The document is a Python script for reading a capacitive sensor using a Raspberry Pi GPIO pin. It defines a function to measure the charge time of a capacitor and continuously records the maximum and minimum values of the charge time. The script uses the RPi.GPIO library for GPIO operations and includes a loop that prints the measured value along with the min and max values.

1. #!/usr/bin/env python
# Reading capacitive sensor with
# a single GPIO pin
import RPi.GPIO as GPIO, time
# Tell the GPIO library to use
# Broadcom GPIO references
GPIO.setmode(GPIO.BCM)
# Define function to measure charge time
def RCtime (RCpin):
measurement = 0
# Discharge capacitor
GPIO.setup(RCpin, GPIO.OUT)
GPIO.output(RCpin, GPIO.LOW)
time.sleep(0.1)
GPIO.setup(RCpin, GPIO.IN)
# Count loops until voltage across
# capacitor reads high on GPIO
while (GPIO.input(RCpin) == GPIO.LOW):
measurement += 1
return measurement
max=0
min=9999
# Main loop
while True:
value=RCtime(27)
if value > max:
max=value
elif value < min:
min=value
print '{0:3d} {1:3d} {2:3d}'.format(value,min,max)