Introduction: Multiple Nodemcu(esp8266) Communication
In this project we collect two transmitter data in mediator trans-receiver and send that data to receiver
//Data transmitter_1
#include
#if defined(ESP8266)
#include
#elifdefined(ESP32)
#include
#endif
char v[255];
char w[255];
static uint8_t PEER[] {0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX}; // put mac address of your trans-receiver
float a=0;
voidprintReceivedMessage(const uint8_t mac[6], const uint8_t* buf, size_t count, void* cbarg) {
Serial.printf("Message from %02X:%02X:%02X:%02X:%02X:%02X\n", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
for (int i = 0; i < count; ++i) {
Serial.print(static_cast(buf[i]));
}
Serial.println();
}
void setup() {
Serial.begin(115200);
Serial.println();
WiFi.persistent(false);
WiFi.mode(WIFI_AP);
WiFi.softAP("ESPNOW", nullptr, 3);
WiFi.softAPdisconnect(false);
Serial.print("MAC address of this node is ");
Serial.println(WiFi.softAPmacAddress());
bool ok = WifiEspNow.begin();
if (!ok) {
Serial.println("WifiEspNow.begin() failed");
ESP.restart();
}
WifiEspNow.onReceive(printReceivedMessage, nullptr);
ok = WifiEspNow.addPeer(PEER);
if (!ok) {
Serial.println("WifiEspNow.addPeer() failed");
ESP.restart();
}
}
void loop()
{
charmsg[60];
a=a+0.1; //data to be transmitted
Intlen= snprintf(msg, sizeof(msg), "%f", a);
WifiEspNow.send(PEER, reinterpret_cast(msg), len);
delay(1000);
}
// DATA transmitter_2
#include
#if defined(ESP8266)
#include
#elifdefined(ESP32)
#include
#endif
//const uint8_t* buf;
char v[255];
char w[255];
static uint8_t PEER[] {0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX}; // put mac address of your trans-receiver
float a=0;
voidprintReceivedMessage(const uint8_t mac[6], const uint8_t* buf, size_t count, void* cbarg) {
Serial.printf("Message from %02X:%02X:%02X:%02X:%02X:%02X\n", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
for (int i = 0; i < count; ++i) {
Serial.print(static_cast(buf[i]));
}
Serial.println();
}
void setup() {
Serial.begin(115200);
Serial.println();
WiFi.persistent(false);
WiFi.mode(WIFI_AP);
WiFi.softAP("ESPNOW", nullptr, 3);
WiFi.softAPdisconnect(false);
Serial.print("MAC address of this node is ");
Serial.println(WiFi.softAPmacAddress());
bool ok = WifiEspNow.begin();
if (!ok) {
Serial.println("WifiEspNow.begin() failed");
ESP.restart();
}
WifiEspNow.onReceive(printReceivedMessage, nullptr);
ok = WifiEspNow.addPeer(PEER);
if (!ok) {
Serial.println("WifiEspNow.addPeer() failed");
ESP.restart();
}
}
void loop()
{
charmsg[60];
a=a+3.1;
Int len= snprintf(msg, sizeof(msg), "%f", a);
WifiEspNow.send(PEER, reinterpret_cast(msg), len);
delay(1010);
}
// DATA Trans_receiver
#include
#if defined(ESP8266)
#include
#elifdefined(ESP32)
#include
#endif
char v[255];
char w[255];
static uint8_t PEER[] {0xWW, 0xWW, 0xWW, 0xWW, 0xWW, 0xWW}; //put your receiver mac address
//3E:71:BF:A6:AA:AE
//EE:FA:BC:BA:3D:AA
float a=0;
voidprintReceivedMessage(const uint8_t mac[6], const uint8_t* buf, size_t count, void* cbarg) {
Serial.printf("Message from %02X:%02X:%02X:%02X:%02X:%02X\n", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
if(mac[0]== 0x3E) // 3E:71:BF:A6:AA:AE it is mac address of my transmitter nodemcu_1
{
for (int i = 0; i < count; ++i) {
Serial.print(static_cast(buf[i]));
v[i]=buf[i];
}
}
