At the moment the only thing that separates your numbers is comma, yuo extract a number like this you read the serial port one bit at a time until you find a comma, that marks the end of your last number. Then you gather bytes into a list until you get another comma, don’t add that to the list. Then you convert each byte from the character into a number with an (ord(data).
For each successive number you then multiply the previous number by ten and add the next byte to it.
Bottom line is you have to think about what data format you are sending and how you communicate with the arduino.
This bit of code I used to get two 16 bit ints from the arduino. Each byte was tagged with a unique top two bits so I could identify them.
def openPort(): global running ser.flushInput() # tell the arduino to start sending running = True ser.write('3') ser.write('G') def checkInput(b): # see if the bytes have been received in the correct order correct = True for i in range(0,4): #print i," - " # ,hex(ord(b[i])) if (ord(b[i]) >> 6) != i : correct = False return correct def getData(): global reading, running if running : a = ser.read(4) if checkInput(a) : reading = ((ord(a) & 0x1f)<< 5) | (ord(a) &0x1f) reading = ((ord(a) & 0x1f)<<5) | (ord(a) &0x1f) #print reading," - ",reading else: correct = False while correct == False : # resyncronise print "lost sync ",ser.inWaiting() b = ser.read(1) t = a + a + a + b a = t correct = checkInput(a)
The code is from my book:-
Which describes both the arduino code and the python code. You should be able to down load both from the book’s web site.
It is chapter 16.
Would you recommend breaking the numbers down before sending them?
You have no choice the numbers are sent only one byte at a time by the hardware so they are broken down.