I am trying to use GPIO pin to get input from the sensonr, after connecting the sensor I noticed I have a lot of noise ( fluctuating signals between 0 and one). After further troubleshooting I noticed some abnoral phonamena. My Raspberry Pi input pin shows constant "1" input when nothing is connected to the pin, however as soon as I connec a jumper wire to the pin ( currently using GPIO pin 27, but I test this with other pins like GPIO 20 and GPIO21 with the same result) input signal keeps fluctuating between 0 and 1.) I also moved the Raspberry pi to different location in case I was getting this signal from nearby cable and it didnt help.
Here is the code that I am using with different output,if I remove the jumper wire I get the first plot ( which means there is no noise), and as soon as I connect the jumper wire I get the second plot. Anyone has any idea why this is happening? Is my raspberry pi damaged? I have done this before and didnt have this issue.
from datetime import datetime import matplotlib.pyplot as pyplot import RPi.GPIO as GPIO RECEIVED_SIGNAL = [, ] #[[time of reading], [signal reading]] MAX_DURATION = 15 RECEIVE_PIN = 27 if __name__ == '__main__': GPIO.setmode(GPIO.BCM) GPIO.setup(RECEIVE_PIN, GPIO.IN) cumulative_time = 0 beginning_time = datetime.now() print ('**Started recording**') while cumulative_time < MAX_DURATION: time_delta = datetime.now() - beginning_time RECEIVED_SIGNAL.append(time_delta) print(GPIO.input(RECEIVE_PIN)) RECEIVED_SIGNAL.append(GPIO.input(RECEIVE_PIN)) cumulative_time = time_delta.seconds print ('**Ended recording**') print (len(RECEIVED_SIGNAL), 'samples recorded') GPIO.cleanup() print ('**Processing results**') for i in range(len(RECEIVED_SIGNAL)): RECEIVED_SIGNAL[i] = RECEIVED_SIGNAL[i].seconds + RECEIVED_SIGNAL[i].microseconds/1000000.0 print ('**Plotting results**') pyplot.plot(RECEIVED_SIGNAL, RECEIVED_SIGNAL) pyplot.axis([0, MAX_DURATION, -1, 2]) pyplot.show()