This class provides a driver for the LoRa network processor in the LoPy. Below is an example demonstrating LoRaWAN Activation by Personalisation usage:
from network import LoRa import socket import binascii import struct # Initialize LoRa in LORAWAN mode. lora = LoRa(mode=LoRa.LORAWAN) # create an ABP authentication params dev_addr = struct.unpack(">l", binascii.unhexlify('00 00 00 05'.replace(' ',''))) nwk_swkey = binascii.unhexlify('2B 7E 15 16 28 AE D2 A6 AB F7 15 88 09 CF 4F 3C'.replace(' ','')) app_swkey = binascii.unhexlify('2B 7E 15 16 28 AE D2 A6 AB F7 15 88 09 CF 4F 3C'.replace(' ','')) # join a network using ABP (Activation By Personalization) lora.join(activation=LoRa.ABP, auth=(dev_addr, nwk_swkey, app_swkey)) # create a LoRa socket s = socket.socket(socket.AF_LORA, socket.SOCK_RAW) # set the LoRaWAN data rate s.setsockopt(socket.SOL_LORA, socket.SO_DR, 5) # make the socket non-blocking s.setblocking(False) # send some data s.send(bytes([0x01, 0x02, 0x03])) # get any data received... data = s.recv(64) print(data)
Please ensure that there is an antenna connected to your device before sending/receiving LoRa messages as inproper use (e.g. without an antenna), may damage the device.
For various other complete LoRa examples, check here for additional examples.
Create and configure a LoRa object. See init for params of configuration.
lora = LoRa(mode=LoRa.LORAWAN)
This method is used to set the LoRa subsystem configuration and to specific raw LoRa or LoRaWAN.
The arguments are:
modecan be either
frequencyaccepts values between 863000000 and 870000000 in the 868 band, or between 902000000 and 928000000 in the 915 band.
tx_poweris the transmit power in dBm. It accepts between 2 and 14 for the 868 band, and between 5 and 20 in the 915 band.
bandwidthis the channel bandwidth in KHz. In the 868 band the accepted values are
LoRa.BW_125KHZand LoRa.BW_250KHZ. In the 915 band the accepted values are LoRa.BW_125KHZand LoRa.BW_500KHZ.
sfsets the desired spreading factor. Accepts values between 7 and 12.
preambleconfigures the number of pre-amble symbols. The default value is 8.
coding_ratecan take the following values:
LoRa.CODING_4_5, LoRa.CODING_4_6, LoRa.CODING_4_7or LoRa.CODING_4_8.
power_modecan be either
LoRa.ALWAYS_ON, LoRa.TX_ONLYor LoRa.SLEEP. In ALWAYS_ONmode, the radio is always listening for incoming - packets whenever a transmission is not taking place. In TX_ONLYthe radio goes to sleep as soon as the transmission completes. In SLEEPmode the radio is sent to sleep permanently and won’t accept any commands until the power mode is changed.
tx_iqenables TX IQ inversion.
rx_iqenables RX IQ inversion.
adrenables Adaptive Data Rate.
publicselects between the public and private sync word.
tx_retriessets the number of TX retries in
device_classsets the LoRaWAN device class. Can be either
device_class are used. All the other params will be ignored as they are handled by the LoRaWAN stack directly. On the other hand, in
device_class are ignored since they are only relevant to the LoRaWAN stack.
For example, you can do:
# initialize in raw LoRa mode lora.init(mode=LoRa.LORA, tx_power=14, sf=12)
# initialize in LoRaWAN mode lora.init(mode=LoRa.LORAWAN)
Join a LoRaWAN network. Internally the stack will automatically retry every 15 seconds until a Join Accept message is received. The parameters are:
activation: can be either
auth: is a tuple with the authentication data.
timeout: is the maximum time in milliseconds to wait for the Join Accept message to be received. If no timeout (or zero) is given, the call returns immediatelly and the status of the join request can be checked with
dr: is an optional value to specify the initial data rate for the Join Request. Possible values are 0 to 5 for EU868, or 0 to 4 for US915.
In the case of
from network import LoRa import socket import time import binascii # Initialize LoRa in LORAWAN mode. lora = LoRa(mode=LoRa.LORAWAN) # create an OTAA authentication parameters app_eui = binascii.unhexlify('AD A4 DA E3 AC 12 67 6B'.replace(' ','')) app_key = binascii.unhexlify('11 B0 28 2A 18 9B 75 B0 B4 D2 D8 C7 FA 38 54 8B'.replace(' ','')) # join a network using OTAA (Over the Air Activation) lora.join(activation=LoRa.OTAA, auth=(app_eui, app_key), timeout=0) # wait until the module has joined the network while not lora.has_joined(): time.sleep(2.5) print('Not yet joined...')
