#!/usr/bin/env python # coding: Latin-1 # Creates a web-page interface for DiddyBorg Metal Edition # Import library functions we need import PicoBorgRev import time import sys import threading import SocketServer import picamera import picamera.array import cv2 import UltraBorg # Settings for the web-page webPort = 80 # Port number for the web-page, 80 is what web-pages normally use imageWidth = 240 # Width of the captured image in pixels imageHeight = 180 # Height of the captured image in pixels frameRate = 10 # Number of images to capture per second displayRate = 2 # Number of images to request per second # Global values global PBR global lastFrame global lockFrame global camera global processor global running global watchdog running = True # Setup the UltraBorg global UB UB = UltraBorg.UltraBorg() # Create a new UltraBorg object UB.Init() # Set the board up (checks the board is connected) # Setup the PicoBorg Reverse PBR = PicoBorgRev.PicoBorgRev() #PBR.i2cAddress = 0x44 # Uncomment and change the value if you have changed the board address PBR.Init() if not PBR.foundChip: boards = PicoBorgRev.ScanForPicoBorgReverse() if len(boards) == 0: print 'No PicoBorg Reverse found, check you are attached :)' else: print 'No PicoBorg Reverse at address %02X, but we did find boards:' % (PBR.i2cAddress) for board in boards: print ' %02X (%d)' % (board, board) print 'If you need to change the I²C address change the setup line so it is correct, e.g.' print 'PBR.i2cAddress = 0x%02X' % (boards[0]) sys.exit() #PBR.SetEpoIgnore(True) # Uncomment to disable EPO latch, needed if you do not have a switch / jumper PBR.SetCommsFailsafe(False) # Disable the communications failsafe PBR.ResetEpo() # Power settings voltageIn = 1.2 * 12 # Total battery voltage to the PicoBorg Reverse voltageOut = 12.0 # Maximum motor voltage # Setup the power limits if voltageOut > voltageIn: maxPower = 1.0 else: maxPower = voltageOut / float(voltageIn) # Timeout thread class Watchdog(threading.Thread): def __init__(self): super(Watchdog, self).__init__() self.event = threading.Event() self.terminated = False self.start() self.timestamp = time.time() def run(self): timedOut = True # This method runs in a separate thread while not self.terminated: # Wait for a network event to be flagged for up to one second if timedOut: if self.event.wait(1): # Connection print 'Reconnected...' timedOut = False self.event.clear() else: if self.event.wait(1): self.event.clear() else: # Timed out print 'Timed out...' timedOut = True PBR.MotorsOff() # Image stream processing thread class StreamProcessor(threading.Thread): def __init__(self): super(StreamProcessor, self).__init__() self.stream = picamera.array.PiRGBArray(camera) self.event = threading.Event() self.terminated = False self.start() self.begin = 0 def run(self): global lastFrame global lockFrame # This method runs in a separate thread while not self.terminated: # Wait for an image to be written to the stream if self.event.wait(1): try: # Read the image and save globally self.stream.seek(0) flippedArray = cv2.flip(self.stream.array, -1) # Flips X and Y retval, thisFrame = cv2.imencode('.jpg', flippedArray) del flippedArray lockFrame.acquire() lastFrame = thisFrame lockFrame.release() finally: # Reset the stream and event self.stream.seek(0) self.stream.truncate() self.event.clear() # Image capture thread class ImageCapture(threading.Thread): def __init__(self): super(ImageCapture, self).__init__() self.start() def run(self): global camera global processor print 'Start the stream using the video port' camera.capture_sequence(self.TriggerStream(), format='bgr', use_video_port=True) print 'Terminating camera processing...' processor.terminated = True processor.join() print 'Processing terminated.' # Stream delegation loop def TriggerStream(self): global running while running: if processor.event.is_set(): time.sleep(0.01) else: yield processor.stream processor.event.set() # Class used to implement the web server class WebServer(SocketServer.BaseRequestHandler): def handle(self): global PBR global lastFrame global watchdog # Get the HTTP request data reqData = self.request.recv(1024).strip() reqData = reqData.split('\n') # Get the URL requested getPath = '' for line in reqData: if line.startswith('GET'): parts = line.split(' ') getPath = parts[1] break watchdog.event.set() if getPath.startswith('/distances-once'): # Ultrasonic distance readings # Get the readings distance1 = int(UB.GetDistance1()) distance2 = int(UB.GetDistance2()) distance3 = int(UB.GetDistance3()) distance4 = int(UB.GetDistance4()) # Build a table for the values httpText = '' if distance1 == 0: httpText += '' else: httpText += '' % (distance1) if distance2 == 0: httpText += '' else: httpText += '' % (distance2) if distance3 == 0: httpText += '' else: httpText += '' % (distance3) if distance4 == 0: httpText += '' else: httpText += '' % (distance4) httpText += '

