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en:iot-open:espressif_arduino [2023/10/03 09:12] – created ktokarzen:iot-open:espressif_arduino [2023/11/21 21:57] (current) – ktokarz
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-====  ==== +====== Programming ESP8266 for the Network ======
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-====  Programming for IoT Networking ==== +
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-Using Espressif SoC devices in Arduino platform we can use all the previously described Arduino examples for sensors and actuators. But the most interesting are are those that use wireless networking functions. Both Espressif chip ESP32 and ESP8266  families can use similar network modes. As a WiFi device Espressif SoC can  work in different networking  modes (applies to medial layers 1--3 ISO-OSI model): +Programming networking services with Espressif SoCs requires the connection established on the networking layer between parties, mainly with TCP protocol.\\ 
-  * as WiFi client connected to WiFi router (Figure {{ref>esp_client}}),  +Below are two code examples for ESP8266 of how to implement access point and network station modes using libraries that came during installation of the development environment for Arduino framework.\\ 
-<figure esp_client> +The third example shows how to send and receive a UDP packet while in client mode. It is the full solution to connect ESP8266 to the NTP (Network Time Protocol) server to obtain the current date and time from the Internet.\\ 
-{{ :en:iot-open:getting_familiar_with_your_hardware_rtu_itmo_sut:esp:esp_client.png?nolink&200 |}} +Examples on further pages show how to make a handy WiFi scanner showing available networks nearby. 
-<caption>ESP client mode.</caption> + 
-</figure> +== ESP8266 AP (Access Point) Mode == 
-  * as independent WiFi access point (Figure {{ref>esp_ap}}), +Based on a standard example, this program demonstrates how to program ESP8266 in AP mode. After compilation and uploading this program, an ESP8266 starts serving as the access point that can be connected to, e.g., a smartphone. It presents a simple web server available at the local IP address 192.168.4.1 (the default address of the ESP access point). This web server responds with a short message: "You are connected". 
-<figure esp_ap> + 
-{{ :en:iot-open:getting_familiar_with_your_hardware_rtu_itmo_sut:esp:esp_ap.png?nolink&200 |}} +<code c> 
-<caption>ESP AP  mode.</caption> + 
-</figure> +#include <ESP8266WiFi.h> 
-  * as a repeater with devices connected to ESP and ESP connected to external router (Figure {{ref>esp_both}}), +#include <WiFiClient.h>  
-<figure esp_both> +#include <ESP8266WebServer.h> 
-{{ :en:iot-open:getting_familiar_with_your_hardware_rtu_itmo_sut:esp:esp_both.png?nolink&200 |}} + 
-<caption>ESP dual mode.</caption> +/* Set these variables to your desired credentials. */ 
-</figure> +const char *ssid = "APmode"; 
-  * as client and server in mesh network (Figure {{ref>esp_mesh}}). +const char *password = "password"; 
-<figure esp_mesh> + 
-{{ :en:iot-open:getting_familiar_with_your_hardware_rtu_itmo_sut:esp:esp_mesh.png?nolink&200 |}} +ESP8266WebServer server(80); 
-<caption>ESP mesh networking.</caption> + 
-</figure> +void hRoot() { 
-ESP32 can also use Bluetooth networking in the same configuration as WiFi.+ server.send(200, "text/html", "<h1>You are connected</h1>"); 
 +} 
 + 
 +/* Initialization */ 
 +void setup() { 
 + delay(1500); 
 + /* You can remove the password parameter  
 +           if you want the AP to be open. */ 
 + WiFi.softAP(ssid, password); 
 + 
 + IPAddress myIP = WiFi.softAPIP(); 
 + 
 + server.on("/", hRoot); 
 + server.begin(); 
 +} 
 + 
 +void loop() { 
 + server.handleClient(); 
 +} 
 +</code> 
 + 
 +== ESP8266 Client Mode == 
 +This standard example demonstrates how to program ESP8266 in client mode. It tries to connect to the WiFi network with a specified name (SSID) and password.  
