Current ch-11 state

.gitignore

@@ -5,3 +5,4 @@
 *.FCStd1
 secrets.py
 libs
+.idea/

ch-11/1-measuring_wheel_speeds/code.py

@@ -34,6 +34,7 @@ async def command_handler():
       elif command == "O":
         robot.stop()
       elif command.startswith("O"):
+        await asyncio.sleep(5)
         robot.set_left(Settings.speed)
         robot.set_right(Settings.speed)
         asyncio.create_task(stop_motors_after(float(command[1:])))

ch-11/1.5-speed-control/code.py

@@ -0,0 +1,100 @@
+import asyncio
+import board
+import busio
+import robot
+import time
+
+import pid_controller
+uart = busio.UART(board.GP12, board.GP13, baudrate=9600)
+
+class Settings:
+  # work in ticks only  - 1 rpm
+  speed = 0.5
+  time_interval = 0.2
+  motors_enabled = False
+  dead_zone = 0.2
+
+class SpeedController:
+  def __init__(self, encoder, motor_fn) -> None:
+    self.encoder = encoder
+    self.motor_fn = motor_fn
+    #P1.4,I2.8,D1
+    #P0, I2.5, D1.1
+    self.pid = pid_controller.PIDController(0.1, 1.5, 0)
+    self.reset()
+
+  def reset(self):
+    self.last_ticks = self.encoder.read()
+    self.error = 0
+    self.control_signal = 0
+    self.pid.reset()
+
+  def update(self, dt):
+    current_ticks = self.encoder.read()
+    actual_speed_in_rpm = (current_ticks - self.last_ticks) / (dt * robot.ticks_per_revolution)
+    self.last_ticks = current_ticks
+    # calculate the error  
+    self.error = (Settings.speed * Settings.motors_enabled) - actual_speed_in_rpm
+    # calculate the control signal
+    self.control_signal = self.pid.calculate(self.error, dt)
+    self.motor_fn(self.control_signal)
+    
+
+left = SpeedController(robot.left_encoder, robot.set_left)
+
+async def speed_controller_loop():
+  last_time = time.monotonic()
+  while True:
+    await asyncio.sleep(Settings.time_interval)
+    current_time = time.monotonic()
+    dt = current_time - last_time
+    left.update(dt)
+    last_time = current_time
+    print(f"{dt:.2f}")
+    uart.write(f"{Settings.speed * Settings.motors_enabled}, {left.error:.2f},{left.control_signal:.2f}\n".encode())
+
+
+async def stop_motors_after(seconds):
+  await asyncio.sleep(seconds)
+  Settings.motors_enabled = False
+  # robot.stop()
+
+async def command_handler():
+  while True:
+    if uart.in_waiting:
+      command = uart.readline().decode().strip()
+      # PID settings
+      if command.startswith("P"):
+        left.pid.kp = float(command[1:])
+      elif command.startswith("I"):
+        left.pid.ki = float(command[1:])
+        left.pid.reset()
+      elif command.startswith("D"):
+        left.pid.kd = float(command[1:])
+      # Speed settings
+      elif command.startswith("M"):
+        Settings.speed = float(command[1:])
+      elif command.startswith("T"):
+        Settings.time_interval = float(command[1:])
+      # Start/stop commands
+      elif command == "O":
+        Settings.motors_enabled = False
+      elif command.startswith("O"):
+        asyncio.create_task(stop_motors_after(float(command[1:])))
+        Settings.motors_enabled = True
+        left.reset()
+      # Print settings
+      elif command.startswith("?"):
+        uart.write(f"M{Settings.speed:.1f}\n".encode())
+        uart.write(f"T{Settings.time_interval:.1f}\n".encode())
+        uart.write(f"P{left.pid.kp:.2f}:I{left.pid.ki:.2f}:D{left.pid.kd:.2f}\n".encode())
+        await asyncio.sleep(3)      
+    await asyncio.sleep(0)
+
+try:
+  asyncio.create_task(speed_controller_loop())
+  asyncio.create_task(stop_motors_after(10))
+  Settings.motors_enabled = True
+  asyncio.run(command_handler())
+finally:
+  robot.stop()

