Chapter 11 code changes - async and bluetooth

ch-11/1-encoder-speed/encoder_speed.py

@@ -1,73 +0,0 @@
-import time
-import json
-
-from adafruit_esp32spi import adafruit_esp32spi_wsgiserver
-from adafruit_wsgi.wsgi_app import WSGIApp
-
-import robot
-import robot_wifi
-
-
-class SpeedCountApp:
-    def __init__(self):
-        self.intended_speed = 0.9
-        self.last_time = time.monotonic()
-        self.wifi = None
-        self.server = None
-
-    def setup_wifi(self, app):
-        print("Setting up wifi.")
-        self.wifi, esp = robot_wifi.connect_to_wifi()
-        self.server = adafruit_esp32spi_wsgiserver.WSGIServer(80, application=app)
-        adafruit_esp32spi_wsgiserver.set_interface(esp)
-        print("Starting server")
-
-        self.server.start()
-        ip_int = ".".join(str(int(n)) for n in esp.ip_address)
-        print(f"IP Address is {ip_int}")
-
-    def index(self, request):
-        new_time = time.monotonic()
-        time_delta = new_time - self.last_time
-        self.last_time = new_time
-
-        left_speed = robot.left_encoder.get_speed(time_delta)
-        right_speed = robot.right_encoder.get_speed(time_delta)
-        return (
-            200,
-            [("Content-Type", "application/json")],
-            [
-                json.dumps(
-                    {
-                        "left_speed": left_speed,
-                        "right_speed": right_speed,
-                        "time": self.last_time,
-                    }
-                )
-            ],
-        )
-
-    def main_loop(self):
-        robot.set_left(self.intended_speed)
-        robot.set_right(self.intended_speed)
-        while True:
-            try:
-                self.server.update_poll()
-            except RuntimeError as e:
-                print(f"Server poll error: {type(e)}, {e}")
-                print(f"Resetting ESP...")
-                self.wifi.reset()
-                print("Reset complete.")
-
-    def start(self):
-        app = WSGIApp()
-        app.route("/")(self.index)
-        print("Starting")
-        try:
-            self.setup_wifi(app)
-            self.main_loop()
-        finally:
-            robot.stop()
-
-
-SpeedCountApp().start()

ch-11/1-encoder-speed/robot_wifi.py

@@ -1,25 +0,0 @@
-import board
-import busio
-from digitalio import DigitalInOut
-from adafruit_esp32spi import adafruit_esp32spi
-from adafruit_esp32spi import adafruit_esp32spi_wifimanager
-
-try:
-    from secrets import secrets
-except ImportError:
-    print("WiFi secrets are kept in secrets.py, please add them there!")
-    raise
-
-
-def connect_to_wifi():
-    esp32_cs = DigitalInOut(board.GP10)
-    esp32_ready = DigitalInOut(board.GP9)
-    esp32_reset = DigitalInOut(board.GP8)
-
-    spi = busio.SPI(board.GP14, MOSI=board.GP11, MISO=board.GP12)
-    esp = adafruit_esp32spi.ESP_SPIcontrol(spi, esp32_cs, esp32_ready, esp32_reset)
-    esp.reset()
-    wifi = adafruit_esp32spi_wifimanager.ESPSPI_WiFiManager(esp, secrets)
-    wifi.connect()
-
-    return wifi, esp

ch-11/1-measuring_wheel_speeds/code.py

@@ -0,0 +1,47 @@
+import asyncio
+import board
+import busio
+import robot
+uart = busio.UART(board.GP12, board.GP13, baudrate=9600)
+
+class Settings:
+  speed = 0.7
+  time_interval = 0.2
+
+async def motor_speed_loop():
+  left_last, right_last = robot.left_encoder.read(), robot.right_encoder.read()
+  while True:
+    await asyncio.sleep(Settings.time_interval)
+    left_new, right_new = robot.left_encoder.read(), robot.right_encoder.read()
+    left_speed = robot.ticks_to_mm(left_new - left_last) / Settings.time_interval
+    left_last = left_new
+    right_speed = robot.ticks_to_mm(right_new - right_last) / Settings.time_interval
+    right_last = right_new
+    uart.write(f"{left_speed:.3f},{right_speed:.3f},0\n".encode())
+
+async def stop_motors_after(seconds):
+  await asyncio.sleep(seconds)
+  robot.stop()
+
+async def command_handler():
+  while True:
+    if uart.in_waiting:
+      command = uart.readline().decode().strip()
+      if command.startswith("M"):
+        speed = float(command[1:])
+      elif command.startswith("T"):
+        Settings.time_interval = float(command[1:])
+      elif command == "O":
+        robot.stop()
+      elif command.startswith("O"):
+        robot.set_left(Settings.speed)
+        robot.set_right(Settings.speed)
+        asyncio.create_task(stop_motors_after(float(command[1:])))
+      elif command.startswith("?"):
+        uart.write(f"M{Settings.speed:.1f}\n".encode())
+        uart.write(f"T{Settings.time_interval:.1f}\n".encode())
+        await asyncio.sleep(3)
+    await asyncio.sleep(0)
+
+asyncio.create_task(motor_speed_loop())
+asyncio.run(command_handler())

ch-11/1-measuring_wheel_speeds/pid_controller.py

@@ -0,0 +1,20 @@
+class PIDController:
+    def __init__(self, kp, ki, kd, d_filter_gain=0.1):
+        self.kp = kp
+        self.ki = ki
+        self.kd = kd
+        self.d_filter_gain = d_filter_gain
+
+        self.integral = 0
+        self.error_prev = 0
+        self.derivative = 0
+
+    def calculate(self, error, dt):
+        self.integral += error * dt
+
+        # 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-measuring_wheel_speeds/pio_encoder.py

