ultra

    def pinSonar(self, pin):
        #print pin
        #print self.pinUse[pin]
        self.pinUse[pin] = self.PSONAR
        GPIO.setup(pin,GPIO.OUT)
        ti = time.time()
        # setup a list to hold 3 values and then do 3 distance calcs and store them
        #print 'sonar started'
        distlist = [0.0,0.0,0.0]
        distance = 0
        ts=time.time()
        try:
            for k in range(3):
                #print "sonar pulse" , k
                GPIO.output(pin, 0)
                time.sleep(0.05)#set pin low for 50ms as per spec
                GPIO.output(pin, 1)    # Send Pulse high
                time.sleep(0.00001)     #  wait
                GPIO.output(pin, 0)  #  bring it back low - pulse over.
                t0=time.time() # remember current time
                GPIO.setup(pin,GPIO.IN)
                #PIN_USE[i] = PINPUT don't bother telling system

                t1=t0
                # This while loop waits for input pin (7) to be low but with a 0.04sec timeout
                while ((GPIO.input(pin)==0) and ((t1-t0) < 0.02)):
                    #time.sleep(0.00001)
                    t1=time.time()
                t1=time.time()
                #print 'low' , (t1-t0).microseconds
                t2=t1
                #  This while loops waits for input pin to go high to indicate pulse detection
                #  with 0.04 sec timeout
                while ((GPIO.input(pin)==1) and ((t2-t1) < 0.02)):
                    #time.sleep(0.00001)
                    t2=time.time()
                t2=time.time()
                #print 'high' , (t2-t1).microseconds
                t3=(t2-t1)  # t2 contains time taken for pulse to return
                #print "total time " , t3
                distance=t3*343/2*100  # calc distance in cm
                distlist[k]=distance
                #print distance
                GPIO.setup(pin,GPIO.OUT)
            tf = time.time() - ts
            distance = sorted(distlist)[1] # sort the list and pick middle value as best distance
        except:
            pass