92 lines
2.8 KiB
C++
92 lines
2.8 KiB
C++
/**
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* @file
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*
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* EspNowUnicast.ino demonstrates how to transmit unicast ESP-NOW messages with @c WifiEspNow .
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* You need two ESP8266 or ESP32 devices to run this example.
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*
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* Unicast communication requires the sender to specify the MAC address of the recipient.
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* Thus, you must modify this program for each device.
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*
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* The recommended workflow is:
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* @li 1. Flash the program onto device A.
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* @li 2. Run the program on device A, look at serial console for its MAC address.
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* @li 3. Copy the MAC address of device A, paste it in the @c PEER variable below.
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* @li 4. Flash the program that contains A's MAC address onto device B.
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* @li 5. Run the program on device A, look at serial console for its MAC address.
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* @li 6. Copy the MAC address of device B, paste it in the @c PEER variable below.
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* @li 7. Flash the program that contains B's MAC address onto device A.
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*/
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#include <WifiEspNow.h>
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#if defined(ARDUINO_ARCH_ESP8266)
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#include <ESP8266WiFi.h>
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#elif defined(ARDUINO_ARCH_ESP32)
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#include <WiFi.h>
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#endif
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// The recipient MAC address. It must be modified for each device.
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static uint8_t PEER[]{0x02, 0x00, 0x00, 0x45, 0x53, 0x50};
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void
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printReceivedMessage(const uint8_t mac[WIFIESPNOW_ALEN], const uint8_t* buf, size_t count,
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void* arg)
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{
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Serial.printf("Message from %02X:%02X:%02X:%02X:%02X:%02X\n", mac[0], mac[1], mac[2], mac[3],
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mac[4], mac[5]);
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for (int i = 0; i < static_cast<int>(count); ++i) {
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Serial.print(static_cast<char>(buf[i]));
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}
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Serial.println();
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}
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void
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setup()
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{
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Serial.begin(115200);
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Serial.println();
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WiFi.persistent(false);
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WiFi.mode(WIFI_AP);
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WiFi.disconnect();
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WiFi.softAP("ESPNOW", nullptr, 3);
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WiFi.softAPdisconnect(false);
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// WiFi must be powered on to use ESP-NOW unicast.
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// It could be either AP or STA mode, and does not have to be connected.
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// For best results, ensure both devices are using the same WiFi channel.
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Serial.print("MAC address of this node is ");
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Serial.println(WiFi.softAPmacAddress());
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uint8_t mac[6];
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WiFi.softAPmacAddress(mac);
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Serial.println();
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Serial.println("You can paste the following into the program for the other device:");
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Serial.printf("static uint8_t PEER[]{0x%02X, 0x%02X, 0x%02X, 0x%02X, 0x%02X, 0x%02X};\n", mac[0],
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mac[1], mac[2], mac[3], mac[4], mac[5]);
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Serial.println();
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bool ok = WifiEspNow.begin();
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if (!ok) {
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Serial.println("WifiEspNow.begin() failed");
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ESP.restart();
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}
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WifiEspNow.onReceive(printReceivedMessage, nullptr);
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ok = WifiEspNow.addPeer(PEER);
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if (!ok) {
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Serial.println("WifiEspNow.addPeer() failed");
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ESP.restart();
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}
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}
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void
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loop()
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{
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char msg[60];
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int len = snprintf(msg, sizeof(msg), "hello ESP-NOW from %s at %lu",
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WiFi.softAPmacAddress().c_str(), millis());
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WifiEspNow.send(PEER, reinterpret_cast<const uint8_t*>(msg), len);
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delay(1000);
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}
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