriggerPin, HIGH);
//pin stays HIGH (5v) for 10 microseconds to trigger a pulse
delayMicroseconds(10);
//Pin taken LOW (0v) after pulse triggered ready for next pulse
digitalWrite(funcTriggerPin, LOW);
duration = pulseIn(funcEchoPin, HIGH);
myDistance = duration * 0.34 / 2;
return myDistance;
}
void setup() {
Serial.begin(9600);
Serial.println("HCSR04UltrasonicDistanceSensorv3Function...");
Serial.println(" ");//Blank line
//pinMode set for OUTPUT...sending HIGH of LOW
pinMode(triggerPin, OUTPUT); //sends signal
//pinMode set for INPUT, we will receive an incoming HIGH or LOW on this pin
pinMode(echoPin, INPUT); //receives signal
//more pinModes for 2 more sensors
pinMode(triggerPin2, OUTPUT); //sends signal
pinMode(echoPin2, INPUT); //receives signal
pinMode(triggerPin3, OUTPUT); //sends signal
pinMode(echoPin3, INPUT); //receives signal
}
void loop() {
//Local variable
int distance; //in mm
if(millis() > sensorTimer1){
sensorTimer1 = millis() + 1600;
distance = getDistanceHCSSR04(triggerPin,echoPin);
// Displays the distance on the Serial Monitor
Serial.print(" Sensor 1 Distance: ");
Serial.print(distance);
Serial.println(" mm");
}
if(millis() > sensorTimer2){
sensorTimer2 = millis() + 1500;
//different set of pins passed to function
distance = getDistanceHCSSR04(triggerPin2,echoPin2);
// Displays the distance on the Serial Monitor
Serial.print(" Sensor 2 Distance: ");
Serial.print(distance);
Serial.println(" mm");
}
if(millis() > sensorTimer3){
sensorTimer3 = millis() + 1400;
//different set of pins passed to function
distance = getDistanceHCSSR04(triggerPin3,echoPin3);
// Displays the distance on the Serial Monitor
Serial.print(" Sensor 3 Distance: ");
Serial.print(distance);
Serial.println(" mm");
}
}
Example 4: HCSR04UltrasonicDistanceSensorv4Function.ino
Click to Download code:HCSR04UltrasonicDistanceSensorv4Function.ino
This sketch reads from 3 sensors in sequence at a specified time controlled by a millis() timer.
This code uses lessons learnt in:
Lesson 5: using switch() to control code
Lesson 7: delay() v's millis(), controlling timing of programs
Lesson 9: Basics of creating and using functions
/* HCSR04UltrasonicDistanceSensorv4Function
The goal of this sketch is to use multiple HC-SR04 modules triggered in Order
pins used
pin 7 to Trig Pin...sensor 1
pin 6 to Echo pin...sensor 1
pin 5 Trig pin...sensor 2
pin 4 Echo pin...sensor 2
pin 3 Trig pin...sensor 3
pin 2 Echo pin...sensor 3
*/
//Global Variables
//const int is a constant integer that cannot have it's value changed.
const int triggerPin = 7;
const int echoPin = 6;
const int triggerPin2 = 5;
const int echoPin2 = 4;
const int triggerPin3 = 3;
const int echoPin3 = 2;
//nextsensor keeps a record of which sensor to trigger next
int nextSensor = 0;
unsigned long sensorTimer1;
//Function to trigger a sensor
//It receives the pins of the sensor and send back the distance
int getDistanceHCSSR04(int funcTriggerPin, int funcEchoPin) {
//An unsigned long is needed because the numbers produced can be much larger
//than an int can hold (max value 32,767)
//Local Variables
unsigned long duration; //time taken for echo
int myDistance;
digitalWrite(funcTriggerPin, LOW);
//A tiny delay 2 millionths of a second
delayMicroseconds(2);
// Sets the trigPin HIGH (ACTIVE) for 10 microseconds
//same as turing the LED on in the blink sketch
digitalWrite(funcTriggerPin, HIGH);
//pin stays HIGH (5v) for 10 microseconds to trigger a pulse
delayMicroseconds(10);
//Pin taken LOW (0v) after pulse triggered ready for next pulse
digitalWrite(funcTriggerPin, LOW);
duration = pulseIn(funcEchoPin, HIGH);
myDistance = duration * 0.34 / 2;
return myDistance;
}
void setup() {
Serial.begin(9600);
Serial.println("HCSR04UltrasonicDistanceSensorv4Function...");
Serial.println(" ");//Blank line
//pinMode set for OUTPUT...sending HIGH of LOW
pinMode(triggerPin, OUTPUT); //sends signal
//pinMode set for INPUT, we will receive an incoming HIGH or LOW on this pin
pinMode(echoPin, INPUT); //receives signal
//more pinModes for 2 more sensors
pinMode(triggerPin2, OUTPUT); //sends signal
pinMode(echoPin2, INPUT); //receives signal
pinMode(triggerPin3, OUTPUT); //sends signal
pinMode(echoPin3, INPUT); //receives signal
}
void loop() {
//Local variable
int distance; //in mm
//A single millis() timer loop
if (millis() > sensorTimer1) {
sensorTimer1 = millis() + 500;
//A switch statement to decide which sensor to trigger next
switch (nextSensor) {
case 1:
distance = getDistanceHCSSR04(triggerPin2, echoPin2);
Serial.print(" Sensor 2 Distance: ");
Serial.print(distance);
Serial.println(" mm");
break;
case 2:
distance = getDistanceHCSSR04(triggerPin3, echoPin3);
Serial.print(" Sensor 3 Distance: ");
Serial.print(distance);
Serial.println(" mm");
break;
default:
distance = getDistanceHCSSR04(triggerPin, echoPin);
Serial.print(" Sensor 1 Distance: ");
Serial.print(distance);
Serial.println(" mm");
break;
}
//increment the vale of nextSensor so that the next sensor will be selected next time round
nextSensor++;
//If the value is greater than 2 got back to sensor 0
if (nextSensor > 2) {
nextSensor = 0;
}
}
}
Additional Resource Links
How to use an HC-SR04 Ultrasonic Distance Sensor with Arduino
Ultrasonic Sensor HC-SR04 and Arduino Tutorial
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