Removed option to change CHANNEL

Author: PilnyTomas

libraries/ESP32/examples/ESPNow/Basic/Master/Master.ino

@@ -34,17 +34,16 @@
 
 // Global copy of slave
 esp_now_peer_info_t slave;
-#define CHANNEL 1
-#define PRINTSCANRESULTS 0
-#define DELETEBEFOREPAIR 0
+bool slaveFound;
+#define PRINT_ALL_SCAN_RESULTS 0
+#define DELETE_PEER_BEFORE_PAIRING 0
 
 // Init ESP Now with fallback
 void InitESPNow() {
   WiFi.disconnect();
   if (esp_now_init() == ESP_OK) {
     Serial.println("ESPNow Init Success");
-  }
-  else {
+  } else {
     Serial.println("ESPNow Init Failed");
     // Retry InitESPNow, add a counte and then restart?
     // InitESPNow();
@@ -57,53 +56,59 @@ void InitESPNow() {
 void ScanForSlave() {
   int8_t scanResults = WiFi.scanNetworks();
   // reset on each scan
-  bool slaveFound = 0;
+  slaveFound = false;
   memset(&slave, 0, sizeof(slave));
 
   Serial.println("");
   if (scanResults == 0) {
     Serial.println("No WiFi devices in AP Mode found");
   } else {
-    Serial.print("Found "); Serial.print(scanResults); Serial.println(" devices ");
-    for (int i = 0; i < scanResults; ++i) {
-      // Print SSID and RSSI for each device found
-      String SSID = WiFi.SSID(i);
-      int32_t RSSI = WiFi.RSSI(i);
-      String BSSIDstr = WiFi.BSSIDstr(i);
-
-      if (PRINTSCANRESULTS) {
-        Serial.print(i + 1);
+    if (PRINT_ALL_SCAN_RESULTS) {
+      Serial.print("Found "); Serial.print(scanResults); Serial.println(" devices ");
+      for (int i = 0; i < scanResults; ++i) {
+        // Print SSID and RSSI for each device found
+        String SSID = WiFi.SSID(i);
+        int32_t RSSI = WiFi.RSSI(i);
+        String BSSIDstr = WiFi.BSSIDstr(i);
+        Serial.print(i);
         Serial.print(": ");
         Serial.print(SSID);
         Serial.print(" (");
         Serial.print(RSSI);
         Serial.print(")");
         Serial.println("");
-      }
-      delay(10);
+      } // for - loop through scanResults
+    } // if PRINT_ALL_SCAN_RESULTS
+
+    for (int i = 0; i < scanResults; ++i) {
+      // Print SSID and RSSI for each device found
+      String SSID = WiFi.SSID(i);
+      int32_t RSSI = WiFi.RSSI(i);
+      String BSSIDstr = WiFi.BSSIDstr(i);
+
       // Check if the current device starts with `Slave`
       if (SSID.indexOf("Slave") == 0) {
         // SSID of interest
-        Serial.println("Found a Slave.");
-        Serial.print(i + 1); Serial.print(": "); Serial.print(SSID); Serial.print(" ["); Serial.print(BSSIDstr); Serial.print("]"); Serial.print(" ("); Serial.print(RSSI); Serial.print(")"); Serial.println("");
+        Serial.print("Found a Slave: "); Serial.print(i); Serial.print(": "); Serial.print(SSID);
+        Serial.print(" ["); Serial.print(BSSIDstr); Serial.print("]");
+        Serial.print(" ("); Serial.print(RSSI); Serial.print(")"); Serial.println("");
         // Get BSSID => Mac Address of the Slave
-        int mac[6];
-        if ( 6 == sscanf(BSSIDstr.c_str(), "%x:%x:%x:%x:%x:%x",  &mac[0], &mac[1], &mac[2], &mac[3], &mac[4], &mac[5] ) ) {
-          for (int ii = 0; ii < 6; ++ii ) {
-            slave.peer_addr[ii] = (uint8_t) mac[ii];
-          }
+        uint8_t mac[6];
+        if (6 == sscanf(BSSIDstr.c_str(), "%x:%x:%x:%x:%x:%x",  &mac[0], &mac[1], &mac[2], &mac[3], &mac[4], &mac[5] ) ) {
+          Serial.printf("Adding peer with MAC [%02x:%02x:%02x:%02x:%02x:%02x]\n", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
+          memcpy(slave.peer_addr, mac, 6);
         }
 
-        slave.channel = CHANNEL; // pick a channel
-        slave.encrypt = 0; // no encryption
+        slave.channel = 0; // 0 = Use whatever channel the Slave (AP) is using
+        slave.encrypt = false; // no encryption
 
-        slaveFound = 1;
+        slaveFound = true;
         // we are planning to have only one slave in this example;
         // Hence, break after we find one, to be a bit efficient
         break;
-      }
-    }
-  }
+      } // if SSID starts with "Slave"
+    } // for - loop in scanResults
+  } // scanResults > 0
 
   if (slaveFound) {
     Serial.println("Slave Found, processing..");
@@ -118,15 +123,14 @@ void ScanForSlave() {
 // Check if the slave is already paired with the master.
 // If not, pair the slave with master
 bool manageSlave() {
-  if (slave.channel == CHANNEL) {
-    if (DELETEBEFOREPAIR) {
+  if (slaveFound) {
+    if (DELETE_PEER_BEFORE_PAIRING) {
       deletePeer();
     }
 
