kettler.py

import serial, time


def roundto(x, base=5):
    return int(base * round(float(x)/base))


def add(x,y):
    return x + y


class Kettler():
    def __init__(self, device=None):
        self.device = device
        
        self.pulse = 0
        self.pulses = []
        self.rpm = 0
        self.rpms = []
        self.power = 0
        self.xpower = float(self.power)
        
        self.serialport = serial.Serial(self.device, 9600, timeout=0.1)
        
        if not self.device:
            raise NameError, 'Serial port not specified'
        
        if not self.serialport.isOpen():
            raise IOError, 'Serial port could not be opened'
        
        time.sleep(1)

        self.serialport.write('RS\r\n')
        time.sleep(5)
        if not self.serialport.readline().startswith('ACK'):
            raise IOError, 'Could not connect to bike'

        self.serialport.write('CM\r\n')
        time.sleep(1)
        if not self.serialport.readline().startswith('ACK'):
            raise IOError, 'Could not connect to bike'
    
    def status(self):
        self.serialport.write('ST\r\n')
        parts = self.serialport.readline().rstrip('\r\n').split('\t')
        
        try:
            if len(self.pulses) > 4:
                self.pulses.pop()
            self.pulses.insert(0, int(parts[0], 10))
            self.pulse = int(reduce(add, self.pulses)/len(self.pulses))
            
            if len(self.rpms) > 4:
                self.rpms.pop()
            self.rpms.insert(0, int(parts[1], 10))
            self.rpm = int(reduce(add, self.rpms)/len(self.rpms))
        except:
            pass
        
    def set_power(self, absolute=0.0, relative=0.0):        
        if relative != 0.0:
            self.xpower += relative
        elif absolute > 0.0:
            self.xpower = absolute
        
        if roundto(self.power) != roundto(self.xpower):
            self.power = roundto(self.xpower)
            watts = self.power
            if watts < 25:
                watts = 25
                self.power = watts
            if watts > 400:
                watts = 400
                self.power = watts
            self.serialport.write('PW ' + str(watts) + '\r\n')