mkjanke / ESP32-Nextion-NOW

ESP-NOW interface to Nextion Serial Displays.

Nextion ESP-NOW interface

ESP-NOW interface to Nextion Serial Displays.

• Listens for JSON-formatted data on ESP-NOW and forwards to Nextion serial port.
• Listens on Nextion serial port and forwards messages to ESP-NOW as JSON-formatted data

Uses:

• ArduinoJson

ESP_NOW message format:

JSON Message sent to Nextion via ESP-NOW:

• {"D": "ESP DEVICE NAME", "CMD": "Nextion Command"}

Example: To send the nextion command "page0.Ah1.val=123" to the Nextion (update Nextion object Ah1 on page0 to the value 123):

• {"D": "ESP-Display", "CMD": "page0.Ah1.val=123"}

JSON Message from Nextion sent via ESP-NOW:

• {"D":"ESP-DEVICE-NAME","MSG":"Hex message converted to ASCII representation"}\r\n

Exmple: Message from Nextion '66 00' (Nextion 'sendme' response)

• {"D":"ESP-Test","MSG":"66 00 FF FF FF "}\r\n'

Note that Nextion responses are formatted and sent as ASCII representation of the hexadecimal emitted by Nextion

The companion app to this: https://github.com/mkjanke/ESP32-Now-JSON-GW. This gateway app receives ESP-NOW broadcasts and forwards them to an attached serial port.

Key components:

• ESP_NOW callback:

  • Receive data from ESP Now, send to serial queue:
    • Incoming ESP-NOW packet --> onDataRecv --> send_to_Serial_queue

• Task writeToNextion:

  • Dequeue data from serial queue, send to serial port:
  • send_to_Serial_queue --> writeToNextion --> Nextion Serial Port

• Task handleNextion:

  • Recieve data from Nextion serial port, send to ESP-NOW queue:
  • handleNextion --> espNowSend() --> send_to_EspNow_queue

• Task writeToEspNow:

  • Dequeue data from ESP-NOW queue, forward to ESP-NOW:
    • send_to_EspNow_Queue --> writeToEspNow() --> Outgoing ESP-NOW packet

• Task espnowHeartbeat:

  • Send uptime and stack data to send_to_EspNow_Queue
  • Send uptime and stack data to Nextion serial port