if(mac[0]== 0x EE) // EE:FA:BC:BA:3D:AA it is a mac address of my transmitter nodemcu_2
{
for (int i = 0; i < count; ++i) {
Serial.print(static_cast(buf[i]));
w[i]=buf[i];
}
}
Serial.println();
}
void setup() {
Serial.begin(115200);
Serial.println();
WiFi.persistent(false);
WiFi.mode(WIFI_AP);
WiFi.softAP("ESPNOW", nullptr, 3);
WiFi.softAPdisconnect(false);
Serial.print("MAC address of this node is ");
Serial.println(WiFi.softAPmacAddress());
bool ok = WifiEspNow.begin();
if (!ok) {
Serial.println("WifiEspNow.begin() failed");
ESP.restart();
}
WifiEspNow.onReceive(printReceivedMessage, nullptr);
ok = WifiEspNow.addPeer(PEER);
if (!ok) {
Serial.println("WifiEspNow.addPeer() failed");
ESP.restart();
}
}
void loop()
{
delay(1000);
char msg[60];
Int len = snprintf(msg, sizeof(msg), "%s+nodemcu_1", v);
WifiEspNow.send(PEER, reinterpret_cast(msg), len);
delay(10);
msg[60];
len = snprintf(msg, sizeof(msg), "%s+ nodemcu_2", w);
WifiEspNow.send(PEER, reinterpret_cast(msg), len);
}
// DATA receiver
#include
#if defined(ESP8266)
#include
#elifdefined(ESP32)
#include
#endif
char v[255];
char w[255];
static uint8_t PEER[] {0xWW, 0xWW, 0xWW, 0xWW, 0xWW, 0xWW}; //put mac address your receiver
float a=0;
voidprintReceivedMessage(const uint8_t mac[6], const uint8_t* buf, size_t count, void* cbarg)
{
Serial.printf("Message from %02X:%02X:%02X:%02X:%02X:%02X\n", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
for (int i = 0; i < count; ++i) {
Serial.print(static_cast(buf[i]));
v[i]=buf[i];
}
Serial.println();
}
void setup() {
Serial.begin(115200);
Serial.println();
WiFi.persistent(false);
WiFi.mode(WIFI_AP);
WiFi.softAP("ESPNOW", nullptr, 3);
WiFi.softAPdisconnect(false);
Serial.print("MAC address of this node is ");
Serial.println(WiFi.softAPmacAddress());
bool ok = WifiEspNow.begin();
if (!ok) {
Serial.println("WifiEspNow.begin() failed");
ESP.restart();
}
WifiEspNow.onReceive(printReceivedMessage, nullptr);
ok = WifiEspNow.addPeer(PEER);
if (!ok) {
Serial.println("WifiEspNow.addPeer() failed");
ESP.restart();
}
}
void loop()
{
}
Step 1: The First Transmitter(nodemcu_1) Code
//Data transmitter_1
#include
#if defined(ESP8266)
#include
#elifdefined(ESP32)
#include
#endif
char v[255];
char w[255];
static uint8_t PEER[] {0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX}; // put mac address of your trans-receiver
float a=0;
voidprintReceivedMessage(const uint8_t mac[6], const uint8_t* buf, size_t count, void* cbarg) {
Serial.printf("Message from %02X:%02X:%02X:%02X:%02X:%02X\n", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
for (int i = 0; i < count; ++i) {
Serial.print(static_cast(buf[i]));
}
Serial.println();
}
void setup() {
Serial.begin(115200);
Serial.println();
WiFi.persistent(false);
WiFi.mode(WIFI_AP);
WiFi.softAP("ESPNOW", nullptr, 3);
WiFi.softAPdisconnect(false);
Serial.print("MAC address of this node is ");
Serial.println(WiFi.softAPmacAddress());
bool ok = WifiEspNow.begin();
if (!ok) {
Serial.println("WifiEspNow.begin() failed");
ESP.restart();
}
WifiEspNow.onReceive(printReceivedMessage, nullptr);
ok = WifiEspNow.addPeer(PEER);
if (!ok) {
Serial.println("WifiEspNow.addPeer() failed");
ESP.restart();
}
}
void loop()
{
charmsg[60];
a=a+0.1; //data to be transmitted
Intlen= snprintf(msg, sizeof(msg), "%f", a);
WifiEspNow.send(PEER, reinterpret_cast(msg), len);
delay(1000);
}
