I am using the ESP32 to make a number of modules which are powered by PoE. I have also written an app for the PC (windows 8.1) which sends requests to these modules on a scheduled basis and the modules send data back to the PC. The PC also looks for new modules on the network using the 'arp -a' command, getting the reply back as a text string it can parse and see what devices are on the network. It is all working well apart from one thing. When the ESP32 connects to the network, it is allocated an IP address by DHCP but this IP address does not immediately show up on the ARP table. I have got round this by setting my PC to a static IP address - 192.168.2.14 and getting the ESP32 to try to connect to it as a server, this action ensures that the ESP32's IP address is immediately added to the ARP table.
This is the code I use to manage it
Code: Select all
#include <SPI.h>
#include <Ethernet2.h>
byte mac[6];
EthernetServer server(6000);
IPAddress ip(192, 168, 2, 14);
EthernetClient client;
void setup()
{
Serial.begin(115200);
delay(3000);
esp_efuse_mac_get_default(mac); // get unit mac address from efuse
pinMode(5, OUTPUT);
Serial.println("App started ..... ");
Serial.print("Unit MAC address : ");
for(int i=0; i<5; i++)
{
Serial.print(mac[i], HEX);
Serial.print(":");
}
Serial.println(mac[5], HEX);
Serial.println("Starting Ethernet connection now ...");
Ethernet.init(5);
if(Ethernet.begin(mac))
{
server.begin();
Serial.print("server is at ");
Serial.println(Ethernet.localIP());
client.connect(ip, 80);
}
else
Serial.println("Network FAIL");
}
void loop()
{
}
These devices are to be installed at a manufacturing plant and need to be 'plug and play' ie connect them to the network and they appear on the PC app.
Cheers, Steve.
