ESPNow and Wifi simultaneously

Gateway.cpp

// use ESP-NOW to do something based on a message from another device
//   and also connect to WiFi to display a web page, deal with MQTT etc
//     in this case just light an LED and get UNIX timestamp from an NTP server

// NOTE: WiFi router must be on Channel 1 for this simple version to work

// Compiled using Arduino 1.8.19, and ESP32 v2.0.2
// Compiled for board: ESP32 Dev Module
//   (but running on an AI Thinker ESP-CAM since I have a bunch of them)

// Based on "ResponderA_22A.ino v01

// ...... program information
char programName[] = "ResponderA_22A";
char versionNumber[] = "v01";
char programDate[] = "2022-09-25";
char programAuthor[] = "Donald Weiman";

// ...... required libraries
#include <esp_now.h>
#include <WiFi.h>
#include "esp_sntp.h"               // ntp

// define data structure for received data
struct s_message {
    int i_id;
    int i_count; 
    char c_level[20];
} ;

// create structured data object
s_message s_switchInfo;             // from initiator

// ...... LED
const byte flashLedPin = 4;         // white led on AI Thinker ESP-CAM board
#define flashLedOff 0               // active high

const byte builtinLedPin = 33;      // red led on AI Thinker ESP-CAM board
#define builtinLedOff 1             // active low

// ...... misc
char thisDeviceMac[20] ;            // Mac address for this device (for info only)
bool newDataFlag = false;

// ...... WiFi
const char* ssid = "plugh";         // on WiFi channel 1
const char* pass = "xyzzy";

// ...... NTP
char ntpPool[] = "pool.ntp.org";
char ntpTzEnvData[] = "EST+5EDT,M3.2.0/2:00:00,M11.1.0/2:00:00";    // US/Eastern
bool ntpUpdateFlag = false;
bool changeNtpSync = true;             // false --> use default 3600 seconds
const uint32_t ntpSyncInterval = 120;   // true --> use this interval (seconds)

// ...... timing parameters (for example procedure in loop())
time_t timestampNow;

//  ....................................................................................
void setup() {
  Serial.begin(115200);
  delay(1000);

// ...... display sign-on message
  Serial.println();
  Serial.println();   
  Serial.print(programName);
  Serial.print(" ");
  Serial.print(versionNumber);
  Serial.print("   ");
  Serial.print(programDate);
  Serial.print("   ");
  Serial.print(programAuthor); 
  Serial.print("\n");

// ...... display MAC address (of this device)
  WiFi.macAddress().toCharArray(thisDeviceMac, 20);
  Serial.printf("\nMAC address: %s", thisDeviceMac);

// ...... WiFi
  WiFi.mode(WIFI_AP_STA);          // AP needed to maintain ESP-NOW
  WiFi.begin(ssid, pass);

  // Wait for connection
  Serial.println("");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.print("Connected to ");
  Serial.println(ssid);
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());

// ...... NTP
  Serial.print("\nconnecting to NTP time server");
  connectToNtp(); 
  
// ...... esp-now 
  // initalize ESP-NOW 
  if (esp_now_init() != ESP_OK) {
    Serial.println("Error initializing ESP-NOW");
    return;
  }  

  // register callback function
  esp_now_register_recv_cb(OnDataRecv); 

// ...... LEDs
  pinMode(flashLedPin, OUTPUT);           // turn LEDs off
  digitalWrite(flashLedPin, flashLedOff);
  
  pinMode(builtinLedPin, OUTPUT);
  digitalWrite(builtinLedPin, builtinLedOff);
  
// ...... end of setup
  Serial.print("\nsetup complete\n");
}

//  ....................................................................................
void loop() {

  // act on received data if appropriate
  if(newDataFlag == true) {
    newDataFlag = false; 
    // act on received data
    if(strcmp (s_switchInfo.c_level, "HIGH") == 0) {
      digitalWrite(flashLedPin, !flashLedOff);
      digitalWrite(builtinLedPin, builtinLedOff);      
    } else {
      digitalWrite(flashLedPin, flashLedOff);
      digitalWrite(builtinLedPin, !builtinLedOff);
    } 
  } 

  // NTP
  timestampNow = time(nullptr);
  
  if(ntpUpdateFlag == true) {
    ntpUpdateFlag = false;
    Serial.print("\n *** NTP update ***    ");
    Serial.print(timestampNow);    
  }
  
  // do something else ...

