pythonraspberry-pi-zeroarduino-ultra-sonic

I want to know if I any mistakes?

I have a problem with the Jsn-sr04t water proof ultrasonic sensor, knowing that the connection in the raspberry pi zero W1 is well made becouse it is activated but the readings of this are totally wrong, the pins were entered correctly but this one seems to have a data entry error. I tried several programs in python that were used on this same sensor model

PD: I'm aware that this works, because I tested it on an arduino mega and the sensor worked correctly

import RPi.GPIO as GPIO
import os
import time

GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
GPIO_TRIGGER = 10
GPIO_ECHO = 8

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)

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

    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)

    except KeyboardInterrupt:
        print("Measurement stopped by User")
        GPIO.cleanup()

constantly OUTPUT: "#"

Solution

  • Seems like an issue with the GPIO settings or a timing issue as the same setup works with an Arduino.

    1. Try with higher trigger on time (maybe 20us)
    2. After elapsed calculation, print the elapsed time on the screen and check the actual value

    If it still doesn't work, then you can also checkout the alternate output options like serial UART, PWM, etc. You can get more details here -