TestTemp.py

#!/usr/bin/env python3

"""
Send state:
  struct settingsStruct {
    uint8_t temp_setting; // Temperature setting
    uint8_t heat; // On or Off?
    uint8_t cool; // On or Off?
    uint8_t fan_mode; // Auto or On?
  } settings_struct;

Receive state:
  struct thermostatStruct {
    uint8_t _temp; // Current temperature
    uint8_t _temp_setting; // Temperature setting
    uint8_t _heat; // On or Off?
    uint8_t _heat_relay; // On or Off?
    uint8_t _cool; // On or Off?
    uint8_t _cool_relay; // On or Off?
    uint8_t _fan_mode; // Auto or On?
    uint8_t _fan_relay; // On or Off?
    unsigned long _run_stop; // When the system turned off, using system millis()
    unsigned long _run_start; // When the system turned on, using system millis()
} thermostat_struct;
"""

from time import sleep

from digi.xbee.devices import XBeeDevice
from digi.xbee.exception import TimeoutException

PORT = "/dev/ttyUSB0"
BAUD_RATE = 9600

REMOTE_STATE_REQUEST = bytearray([0x01])
SEND_TEMP = bytearray([0x10])
REMOTE_NODE_ID = "Thermostat"

crc_table = [
    247, 250, 54, 124, 174, 56, 24, 25, 76, 240, 58, 22, 88,
    134, 30, 79, 114, 93, 154, 41, 238, 78, 102, 185, 153, 4,
    203, 252, 113, 10, 237, 92, 3, 70, 196, 32, 55, 140, 229,
    244, 242, 116, 106, 209, 204, 77, 144, 15, 253, 217, 164, 246,
    248, 216, 12, 49, 125, 226, 53, 207, 84, 239, 17, 62, 156,
    96, 7, 117, 233, 162, 111, 225, 130, 97, 219, 135, 227, 67,
    45, 141, 83, 243, 8, 118, 129, 59, 43, 188, 180, 86, 231,
    71, 206, 136, 184, 82, 50, 155, 210, 181, 95, 100, 90, 189,
    178, 35, 28, 126, 202, 171, 133, 224, 87, 165, 214, 168, 131,
    98, 128, 173, 249, 42, 255, 177, 119, 221, 208, 120, 132, 222,
    36, 193, 44, 85, 39, 183, 199, 123, 74, 73, 60, 159, 151,
    105, 57, 27, 170, 18, 89, 107, 23, 21, 145, 91, 201, 176,
    19, 192, 190, 115, 112, 230, 94, 245, 72, 75, 38, 152, 61,
    198, 46, 149, 63, 99, 127, 179, 215, 232, 6, 191, 66, 138,
    9, 80, 143, 5, 31, 81, 212, 14, 11, 146, 34, 150, 167,
    254, 69, 213, 142, 169, 235, 251, 122, 148, 163, 157, 137, 37,
    47, 65, 175, 110, 220, 158, 223, 13, 195, 1, 101, 20, 200,
    218, 234, 40, 228, 166, 205, 147, 194, 161, 211, 68, 0, 16,
    236, 109, 241, 64, 104, 51, 33, 182, 2, 121, 172, 48, 186,
    103, 108, 52, 197, 26, 187, 160, 29, 139
]


def crc_calc(data):
    """Calculate a CRC-8 of the object passed

    Source: https://www.maximintegrated.com/en/app-notes/index.mvp/id/27

    Parameters
    ----------
    data : bytearray
        Binary data to calculate the CRC-8 for.

    Returns
    -------
    int
        CRC integer.
    """

    crc = 0x0

    for d in data:
        crc = crc_table[crc ^ d]

    return crc


def get_remote_state(device, remote_device, data_to_send):
    """
    Get remote state
    """
    attempt = 0
    while attempt < 10:
        try:
            print('Sending request for current state')

            device.send_data(remote_device, data_to_send)

            print("Successfully sent")

            xbee_message = device.read_data(10)  # Seconds

            # Verify CRC
            if crc_calc(xbee_message.data[2:]) != xbee_message.data[1]:
                print('CRC does not match! Try again...')
                raise TimeoutException  # Lazy so using this for now
            else:
                print('CRC match')

            return xbee_message, None
        except TimeoutException:
            print("Timed out, try again")
            attempt += 1
            sleep(7)
    return True, 'Failed to get remote state'


def send_state(device, remote_device, data_to_send):
    """
    Send new state to remote
    """
    attempt = 0
    while attempt < 10:
        try:
            print("Sending data to %s >> %s..." % (remote_device.get_64bit_addr(), data_to_send))
            device.send_data(remote_device, data_to_send)

            print("Successfully sent")

            return None, None
        except Exception:
            print("Exception while trying to send state, trying again")
            attempt += 1
            sleep(7)
    return None, "Failed to send state to remote"


def main():
    print(" +--------------------------------------+")
    print(" | XBee send update to thermostat       |")
    print(" +--------------------------------------+\n")

    device = XBeeDevice(PORT, BAUD_RATE)

    try:
        device.open()

        # Obtain the remote XBee device from the XBee network.
        xbee_network = device.get_network()
        remote_device = xbee_network.discover_device(REMOTE_NODE_ID)
        if remote_device is None:
            print("Could not find the remote device")
            exit(1)

        # Send request for state
        xbee_message, err = get_remote_state(device, remote_device, REMOTE_STATE_REQUEST)
        if err:
            print(err)
            exit(1)
        data = xbee_message.data[1:]

        print(data)

        settings_to_send = bytearray([73, 0x10])

        crc = bytearray([crc_calc(settings_to_send)])

        print('DATA_TYPE', SEND_TEMP)
        print('crc_calc', crc_calc(settings_to_send))
        print('crc', crc[0])
        print('settings_to_send', settings_to_send)

        data_to_send = SEND_TEMP + crc + settings_to_send

        send_state(device, remote_device, data_to_send)

    finally:
        if device is not None and device.is_open():
            device.close()


if __name__ == '__main__':
    main()