}

//  ....................................................................................
void OnDataRecv(const uint8_t * mac, const uint8_t *incomingData, int len) {
  // extract the received data
  char receivedData[100];
  memcpy(&s_switchInfo, incomingData, sizeof(s_switchInfo));

  // deal with received data
  newDataFlag = true;           // handled in loop()

  // display received data - (interesting, but not essential)
  char recvStr[50];  
  snprintf(recvStr, sizeof(recvStr), "\n %u  %u  %s",
           s_switchInfo.i_id, s_switchInfo.i_count, s_switchInfo.c_level);
  Serial.print(recvStr);
  
  // display MAC of sending device - (interesting, but not essential)
  char macStr[20];
  snprintf(macStr, sizeof(macStr), "%02x:%02x:%02x:%02x:%02x:%02x",
            mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
  Serial.print("   Received from ");
  Serial.print(macStr);
  
  // display UNIX timestamp obtained from NTP server
  Serial.print(" at ");
  Serial.print(timestampNow);
}

//  ....................................................................................
// NTP time synchronization callback
// this callback will place the current UNIX timestamp that was obtained 
//   via NTP into a structure of type 'timeval' which is defined in time.h 
// it looks like this must be done even if the data isn't subsequently used

// NOTE: This is apparently being executed in a different core from the 
//       main program.  Any Serial.print data here may be interspersed with 
//       Serial.print data from the main program.

void time_is_set (struct timeval *bogus) {
  ntpUpdateFlag = true;
}

// ....................................................................................  
void connectToNtp() {
  // possibly change NTP sync interval (default = 3600 seconds)  
  if(changeNtpSync == true) {
    sntp_set_sync_interval(ntpSyncInterval * 1000);
  }
    
  // register a callback to notify about the time synchronization process
  sntp_set_time_sync_notification_cb(time_is_set);

  // obtain system time from an NTP server, do not adjust for timezone or dst here
  configTime(0, 0, ntpPool);                // obtain time from an NTP server
  
  // set the TZ environment variable to the correct value for the device location
  setenv("TZ", ntpTzEnvData, 1);
  
  // update the C library runtime data for the new time zone
  tzset();   
}

//  ....................................................................................

Initiator.cpp

// use ESP-NOW to send input level information to another device
//   input can be from switch, PIR sensor, light sensor, etc.

// Compiled using Arduino 1.8.19, and ESP32 v2.0.2
// Compiled for board: ESP32 Dev Module
//   (but running on an AI Thinker ESP-CAM since I have a bunch of them)

// ...... program information
char programName[] = "InitiatorA_22A";
char versionNumber[] = "v01";
char programDate[] = "2022-09-25";
char programAuthor[] = "Donald Weiman";

// ...... hardware connections
//  Push-button switch between Vcc and GPIO13
//    or 
//  HC-SR501 PIR Motion Detector module connected to GPIO13

// ...... required libraries
#include <esp_now.h>
#include <WiFi.h>

// ...... esp-now
// remote MAC Address
uint8_t responderAddress[] = {0x34, 0x94, 0x54, 0x24, 0x3D, 0xE0};

// specify where to store information about the other devices
//   NOTE: this structure is defined in 'esp_now.h'
esp_now_peer_info_t responderInfo;

// define data structure for transmitted data
struct s_message {
    int i_id;
    int i_count; 
    char c_level[20];
} ;

// create structured data object
s_message s_switchInfo;          // to responder

