pyRF95

HopeRF RF95 (and similar LoRa modules) python library

Based in RadioHead library code: http://www.airspayce.com/mikem/arduino/RadioHead/

Installation

Just import rf95 module in your python project

Use

When creating the RF95 object, you need to pass the CS channel (On Raspberry Pi you have spidev 0 and 1 devices) and the external interrupt pin (Broadcom GPIO).

Then you can set channel, TX Power, and predefined modes of operation:

• Bw125Cr45Sf128 : Bw = 125 kHz, Cr = 4/5, Sf = 128chips/symbol, CRC on. Default medium range.
• Bw500Cr45Sf128 : Bw = 500 kHz, Cr = 4/5, Sf = 128chips/symbol, CRC on. Fast+short range.
• Bw31_25Cr48Sf512 : Bw = 31.25 kHz, Cr = 4/8, Sf = 512chips/symbol, CRC on. Slow+long range.
• Bw125Cr48Sf4096 : Bw = 125 kHz, Cr = 4/8, Sf = 4096chips/symbol, CRC on. Slow+long range.

You can also set custom modes using the rf95.set_modem_config_custom()and the following constants:

set_modem_config_custom(bandwidth, coding_rate, imp_header,
		spreading_factor, crc, continuous_tx,
		timeout, agc_auto)

Bandwidth:
rf95.BW_7K8HZ
rf95.BW_10K4HZ
rf95.BW_15K6HZ
rf95.BW_20K8HZ
rf95.BW_31K25HZ
rf95.BW_41K7HZ
rf95.BW_62K5HZ
rf95.BW_125KHZ
rf95.BW_250KHZ
rf95.BW_500KHZ

Coding Rate:
rf95.CODING_RATE_4_5
rf95.CODING_RATE_4_6
rf95.CODING_RATE_4_7
rf95.CODING_RATE_4_8

Implicit header:
rf95.IMPLICIT_HEADER_MODE_ON
rf95.IMPLICIT_HEADER_MODE_OFF

Spreading factor:
rf95.SPREADING_FACTOR_64CPS
rf95.SPREADING_FACTOR_128CPS
rf95.SPREADING_FACTOR_256CPS
rf95.SPREADING_FACTOR_512CPS
rf95.SPREADING_FACTOR_1024CPS
rf95.SPREADING_FACTOR_2048CPS
rf95.SPREADING_FACTOR_4096CPS

TX Continuous mode
rf95.TX_CONTINUOUS_MODE_ON
rf95.TX_CONTINUOUS_MODE_OFF

CRC:
rf95.RX_PAYLOAD_CRC_ON
rf95.RX_PAYLOAD_CRC_OFF

Timeout:
rf95.SYM_TIMEOUT_MSB

AGC Auto:
rf95.AGC_AUTO_ON
rf95.AGC_AUTO_OFF

Example

import rf95

# Create rf95 object with CS0 and external interrupt on pin 25
lora = rf95.RF95(0, 25)

if not lora.init(): # returns True if found
	print("RF95 not found")
	quit(1)
else:
	print("RF95 LoRa mode ok")

# set frequency, power and mode
lora.set_frequency(868.5)
lora.set_tx_power(5)
lora.set_modem_config(Bw31_25Cr48Sf512)

# Send some data
lora.send([0x00, 0x01, 0x02, 0x03])
lora.wait_packet_sent()
# Send a string
lora.send(lora.str_to_data("$TELEMETRY TEST"))
lora.wait_packet_sent()

# Wait until data is available 
while not lora.available():
	pass
# Receive
data = lora.recv()
print (data)
for i in data:
	print(chr(i), end="")
print()
lora.set_mode_idle()