Python Multi Processing

[MCeGEAR]

Hello All,

I need some help with multi-processing in python on the bot. I would use multi threading but because of the global lock in CPython that isn't doable, or at least that is what i assume is what is blocking its use i could be just completely wrong and miss using the threading.

None-the-less, here is a class i wrote up to get rate from a infinite turn pot hooked up to a roller, it works as long as it is ran fast enough, other wise it will miss a turn or two and give out some funky data, it isn't very clean and doesn't work on the bot because of no multi-threading support.

If i could get some help it would be great, I would prefer to get multi-processing working, but if i could have it run under a timed event properly instead that would be fine as well.

Thank you all very much the code is below, feel free to take and use or re-write it any way you feel.

class potRate(): 
    def __init__(self, potObj, timerObj):
        self.rate = 0.0
        self.stopThread = False
        self.lastRate = 0.0
        self.lastPotVal = potObj.GetVoltage()
        self.potObj = potObj
        self.timerObj = timerObj
        self.timerObj.Start()
        self.timerObj.Reset()

    def calcValue(self): 
        while not self.stopThread:  
            try:
                #This tells us how much it has traveled since it was last looked at by comparing last to current
                Rate = 0.0
                lastRate = self.rate
                potVal = self.potObj.GetVoltage()
                potDiff = (self.potObj.GetVoltage() - self.lastPotVal)
                
                #The pots give some jumpy data so this is a very basic filter that seprates out any garbage in readings
                if (abs(potDiff) >= 0.02):
                    #here we actually calulate out the rate, rate is just distance travled over time, we time how fast the pot moved
                    #Becuase of the way the shooter works, we don't want negitive values
                    if (potDiff > 0):
                        Rate = potDiff/self.timerObj.Get()
                        Rate = (Rate + lastRate)/2
                    else:
                        pass
            except ZeroDivisionError:
                Rate = 0.0
                print("RPM error zero divison")
            except:
                print("RPM error unhaneled")
                self.stopThread = True
            self.rate = Rate       
            self.lastPotVal = potVal     
            self.timerObj.Reset()

    def Start(self):
        self.stopThread = False
        self.rateThread = threading.Thread(target=self.calcValue, args = ())
        self.rateThread.daemon = True
        self.rateThread.start()
    def Stop(self):
        self.stopThread = True
        self.rateThread.join()
    def getRate(self):
        return self.rate