PRE2017 3 11 Python Code

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(Makes Cylinders and platform move if the correct code is presented)
 
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__NOTOC__
__NOTOC__
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==QR scanner with cylinder and platform response==
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==Main Code==
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The main script scans QR codes in front of the camera, opens the cylinder and moves the platform down if a correct code is presented.
===Import required packages===
===Import required packages===
<pre>
<pre>
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imgname = "image2.jpg"  # File frame is temporarily saved in
imgname = "image2.jpg"  # File frame is temporarily saved in
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</pre>
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===Imports access codes===
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<pre>
# Imports allowed QRcodes
# Imports allowed QRcodes
passcodelist = []
passcodelist = []
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</pre>
</pre>
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===Opens/closes the cylinder and moves down the platform===
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 +
<pre>
if rightcode:
if rightcode:
servo1.ChangeDutyCycle(s1right) # Cylinders open
servo1.ChangeDutyCycle(s1right) # Cylinders open
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     servo2.ChangeDutyCycle(s2center) # Platform stops moving
     servo2.ChangeDutyCycle(s2center) # Platform stops moving
print("Platform stopped moving down, new code can be scanned")
print("Platform stopped moving down, new code can be scanned")
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</pre>
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 +
==Calibrator==
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In order to make sure that the servos rotated exactly long enough, a python script was written which starts and stops the servos on the press of a button:
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 +
<pre>
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import RPi.GPIO as GPIO # GPIO pin control
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import signal # Cleanup when ending script
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 +
# Releases pins when script is interrupted
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def end_run(signal,frame):
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global running
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print("Ctrl+C captured, ending script")
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running = False
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servo1.stop()
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servo2.stop()
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GPIO.cleanup()
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# Runs end_run if ctrl+C is clicked
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signal.signal(signal.SIGINT, end_run)
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 +
pin_s1  = 29 # Continuous servo 1
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pin_s2  = 33            # Continuous servo 2
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freq = 50 # Continuous servo frequency [Hz]
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 +
s1left  = 5.00        # 100% velocity to left
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s1center = 6.70        # no movement
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s1right  = 8.00        # 100% velocity to right
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 +
s2left  = 5.00        # 100% velocity to left
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s2center = 6.60        # no movement
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s2right  = 8.00        # 100% velocity to right
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 +
GPIO.setmode(GPIO.BOARD)
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GPIO.setup(pin_s1,GPIO.OUT)
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GPIO.setup(pin_s2,GPIO.OUT)
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servo1 = GPIO.PWM(pin_s1,freq)
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servo2 = GPIO.PWM(pin_s2,freq)
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servo1.start(s1center) # Starts servos in neutral position
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servo2.start(s2center)
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running = True
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print("1(l,c,r), 2(l,c,r): ")
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while running:
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    n = raw_input()
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    if n == "1l":
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        servo1.ChangeDutyCycle(s1left)
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    elif n == "1c":
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        servo1.ChangeDutyCycle(s1center)
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    elif n == "1r":
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        servo1.ChangeDutyCycle(s1right)
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    elif n == "2l":
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        servo2.ChangeDutyCycle(s2left)
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    elif n == "2c":
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        servo2.ChangeDutyCycle(s2center)
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    elif n == "2r":
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        servo2.ChangeDutyCycle(s2right)
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</pre>
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 +
==Platform Resetter==
 +
After the storage box is emptied, the platform has to move back up, which is done with the following python code:
 +
 +
<pre>
 +
import RPi.GPIO as GPIO        # GPIO pin control
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import time
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import signal # Cleanup when ending script
 +
 +
# Releases pins when script is interrupted
 +
def end_run(signal,frame):
 +
print("Ctrl+C captured, ending script")
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servo2.stop()
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GPIO.cleanup()
 +
 +
# Runs end_run if ctrl+C is clicked
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signal.signal(signal.SIGINT, end_run)
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 +
 +
pin_s2  = 33            # Continuous servo 2
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freq = 50        # Continuous servo frequency [Hz]
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 +
s2left  = 5.00        # 100% velocity to left
 +
 +
platformdelay = 4.25    # Time it takes for platform to move down
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 +
GPIO.setmode(GPIO.BOARD)
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GPIO.setup(pin_s2, GPIO.OUT)
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servo2 = GPIO.PWM(pin_s2, freq)
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servo2.start(s2left)
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time.sleep(platformdelay)
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servo2.stop()
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GPIO.cleanup()
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 +
</pre>
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 +
==Cylinder Resetter==
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If any failures occur when the cylinder is opened, this script can be activated to close the cylinder:
 +
 +
<pre>
 +
import RPi.GPIO as GPIO        # GPIO pin control
 +
import time              # Posibility to delay
 +
import signal # Cleanup when ending script
 +
 +
pin_s1  = 29 # Continuous servo 1
 +
freq = 50        # Continuous servo frequency [Hz]
 +
 +
s1left  = 5.00        # 100% velocity to left
 +
s1center = 6.70        # no movement
 +
s1right  = 8.00        # 100% velocity to right
 +
 +
cyldelay      = 1.35 # Time it takes for cylinder to rotate
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 +
# Releases pins when script is interrupted
 +
def end_run(signal,frame):
 +
global running
 +
print("Ctrl+C captured, ending script")
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running = False
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servo1.stop()
 +
servo2.stop()
 +
GPIO.cleanup()
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 +
# Runs end_run if ctrl+C is clicked
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signal.signal(signal.SIGINT, end_run)
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 +
GPIO.setmode(GPIO.BOARD)    # Board numbering sceme pins
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GPIO.setup(pin_s1, GPIO.OUT) # Sets pins as output
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servo1 = GPIO.PWM(pin_s1, freq) # Assigns frequency to pins
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servo1.start(s1left) # Starts servos in neutral position
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time.sleep(cyldelay)
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servo1.stop()
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GPIO.cleanup()
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 +
</pre>

