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92 lines
2.9 KiB
C++
92 lines
2.9 KiB
C++
/**
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ESPNOW - Basic communication - Slave
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Date: 26th September 2017
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Author: Arvind Ravulavaru <https://github.com/arvindr21>
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Purpose: ESPNow Communication between a Master ESP32 and a Slave ESP32
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Description: This sketch consists of the code for the Slave module.
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Resources: (A bit outdated)
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a. https://espressif.com/sites/default/files/documentation/esp-now_user_guide_en.pdf
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b. http://www.esploradores.com/practica-6-conexion-esp-now/
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<< This Device Slave >>
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Flow: Master
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Step 1 : ESPNow Init on Master and set it in STA mode
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Step 2 : Start scanning for Slave ESP32 (we have added a prefix of `slave` to the SSID of slave for an easy setup)
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Step 3 : Once found, add Slave as peer
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Step 4 : Register for send callback
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Step 5 : Start Transmitting data from Master to Slave
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Flow: Slave
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Step 1 : ESPNow Init on Slave
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Step 2 : Update the SSID of Slave with a prefix of `slave`
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Step 3 : Set Slave in AP mode
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Step 4 : Register for receive callback and wait for data
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Step 5 : Once data arrives, print it in the serial monitor
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Note: Master and Slave have been defined to easily understand the setup.
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Based on the ESPNOW API, there is no concept of Master and Slave.
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Any devices can act as master or salve.
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*/
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#include <esp_now.h>
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#include <WiFi.h>
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#define CHANNEL 1
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// Init ESP Now with fallback
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void InitESPNow() {
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WiFi.disconnect();
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if (esp_now_init() == ESP_OK) {
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Serial.println("ESPNow Init Success");
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}
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else {
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Serial.println("ESPNow Init Failed");
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// Retry InitESPNow, add a counte and then restart?
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// InitESPNow();
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// or Simply Restart
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ESP.restart();
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}
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}
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// config AP SSID
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void configDeviceAP() {
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const char *SSID = "Slave_1";
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bool result = WiFi.softAP(SSID, "Slave_1_Password", CHANNEL, 0);
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if (!result) {
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Serial.println("AP Config failed.");
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} else {
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Serial.println("AP Config Success. Broadcasting with AP: " + String(SSID));
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}
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}
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void setup() {
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Serial.begin(115200);
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Serial.println("ESPNow/Basic/Slave Example");
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//Set device in AP mode to begin with
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WiFi.mode(WIFI_AP);
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// configure device AP mode
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configDeviceAP();
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// This is the mac address of the Slave in AP Mode
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Serial.print("AP MAC: "); Serial.println(WiFi.softAPmacAddress());
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// Init ESPNow with a fallback logic
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InitESPNow();
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// Once ESPNow is successfully Init, we will register for recv CB to
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// get recv packer info.
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esp_now_register_recv_cb(OnDataRecv);
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}
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// callback when data is recv from Master
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void OnDataRecv(const uint8_t *mac_addr, const uint8_t *data, int data_len) {
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char macStr[18];
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snprintf(macStr, sizeof(macStr), "%02x:%02x:%02x:%02x:%02x:%02x",
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mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5]);
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Serial.print("Last Packet Recv from: "); Serial.println(macStr);
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Serial.print("Last Packet Recv Data: "); Serial.println(*data);
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Serial.println("");
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}
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void loop() {
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// Chill
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}
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