ch-11/1.5-speed-control/pid_controller.py

@@ -0,0 +1,27 @@
+class PIDController:
+    def __init__(self, kp, ki, kd, d_filter_gain=0.1, imax=None, imin=None):
+        self.kp = kp
+        self.ki = ki
+        self.kd = kd
+        self.d_filter_gain = d_filter_gain
+        self.imax = imax
+        self.imin = imin
+        self.reset()
+
+    def reset(self):
+        self.integral = 0
+        self.error_prev = 0
+        self.derivative = 0
+
+    def calculate(self, error, dt):
+        self.integral += error * dt
+        if self.imax is not None and self.integral > self.imax:
+            self.integral = self.imax
+        if self.imin is not None and self.integral < self.imin:
+            self.integral = self.imin
+        # Add a low pass filter to the difference
+        difference = (error - self.error_prev) * self.d_filter_gain
+        self.error_prev += difference
+        self.derivative = difference / dt
+
+        return self.kp * error + self.ki * self.integral + self.kd * self.derivative

ch-11/1.5-speed-control/pio_encoder.py

@@ -0,0 +1,84 @@
+import rp2pio
+import adafruit_pioasm
+import array
+import asyncio
+
+
+program = """
+; use the osr for count
+; input pins c1 c2
+
+    set y, 0            ; clear y
+    mov osr, y          ; and clear osr
+read:
+    ; x will be the old value
+    ; y the new values
+    mov x, y            ; store old Y in x
+    in null, 32         ; Clear ISR - using y
+    in pins, 2          ; read two pins into y
+    mov y, isr
+    jmp x!=y, different ; Jump if its different
+    jmp read            ; otherwise loop back to read
+
+different:
+    ; x has old value, y has new.
+    ; extract the upper bit of X.
+    in x, 31             ; get bit 31 - old p1 (remember which direction it came in)
+    in null, 31         ; keep only 1 bit
+    mov x, isr          ; put this back in x
+    jmp !x, c1_old_zero
+
+c1_old_not_zero:
+    jmp pin, count_up
+    jmp count_down
+
+c1_old_zero:
+    jmp pin, count_down
+    ; fall through
+count_up:
+    ; for a clockwise move - we'll add 1 by inverting
+    mov x, ~ osr        ; store inverted OSR on x
+    jmp x--, fake       ; use jump to take off 1
+fake:
+    mov x, ~ x          ; invert back
+    jmp send
+count_down:
+    ; for a clockwise move, just take one off
+    mov x, osr          ; store osr in x
+    jmp x--, send       ; dec and send
+send:
+    ; send x.
+    mov isr, x          ; send it
+    push noblock        ; put ISR into input FIFO
+    mov osr, x          ; put X back in OSR
+    jmp read            ; loop back
+"""
+
+assembled = adafruit_pioasm.assemble(program)
+
+
+class QuadratureEncoder:
+    def __init__(self, first_pin, second_pin, reversed=False):
+        """Encoder with 2 pins. Must use sequential pins on the board"""
+        self.sm = rp2pio.StateMachine(
+            assembled,
+            frequency=0,
+            first_in_pin=first_pin,
+            jmp_pin=second_pin,
+            in_pin_count=2,
+        )
+        self.reversed = reversed
+        self._buffer = array.array("i", [0])
+        asyncio.create_task(self.poll_loop())
+
+    async def poll_loop(self):
+        while True:
+            await asyncio.sleep(0)
+            while self.sm.in_waiting:
+                self.sm.readinto(self._buffer)
+
+    def read(self):
+        if self.reversed:
+            return -self._buffer[0]
+        else:
+            return self._buffer[0]

