ESPNOW

This module implements interface to ESP-NOW protocol: https://www.espressif.com/en/products/software/esp-now/overview

Usage Example

from network import WLAN
from network import ESPNOW
import binascii
import time

# The callback to be registered when a message has been sent to a Peer
def espnow_tx(result):
    # "result" is the parameter in form of 2 element long tuple
    # "peer" is the Peer which the message has been sent to
    # "sent" is a boolean showing whether the message could be sent
	peer, sent = result
	mac = peer.addr()
	if(sent == False):
		print("Sending message to %s failed!" % binascii.hexlify(mac))
	else:
		print("Message sent to: %s" % (binascii.hexlify(mac)))

# The callback to be registered when a message has been received
def espnow_rx(result):
	# "result" is the parameter in form of 3 element long tuple
    # "mac" is the MAC address of the sender
    # "peer" is the Peer which the message has been received from. If message has been received from a not registered Peer this parameter is None
    # "msg" is the payload from the received message
    mac, peer, msg = result
	if(peer is not None):
		print("Message received from %s with content: %s" % (binascii.hexlify(mac), msg))
		peer.send("Sending back an answer")

# The ESPNOW module needs that WLAN is initialized
w = WLAN()
# Initialize the ESPNOW module
ESPNOW.init()

# Register the callback which will be called on TX
ESPNOW.on_send(espnow_tx)
# Register the callback which will be called on RX
ESPNOW.on_recv(espnow_rx)

# Add a dedicated Peer with MAC address: 11:22:33:44:55:66
p = ESPNOW.add_peer("112233445566")
# Send a message dedicated to the Peer
p.send("My Message")
# Sending 1 message to all Peers which are registered
ESPNOW.send(None, "Hello all Peers!")

Initialization

ESPNOW.init()

Initialize the ESP-NOW module. The module needs that WLAN has already been initialized.

Methods:

ESPNOW.deinit()

Deinitialize the ESP-NOW module.

ESPNOW.pmk(pmk)

Configures the Primary Master Key which is used to encrypt the Local Master Key.

• pmk is the Primary Master Key to be configured.

The PMK specified by pmk is accepted in format of string with length 16.

ESPNOW.send(addr, msg)

Sends a message msg to a remote device with MAC address addr.

• addr is the MAC address of the remote device. If None is passed then the message is sent to all registered Peers.
• msg is the message to send.

ESPNOW.on_recv(cb)

Registers the cb callback which will be called when a new message has been received.

• cb is the callback function to be called, it expects 1 parameter which is a tuple with 3 elements:
  • Element 0: is the MAC address of the sender.
  • Element 1: is the Peer which the message has been received from. If message has been received from a not registered Peer this parameter is None.
  • Element 2: is the payload from the received message.

ESPNOW.on_send(cb)

Registers the cb callback which will be called when a new message has been sent.

• cb is the callback function to be called, it expects 1 parameter which is a tuple with 2 elements:
  • Element 0: is the Peer which the message has been sent to.
  • Element 1: is a boolean showing whether the message could be sent.

ESPNOW.peer_count()

Returns with the number of registered Peers in a form of tuple with 2 elements:

• Element 0: is the number of all the registered Peers.
• Element 1: is the number of encrypted Peers.

ESPNOW.version()

Returns with the curently used version of the ESP-NOW protocol.

ESPNOW.add_peer(addr, lmk=None)

Creates a new Peer object and registers it into ESP-NOW module.

• addr is the MAC address of the Peer to be created. MAC address is accepted in either String format or as a Byte array.
• lmk is the Local Master Key to be used when communicating with the Peer. By default it is None which means the communication will not be encrypted.

The LMK specified by lmk is accepted in format of string with length 16.

This function returns with an ESPNOW_Peer object.

ESPNOW.del_peer(Peer)

Destroys the Peer object with type ESPNOW_Peer.

Class ESPNOW_Peer

The ESPNOW_Peer class represents a Peer in the scope of the ESP-NOW module. A new resource can only be created with the ESPNOW.add_peer function.

Class methods

ESPNOW_Peer.addr(addr=None)

Returns with the MAC address of the Peer.

ESPNOW_Peer.lmk(lmk=None)

Configures or returns the Local Master Key of the Peer.

• lmk is the new LMK to be set to this Peer.

If lmk is not used then this functions returns the LMK of the Peer. The LMK specified by lmk is accepted in format of string with length 16.

ESPNOW_Peer.send(msg)

Sends a message to the Peer.

• msg is the message to send.