Add 'car/' from commit 'eee0e8dc445691e600680f4abc77f2814b20b054'

git-subtree-dir: car
git-subtree-mainline: 1d29a5526c
git-subtree-split: eee0e8dc44

car/control/gpio/vehicle.py

@@ -0,0 +1,83 @@
+from gpiozero import Servo, Device
+from gpiozero.pins.pigpio import PiGPIOFactory
+import subprocess
+
+
+def _safely_set_servo_value(servo, value):
+    try:
+        if value < -1 or value > 1:
+            print("Not setting throttle, invalid value set.")
+            return False
+        servo.value = value
+    except TypeError:
+        print("throttle should be a number, preferably a float.")
+        return False
+    return True
+
+def _is_pin_valid(pin):
+    if isinstance(pin, int):
+        if pin < 2 or pin > 21:
+            print("Invalid GPIO pin")
+            return False
+        return True
+    else:
+        print("Value must be an int.")
+        return False
+
+# TODO: Allow a vector to be set to change the throttle/steering, for vehicles that don't use
+# two servos for controls (e.g. drone, dog)
+class Vehicle:
+    def __init__(self, motor_pin=19, servo_pin=18):
+        subprocess.call(['sudo', 'pigpiod'])
+        Device.pin_factory = PiGPIOFactory()
+        print('Using pin factory:')
+        print(Device.pin_factory)
+        self.motor_pin = motor_pin
+        self.steering_pin = servo_pin
+        self.initialise_motor()
+
+    def initialise_motor(self):
+        self._motor_servo = Servo(
+            self._motor_pin, pin_factory=Device.pin_factory)
+        self._steering_servo = Servo(self._steering_pin, pin_factory=Device.pin_factory)
+
+    @property
+    def throttle(self):
+        return self._motor_servo.value
+
+    @throttle.setter
+    def throttle(self, value):
+        _safely_set_servo_value(self._motor_servo, value)
+
+    @property
+    def steering(self):
+        return self._motor_servo.value
+
+    @steering.setter
+    def steering(self, value):
+        _safely_set_servo_value(self._motor_servo, value)
+
+    @property
+    def motor_pin(self):
+        return self._motor_pin
+
+    @motor_pin.setter
+    def motor_pin(self, value):
+        # TODO: Reinitialise the servo when the pin changes, or discard this method
+        # (probably don't want to allow pin changes whilst the device is in use anyway)
+        self._motor_pin = value if _is_pin_valid(value) else self._motor_pin
+
+    @property
+    def steering_pin(self):
+        return self._steering_pin
+
+    @steering_pin.setter
+    def steering_pin(self, value):
+        self._steering_pin = value if _is_pin_valid(value) else self._steering_pin
+
+    def stop(self):
+        self.throttle = 0
+        self.steering = 0
+
+    def change_with_vector(self, vector):
+        pass