How to use JSN-SR04T on a Raspberry Pi?

Question

I want to try out JSN-SR04T, which is an ultrasonic distance measuring module, that is also supposedly water proof. The main reason that i want to try this module over the HC-SR04, is because the JSN-SR04T is waterproof, which is what I need. Unfortunately, I am not sure how to use it on a Raspberry Pi. I am not sure how to connect it, and how to program it using Python. If someone is able to help me, on how to properly connect and program this module using python, on the Raspberry Pi, please post below, and this will help me a lot.

More Information and specifications about the module can be found here :

http://www.ebay.ca/itm/Ultrasonic-Module-Distance-Measuring-Transducer-Sensor-Perfect-Waterproof-/141728581416?hash=item20ffae8728

and

http://www.icstation.com/ultrasonic-module-sr04t-distance-measuring-transducer-sensor-p-5046.html

Thank You!

score 4 · Accepted Answer · answered Jul 29 '15 at 21:20

It has exactly the same programming interface as the HC-SR04.

You send a trigger pulse of 10µs or more on the trigger line.

Shortly after the trigger line goes low the echo line will go high. The echo line will stay high until the echo has returned (or the echo times out). The echo line high time is the time the sound took to travel to the detected object and back.

Sonar trigger and echo

The distance in centimetres may be calculated as

distance = (echo_high_time_in_µs / 1000000.0) * 17015

score 4 · Answer 2 · edited Oct 24 '22 at 12:07

The JSN-SR04T can be used pretty easily with the Raspberry Pi. The only really important thing to remember is that the electronics module is expecting to signal a time corresponding to distance using a 5V pulse. The Pi's GPIO pins are only designed to accept a 3.3V input, so we need to step the voltage down with a voltage divider.

Connection: For the sake of keeping the connecting pins together on the Pi’s GPIO block I have preferred to connect as follows;

Pin 4 connects directly to the +5V connector
Pin 6 Connects directly to the GND connector, but is incorporated into the voltage divider for the Echo pin.
Pin 8 (GPIO 14 TXD) connects to the centre of the voltage divider
Pin 10 (GPIO 15 RXD) connects directly to the Trig connector.

The following python script will get you started. save it as something (e.g. distance.py) and then run it by typing python distance.py at the command line.

 #!/usr/bin/python
#encoding:utf-8
import RPi.GPIO as GPIO                    #Import GPIO library
import time                                #Import time library
GPIO.setmode(GPIO.BCM)                     #Set GPIO pin numbering
TRIG = 15                                  #Associate pin 15 to TRIG
ECHO = 14                                  #Associate pin 14 to Echo
print "Distance measurement in progress"
GPIO.setup(TRIG,GPIO.OUT)                  #Set pin as GPIO out
GPIO.setup(ECHO,GPIO.IN)                   #Set pin as GPIO in
while True:
GPIO.output(TRIG, False)                 #Set TRIG as LOW
  print "Waiting For Sensor To Settle"
  time.sleep(2)                            #Delay of 2 seconds
GPIO.output(TRIG, True)                  #Set TRIG as HIGH
  time.sleep(0.00001)                      #Delay of 0.00001 seconds
  GPIO.output(TRIG, False)                 #Set TRIG as LOW
while GPIO.input(ECHO)==0:               #Check if Echo is LOW
    pulse_start = time.time()              #Time of the last  LOW pulse
while GPIO.input(ECHO)==1:               #Check whether Echo is HIGH
    pulse_end = time.time()                #Time of the last HIGH pulse
pulse_duration = pulse_end - pulse_start #pulse duration to a variable
distance = pulse_duration * 17150        #Calculate distance
  distance = round(distance, 2)            #Round to two decimal points
if distance > 20 and distance < 400:     #Is distance within range
    print "Distance:",distance - 0.5,"cm"  #Distance with calibration
  else:
    print "Out Of Range"                   #display out of range

When executed the sensor will settle and then start displaying the distance every two seconds.

Waitng For Sensor To Settle
Distance: 53.44 cm
Waitng For Sensor To Settle
Distance: 52.95 cm

There is more information on operation, connection and code here.

score 3 · Answer 3 · answered Sep 19 '18 at 09:44

I wanted to add an improved version of the code which uses timeouts to make sure the script doesn't hang:

import RPi.GPIO as GPIO
import os
import time

# Define GPIO to use on Pi
GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
GPIO_TRIGGER = 23
GPIO_ECHO = 24

TRIGGER_TIME = 0.00001
MAX_TIME = 0.004  # max time waiting for response in case something is missed
GPIO.setup(GPIO_TRIGGER, GPIO.OUT)  # Trigger
GPIO.setup(GPIO_ECHO, GPIO.IN, pull_up_down=GPIO.PUD_UP)  # Echo

GPIO.output(GPIO_TRIGGER, False)

# This function measures a distance


def measure():
    # Pulse the trigger/echo line to initiate a measurement
    GPIO.output(GPIO_TRIGGER, True)
    time.sleep(TRIGGER_TIME)
    GPIO.output(GPIO_TRIGGER, False)

    # ensure start time is set in case of very quick return
    start = time.time()
    timeout = start + MAX_TIME

    # set line to input to check for start of echo response
    while GPIO.input(GPIO_ECHO) == 0 and start <= timeout:
        start = time.time()

    if(start > timeout):
        return -1

    stop = time.time()
    timeout = stop + MAX_TIME
    # Wait for end of echo response
    while GPIO.input(GPIO_ECHO) == 1 and stop <= timeout:
        stop = time.time()

    if(stop <= timeout):
        elapsed = stop-start
        distance = float(elapsed * 34300)/2.0
    else:
        return -1
    return distance


if __name__ == '__main__':
    try:
        while True:
            distance = measure()
            if(distance > -1):
                print("Measured Distance = %.1f cm" % distance)
            else:
                print("#")
            time.sleep(0.5)
        # Reset by pressing CTRL + C
    except KeyboardInterrupt:
        print("Measurement stopped by User")
        GPIO.cleanup()

How to use JSN-SR04T on a Raspberry Pi?

3 Answers3