Karen Abruzzo and Jason Perez

Statement

Our initial intent was to create music by having marbles drop on differently shaped wooden pieces. The user would have control over the rate at which the marbles would drop through a spinning gate. The final outcome was realized through a spinning gate controlled by the user with a set of instructions. At the console, the user can define a sequence of six values that determine the speed and direction of the gate. These controls allow the user to create a rhythmic pattern with the motor and sound effects with the falling marbles.

Files

https://drive.google.com/file/d/1uyl0Dj6D769WWmYuC_1VhlOsYWAuSpW-/view?usp=sharing

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# musical_rotator.py
#
# This assumes a Pololu DRV8833 dual motor driver has been wired up to the Pico as follows:
#   Pico pin 24, GPIO18   -> AIN1
#   Pico pin 25, GPIO19   -> AIN2
#   any Pico GND          -> GND
 
# DRV8833 carrier board: https://www.pololu.com/product/2130
 
################################################################
# CircuitPython module documentation:
# time    https://circuitpython.readthedocs.io/en/latest/shared-bindings/time/index.html
# math    https://circuitpython.readthedocs.io/en/latest/shared-bindings/math/index.html
# board   https://circuitpython.readthedocs.io/en/latest/shared-bindings/board/index.html
# pwmio   https://circuitpython.readthedocs.io/en/latest/shared-bindings/pwmio/index.html
 
################################################################################
 
# load standard Python modules
import math, time
 
# load the CircuitPython hardware definition module for pin definitions
import board
 
# load the CircuitPython pulse-width-modulation module for driving hardware
import pwmio
 
#--------------------------------------------------------------------------------
# Class to represent a single dual H-bridge driver.
 
class DRV8833():
    def __init__(self, AIN1=board.GP18, AIN2=board.GP19, BIN2=board.GP20, BIN1=board.GP21, pwm_rate=20000):
        # Create a pair of PWMOut objects for each motor channel.
        self.ain1 = pwmio.PWMOut(AIN1, duty_cycle=0, frequency=pwm_rate)
        self.ain2 = pwmio.PWMOut(AIN2, duty_cycle=0, frequency=pwm_rate)
 
        self.bin1 = pwmio.PWMOut(BIN1, duty_cycle=0, frequency=pwm_rate)
        self.bin2 = pwmio.PWMOut(BIN2, duty_cycle=0, frequency=pwm_rate)
 
    def write(self, channel, rate):
        """Set the speed and direction on a single motor channel.
 
        :param channel:  0 for motor A, 1 for motor B
        :param rate: modulation value between -1.0 and 1.0, full reverse to full forward."""
 
        # convert the rate into a 16-bit fixed point integer
        pwm = min(max(int(2**16 * abs(rate)), 0), 65535)
 
        if channel == 0:
            if rate < 0:
                self.ain1.duty_cycle = pwm
                self.ain2.duty_cycle = 0
            else:
                self.ain1.duty_cycle = 0
                self.ain2.duty_cycle = pwm
        else:
            if rate < 0:
                self.bin1.duty_cycle = pwm
                self.bin2.duty_cycle = 0
            else:
                self.bin1.duty_cycle = 0
                self.bin2.duty_cycle = pwm
 
 
#--------------------------------------------------------------------------------
# Create an object to represent a dual motor driver.
print("Creating driver object.")
driver = DRV8833()
 
#--------------------------------------------------------------------------------
# Begin the main processing loop.  This is structured as a looping script, since
# each movement primitive 'blocks', i.e. doesn't return until the action is
# finished.
#---------------------------------------------------------------
class Logic:
    def __init__(self):
        """Application state machine."""
        self.update_interval = 100000000           # period of 2 Hz in nanoseconds
        self.update_timer    = 0
 
        # initialize the state machine
        self.state = 'init'
        self.state_changed = False
        self.state_timer = 0
        self.intList  = []
 
    def poll(self, elapsed):
        """Polling function to be called as frequently as possible from the event loop
        with the nanoseconds elapsed since the last cycle."""
        self.update_timer -= elapsed
        if self.update_timer < 0:
            self.update_timer += self.update_interval
            self.tick()            # evaluate the state machine
 
    def transition(self, new_state):
        """Set the state machine to enter a new state on the next tick."""
        self.state         = new_state
        self.state_changed = True
        self.state_timer   = 0
        print("Entering state:", new_state)
 
    def tick(self):
        """Evaluate the state machine rules."""
 
        # advance elapsed time in seconds
        self.state_timer += 1e-9 * self.update_interval
        #print(self.state_timer)
 
 
        # set up a flag to process transitions within a state clause
        entering_state = self.state_changed
        self.state_changed = False
 
        # select the state clause to evaluate
        if self.state == 'init':
            self.transition('idle')
 
        elif self.state == 'idle':
            if entering_state:
                self.intList = []
                driver.write(0, .7)
                print("Please enter 6 numbers 0-5, negative numbers reverse motor")
                print("Example: 0 1 2 -3 -4 -5")
                userInput = input("Enter: ")
                listTemp = list(userInput.split())
                self.intList = list(map(int,listTemp))
                #print(self.intList)
                self.transition('userState')
 
        elif self.state == 'userState':
            if self.intList[0] &gt; 0:
                driver.write(0, .55+.05*self.intList[0])
            else:
                driver.write(0, -.55+.05*self.intList[0])
            time.sleep(2.0)
            if self.intList[1] &gt; 0:
                driver.write(0, .55+.05*self.intList[1])
            else:
                driver.write(0, -.55+.05*self.intList[1])
            time.sleep(2.0)
            if self.intList[2] &gt; 0:
                driver.write(0, .55+.05*self.intList[2])
            else:
                driver.write(0, -.55+.05*self.intList[2])
            time.sleep(2.0)
            if self.intList[3] &gt; 0:
                driver.write(0, .55+.05*self.intList[3])
            else:
                driver.write(0, -.55+.05*self.intList[3])
            time.sleep(2.0)
            if self.intList[4] &gt; 0:
                driver.write(0, .55+.05*self.intList[4])
            else:
                driver.write(0, -.55+.05*self.intList[4])
            time.sleep(2.0)
            if self.intList[5] &gt; 0:
                driver.write(0, .55+.05*self.intList[5])
            else:
                driver.write(0, -.55+.05*self.intList[5])
            time.sleep(2.0)
            self.transition('idle')
 
#---------------------------------------------------------------
print("Starting main script.")
last_clock = time.monotonic_ns()
logic = Logic()
while True:
    now = time.monotonic_ns()
    elapsed = now - last_clock
    last_clock = now
    logic.poll(elapsed)