     Serial.print("Slave Status: ");
     // check if the peer exists
-    bool exists = esp_now_is_peer_exist(slave.peer_addr);
-    if ( exists) {
+    if (esp_now_is_peer_exist(slave.peer_addr)) {
       // Slave already paired.
       Serial.println("Already Paired");
       return true;
@@ -140,23 +144,18 @@ bool manageSlave() {
       } else if (addStatus == ESP_ERR_ESPNOW_NOT_INIT) {
         // How did we get so far!!
         Serial.println("ESPNOW Not Init");
-        return false;
       } else if (addStatus == ESP_ERR_ESPNOW_ARG) {
         Serial.println("Invalid Argument");
-        return false;
       } else if (addStatus == ESP_ERR_ESPNOW_FULL) {
         Serial.println("Peer list full");
-        return false;
       } else if (addStatus == ESP_ERR_ESPNOW_NO_MEM) {
         Serial.println("Out of memory");
-        return false;
       } else if (addStatus == ESP_ERR_ESPNOW_EXIST) {
         Serial.println("Peer Exists");
-        return true;
       } else {
-        Serial.println("Not sure what happened");
-        return false;
+        Serial.println("Undefined Error");
       }
+      return false;
     }
   } else {
     // No slave found to process
@@ -183,16 +182,19 @@ void deletePeer() {
   }
 }
 
-uint8_t data = 0;
 // send data
 void sendData() {
-  data++;
+  static uint8_t data = 0;
   const uint8_t *peer_addr = slave.peer_addr;
-  Serial.print("Sending: "); Serial.println(data);
+  char peer_addr_str[18];
+  snprintf(peer_addr_str, sizeof(peer_addr_str), "%02x:%02x:%02x:%02x:%02x:%02x",
+           peer_addr[0], peer_addr[1], peer_addr[2], peer_addr[3], peer_addr[4], peer_addr[5]);
+  Serial.print("Sending: "); Serial.print(data); Serial.print(" to addr: "); Serial.println(peer_addr_str);
   esp_err_t result = esp_now_send(peer_addr, &data, sizeof(data));
-  Serial.print("Send Status: ");
+  Serial.print("Send Status code= "); Serial.print(result); Serial.print(": ");
   if (result == ESP_OK) {
     Serial.println("Success");
+    data++;
   } else if (result == ESP_ERR_ESPNOW_NOT_INIT) {
     // How did we get so far!!
     Serial.println("ESPNOW not Init.");
@@ -209,13 +211,13 @@ void sendData() {
   }
 }
 
-// callback when data is sent from Master to Slave
+// Callback when data is sent from Master to Slave
 void OnDataSent(const uint8_t *mac_addr, esp_now_send_status_t status) {
   char macStr[18];
   snprintf(macStr, sizeof(macStr), "%02x:%02x:%02x:%02x:%02x:%02x",
            mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5]);
   Serial.print("Last Packet Sent to: "); Serial.println(macStr);
-  Serial.print("Last Packet Send Status: "); Serial.println(status == ESP_NOW_SEND_SUCCESS ? "Delivery Success" : "Delivery Fail");
+  Serial.print("Last Packet Send Status code="); Serial.print(status); Serial.print(" : ");  Serial.println(status == ESP_NOW_SEND_SUCCESS ? "Delivery Success" : "Delivery Fail");
 }
 
 void setup() {
@@ -235,13 +237,10 @@ void setup() {
 void loop() {
   // In the loop we scan for slave
   ScanForSlave();
-  // If Slave is found, it would be populate in `slave` variable
-  // We will check if `slave` is defined and then we proceed further
-  if (slave.channel == CHANNEL) { // check if slave channel is defined
-    // `slave` is defined
+  // Check if slave was found
+  if (slaveFound) {
     // Add slave as peer if it has not been added already
-    bool isPaired = manageSlave();
-    if (isPaired) {
+    if(manageSlave()){
       // pair success or already paired
       // Send data to device
       sendData();
@@ -250,10 +249,6 @@ void loop() {
       Serial.println("Slave pair failed!");
     }
   }
-  else {
-    // No slave found to process
-  }
-
   // wait for 3seconds to run the logic again
   delay(3000);
 }

libraries/ESP32/examples/ESPNow/Basic/Slave/Slave.ino

@@ -32,7 +32,6 @@
 #include <esp_now.h>
 #include <WiFi.h>
 
-#define CHANNEL 1
 
 // Init ESP Now with fallback
 void InitESPNow() {
@@ -52,7 +51,7 @@ void InitESPNow() {
 // config AP SSID
 void configDeviceAP() {
   const char *SSID = "Slave_1";
-  bool result = WiFi.softAP(SSID, "Slave_1_Password", CHANNEL, 0);
+  bool result = WiFi.softAP(SSID, "Slave_1_Password");
   if (!result) {
     Serial.println("AP Config failed.");
   } else {
@@ -87,5 +86,5 @@ void OnDataRecv(const uint8_t *mac_addr, const uint8_t *data, int data_len) {
 }
 
 void loop() {
-  // Chill
+  // Behavior is handled in callback function
 }