ch-11/1.5-speed-control/robot.py

@@ -0,0 +1,68 @@
+import board
+import pwmio
+import pio_encoder
+import busio
+import adafruit_vl53l1x
+import math
+
+wheel_diameter_mm = 70
+wheel_circumference_mm = math.pi * wheel_diameter_mm
+gear_ratio = 298
+encoder_poles = 28
+ticks_per_revolution = encoder_poles * gear_ratio
+ticks_to_mm_const = wheel_circumference_mm / ticks_per_revolution
+
+def ticks_to_mm(ticks):
+    return ticks_to_mm_const * ticks
+
+motor_A2 = pwmio.PWMOut(board.GP17, frequency=100)
+motor_A1 = pwmio.PWMOut(board.GP16, frequency=100)
+motor_B2 = pwmio.PWMOut(board.GP18, frequency=100)
+motor_B1 = pwmio.PWMOut(board.GP19, frequency=100)
+
+right_motor = motor_A1, motor_A2
+left_motor = motor_B1, motor_B2
+motor_dead_zone = 0.2
+
+right_encoder = pio_encoder.QuadratureEncoder(board.GP20, board.GP21)
+left_encoder = pio_encoder.QuadratureEncoder(board.GP26, board.GP27, reversed=True)
+
+i2c0 = busio.I2C(sda=board.GP0, scl=board.GP1)
+i2c1 = busio.I2C(sda=board.GP2, scl=board.GP3)
+
+left_distance = adafruit_vl53l1x.VL53L1X(i2c0)
+right_distance = adafruit_vl53l1x.VL53L1X(i2c1)
+
+
+def stop():
+    motor_A1.duty_cycle = 0
+    motor_A2.duty_cycle = 0
+    motor_B1.duty_cycle = 0
+    motor_B2.duty_cycle = 0
+
+
+def set_speed(motor, speed):
+    # stop completely if in the dead zone
+    if abs(speed) < motor_dead_zone:
+        motor[0].duty_cycle = 0
+        motor[1].duty_cycle = 0
+        return
+    # Swap motor pins if we reverse the speed
+    if speed < 0:
+        direction = motor[1], motor[0]
+        speed = -speed
+    else:
+        direction = motor
+    speed = min(speed, 1)  # limit to 1.0
+    max_speed = 2 ** 16 - 1
+
+    direction[0].duty_cycle = int(max_speed * speed)
+    direction[1].duty_cycle = 0
+
+
+def set_left(speed):
+    set_speed(left_motor, speed)
+
+
+def set_right(speed):
+    set_speed(right_motor, speed)

