speed test esp_now --> very good.

espnow/platformio.ini

@@ -0,0 +1,43 @@
+; < NOTE >
+
+; to enable verbose output add option -->
+; $ platformio run --verbose
+
+; to make this permanent for the proj. -->
+; $ platformio settings set force_verbose Yes
+
+; then confirm the change -->
+; $ platformio settings get
+
+
+; // pio v 4.0 'Build options'
+;    - build_type
+;    - build_flags
+;    - src_build_flags
+;    - build_unflags
+;    - src_filter
+;    - targets
+
+
+[platformio]
+default_envs = d1_mini_pro
+
+[env]
+framework = arduino
+upload_speed = 460800
+upload_port = /dev/ttyUSB0
+lib_deps =
+
+[env:nodemcuv2]
+platform = espressif8266
+board = nodemcuv2
+lib_deps =
+  ${env.lib_deps}
+
+[env:d1_mini_pro]
+platform = espressif8266
+board = d1_mini_pro
+upload_speed = 460800
+; 9600, 19200, 38400, 57600, 115200, 230400, 460800, 921600
+lib_deps =
+  ${env.lib_deps}

espnow/src/main.cpp

@@ -0,0 +1,90 @@
+#include <Arduino.h>
+#include <ESP8266WiFi.h>
+#include <espnow.h>
+
+//uint8_t broadcastAddress[] = {0xF4, 0xCF, 0xA2, 0xED, 0xB3, 0xC5};
+uint8_t broadcastAddress[] = {0xF4, 0xCF, 0xA2, 0xED, 0xB7, 0x21};
+
+typedef struct struct_message {
+  char a[32];
+  int b;
+  float c;
+  String d;
+  bool e;
+} struct_message;
+
+struct_message myData;
+
+unsigned long lastTime = 0;
+unsigned long timerDelay = 20;  // send readings timer
+
+// Callback when data is sent
+void OnDataSent(uint8_t *mac_addr, uint8_t sendStatus) {
+  Serial.print("Last Packet Send Status: ");
+  if (sendStatus == 0) {
+    Serial.println("Delivery success");
+  }
+  else{
+    Serial.println("Delivery fail");
+  }
+}
+
+// Callback function that will be executed when data is received
+void OnDataRecv(uint8_t * mac, uint8_t *incomingData, uint8_t len) {
+  memcpy(&myData, incomingData, sizeof(myData));
+  Serial.print("Bytes received: ");
+  Serial.println(len);
+  Serial.print("Char: ");
+  Serial.println(myData.a);
+  Serial.print("Int: ");
+  Serial.println(myData.b);
+  Serial.print("Float: ");
+  Serial.println(myData.c);
+  Serial.print("String: ");
+  Serial.println(myData.d);
+  Serial.print("Bool: ");
+  Serial.println(myData.e);
+  Serial.println();
+}
+
+void setup() {
+  Serial.begin(115200);
+  Serial.println();
+  Serial.print("ESP8266 Board MAC Address:  ");
+  Serial.println(WiFi.macAddress());
+
+  WiFi.mode(WIFI_STA);
+
+  // Init ESP-NOW
+  if (esp_now_init() != 0) {
+    Serial.println("Error initializing ESP-NOW");
+    return;
+  }
+
+  // Once ESPNow is successfully Init, we will register for Send CB to
+  // get the status of Trasnmitted packet
+  esp_now_set_self_role(ESP_NOW_ROLE_COMBO);
+  esp_now_register_send_cb(OnDataSent);
+  esp_now_register_recv_cb(OnDataRecv);
+
+  // Register peer
+  esp_now_add_peer(broadcastAddress, ESP_NOW_ROLE_SLAVE, 1, NULL, 0);
+}
+
+void loop() {
+  if ((millis() - lastTime) > timerDelay) {
+    static int count = 0;
+    count++;
+    // Set values to send
+    strcpy(myData.a, "THIS IS A CHAR");
+    myData.b = count;
+    myData.c = 1.2;
+    myData.d = "Hello";
+    myData.e = false;
+
+    // Send message via ESP-NOW
+    esp_now_send(broadcastAddress, (uint8_t *) &myData, sizeof(myData));
+
+    lastTime = millis();
+  }
+}