GROUND.py

#!/usr/bin/python

# Carlson GROUND station v0.3
#
# 5 October 2017, Benjamin Shanahan.

from lib.state import State
from lib.telemetry import Telemetry, PORT

import sys
import threading
import Queue
import argparse

# Default port for telemetry radio
DEFAULT_PORT = "/dev/ttyUSB0"

if __name__ == "__main__":

    state = State()

    ###########################################################################
    ## Functions
    ###########################################################################

    # Asynchronously add any screen input to a queue
    def add_input(input_queue):
        while True:
            input_queue.put(sys.stdin.read(1))

    # Write command to telemetry radio
    def broadcast(cmd=None):
        if cmd is not None:
            radio.write(chr(cmd))

    ###########################################################################
    ## Input Buffer
    ###########################################################################

    # Set up argument parser to specify different port for radio via terminal
    parser = argparse.ArgumentParser(description="Ground station for the Carlson rocket flight computer.")
    parser.add_argument("-p", "--port", default=DEFAULT_PORT, help="Serial port of the telemetry radio.")
    args = parser.parse_args()

    # Initialize Telemetry radio with port from ArgumentParser
    radio = Telemetry(args.port)

    # Add Queue and launch a thread to monitor user input.
    input_queue = Queue.Queue()
    input_thread = threading.Thread(target=add_input, args=(input_queue,))
    input_thread.daemon = True
    input_thread.start()

    print '''
    a:\tArm
    d:\tDisarm
    l:\tArm and log
    c:\tForce chute deploy
    k:\tDisarm and poweroff
    '''
    # Respond to user input, non-blocking.
    while (True):

        if not input_queue.empty():
            arg = input_queue.get().lower().strip()
            if arg != "":
                # Arm
                if arg == "a":
                    print "arm"
                    broadcast(state.ARM)
                # Disarm
                if arg == "d":
                    print "disarm"
                    broadcast(state.IDLE)
                # Start logger (i.e. ready for launch)
                if arg == "l":
                    print "start logging"
                    broadcast(state.ARM + state.LOGGING)
                # Deploy chute
                if arg == "c":
                    print "deploy chute"
                    broadcast(state.ARM + state.LOGGING + state.CHUTE)
                # Shutdown Carlson
                if arg == "k":
                    print "power off"
                    broadcast(state.POWER_OFF)

        # Read (non-blocking) from telemetry radio
        received = radio.read()
        if received != "":
            state.set(ord(received))
            print "Air State: %s" % state