ESP-Now

ESP-NowESP-Now is another protocol developed by Espressif, which enables multiple devices to communicate without using Wi-Fi. The protocol is akin to the low power 2.4GHz wireless connectivity that is often deployed in wireless mice — the pairing between devices is needed prior to the communication. After the pairing is done, the connection is persistent, peer-to-peer, and no handshake is required.

OverviewESP-NOW is a fast, connectionless communication technology featuring short packet transmission. ESP-NOW is ideal for smart lights, remote control devices, sensors and other applications.

ESP-NOW applies the IEEE802.11 Action Vendor frame technology, along with the IE function developed by Espressif, and CCMP encryption technology, realizing a secure, connectionless communication solution.

Features • Encrypted and unencrypted unicast communication. • Mixed encrypted and unencrypted peer devices. • Up to 250-byte payload can be carried. • The sending callback function that can be set to inform the application layer of transmission success or failure.

Limitations • Broadcast is not supported. • Limited encrypted peers. 10 encrypted peers at the most are supported in Station mode; 6 at the most in SoftAP or SoftAP + Station mode. Multiple unencrypted peers are supported, however, their total number should be less than 20, including encrypted peers. • Payload is limited to 250 bytes.

* esp_now_get_peer_role * esp_now_set_peer_key* esp_now_get_peer_key* esp_now_set_peer_channel * esp_now_get_peer_channel * esp_now_is_peer_exist* esp_now_fetch_peer * esp_now_get_cnt_info* esp_now_set_kok

APIs* esp_now_init * esp_now_deinit * esp_now_register_recv_cb* esp_now_unregister_recv_cb * esp_now_register_send_cb * esp_now_unregister_send_cb * esp_now_send * esp_now_add_peer* esp_now_del_peer * esp_now_set_self_role* esp_now_get_self_role

code - http://github.com/cmmakerclub/espnow article - http://bit.ly/c-espnow

Slides

API Reference

• https://espressif.com/sites/default/files/documentation/esp-now_user_guide_en.pdf

• https://www.espressif.com/sites/default/files/documentation/2c-esp8266_non_os_sdk_api_reference_en.pdf

Controller

{0x5C,0xCF,0x7F,0xD8,0x54,0x20};

Get your hands dirty!

bit.ly/cmmc-espnow2