ch-11/2-speed-control-acceleration/code.py

@@ -0,0 +1,103 @@
+import asyncio
+import time
+import robot
+import pid_controller
+
+class Settings:
+  speed = 0.17
+  distance = 1
+  time_interval = 0.2
+  motors_enabled = False
+
+
+class SpeedController:
+  def __init__(self, encoder, motor_fn):
+    self.encoder = encoder
+    self.motor_fn = motor_fn
+    self.pid = pid_controller.PIDController(3, 0, 1)
+    self.reset()
+
+  def reset(self):
+    self.last_ticks = self.encoder.read()
+    self.error = 0
+    self.speed = 0
+    self.actual_speed = 0
+    self.pid.reset()
+
+  def update(self, dt):
+    current_ticks = self.encoder.read()
+    speed_in_ticks = (current_ticks - self.last_ticks) / dt
+    self.last_ticks = current_ticks
+    self.actual_speed = robot.ticks_to_mm(speed_in_ticks) / 1000
+    # calculate the error  
+    self.error = (Settings.speed * Settings.motors_enabled) - self.actual_speed
+    # calculate the control signal
+    control_signal = self.pid.calculate(self.error, dt)
+    self.speed += control_signal
+    self.motor_fn(self.speed)
+
+
+left = SpeedController(robot.left_encoder, robot.set_left)
+right = SpeedController(robot.right_encoder, robot.set_right)
+
+
+async def motor_speed_loop():
+  last_time = time.monotonic()
+  while True:
+    await asyncio.sleep(Settings.time_interval)
+    current_time = time.monotonic()
+    dt = current_time - last_time
+    last_time = current_time
+    left.update(dt)
+    right.update(dt)
+    robot.uart.write(f"0, {left.actual_speed:.2f},{Settings.speed:.2f}\n".encode())
+
+
+async def stop_motors_after(seconds):
+  await asyncio.sleep(seconds)
+  Settings.motors_enabled = False
+
+
+async def command_handler():
+  while True:
+    if robot.uart.in_waiting:
+      command = robot.uart.readline().decode().strip()
+      # PID settings
+      if command.startswith("P"):
+        left.pid.kp = float(command[1:])
+        right.pid.kp = float(command[1:])
+      elif command.startswith("I"):
+        left.pid.ki = float(command[1:])
+        left.pid.reset()
+        right.pid.ki = float(command[1:])
+        right.pid.reset()
+      elif command.startswith("D"):
+        left.pid.kd = float(command[1:])
+        right.pid.kd = float(command[1:])
+      elif command.startswith("T"):
+        Settings.time_interval = float(command[1:])
+      # Speed settings
+      elif command.startswith("M"):
+        Settings.speed = float(command[1:])
+      # Start/stop commands
+      elif command == "O":
+        Settings.motors_enabled = False
+      elif command.startswith("O"):
+        await asyncio.sleep(5)
+        asyncio.create_task(stop_motors_after(float(command[1:])))
+        Settings.motors_enabled = True
+        left.reset()
+        right.reset()
+      # Print settings
+      elif command.startswith("?"):
+        robot.uart.write(f"M{Settings.speed:.1f}\n".encode())
+        robot.uart.write(f"P{left.pid.kp:.2f}:I{left.pid.ki:.2f}:D{left.pid.kd:.2f}\n".encode())
+        robot.uart.write(f"T{Settings.time_interval:.1f}\n".encode())
+        await asyncio.sleep(3)
+    await asyncio.sleep(0)
+
+try:
+  asyncio.create_task(motor_speed_loop())
+  asyncio.run(command_handler())
+finally:
+  robot.stop()

ch-11/2-speed-control-acceleration/pid_controller.py

@@ -0,0 +1,27 @@
+class PIDController:
+    def __init__(self, kp, ki, kd, d_filter_gain=0.1, imax=None, imin=None):
+        self.kp = kp
+        self.ki = ki
+        self.kd = kd
+        self.d_filter_gain = d_filter_gain
+        self.imax = imax
+        self.imin = imin
+        self.reset()
+
+    def reset(self):
+        self.integral = 0
+        self.error_prev = 0
+        self.derivative = 0
+
+    def calculate(self, error, dt):
+        self.integral += error * dt
+        if self.imax is not None and self.integral > self.imax:
+            self.integral = self.imax
+        if self.imin is not None and self.integral < self.imin:
+            self.integral = self.imin
+        # Add a low pass filter to the difference
+        difference = (error - self.error_prev) * self.d_filter_gain
+        self.error_prev += difference
+        self.derivative = difference / dt
+
+        return self.kp * error + self.ki * self.integral + self.kd * self.derivative