 +<code c> 
 + 
 +#include <ESP8266WiFi.h> 
 +#include <ESP8266WiFiMulti.h> 
 + 
 +ESP8266WiFiMulti WiFiMulti; 
 + 
 +void setup() { 
 +    delay(1000); 
 +     
 +    // Initialise serial port to monitor program behaviour 
 +    Serial.begin(115200); 
 + 
 +    // We start by connecting to a WiFi network 
 +    WiFi.mode(WIFI_STA); 
 +    WiFiMulti.addAP("SSID", "password"); 
 + 
 +    while(WiFiMulti.run() != WL_CONNECTED) { 
 +        delay(500); 
 +    } 
 +    delay(500); 
 +} 
 + 
 + 
 +void loop() { 
 +    const uint16_t port = 80; 
 +    const char * host = "192.168.1.1"; // ip or dns 
 + 
 +    // Use WiFiClient class to create TCP connections 
 +    WiFiClient client; 
 + 
 +    if (!client.connect(host, port)) { 
 +        delay(5000); 
 +        return; 
 +    } 
 +    // This will print the IP address assigned by the DHCP server 
 +    Serial.println(WiFi.localIP()); 
 + 
 +    // This will send the request to the server 
 +    client.println("Send this data to server"); 
 +    // Trying to send the GET request possibly responses (with error) 
 +    // client.println("GET /echo"); 
 + 
 +    //read back one line from server 
 +    String line = client.readStringUntil('\r'); 
 +    Serial.println(line); 
 + 
 +    Serial.println("closing connection"); 
 +    client.stop(); 
 +     
 +    Serial.println("wait 5 sec..."); 
 +    delay(5000); 
 +} 
 +</code> 
 + 
 +== ESP8266 and UDP == 
 +This sketch (based on a standard example) demonstrates how to program ESP8266 as an NTP client using UDP packets (send and receive): 
 +<code c> 
 + 
 +#include <ESP8266WiFi.h> 
 +#include <WiFiUdp.h> 
 + 
 + 
 +char ssid[] = "**************";  //  your network SSID (name) 
 +char pass[] = "**************";  // your network password 
 + 
 +unsigned int localPort = 2390;   // local port to listen for UDP packets 
 + 
 +// NTP servers 
 +IPAddress ntpServerIP; // 0.pl.pool.ntp.org NTP server address 
 +const char* ntpServerName[] =  
 + {"0.pl.pool.ntp.org","1.pl.pool.ntp.org","2.pl.pool.ntp.org","3.pl.pool.ntp.org"}; 
 + 
 +const int timeZone = 1;  //Central European Time 
 +int servernbr=0; 
 + 
 +// NTP time stamp is in the first 48 bytes of the message 
 +const int NTP_PACKET_SIZE = 48;  
 + 
 +//buffer to hold incoming and outgoing packets 
 +byte packetBuffer[ NTP_PACKET_SIZE];  
 + 
 +// A UDP instance to let us send and receive packets over UDP 
 +WiFiUDP udp; 
 + 
 +// Prototype of the function defined at the end of this file  
 +// (required in Visual Studio Code) 
 +void sendNTPpacket(IPAddress& address); 
 + 
 +void setup() 
 +{ 
 +  Serial.begin(115200); 
 +  Serial.println(); 
 +    
 +  Serial.print("Connecting to "); 
 +  Serial.println(ssid); 
 +   
 +//  WiFi.persistent(false); 
 +  WiFi.mode(WIFI_OFF); 
 +  delay(2000); 
 +   
 +// We start by connecting to a WiFi network 
 +  WiFi.mode(WIFI_STA); 
 +  delay(3000);  
 +  WiFi.begin(ssid, pass);  
 +   
 +  while (WiFi.status() != WL_CONNECTED) {    
 +    delay(500); 
 +    Serial.print("."); 
 +  } 
 +     
 +  Serial.println(""); 
 +   
 +  Serial.println("WiFi connected"); 
 +  Serial.println("DHCP assigned IP address: "); 
 +  Serial.println(WiFi.localIP()); 
 + 
 +  Serial.println("Starting UDP"); 
 +  udp.begin(localPort); 
 +  Serial.print("Local port: "); 
 +  Serial.println(udp.localPort()); 
 + 
 +  // first ntp server 
 +  servernbr = 0; 
 +} 
 + 
 +void loop() 
 +{ 
 +  //get a random server from the pool 
 + 
 +  WiFi.hostByName(ntpServerName[servernbr], ntpServerIP);  
 +  Serial.print(ntpServerName[servernbr]);  
 +  Serial.print(":"); 
 +  Serial.println(ntpServerIP); 
