1  # Example to send a packet periodically between addressed nodes
 2  # Author: Jerry Needell
 3  #
 4  import time
 5  import board
 6  import busio
 7  import digitalio
 8  import adafruit_rfm69
 9  
10  # Define radio parameters.
11  RADIO_FREQ_MHZ = 915.0  # Frequency of the radio in Mhz. Must match your
12  # module! Can be a value like 915.0, 433.0, etc.
13  
14  # Define pins connected to the chip.
15  CS = digitalio.DigitalInOut(board.CE1)
16  RESET = digitalio.DigitalInOut(board.D25)
17  
18  # Initialize SPI bus.
19  spi = busio.SPI(board.SCK, MOSI=board.MOSI, MISO=board.MISO)
20  
21  # Initialze RFM radio
22  rfm69 = adafruit_rfm69.RFM69(spi, CS, RESET, RADIO_FREQ_MHZ)
23  
24  # Optionally set an encryption key (16 byte AES key). MUST match both
25  # on the transmitter and receiver (or be set to None to disable/the default).
26  rfm69.encryption_key = (
27      b"\x01\x02\x03\x04\x05\x06\x07\x08\x01\x02\x03\x04\x05\x06\x07\x08"
28  )
29  
30  # set node addresses
31  rfm69.node = 2
32  rfm69.destination = 1
33  # initialize counter
34  counter = 0
35  # send a broadcast message from my_node with ID = counter
36  rfm69.send(bytes("startup message from node {} ".format(rfm69.node), "UTF-8"))
37  
38  # Wait to receive packets.
39  print("Waiting for packets...")
40  # initialize flag and timer
41  time_now = time.monotonic()
42  while True:
43      # Look for a new packet: only accept if addresses to my_node
44      packet = rfm69.receive(with_header=True)
45      # If no packet was received during the timeout then None is returned.
46      if packet is not None:
47          # Received a packet!
48          # Print out the raw bytes of the packet:
49          print("Received (raw header):", [hex(x) for x in packet[0:4]])
50          print("Received (raw payload): {0}".format(packet[4:]))
51          print("Received RSSI: {0}".format(rfm69.last_rssi))
52          # send reading after any packet received
53          counter = counter + 1
54          # after 10 messages send a response to destination_node from my_node with ID = counter&0xff
55          if counter % 10 == 0:
56              time.sleep(0.5)  # brief delay before responding
57              rfm69.identifier = counter & 0xFF
58              rfm69.send(
59                  bytes(
60                      "message number {} from node {} ".format(counter, rfm69.node),
61                      "UTF-8",
62                  ),
63                  keep_listening=True,
64              )