ch-11/2-speed-control-acceleration/pio_encoder.py

@@ -0,0 +1,84 @@
+import rp2pio
+import adafruit_pioasm
+import array
+import asyncio
+
+
+program = """
+; use the osr for count
+; input pins c1 c2
+
+    set y, 0            ; clear y
+    mov osr, y          ; and clear osr
+read:
+    ; x will be the old value
+    ; y the new values
+    mov x, y            ; store old Y in x
+    in null, 32         ; Clear ISR - using y
+    in pins, 2          ; read two pins into y
+    mov y, isr
+    jmp x!=y, different ; Jump if its different
+    jmp read            ; otherwise loop back to read
+
+different:
+    ; x has old value, y has new.
+    ; extract the upper bit of X.
+    in x, 31             ; get bit 31 - old p1 (remember which direction it came in)
+    in null, 31         ; keep only 1 bit
+    mov x, isr          ; put this back in x
+    jmp !x, c1_old_zero
+
+c1_old_not_zero:
+    jmp pin, count_up
+    jmp count_down
+
+c1_old_zero:
+    jmp pin, count_down
+    ; fall through
+count_up:
+    ; for a clockwise move - we'll add 1 by inverting
+    mov x, ~ osr        ; store inverted OSR on x
+    jmp x--, fake       ; use jump to take off 1
+fake:
+    mov x, ~ x          ; invert back
+    jmp send
+count_down:
+    ; for a clockwise move, just take one off
+    mov x, osr          ; store osr in x
+    jmp x--, send       ; dec and send
+send:
+    ; send x.
+    mov isr, x          ; send it
+    push noblock        ; put ISR into input FIFO
+    mov osr, x          ; put X back in OSR
+    jmp read            ; loop back
+"""
+
+assembled = adafruit_pioasm.assemble(program)
+
+
+class QuadratureEncoder:
+    def __init__(self, first_pin, second_pin, reversed=False):
+        """Encoder with 2 pins. Must use sequential pins on the board"""
+        self.sm = rp2pio.StateMachine(
+            assembled,
+            frequency=0,
+            first_in_pin=first_pin,
+            jmp_pin=second_pin,
+            in_pin_count=2,
+        )
+        self.reversed = reversed
+        self._buffer = array.array("i", [0])
+        asyncio.create_task(self.poll_loop())
+
+    async def poll_loop(self):
+        while True:
+            await asyncio.sleep(0)
+            while self.sm.in_waiting:
+                self.sm.readinto(self._buffer)
+
+    def read(self):
+        if self.reversed:
+            return -self._buffer[0]
+        else:
+            return self._buffer[0]

ch-11/2-speed-control-acceleration/robot.py

@@ -0,0 +1,65 @@
+import board
+import pwmio
+import pio_encoder
+import busio
+import adafruit_vl53l1x
+import math
+import busio
+
+uart = busio.UART(board.GP12, board.GP13, baudrate=9600)
+
+wheel_diameter_mm = 70
+wheel_circumference_mm = math.pi * wheel_diameter_mm
+gear_ratio = 298
+encoder_poles = 28
+ticks_per_revolution = encoder_poles * gear_ratio
+ticks_to_mm_const = wheel_circumference_mm / ticks_per_revolution
+
+def ticks_to_mm(ticks):
+    return ticks_to_mm_const * ticks
+
+motor_A2 = pwmio.PWMOut(board.GP17, frequency=100)
+motor_A1 = pwmio.PWMOut(board.GP16, frequency=100)
+motor_B2 = pwmio.PWMOut(board.GP18, frequency=100)
+motor_B1 = pwmio.PWMOut(board.GP19, frequency=100)
+
+right_motor = motor_A1, motor_A2
+left_motor = motor_B1, motor_B2
+
+right_encoder = pio_encoder.QuadratureEncoder(board.GP20, board.GP21)
+left_encoder = pio_encoder.QuadratureEncoder(board.GP26, board.GP27, reversed=True)
+
+i2c0 = busio.I2C(sda=board.GP0, scl=board.GP1)
+i2c1 = busio.I2C(sda=board.GP2, scl=board.GP3)
+
+left_distance = adafruit_vl53l1x.VL53L1X(i2c0)
+right_distance = adafruit_vl53l1x.VL53L1X(i2c1)
+
+
+def stop():
+    motor_A1.duty_cycle = 0
+    motor_A2.duty_cycle = 0
+    motor_B1.duty_cycle = 0
+    motor_B2.duty_cycle = 0
+
+
+def set_speed(motor, speed):
+    # Swap motor pins if we reverse the speed
+    if speed < 0:
+        direction = motor[1], motor[0]
+        speed = -speed
+    else:
+        direction = motor
+    speed = min(speed, 1)  # limit to 1.0
+    max_speed = 2 ** 16 - 1
+
+    direction[0].duty_cycle = int(max_speed * speed)
+    direction[1].duty_cycle = 0
+
+
+def set_left(speed):
+    set_speed(left_motor, speed)
+
+
+def set_right(speed):
+    set_speed(right_motor, speed)

