Users Examples

#!/usr/bin/env python
# coding: Latin-1

# Load library functions we want
import time
import os
import ZeroBorg

#======================================================================
# Reading single character by forcing stdin to raw mode
import sys
import tty
import termios

def readchar():
    fd = sys.stdin.fileno()
    old_settings = termios.tcgetattr(fd)
    try:
        tty.setraw(sys.stdin.fileno())
        ch = sys.stdin.read(1)
    finally:
        termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
    if ch == '0x03':
        raise KeyboardInterrupt
    return ch

def readkey(getchar_fn=None):
    getchar = getchar_fn or readchar
    c1 = getchar()
    if ord(c1) != 0x1b:
        return c1
    c2 = getchar()
    if ord(c2) != 0x5b:
        return c1
    c3 = getchar()
    return chr(0x10 + ord(c3) - 65)  # 16=Up, 17=Down, 18=Right, 19=Left arrows

# End of single character reading
#======================================================================


# Setup the ZeroBorg
ZB = ZeroBorg.ZeroBorg()
#ZB.i2cAddress = 0x40                  # Uncomment and change the value if you have changed the board address
ZB.Init()
if not ZB.foundChip:
    boards = ZeroBorg.ScanForZeroBorg()
    if len(boards) == 0:
        print 'No ZeroBorg found, check you are attached :)'
    else:
        print 'No ZeroBorg at address %02X, but we did find boards:' % (ZB.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 'ZB.i2cAddress = 0x%02X' % (boards[0])
    sys.exit()
#ZB.SetEpoIgnore(True)                 # Uncomment to disable EPO latch, needed if you do not have a switch / jumper
ZB.SetCommsFailsafe(False)
ZB.ResetEpo()

# Power settings
voltageIn = 9.0                         # Total battery voltage to the ZeroBorg (change to 9V if using a non-rechargeable battery)
voltageOut = 6.0                        # Maximum motor voltage

# Setup the power limits
if voltageOut > voltageIn:
    maxPower = 1.0
else:
    maxPower = voltageOut / float(voltageIn)



# Remote control commands
def Move(left, right):
    print '%0.2f | %0.2f' % (left, right)
    ZB.SetMotor1(-left * maxPower)
    ZB.SetMotor4(-left * maxPower)
    ZB.SetMotor2(right * maxPower)
    ZB.SetMotor3(right * maxPower)  

def MoveForward():
    Move(+1.0, +1.0)

def MoveBackward():
    Move(-1.0, -1.0)

def SpinLeft():
    Move(-1.0, +1.0)

def SpinRight():
    Move(+1.0, -1.0)

def Stop():
    Move(0.0, 0.0)

def Shutdown():
    global running
    running = False


# The remote decoding loop
global running
running = True
ZB.SetLedIr(True)
try:
    print 'Press CTRL+C to quit'
    print 'Press arrow keys to control the Raspberry Pi - Spacebar to stop!'
    # Loop indefinitely
    while running:   
        keyp = readkey()
        if keyp == 'w' or ord(keyp) == 16:
            MoveForward ()
            print 'Forward'
        elif keyp == 'z' or ord(keyp) == 17:
            MoveBackward ()
            print 'Reverse'
        elif keyp == 's' or ord(keyp) == 18:
            SpinRight ()
            print 'Spin Right'
        elif keyp == 'a' or ord(keyp) == 19:
            SpinLeft ()
            print 'Spin Left'
        elif keyp == ' ':
            Stop()
            print 'Stop'
        elif ord(keyp) == 3:
            break

except KeyboardInterrupt:
    print



print

Hi!

I have noticed some strange behaviour with the speed of the motors.
M1 & M2 and M3 & M4 running at different speeds. On the contrary the speeds of M1 & M4 and M2 & M3 are the same...

I have changed the code to compensate this behavior.

def Move(left, right):
    print '%0.2f | %0.2f' % (left, right)
    ZB.SetMotor2(-left * maxPower)
    ZB.SetMotor3(-left * maxPower)
    ZB.SetMotor1(-right * maxPower)
    ZB.SetMotor4(-right * maxPower)

I notice with negative speeds the motors run a little bit faster and with positive speeds they run a little bit slower. Is it a defect of my zeroborg ?