--- a/robot.py	Mon Nov 24 00:35:13 2014 +0100
+++ b/robot.py	Tue Nov 25 22:59:41 2014 +0100
@@ -35,6 +35,7 @@
         positions = [int(pos * 1000) for pos in self.positions]
         packet = struct.pack(format, command, *positions)
         self.serial.write(packet)
+        self.serial.flush()
 
     def move_servo(self, servo, radians=None, degrees=None):
         if degrees is not None:
@@ -77,8 +78,13 @@
         self.leg_positions = [leg.home for leg in self.legs]
         self.shift = [0, 0, 0]
 
-    def _inverse_kinematics(self, (x, y, z), (dx, dy)):
+    def _inverse_kinematics(self, pos, d):
         """Calculate the 3 angles of the leg, in degrees."""
+        # Micropython doesn't support tuple unpacking?
+        x = pos[0]
+        y = pos[1]
+        z = pos[2]
+        dy = d[1]
         f = _norm(x, y) - self.coxa
         d = min(self.femur + self.tibia, _norm(f, z))
         hip = math.atan2(y, x)
@@ -125,12 +131,17 @@
         self.move_leg_to(leg, (rx, -ry * y_dir, None))
 
 
+def make_robot(serial_device='/dev/ttyS0'):
+    serial = open(serial_device, 'w')
+    servos = ServoController(serial)
+    robot = Robot(servos)
+    return robot
+
+
 if __name__ == '__main__':
-    import serial
     import time
 
-    servos = ServoController(serial.Serial('/dev/ttyUSB0', 57600))
-    robot = Robot(servos)
+    robot = make_robot()
     robot.update()
     time.sleep(1)
     steps = 10

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/robot.sh	Tue Nov 25 22:59:41 2014 +0100
@@ -0,0 +1,4 @@
+#!/bin/sh
+
+stty -F /dev/ttyS0 57600 clocal cread cs8 -cstopb -parenb
+micropython robot.py