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ESP-NOW

Espressif's way for ESP32s to send short messages straight to each other, without a Wi-Fi network.

ESP-NOW sends connectionless frames of up to 250 bytes (more in newer versions) between Espressif chips by MAC address over the Wi-Fi radio, with optional encryption and a send-status callback but no retries beyond the link layer.

Examples

  • A button ESP32 on one greenhouse bench sends a 2153 reading with a sequence number straight to another board's MAC address, every 5 s, with no router.

  • Keep ESP-NOW messages to 250 bytes unless every board runs the version 2.0 stack, which allows 1,470.

See also

MAC address channel acknowledgement
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