// ...... switch
const byte inputPin = 13;
int oldValue = 0;
bool newValueFlag = false;
int lowCount = 0;
int highCount = 0;

// ...... misc
char thisDeviceMac[20] ;            // Mac address for this device (for info only)
int unitId = 102;                   // arbitrary 'unit id'

//  ....................................................................................
void setup() {
  Serial.begin(115200);
  delay(1000);

// ...... display sign-on message
  Serial.println();
  Serial.println();   
  Serial.print(programName);
  Serial.print(" ");
  Serial.print(versionNumber);
  Serial.print("   ");
  Serial.print(programDate);
  Serial.print("   ");
  Serial.print(programAuthor); 
  Serial.print("\n");

// ...... display MAC address (of this device)
  WiFi.macAddress().toCharArray(thisDeviceMac, 20);
  Serial.printf("\nMAC address: %s", thisDeviceMac);
  
// ...... switch
  pinMode(inputPin, INPUT_PULLDOWN);           // active HIGH

// ...... WiFi
  WiFi.mode(WIFI_STA);
  
// ...... esp-now 
  // initalize ESP-NOW 
  if (esp_now_init() != ESP_OK) {
    Serial.println("Error initializing ESP-NOW");
    return;
  }  

  // register callback function
  esp_now_register_send_cb(OnDataSent);  

  // register peer (remote device)
  //   put peer information into the 'responderInfo' data structure
  memcpy(responderInfo.peer_addr, responderAddress, 6);      // address has 6 bytes
  responderInfo.channel = 0;                                 // use current channel 
  responderInfo.encrypt = false;                             // don't encrypt

  // add peer to paired device list 
  if (esp_now_add_peer(&responderInfo) != ESP_OK) {
    Serial.println("Failed to add peer");
    return;
  }

// ...... end of setup
  Serial.print("\nsetup complete\n");  
}

//  ....................................................................................
void loop() {

  checkInputLevel();

  // send message if appropriate
  if(newValueFlag == true) {
    newValueFlag = false; 
    if(esp_now_send(responderAddress, (uint8_t *) &s_switchInfo, sizeof(s_switchInfo)) != ESP_OK) {
      Serial.println("Failed to send the data");    
    }
  }
 
  // do something else ...
  
}

//  ....................................................................................
void OnDataSent(const uint8_t *macAddr, esp_now_send_status_t status) {
  // callback when data is sent
  Serial.print("\nMessage sent");
    
  // display MAC of where the data was sent
 char macStr[25];
  snprintf(macStr, sizeof(macStr)," to %02X:%02X:%02X:%02X:%02X:%02X",
            macAddr[0], macAddr[1], macAddr[2], 
             macAddr[3], macAddr[4], macAddr[5]);
  Serial.print(macStr);

  // display the status returned by the other device
  Serial.print(", status: ");
  Serial.print(status == ESP_NOW_SEND_SUCCESS ? "OK" : "Fail");

  // display the data that was sent 
  displayTransmittedData();  
}

//  ....................................................................................
void displayTransmittedData() {
// desired data is in 's_switchInfo' structure
char dataStr[50];
  snprintf(dataStr, sizeof(dataStr), "\n Device number %u, Level %s, Count %u ",
            s_switchInfo.i_id, s_switchInfo.c_level, s_switchInfo.i_count);

  Serial.print(dataStr);
  
}

//  ....................................................................................
void checkInputLevel() {
  int value = digitalRead(inputPin);
  if (value != oldValue) {
    newValueFlag = true;  
    oldValue = value; 
      
    if(value == 1) {
      Serial.print("\n--> level has gone high");
      ++highCount;
      s_switchInfo.i_id = unitId;
      s_switchInfo.i_count = highCount;
      strcpy(s_switchInfo.c_level, "HIGH");
    }
    else {
    if(value == 0)
      Serial.print("\n--> level has gone low");
      ++lowCount;  
      s_switchInfo.i_id = unitId;
      s_switchInfo.i_count = lowCount;
      strcpy(s_switchInfo.c_level, "LOW");
    }
    delay(10);                                          // crude debounce
  }
}

//  ....................................................................................

