PRE2017 3 11 Python Code

From Control Systems Technology Group

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 +
__NOTOC__
 +
==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===
<pre>
<pre>
-
import RPi.GPIO as GPIO     # GPIO pin control
+
#!/usr/bin/python
-
import time                 # Posibility to delay
+
from pyzbar.pyzbar import decode # QR reader
-
GPIO.setmode(GPIO.BOARD)    # Board numbering sceme
+
from PIL import Image              # Image reader
-
pin_cServo1 = 29            # Continuous servo 1
+
import cv2                    # Image reader
-
pin_cServo2 = 33            # Continuous servo 2
+
import RPi.GPIO as GPIO       # GPIO pin control
-
pin_cServo3 = 37            # Continuous servo 3
+
import time               # Posibility to delay
-
pin_mServo1 = 13            # Mini servo 1
+
import signal # Cleanup when ending script
 +
import sys # Needed to stop script if no camera
 +
</pre>
-
# Sets pin as output.
+
===Set up constants===
-
GPIO.setup(cServo1,GPIO.OUT)
+
-
GPIO.setup(cServo2,GPIO.OUT)
+
-
GPIO.setup(cServo3,GPIO.OUT)
+
-
GPIO.setup(mServo1,GPIO.OUT)
+
-
freq = 100                  # Servo frequency [Hz]
+
<pre>
 +
pin_s1  = 29 # Continuous servo 1
 +
pin_s2  = 33            # Continuous servo 2
 +
freq = 50        # Continuous servo frequency [Hz]
-
# Assigns frequency to pins
+
s1left  = 5.00        # 100% velocity to left
-
cServo1 = GPIO.PWM(pin_cServo1, freq)  
+
s1center = 6.70        # no movement
-
cServo2 = GPIO.PWM(pin_cServo2, freq)
+
s1right  = 8.00        # 100% velocity to right
-
cServo3 = GPIO.PWM(pin_cServo3, freq)
+
 
-
mServo1 = GPIO.PWM(pin_mServo1, freq)
+
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
 +
</pre>
 +
===Imports access codes===
 +
<pre>
 +
# Imports allowed QRcodes
 +
passcodelist = []
 +
with open("authcodes") as file:
 +
passcodelist = [line.strip() for line in file]
 +
</pre>
 +
 
 +
===Stops the script safely if CTRL+C is pressed===
 +
 
 +
<pre>
 +
# 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)
 +
</pre>
 +
 
 +
===Takes a picture with the camera===
 +
 
 +
<pre>
 +
# 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
 +
</pre>
 +
 
 +
===Checks if a picture is taken, and if it is not, it looks for other cameras or stops the script===
 +
 
 +
<pre>
 +
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()
 +
</pre>
 +
 
 +
===Reads QR-codes in the image and checks if a correct code is presented===
 +
 
 +
<pre>
 +
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
 +
</pre>
 +
 
 +
===Sets up the output pins that control the servos===
 +
 
 +
<pre>
 +
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)
 +
</pre>
 +
 
 +
===Sets up variables, starts the script, and runs the QR-code reader until correct code is presented or CTRL+C is pressed===
 +
 
 +
<pre>
 +
camslot = 0 # Default camera slot
 +
running = True
 +
print("Program Running, provide QR-code")
 +
 
 +
while running:
 +
rightcode, camslot = QRscanner(passcodelist, camslot)  # Runs QR-reader
 +
</pre>
 +
 
 +
===Opens/closes the cylinder and moves down the platform===
 +
 
 +
<pre>
 +
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")
 +
</pre>
 +
 
 +
==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:
 +
 
 +
<pre>
 +
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)
 +
</pre>
 +
 
 +
==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
 +
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()
 +
 
 +
</pre>
 +
 
 +
==Cylinder Resetter==
 +
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
-
cleft  = 5            # 100% velocity to left
+
pin_s1  = 29 # Continuous servo 1
-
ccenter = 7.5          # no movement
+
freq = 50        # Continuous servo frequency [Hz]
-
cright  = 10            # 100% velocity to right
+
-
mleft   = 5             # 90 degrees left
+
s1left   = 5.00        # 100% velocity to left
-
mcenter = 7.5          # center
+
s1center = 6.70        # no movement
-
mright = 10            # 90 degrees right
+
s1right = 8.00        # 100% velocity to right
-
cyldelay       = 2    # Time it takes for cylinder to rotate
+
cyldelay     = 1.35 # Time it takes for cylinder to rotate
-
dropdelay      = 15    # Time it takes to drop package
+
-
platformdelay  = 2    # Time it takes for platform to move down
+
-
lockdelay      = 20    # Time lock stays opened
+
-
# Sets all servos still at centered position
+
# Releases pins when script is interrupted
-
cServo1.start(ccenter)
+
def end_run(signal,frame):
-
cServo2.start(ccenter)
+
global running
-
cServo3.start(ccenter)
+
print("Ctrl+C captured, ending script")
-
mServo1.start(mcenter)
+
running = False
 +
servo1.stop()
 +
servo2.stop()
 +
GPIO.cleanup()
-
if i=true:
+
# Runs end_run if ctrl+C is clicked
-
    cServo1.ChangeDutyCycle(cleft)      # Inner cylinder opens
+
signal.signal(signal.SIGINT, end_run)
-
    cServo2.ChangeDutyCycle(cright)     # Outer cylinder moves away
+
-
    time.delay(cyldelay)                # Duration of cylinder movement
+
-
    cServo1.ChangeDutyCycle(ccenter)    # Inner Cylinder stops moving
+
-
    cServo2.ChangeDutyCycle(ccenter)    # Outer Cylinder stops moving
+
-
    time.delay(dropdelay)              # Duration of package dropping
+
-
    cServo1.ChangeDutyCycle(cright)    # Inner cylinder closes
+
-
    cServo2.ChangeDutyCycle(cleft)      # Outer cylinder moves back
+
-
    time.delay(cyldelay)                # Duration of cylinder movement
+
-
    cServo1.ChangeDutyCycle(ccenter)
+
-
    cServo2.ChangeDutyCycle(ccenter) 
+
-
   
+
-
    cServo3.ChangeDutyCycle(cleft)      # Platform moves down
+
-
    time.delay(platformdelay)          # Duration of platform moving down
+
-
    cServo3.ChangeDutyCycle(ccenter)    # Platform stops moving
+
-
if j=true:
+
GPIO.setmode(GPIO.BOARD)    # Board numbering sceme pins
-
    mServo1.ChangeDutyCycle(mleft)     # Lock opens
+
GPIO.setup(pin_s1, GPIO.OUT) # Sets pins as output
-
    time.delay(lockdelay)
+
servo1 = GPIO.PWM(pin_s1, freq) # Assigns frequency to pins
-
    mServo1.ChangeDutyCycle(mcenter)   # Lock closes
+
servo1.start(s1left) # Starts servos in neutral position
 +
time.sleep(cyldelay)
 +
servo1.stop()
 +
GPIO.cleanup()
</pre>
</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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