Current revision as of 12:37, 2 April 2018

QR scanner with cylinder and platform response

The main script scans QR codes in front of the camera, opens the cylinder and moves the platform down if a correct code is presented.

Import required packages

#!/usr/bin/python
from pyzbar.pyzbar import decode	# QR reader
from PIL import Image               	# Image reader
import cv2                     		# Image reader
import RPi.GPIO as GPIO    	     	# GPIO pin control
import time               	 	# Posibility to delay
import signal				# Cleanup when ending script
import sys				# Needed to stop script if no camera

Set up constants

pin_s1  = 29		# Continuous servo 1
pin_s2  = 33            # Continuous servo 2
freq 	= 50        	# Continuous servo frequency [Hz]

s1left   = 5.00         # 100% velocity to left
s1center = 6.70         # no movement
s1right  = 8.00         # 100% velocity to right

s2left   = 5.00         # 100% velocity to left
s2center = 6.60         # no movement
s2right  = 8.00         # 100% velocity to right

cyldelay      = 2 	# Time it takes for cylinder to rotate
dropdelay     = 5    	# Time it takes to drop package
pauzedelay    = 2 	# Time between cylinder rotation and platform movement
platformdelay = 2     	# Time it takes for platform to move down

imgname = "image2.jpg"  # File frame is temporarily saved in

Imports access codes

# Imports allowed QRcodes
passcodelist = []
with open("authcodes") as file:
	passcodelist = [line.strip() for line in file]

Stops the script safely if CTRL+C is pressed

# Releases pins when script is interrupted
def end_run(signal,frame):
	global running
	print("Ctrl+C captured, ending script")
	running = False
	servo1.stop()
	servo2.stop()
	GPIO.cleanup()

# Runs end_run if ctrl+C is clicked
signal.signal(signal.SIGINT, end_run)

Takes a picture with the camera

# Takes picture from camera, reads and evaluates QRcode
def QRscanner(passcodelist, camslot):
	camera = cv2.VideoCapture(camslot)	# Initializes camera viewer
	grabbed, im = camera.read()     	# Reads figure

Checks if a picture is taken, and if it is not, it looks for other cameras or stops the script

	if not grabbed:				# Searches for working camera
		if camslot < 5:
			camstr = "No camera connected in slot: " + str(camslot)
			print(camstr)
			camslot = camslot + 1
			return False, camslot
		else:
			print("No camera connected")
			servo1.stop()
			servo2.stop()
			GPIO.cleanup()
			sys.exit()

Reads QR-codes in the image and checks if a correct code is presented

	cv2.imwrite(imgname,im)		# Converts image to jpg
	img = Image.open(imgname)	# Reads jpg
	decodedObjects = decode(img)    # Decodes image
	for obj in decodedObjects:     	# Makes sure every code is read
	   	qrdata = obj.data       # Reads the alphanumerical code
		for passcode in passcodelist:
    			if passcode in qrdata:      # Verifies if code is legit
				print("Correct code, cylinders start opening")
        			return True, camslot
			else:
				print("Wrong code")
	return False, camslot

Sets up the output pins that control the servos

GPIO.setmode(GPIO.BOARD)    	# Board numbering sceme pins
GPIO.setup(pin_s1, GPIO.OUT)	# Sets pins as output
GPIO.setup(pin_s2, GPIO.OUT)
servo1 = GPIO.PWM(pin_s1, freq)	# Assigns frequency to pins
servo2 = GPIO.PWM(pin_s2, freq)
servo1.start(s1center)		# Starts servos in neutral position
servo2.start(s2center)

Sets up variables, starts the script, and runs the QR-code reader until correct code is presented or CTRL+C is pressed

camslot = 0 		# Default camera slot
running = True
print("Program Running, provide QR-code")

while running:
	rightcode, camslot = QRscanner(passcodelist, camslot)  # Runs QR-reader