 + 
 +  // send an NTP packet to a time server 
 +  sendNTPpacket(ntpServerIP);  
 +   
 +  // wait to see if a reply is available 
 +  delay(1000); 
 +   
 +  int cb = udp.parsePacket(); 
 +  if (!cb) { 
 +    Serial.println("no packet yet"); 
 +    if ( servernbr = 5 ) { 
 +      servernbr =0; 
 +    } 
 +    else { 
 +      servernbr++; 
 +    } 
 +  } 
 +  else { 
 +    Serial.print("packet received, length="); 
 +    Serial.println(cb); 
 +    // We've received a packet, read the data from it 
 +    // read the packet into the buffer 
 +    udp.read(packetBuffer, NTP_PACKET_SIZE);  
 + 
 +    // the timestamp starts at byte 40  
 +    // of the received packet and is four bytes, 
 +    // or two words, long. First, extract the two words: 
 + 
 +    unsigned long highWord = word(packetBuffer[40], packetBuffer[41]); 
 +    unsigned long lowWord = word(packetBuffer[42], packetBuffer[43]); 
 +    // combine the four bytes (two words) into a long integer 
 +    // this is NTP time (seconds since Jan 1 1900): 
 +    unsigned long secsSince1900 = highWord << 16 | lowWord; 
 +    Serial.print("Seconds since Jan 1 1900 = " ); 
 +    Serial.println(secsSince1900); 
 + 
 +    // now convert NTP time into everyday time: 
 +    Serial.print("Unix time = "); 
 +    // Unix time starts on Jan 1 1970.  
 +    // In seconds, that's 2208988800: 
 +    const unsigned long seventyYears = 2208988800UL; 
 +    // subtract seventy years: 
 +    unsigned long epoch = secsSince1900 - seventyYears; 
 +    // print Unix time: 
 +    Serial.println(epoch); 
 + 
 + 
 +    // print the hour, minute and second: 
 +    // UTC is the time at Greenwich Meridian (GMT) 
 +    Serial.print("The UTC time is ");        
 +    // print the hour (86400 equals secs per day) 
 +    Serial.print((epoch  % 86400L) / 3600);  
 +    Serial.print(':'); 
 +    if ( ((epoch % 3600) / 60) < 10 ) { 
 +      // In the first 10 minutes of each hour, we'll want a leading '0' 
 +      Serial.print('0'); 
 +    } 
 +    // print the minute (3600 equals secs per minute) 
 +    Serial.print((epoch  % 3600) / 60);  
 +    Serial.print(':'); 
 +    if ( (epoch % 60) < 10 ) { 
 +      // In the first 10 seconds of each minute, we'll want a leading '0' 
 +      Serial.print('0'); 
 +    } 
 +    Serial.println(epoch % 60); // print the second 
 +  } 
 +  // wait ten seconds before asking for the time again 
 +  delay(10000); 
 +} 
 + 
 +// send an NTP request to the time server at the given address 
 +void sendNTPpacket(IPAddress& address) 
 +{ 
 +  Serial.print("sending NTP packet to: "); 
 +  Serial.println( address ); 
 +  // set all bytes in the buffer to 0 
 +  memset(packetBuffer, 0, NTP_PACKET_SIZE); 
 +  // Initialize values needed to form NTP request 
 +  // (see URL above for details on the packets) 
 +  packetBuffer[0] = 0b11100011;   // LI, Version, Mode 
 +  packetBuffer[1] = 0;     // Stratum, or type of clock 
 +  packetBuffer[2] = 6;     // Polling Interval 
 +  packetBuffer[3] = 0xEC;  // Peer Clock Precision 
 +  // 8 bytes of zero for Root Delay & Root Dispersion 
 +  packetBuffer[12]  = 49; 
 +  packetBuffer[13]  = 0x4E; 
 +  packetBuffer[14]  = 49; 
 +  packetBuffer[15]  = 52; 
 + 
 +  // all NTP fields have been given values, now 
 +  // you can send a packet requesting a timestamp: 
 +  udp.beginPacket(address, 123); //NTP requests are to port 123 
 +  udp.write(packetBuffer, NTP_PACKET_SIZE); 
 +  udp.endPacket(); 
 +} 
 + 
 +</code>
  
en/iot-open/espressif_arduino.1696324329.txt.gz · Last modified: 2023/10/03 09:12 by ktokarz
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