None

%04d

None

%04d

None

%04d

None

%04d

' self.send(httpText) elif getPath.startswith('/cam.jpg'): # Camera snapshot lockFrame.acquire() sendFrame = lastFrame lockFrame.release() if sendFrame != None: self.send(sendFrame.tostring()) elif getPath.startswith('/off'): # Turn the drives off httpText = '
' httpText += 'Speeds: 0 %, 0 %' httpText += '
' self.send(httpText) PBR.MotorsOff() elif getPath.startswith('/set/'): # Motor power setting: /set/driveLeft/driveRight parts = getPath.split('/') # Get the power levels if len(parts) >= 4: try: driveLeft = float(parts[2]) driveRight = float(parts[3]) except: # Bad values driveRight = 0.0 driveLeft = 0.0 else: # Bad request driveRight = 0.0 driveLeft = 0.0 # Ensure settings are within limits if driveRight < -1: driveRight = -1 elif driveRight > 1: driveRight = 1 if driveLeft < -1: driveLeft = -1 elif driveLeft > 1: driveLeft = 1 # Report the current settings percentLeft = driveLeft * 100.0; percentRight = driveRight * 100.0; httpText = '
' httpText += 'Speeds: %.0f %%, %.0f %%' % (percentLeft, percentRight) httpText += '
' self.send(httpText) # Set the outputs driveLeft *= maxPower driveRight *= maxPower PBR.SetMotor1(driveRight) PBR.SetMotor2(-driveLeft) elif getPath == '/': # Main page httpText = '\n' httpText += '\n' httpText += '\n' httpText += '\n' httpText += '\n' httpText += '\n' httpText += '\n' httpText += '
\n' httpText += '\n' httpText += '\n' httpText += '\n' httpText += '

\n' httpText += '\n' httpText += '\n' httpText += '\n' httpText += '

\n' httpText += '\n' httpText += '

\n' httpText += '\n' httpText += '
\n' httpText += '

Distances (mm)


\n' httpText += '\n' httpText += '\n' httpText += '\n' self.send(httpText) elif getPath == '/stream': # Streaming frame, set a delayed refresh displayDelay = int(1000 / displayRate) httpText = '\n' httpText += '\n' httpText += '\n' httpText += '\n' httpText += '\n' % (displayDelay) httpText += '
\n' httpText += '\n' httpText += '\n' self.send(httpText) elif getPath == '/distances': # Repeated reading of the ultrasonic distances, set a delayed refresh # We use AJAX to avoid screen refreshes caused by refreshing a frame displayDelay = int(1000 / displayRate) httpText = '\n' httpText += '\n' httpText += '\n' httpText += '\n' httpText += '\n' httpText += '\n' % (displayDelay) httpText += '

Waiting for first distance reading...

\n' httpText += '\n' httpText += '\n' self.send(httpText) else: # Unexpected page self.send('Path : "%s"' % (getPath)) def send(self, content): self.request.sendall('HTTP/1.0 200 OK\n\n%s' % (content)) # Create the image buffer frame lastFrame = None lockFrame = threading.Lock() # Startup sequence print 'Setup camera' camera = picamera.PiCamera() camera.resolution = (imageWidth, imageHeight) camera.framerate = frameRate print 'Setup the stream processing thread' processor = StreamProcessor() print 'Wait ...' time.sleep(2) captureThread = ImageCapture() print 'Setup the watchdog' watchdog = Watchdog() # Run the web server until we are told to close httpServer = SocketServer.TCPServer(("0.0.0.0", webPort), WebServer) try: print 'Press CTRL+C to terminate the web-server' while running: httpServer.handle_request() except KeyboardInterrupt: # CTRL+C exit print '\nUser shutdown' finally: # Turn the motors off under all scenarios PBR.MotorsOff() print 'Motors off' # Tell each thread to stop, and wait for them to end running = False captureThread.join() processor.terminated = True watchdog.terminated = True processor.join() watchdog.join() del camera PBR.SetLed(True) print 'Web-server terminated.'