#!/usr/bin/env python3 """\ suitcase_midi_demo.py : sample code in Python to translate MIDI events into motion commands for an Arduino running StepperWinch No copyright, 2021, Garth Zeglin. This file is explicitly placed in the public domain. """ #================================================================ # Standard Python modules. import argparse import time import platform # This requires a pySerial installation. # Package details: https://pypi.python.org/pypi/pyserial, # Documentation: http://pythonhosted.org/pyserial/ import serial # For documentation on python-rtmidi: https://pypi.org/project/python-rtmidi/ import rtmidi #================================================================ class StepperWinchClient(object): """Class to manage a connection to a serial-connected Arduino running the StepperWinch script. :param port: the name of the serial port device :param verbose: flag to increase console output :param debug: flag to print raw inputs on console :param kwargs: collect any unused keyword arguments """ def __init__(self, port=None, verbose=False, debug=False, **kwargs ): # initialize the client state self.arduino_time = 0 self.position = [0, 0, 0] self.target = [0, 0, 0] self.verbose = verbose self.debug = debug self.awake = False # open the serial port, which should also reset the Arduino if self.verbose: print(f"Opening Arduino on {port}") self.port = serial.Serial( port, 115200, timeout=5 ) if self.verbose: print("Opened serial port named", self.port.name) print("Sleeping briefly while Arduino boots...") # wait briefly for the Arduino to finish booting time.sleep(2) # units are seconds # throw away any extraneous input self.port.flushInput() return def close(self): """Shut down the serial connection to the Arduino, after which this object may no longer be used.""" self.port.close() self.port = None return def _wait_for_input(self): line = self.port.readline().rstrip() if line: elements = line.split() if self.debug: print("Received: '%s'" % line) if elements[0] == b'txyza': self.arduino_time = int(elements[1]) self.position = [int(s) for s in elements[2:]] elif elements[0] == b'awake': self.awake = True elif elements[0] == b'dbg': print("Received debugging message:", line) else: print("Unknown status message: ", line) return def _send_command(self, string): if self.verbose: print("Sending: ", string) self.port.write(string.encode() + b'\n') return def motor_enable( self, value=True): """Issue a command to enable or disable the stepper motor drivers.""" self._send_command( "enable 1" if value is True else "enable 0" ) return def set_freq_damping(self, freq, damping): """Issue a command to set the second-order model gains.""" self._send_command("g xyza %f %f" % (freq, damping)) return def wait_for_wakeup(self): """Issue a status query and wait until an 'awake' status has been received.""" while self.awake is False: self._send_command("ping") self._wait_for_input() def relative_move(self, flags, positions): """Issue a non-blocking relative move command for a subset of channels defined by a set of flag characters.""" values = " ".join(["%d" % (i) for i in positions]) self._send_command("d %s %s" % (flags, values)) def move_to(self, position): """Issue a command to move to a [x, y, z, a] absolute position (specified in microsteps) and wait until completion. :param position: a list or tuple with at least four elements """ self._send_command("a xyza %d %d %d %d" % tuple(position)) self.target = position # wait for all reported positions to be close to the request moving = True while moving: self._wait_for_input() if self.verbose: print ("Position:", self.position) moving = any([abs(pos - target) > 5 for pos, target in zip(self.position, self.target)]) return ################################################################ class MidiDriver(object): """Class to manage a MIDI input connection and translate events to motion commands.""" def __init__(self, client, args): # save the client handle self.client = client if args.verbose: print(f"Opening MIDI input to look for {args.midi}.") # Initialize the MIDI input system and read the currently available ports. self.midi_in = rtmidi.MidiIn() for idx, name in enumerate(self.midi_in.get_ports()): if args.midi in name: print("Found preferred MIDI input device %d: %s" % (idx, name)) self.midi_in.open_port(idx) self.midi_in.set_callback(self.midi_received) break else: print("Ignoring unselected MIDI device: ", name) if not self.midi_in.is_port_open(): if platform.system() == 'Windows': print("Virtual MIDI inputs are not currently supported on Windows, see python-rtmidi documentation.") else: print("Creating virtual MIDI input.") self.midi_in.open_virtual_port(args.midi) def midi_received(self, data, unused): msg, delta_time = data if len(msg) > 2: if msg[0] == 153: # note on, channel 9 key = (msg[1] - 36) % 16 row = key // 4 col = key % 4 velocity = msg[2] print("Pad (%d, %d): %d" % (row, col, velocity)) delta = velocity if row > 1 else -velocity if row == 0 or row == 3: delta = delta * 2 flag = "xyza"[col] # send a single-channel relative move command self.client.relative_move(flag, [delta]) #================================================================ cmd_desc = "Translate MIDI events to motion commands for the StepperWinch firmware on an Arduino." # The following section is run when this is loaded as a script. if __name__ == "__main__": # Initialize the command parser. parser = argparse.ArgumentParser(description = cmd_desc) parser.add_argument('-v', '--verbose', action='store_true', help='Enable more detailed output.' ) parser.add_argument('--debug', action='store_true', help='Enable debugging output.' ) parser.add_argument('--midi', type=str, default = "MPD218 Port A", help = "Keyword identifying the MIDI input device (default: %(default)s).") parser.add_argument('-p', '--port', default='/dev/cu.usbmodem14301', help='Specify the name of the Arduino serial port device (default is %(default)s).') # Parse the command line, returning a Namespace. args = parser.parse_args() # Convert the Namespace to a set of keyword arguments. kwargs = vars(args) # Connect to the Arduino. Note that it will ignore extraneous values, e.g., # from additional command argument inputs unneeded by this object. client = StepperWinchClient(**kwargs) # Connect to the MIDI port. driver = MidiDriver(client, args) # Enter the event loop. MIDI events will arrive at the callback and trigger motion commands. try: print("Waiting for wakeup.") client.wait_for_wakeup() client.set_freq_damping(1.0, 0.5) while True: client._wait_for_input() except KeyboardInterrupt: print("User interrupted motion.") # Issue a command to turn off the drivers, then shut down the connection. client.motor_enable(False) client.close()