In the case of
from network import LoRa import socket import binascii import struct # Initialize LoRa in LORAWAN mode. lora = LoRa(mode=LoRa.LORAWAN) # create an ABP authentication params dev_addr = struct.unpack(">l", binascii.unhexlify('00 00 00 05'.replace(' ',''))) nwk_swkey = binascii.unhexlify('2B 7E 15 16 28 AE D2 A6 AB F7 15 88 09 CF 4F 3C'.replace(' ','')) app_swkey = binascii.unhexlify('2B 7E 15 16 28 AE D2 A6 AB F7 15 88 09 CF 4F 3C'.replace(' ','')) # join a network using ABP (Activation By Personalization) lora.join(activation=LoRa.ABP, auth=(dev_addr, nwk_swkey, app_swkey))
Get or set the bandwidth in raw LoRa mode (
# get raw LoRa Bandwidth lora.bandwidth() # set raw LoRa Bandwidth lora.bandwidth(LoRa.BW_125KHZ)
Get or set the frequency in raw LoRa mode (
# get raw LoRa Frequency lora.frequency() # set raw LoRa Frequency lora.frequency(868000000)
Get or set the coding rate in raw LoRa mode (LoRa.LORA). The allowed values are:
# get raw LoRa Coding Rate lora.coding_rate() # set raw LoRa Coding Rate lora.coding_rate(LoRa.CODING_4_5)
Get or set the number of preamble symbols in raw LoRa mode (
# get raw LoRa preamble symbols lora.preamble() # set raw LoRa preamble symbols lora.preamble(LoRa.CODING_4_5)
Get or set the spreading factor value in raw LoRa mode (
# get raw LoRa spread factor value lora.sf() # set raw LoRa spread factor value lora.sf(7)
Get or set the power mode in raw LoRa mode (
Return a named tuple with useful information from the last received LoRa or LoRaWAN packet. The named tuple has the following form:
rx_timestampis an internal timestamp of the last received packet with microseconds precision.
rssiholds the received signal strength in dBm.
snrcontains the signal to noise ratio id dB (as a single precision float).
sfrxtells the data rate (in the case of LORAWAN mode) or the spreading factor (in the case of LORA mode) of the last packet received.
sftxtells the data rate (in the case of LORAWAN mode) or the spreading factor (in the case of LORA mode) of the last packet transmitted.
tx_trialsis the number of tx attempts of the last transmitted packet (only relevant for LORAWAN confirmed packets).
True if a LoRaWAN network has been joined.
Add a LoRaWAN channel on the specified index. If there’s already a channel with that index it will be replaced with the new one.
The arguments are:
index: Index of the channel to add. Accepts values between 0 and 15 for EU and between 0 and 71 for US.
frequency: Centre frequency in Hz of the channel.
dr_min: Minimum data rate of the channel (0-7).
dr_max: Maximum data rate of the channel (0-7).
lora.add_channel(index=0, frequency=868000000, dr_min=5, dr_max=6)
Removes the channel from the specified index. On the 868MHz band the channels 0 to 2 cannot be removed, they can only be replaced by other channels using the lora.add_channel method. A way to remove all channels except for one is to add the same channel, 3 times on indexes 0, 1 and 2. An example can be seen below:
On the 915MHz band there are no restrictions around this.
Returns a byte object with the 8-Byte MAC address of the LoRa radio.
Specify a callback handler for the LoRa radio. The trigger types are
ack is received. If the ack is not received
tx_retries configured have been performed.
An example of how this callback functions can be seen the in method
This method is used to check for radio activity on the current LoRa channel, and if the
rssi of the measured activity is lower than the
rssi_threshold given, the return value will be
Set the battery level value that will be sent when the LoRaWAN MAC command that retrieves the battery level is received. This command is sent by the network and handled automatically by the LoRaWAN stack. The values should be according to the LoRaWAN specification:
0means that the end-device is connected to an external power source.
1..254specifies the battery level, 1 being at minimum and 254 being at maximum.
255means that the end-device was not able to measure the battery level.
lora.set_battery_level(127) # 50% battery
This method returns a value with bits sets (if any) indicating the events that have triggered the callback. Please note that by calling this function the internal events registry is cleared automatically, therefore calling it immediately for a second time will most likely return a value of 0.
def lora_cb(lora): events = lora.events() if events & LoRa.RX_PACKET_EVENT: print('Lora packet received') if events & LoRa.TX_PACKET_EVENT: print('Lora packet sent') lora.callback(trigger=(LoRa.RX_PACKET_EVENT | LoRa.TX_PACKET_EVENT), handler=lora_cb)
Save the LoRaWAN state (joined status, network keys, packet counters, etc) in non-volatile memory in order to be able to restore the state when coming out of deepsleep or a power cycle.
Restore the LoRaWAN state (joined status, network keys, packet counters, etc) from non-volatile memory. State must have been previously stored with a call to
nvram_save before entering deepsleep. This is useful to be able to send a LoRaWAN message immediately after coming out of deepsleep without having to join the network again.
Working with LoRa and LoRaWAN Sockets
LoRa sockets are created in the following way:
import socket s = socket.socket(socket.AF_LORA, socket.SOCK_RAW)
And they must be created after initialising the LoRa network card.
LoRa sockets support the following standard methods from the socket module:
s.send(bytes([1, 2, 3]))
This method is useful to know the destination port number of the message received. Returns a tuple of the form:
Set the value of the given socket option. The needed symbolic constants are defined in the socket module (SO_* etc.). In the case of LoRa the values are always integers. Examples:
# configuring the data rate s.setsockopt(socket.SOL_LORA, socket.SO_DR, 5) # selecting non-confirmed type of messages s.setsockopt(socket.SOL_LORA, socket.SO_CONFIRMED, False) # selecting confirmed type of messages s.setsockopt(socket.SOL_LORA, socket.SO_CONFIRMED, True)
Socket options are only applicable when the LoRa radio is used in
Sets the socket timeout value in seconds. Accepts floating point values.