ch-11/3-known-distance-acceleration/code.py

@@ -0,0 +1,102 @@
+import asyncio
+import time
+import robot
+import pid_controller
+
+class Settings:
+  speed = 0.17
+  time_interval = 0.2
+  motors_enabled = False
+
+
+class SpeedController:
+  def __init__(self, encoder, motor_fn):
+    self.encoder = encoder
+    self.motor_fn = motor_fn
+    self.pid = pid_controller.PIDController(3, 0, 1)
+    self.reset()
+
+  def reset(self):
+    self.last_ticks = self.encoder.read()
+    self.error = 0
+    self.speed = 0
+    self.actual_speed = 0
+    self.pid.reset()
+
+  def update(self, dt):
+    current_ticks = self.encoder.read()
+    speed_in_ticks = (current_ticks - self.last_ticks) / dt
+    self.last_ticks = current_ticks
+    self.actual_speed = robot.ticks_to_mm(speed_in_ticks) / 1000
+    # calculate the error  
+    self.error = (Settings.speed * Settings.motors_enabled) - self.actual_speed
+    # calculate the control signal
+    control_signal = self.pid.calculate(self.error, dt)
+    self.speed += control_signal
+    self.motor_fn(self.speed)
+
+
+left = SpeedController(robot.left_encoder, robot.set_left)
+right = SpeedController(robot.right_encoder, robot.set_right)
+
+
+async def motor_speed_loop():
+  last_time = time.monotonic()
+  while True:
+    await asyncio.sleep(Settings.time_interval)
+    current_time = time.monotonic()
+    dt = current_time - last_time
+    last_time = current_time
+    left.update(dt)
+    right.update(dt)
+    robot.uart.write(f"0, {left.actual_speed:.2f},{Settings.speed:.2f}\n".encode())
+
+
+async def stop_motors_after(seconds):
+  await asyncio.sleep(seconds)
+  Settings.motors_enabled = False
+
+
+async def command_handler():
+  while True:
+    if robot.uart.in_waiting:
+      command = robot.uart.readline().decode().strip()
+      # PID settings
+      if command.startswith("P"):
+        left.pid.kp = float(command[1:])
+        right.pid.kp = float(command[1:])
+      elif command.startswith("I"):
+        left.pid.ki = float(command[1:])
+        left.pid.reset()
+        right.pid.ki = float(command[1:])
+        right.pid.reset()
+      elif command.startswith("D"):
+        left.pid.kd = float(command[1:])
+        right.pid.kd = float(command[1:])
+      elif command.startswith("T"):
+        Settings.time_interval = float(command[1:])
+      # Speed settings
+      elif command.startswith("M"):
+        Settings.speed = float(command[1:])
+      # Start/stop commands
+      elif command == "O":
+        Settings.motors_enabled = False
+      elif command.startswith("O"):
+        await asyncio.sleep(5)
+        asyncio.create_task(stop_motors_after(float(command[1:])))
+        Settings.motors_enabled = True
+        left.reset()
+        right.reset()
+      # Print settings
+      elif command.startswith("?"):
+        robot.uart.write(f"M{Settings.speed:.1f}\n".encode())
+        robot.uart.write(f"P{left.pid.kp:.2f}:I{left.pid.ki:.2f}:D{left.pid.kd:.2f}\n".encode())
+        robot.uart.write(f"T{Settings.time_interval:.1f}\n".encode())
+        await asyncio.sleep(3)
+    await asyncio.sleep(0)
+
+try:
+  asyncio.create_task(motor_speed_loop())
+  asyncio.run(command_handler())
+finally:
+  robot.stop()