Opens/closes the cylinder and moves down the platform

	if rightcode:
		servo1.ChangeDutyCycle(s1right)	 # Cylinders open
    		time.sleep(cyldelay)             # Duration of cylinder movement
    		servo1.ChangeDutyCycle(s1center) # Cylinders stop moving
		print("Cylinders are open, package can be dropped")
    		time.sleep(dropdelay)            # Duration of package dropping
    		print("Package dropped, cylinders start closing")
		servo1.ChangeDutyCycle(s1left)  # Cylinders close
   		time.sleep(cyldelay)             # Duration of cylinder movement
    		servo1.ChangeDutyCycle(s1center) # Cylinders stop moving
		print("Cylinders are closed")
		time.sleep(pauzedelay)           # Time buffer
		print("Platform starts moving down")
		servo2.ChangeDutyCycle(s2right)   # Platform moves down
    		time.sleep(platformdelay)        # Duration of platform movement
    		servo2.ChangeDutyCycle(s2center) # Platform stops moving
		print("Platform stopped moving down, new code can be scanned")

Calibrator

In order to make sure that the servos rotated exactly long enough, a python script was written which starts and stops the servos on the press of a button:

import RPi.GPIO as GPIO	# GPIO pin control
import signal		# Cleanup when ending script

# Releases pins when script is interrupted
def end_run(signal,frame):
	global running
	print("Ctrl+C captured, ending script")
	running = False
	servo1.stop()
	servo2.stop()
	GPIO.cleanup()

# Runs end_run if ctrl+C is clicked
signal.signal(signal.SIGINT, end_run)

pin_s1  = 29		# Continuous servo 1
pin_s2  = 33            # Continuous servo 2
freq	= 50		# Continuous servo frequency [Hz]

s1left   = 5.00         # 100% velocity to left
s1center = 6.70         # no movement
s1right  = 8.00         # 100% velocity to right

s2left   = 5.00         # 100% velocity to left
s2center = 6.60         # no movement
s2right  = 8.00         # 100% velocity to right

GPIO.setmode(GPIO.BOARD)
GPIO.setup(pin_s1,GPIO.OUT)
GPIO.setup(pin_s2,GPIO.OUT)
servo1 = GPIO.PWM(pin_s1,freq)
servo2 = GPIO.PWM(pin_s2,freq)

servo1.start(s1center)		# Starts servos in neutral position
servo2.start(s2center)

running = True

print("1(l,c,r), 2(l,c,r): ")
while running:
    n = raw_input()
    if n == "1l":
        servo1.ChangeDutyCycle(s1left)
    elif n == "1c":
        servo1.ChangeDutyCycle(s1center)
    elif n == "1r":
        servo1.ChangeDutyCycle(s1right)
    elif n == "2l":
        servo2.ChangeDutyCycle(s2left)
    elif n == "2c":
        servo2.ChangeDutyCycle(s2center)
    elif n == "2r":
        servo2.ChangeDutyCycle(s2right)

Platform Resetter

After the storage box is emptied, the platform has to move back up, which is done with the following python code:

import RPi.GPIO as GPIO    	     	# GPIO pin control
import time
import signal				# Cleanup when ending script

# Releases pins when script is interrupted
def end_run(signal,frame):
	print("Ctrl+C captured, ending script")
	servo2.stop()
	GPIO.cleanup()

# Runs end_run if ctrl+C is clicked
signal.signal(signal.SIGINT, end_run)


pin_s2  = 33            # Continuous servo 2
freq 	= 50        	# Continuous servo frequency [Hz]

s2left   = 5.00         # 100% velocity to left

platformdelay = 4.25     	# Time it takes for platform to move down

GPIO.setmode(GPIO.BOARD)
GPIO.setup(pin_s2, GPIO.OUT)
servo2 = GPIO.PWM(pin_s2, freq)
servo2.start(s2left)
time.sleep(platformdelay)
servo2.stop()
GPIO.cleanup()

Cylinder Resetter

If any failures occur when the cylinder is opened, this script can be activated to close the cylinder:

import RPi.GPIO as GPIO    	     	# GPIO pin control
import time               	 	# Posibility to delay
import signal				# Cleanup when ending script

pin_s1  = 29		# Continuous servo 1
freq 	= 50        	# Continuous servo frequency [Hz]

s1left   = 5.00         # 100% velocity to left
s1center = 6.70         # no movement
s1right  = 8.00         # 100% velocity to right

cyldelay      = 1.35 	# Time it takes for cylinder to rotate

# Releases pins when script is interrupted
def end_run(signal,frame):
	global running
	print("Ctrl+C captured, ending script")
	running = False
	servo1.stop()
	servo2.stop()
	GPIO.cleanup()

# Runs end_run if ctrl+C is clicked
signal.signal(signal.SIGINT, end_run)

GPIO.setmode(GPIO.BOARD)    	# Board numbering sceme pins
GPIO.setup(pin_s1, GPIO.OUT)	# Sets pins as output
servo1 = GPIO.PWM(pin_s1, freq)	# Assigns frequency to pins
servo1.start(s1left)		# Starts servos in neutral position
time.sleep(cyldelay)
servo1.stop()
GPIO.cleanup()

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