@@ -67,7 +67,6 @@ class QuadratureEncoder:
         )
         self.reversed = reversed
         self._buffer = array.array("i", [0])
-        self.previous_reading = 0
 
     def read(self):
         while self.sm.in_waiting:
@@ -76,9 +75,3 @@ class QuadratureEncoder:
             return -self._buffer[0]
         else:
             return self._buffer[0]
-
-    def get_speed(self, delta_time):
-        new_read = self.read()
-        distance = new_read - self.previous_reading
-        self.previous_reading = new_read
-        return distance / delta_time

ch-11/1-measuring_wheel_speeds/robot.py

@@ -3,12 +3,20 @@ import pwmio
 import pio_encoder
 import busio
 import adafruit_vl53l1x
+import math
 
+wheel_diameter_mm = 70
+wheel_circumference_mm = math.pi * wheel_diameter_mm
+ticks_per_revolution = 2800
+ticks_to_mm_const = wheel_circumference_mm / ticks_per_revolution
 
-motor_A1 = pwmio.PWMOut(board.GP17)
-motor_A2 = pwmio.PWMOut(board.GP16)
-motor_B1 = pwmio.PWMOut(board.GP18)
-motor_B2 = pwmio.PWMOut(board.GP19)
+def ticks_to_mm(ticks):
+    return ticks_to_mm_const * ticks
+
+motor_A1 = pwmio.PWMOut(board.GP17, frequency=100)
+motor_A2 = pwmio.PWMOut(board.GP16, frequency=100)
+motor_B1 = pwmio.PWMOut(board.GP18, frequency=100)
+motor_B2 = pwmio.PWMOut(board.GP19, frequency=100)
 
 right_motor = motor_A1, motor_A2
 left_motor = motor_B1, motor_B2

ch-11/_test_encoder_output/code.py

@@ -0,0 +1,34 @@
+import time
+import board
+import busio
+import robot
+
+uart = busio.UART(board.GP12, board.GP13, baudrate=9600)
+
+speed = 0.7
+stop_time = 0
+
+while True:
+  current_time = time.monotonic()
+  if current_time > stop_time:
+    robot.set_left(0)
+    robot.set_right(0)
+  left_value = robot.left_encoder.read()
+  right_value = robot.right_encoder.read()
+  uart.write(f"{left_value:.3f},{right_value:.3f}\n".encode() )
+  time.sleep(0.02)
+  if uart.in_waiting:
+    command = uart.readline().decode().strip()
+    if command.startswith("M"):
+      speed = float(command[1:])
+    elif command == "O":
+      stop_time = 0
+      robot.set_left(0)
+      robot.set_right(0)
+    elif command.startswith("O"):
+      stop_time = float(command[1:]) + current_time
+      robot.set_left(speed)
+      robot.set_right(speed)
+    elif command.startswith("?"):
+      uart.write(f"M{speed:.1f}\n".encode())
+      time.sleep(3)

ch-11/_test_encoder_output/pid_controller.py

@@ -0,0 +1,20 @@
+class PIDController:
+    def __init__(self, kp, ki, kd, d_filter_gain=0.1):
+        self.kp = kp
+        self.ki = ki
+        self.kd = kd
+        self.d_filter_gain = d_filter_gain
+
+        self.integral = 0
+        self.error_prev = 0
+        self.derivative = 0
+
+    def calculate(self, error, dt):
+        self.integral += error * dt
+
+        # 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/_test_encoder_output/pio_encoder.py

@@ -0,0 +1,77 @@
+import rp2pio
+import adafruit_pioasm
+import array
+
+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])
+
+    def read(self):
+        while self.sm.in_waiting:
+            self.sm.readinto(self._buffer)
+        if self.reversed:
+            return -self._buffer[0]
+        else:
+            return self._buffer[0]

ch-11/_test_encoder_output/robot.py

@@ -0,0 +1,60 @@
+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
+ticks_per_revolution = 2800
+ticks_to_mm_const = wheel_circumference_mm / ticks_per_revolution
+
+def ticks_to_mm(ticks):
+    return ticks_to_mm_const * ticks
+
+motor_A1 = pwmio.PWMOut(board.GP17, frequency=100)
+motor_A2 = pwmio.PWMOut(board.GP16, frequency=100)
+motor_B1 = pwmio.PWMOut(board.GP18, frequency=100)
+motor_B2 = 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, reversed=True)
+left_encoder = pio_encoder.QuadratureEncoder(board.GP26, board.GP27)
+
+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)