Simple test¶
Ensure your device works with this simple test.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 | # SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT
# Simple demo of sending and recieving data with the RFM95 LoRa radio.
# Author: Tony DiCola
import board
import busio
import digitalio
import adafruit_rfm9x
# Define radio parameters.
RADIO_FREQ_MHZ = 915.0 # Frequency of the radio in Mhz. Must match your
# module! Can be a value like 915.0, 433.0, etc.
# Define pins connected to the chip, use these if wiring up the breakout according to the guide:
CS = digitalio.DigitalInOut(board.D5)
RESET = digitalio.DigitalInOut(board.D6)
# Or uncomment and instead use these if using a Feather M0 RFM9x board and the appropriate
# CircuitPython build:
# CS = digitalio.DigitalInOut(board.RFM9X_CS)
# RESET = digitalio.DigitalInOut(board.RFM9X_RST)
# Define the onboard LED
LED = digitalio.DigitalInOut(board.D13)
LED.direction = digitalio.Direction.OUTPUT
# Initialize SPI bus.
spi = busio.SPI(board.SCK, MOSI=board.MOSI, MISO=board.MISO)
# Initialze RFM radio
rfm9x = adafruit_rfm9x.RFM9x(spi, CS, RESET, RADIO_FREQ_MHZ)
# Note that the radio is configured in LoRa mode so you can't control sync
# word, encryption, frequency deviation, or other settings!
# You can however adjust the transmit power (in dB). The default is 13 dB but
# high power radios like the RFM95 can go up to 23 dB:
rfm9x.tx_power = 23
# Send a packet. Note you can only send a packet up to 252 bytes in length.
# This is a limitation of the radio packet size, so if you need to send larger
# amounts of data you will need to break it into smaller send calls. Each send
# call will wait for the previous one to finish before continuing.
rfm9x.send(bytes("Hello world!\r\n", "utf-8"))
print("Sent Hello World message!")
# Wait to receive packets. Note that this library can't receive data at a fast
# rate, in fact it can only receive and process one 252 byte packet at a time.
# This means you should only use this for low bandwidth scenarios, like sending
# and receiving a single message at a time.
print("Waiting for packets...")
while True:
packet = rfm9x.receive()
# Optionally change the receive timeout from its default of 0.5 seconds:
# packet = rfm9x.receive(timeout=5.0)
# If no packet was received during the timeout then None is returned.
if packet is None:
# Packet has not been received
LED.value = False
print("Received nothing! Listening again...")
else:
# Received a packet!
LED.value = True
# Print out the raw bytes of the packet:
print("Received (raw bytes): {0}".format(packet))
# And decode to ASCII text and print it too. Note that you always
# receive raw bytes and need to convert to a text format like ASCII
# if you intend to do string processing on your data. Make sure the
# sending side is sending ASCII data before you try to decode!
packet_text = str(packet, "ascii")
print("Received (ASCII): {0}".format(packet_text))
# Also read the RSSI (signal strength) of the last received message and
# print it.
rssi = rfm9x.last_rssi
print("Received signal strength: {0} dB".format(rssi))
|