ch-11/3-known-distance-acceleration/pid_controller.py

@@ -0,0 +1,27 @@
+class PIDController:
+    def __init__(self, kp, ki, kd, d_filter_gain=0.1, imax=None, imin=None):
+        self.kp = kp
+        self.ki = ki
+        self.kd = kd
+        self.d_filter_gain = d_filter_gain
+        self.imax = imax
+        self.imin = imin
+        self.reset()
+
+    def reset(self):
+        self.integral = 0
+        self.error_prev = 0
+        self.derivative = 0
+
+    def calculate(self, error, dt):
+        self.integral += error * dt
+        if self.imax is not None and self.integral > self.imax:
+            self.integral = self.imax
+        if self.imin is not None and self.integral < self.imin:
+            self.integral = self.imin
+        # Add a low pass filter to the difference
+        difference = (error - self.error_prev) * self.d_filter_gain
+        self.error_prev += difference
+        self.derivative = difference / dt
+
+        return self.kp * error + self.ki * self.integral + self.kd * self.derivative

ch-11/3-known-distance-acceleration/pio_encoder.py

@@ -0,0 +1,84 @@
+import rp2pio
+import adafruit_pioasm
+import array
+import asyncio
+
+
+program = """
+; use the osr for count
+; input pins c1 c2
+
+    set y, 0            ; clear y
+    mov osr, y          ; and clear osr
+read:
+    ; x will be the old value
+    ; y the new values
+    mov x, y            ; store old Y in x
+    in null, 32         ; Clear ISR - using y
+    in pins, 2          ; read two pins into y
+    mov y, isr
+    jmp x!=y, different ; Jump if its different
+    jmp read            ; otherwise loop back to read
+
+different:
+    ; x has old value, y has new.
+    ; extract the upper bit of X.
+    in x, 31             ; get bit 31 - old p1 (remember which direction it came in)
+    in null, 31         ; keep only 1 bit
+    mov x, isr          ; put this back in x
+    jmp !x, c1_old_zero
+
+c1_old_not_zero:
+    jmp pin, count_up
+    jmp count_down
+
+c1_old_zero:
+    jmp pin, count_down
+    ; fall through
+count_up:
+    ; for a clockwise move - we'll add 1 by inverting
+    mov x, ~ osr        ; store inverted OSR on x
+    jmp x--, fake       ; use jump to take off 1
+fake:
+    mov x, ~ x          ; invert back
+    jmp send
+count_down:
+    ; for a clockwise move, just take one off
+    mov x, osr          ; store osr in x
+    jmp x--, send       ; dec and send
+send:
+    ; send x.
+    mov isr, x          ; send it
+    push noblock        ; put ISR into input FIFO
+    mov osr, x          ; put X back in OSR
+    jmp read            ; loop back
+"""
+
+assembled = adafruit_pioasm.assemble(program)
+
+
+class QuadratureEncoder:
+    def __init__(self, first_pin, second_pin, reversed=False):
+        """Encoder with 2 pins. Must use sequential pins on the board"""
+        self.sm = rp2pio.StateMachine(
+            assembled,
+            frequency=0,
+            first_in_pin=first_pin,
+            jmp_pin=second_pin,
+            in_pin_count=2,
+        )
+        self.reversed = reversed
+        self._buffer = array.array("i", [0])
+        asyncio.create_task(self.poll_loop())
+
+    async def poll_loop(self):
+        while True:
+            await asyncio.sleep(0)
+            while self.sm.in_waiting:
+                self.sm.readinto(self._buffer)
+
+    def read(self):
+        if self.reversed:
+            return -self._buffer[0]
+        else:
+            return self._buffer[0]