Responder.cpp

// use ESP-NOW to do something based on a message from another device
//   in this case just light an LED

// Compiled using Arduino 1.8.19, and ESP32 v2.0.2
// Compiled for board: ESP32 Dev Module
//   (but running on an AI Thinker ESP-CAM since I have a bunch of them)

// ...... program information
char programName[] = "ResponderA_22A";
char versionNumber[] = "v01";
char programDate[] = "2022-09-25";
char programAuthor[] = "Donald Weiman";

// ...... required libraries
#include <esp_now.h>
#include <WiFi.h>

// define data structure for received data
struct s_message {
    int i_id;
    int i_count; 
    char c_level[20];
} ;

// create structured data object
s_message s_switchInfo;             // from initiator

// ...... LED
const byte flashLedPin = 4;         // white led on AI Thinker ESP-CAM board
#define flashLedOff 0               // active high

const byte builtinLedPin = 33;      // red led on AI Thinker ESP-CAM board
#define builtinLedOff 1             // active low

// ...... misc
char thisDeviceMac[20] ;            // Mac address for this device (for info only)
bool newDataFlag = false;

//  ....................................................................................
void setup() {
  Serial.begin(115200);
  delay(1000);

// ...... display sign-on message
  Serial.println();
  Serial.println();   
  Serial.print(programName);
  Serial.print(" ");
  Serial.print(versionNumber);
  Serial.print("   ");
  Serial.print(programDate);
  Serial.print("   ");
  Serial.print(programAuthor); 
  Serial.print("\n");

// ...... display MAC address (of this device)
  WiFi.macAddress().toCharArray(thisDeviceMac, 20);
  Serial.printf("\nMAC address: %s", thisDeviceMac);

// ...... WiFi
  WiFi.mode(WIFI_STA);
  
// ...... esp-now 
  // initalize ESP-NOW 
  if (esp_now_init() != ESP_OK) {
    Serial.println("Error initializing ESP-NOW");
    return;
  }  

  // register callback function
  esp_now_register_recv_cb(OnDataRecv); 

// ...... LEDs
  pinMode(flashLedPin, OUTPUT);           // turn LEDs off
  digitalWrite(flashLedPin, flashLedOff);
  
  pinMode(builtinLedPin, OUTPUT);
  digitalWrite(builtinLedPin, builtinLedOff);
  
// ...... end of setup
  Serial.print("\nsetup complete\n");
}

//  ....................................................................................
void loop() {

  // act on received data if appropriate
  if(newDataFlag == true) {
    newDataFlag = false; 
    // act on received data
    if(strcmp (s_switchInfo.c_level, "HIGH") == 0) {
      digitalWrite(flashLedPin, !flashLedOff);
      digitalWrite(builtinLedPin, builtinLedOff);      
    } else {
      digitalWrite(flashLedPin, flashLedOff);
      digitalWrite(builtinLedPin, !builtinLedOff);
    } 
  } 

  // do something else ...

}

//  ....................................................................................
void OnDataRecv(const uint8_t * mac, const uint8_t *incomingData, int len) {
  // extract the received data
  char receivedData[100];
  memcpy(&s_switchInfo, incomingData, sizeof(s_switchInfo));

  // deal with received data
  newDataFlag = true;           // handled in loop()

  // display received data - (interesting, but not essential)
  char recvStr[50];  
  snprintf(recvStr, sizeof(recvStr), "\n %u  %u  %s",
           s_switchInfo.i_id, s_switchInfo.i_count, s_switchInfo.c_level);
  Serial.print(recvStr);
  
  // display MAC of sending device - (interesting, but not essential)
  char macStr[20];
  snprintf(macStr, sizeof(macStr), "%02x:%02x:%02x:%02x:%02x:%02x",
            mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
  Serial.print("   Received from ");
  Serial.print(macStr);
} 

//  ....................................................................................