ch-11/3-known-distance-acceleration/robot.py

@@ -0,0 +1,65 @@
+import board
+import pwmio
+import pio_encoder
+import busio
+import adafruit_vl53l1x
+import math
+import busio
+
+uart = busio.UART(board.GP12, board.GP13, baudrate=9600)
+
+wheel_diameter_mm = 70
+wheel_circumference_mm = math.pi * wheel_diameter_mm
+gear_ratio = 298
+encoder_poles = 28
+ticks_per_revolution = encoder_poles * gear_ratio
+ticks_to_mm_const = wheel_circumference_mm / ticks_per_revolution
+
+def ticks_to_mm(ticks):
+    return ticks_to_mm_const * ticks
+
+motor_A2 = pwmio.PWMOut(board.GP17, frequency=100)
+motor_A1 = pwmio.PWMOut(board.GP16, frequency=100)
+motor_B2 = pwmio.PWMOut(board.GP18, frequency=100)
+motor_B1 = pwmio.PWMOut(board.GP19, frequency=100)
+
+right_motor = motor_A1, motor_A2
+left_motor = motor_B1, motor_B2
+
+right_encoder = pio_encoder.QuadratureEncoder(board.GP20, board.GP21)
+left_encoder = pio_encoder.QuadratureEncoder(board.GP26, board.GP27, reversed=True)
+
+i2c0 = busio.I2C(sda=board.GP0, scl=board.GP1)
+i2c1 = busio.I2C(sda=board.GP2, scl=board.GP3)
+
+left_distance = adafruit_vl53l1x.VL53L1X(i2c0)
+right_distance = adafruit_vl53l1x.VL53L1X(i2c1)
+
+
+def stop():
+    motor_A1.duty_cycle = 0
+    motor_A2.duty_cycle = 0
+    motor_B1.duty_cycle = 0
+    motor_B2.duty_cycle = 0
+
+
+def set_speed(motor, speed):
+    # Swap motor pins if we reverse the speed
+    if speed < 0:
+        direction = motor[1], motor[0]
+        speed = -speed
+    else:
+        direction = motor
+    speed = min(speed, 1)  # limit to 1.0
+    max_speed = 2 ** 16 - 1
+
+    direction[0].duty_cycle = int(max_speed * speed)
+    direction[1].duty_cycle = 0
+
+
+def set_left(speed):
+    set_speed(left_motor, speed)
+
+
+def set_right(speed):
+    set_speed(right_motor, speed)

ch-11/_test_encoder_output/lpf.py

@@ -0,0 +1,8 @@
+class LPF:
+  """Low pass filter."""
+  def __init__(self, alpha):
+    self.alpha = alpha
+    self.last = 0
+  def update(self, value):
+    self.last = self.alpha * value + (1 - self.alpha) * self.last
+    return self.last

ch-11/pc-live-graph/live_graph.py

@@ -1,59 +0,0 @@
-""" Turn JSON data stream into graphs"""
-import requests
-import json
-
-import matplotlib.pyplot as plt
-from matplotlib.animation import FuncAnimation
-
-url = "http://192.168.1.128"
-
-
-class AnimatedGraph:
-    def __init__(self):
-        self.fields = {}
-        self.samples = 100
-        self.reset()
-        print("getting source to iterate over")
-        self.source = self._graph_source()
-        print("init completed")
-
-    def reset(self):
-        for field in self.fields:
-            self.fields[field] = []
-
-    def _graph_source(self):
-        while True:
-            try:
-                with requests.get(url, timeout=1, stream=True) as response:
-                    print(f"status: {response.status_code}")
-                    yield from response.iter_lines()
-            except requests.exceptions.RequestException:
-                pass
-
-    def make_frame(self, frame):
-        print("loading next item")
-        item = json.loads(next(self.source))
-        print("item loaded")
-        if 'time' in self.fields and item["time"] < self.fields['time'][-1]:
-            self.reset()
-        for field in item:
-            if field not in self.fields:
-                self.fields[field] = []
-            self.fields[field].append(item[field])
-
-        if len(self.fields['time'] ) > self.samples:
-            for field in self.fields:
-                self.fields[field] = self.fields[field][-self.samples:]
-
-        plt.cla()  # clear axes.
-        # plot the items
-        for field in self.fields:
-            if field != "time":
-                plt.plot("time", field, data=self.fields)
-
-        plt.legend(loc="upper right")
-
-# Create the animation. gcf - get current figure. random_stream - callback func.
-animation = FuncAnimation(plt.gcf(), AnimatedGraph().make_frame, interval=200)
-plt.tight_layout()
-plt.show()

ch-11/pc-live-graph/requirements.txt

@@ -1,2 +0,0 @@
-matplotlib
-requests