ESP8266 STA mode connect via LAN to another 8266 in STA Mode
Posted: Fri May 06, 2022 12:33 amThere are lots of examples of client-server with STA-AP mode. But has anyone got a working example of an 8266 in STA mode using either http.begin(client, target string) or WiFiClient client.connect(host,port) to connect to another 8266 on the same LAN, and therefore connected in STA mode, but running a web server?
1. I have a very simple sketch that always fails. See below
2. A very sophisticated app where I see it succeed once and then never work without restarting.
It suggests that some kind of WiFi state or configuration has to be present and which can get modified easily. The simple sketch doesn’t reproduce this behavior.
3. And that was with version 2.7.4 and I haven’t yet had time to test everything on version 3.x.x. I recently updated to the main branch and set up the Gdb debugger to try to figure it out.
4. Note that if the target is my raspberry pi or a server I have running on Digital Ocean, it always connects and succeeds. But if it's another 8266, it always fails, with the noted exception above.
5. If I use client.connect, the connection also fails.
6. Targets that fail include my code running a ESPAsyncWebServer server, a Tasmota smart switch. Both of them work with http messages sent from a browser.
And don't tell me to use MQTT because I'm building a product where I don't want that overhead, and I'm not sending the data anywhere. I just want to control a switch from my other 8266.
7. My sense is that somehow this "Elephant in the Room" example isn't well supported but the tcp transport layer should be quite independent of the radio connection mode. Once two devices are connected to the LAN they should be able to send bi-directional tcp messages, in this case with HTTP protocols running.
1. I have a very simple sketch that always fails. See below
2. A very sophisticated app where I see it succeed once and then never work without restarting.
It suggests that some kind of WiFi state or configuration has to be present and which can get modified easily. The simple sketch doesn’t reproduce this behavior.
3. And that was with version 2.7.4 and I haven’t yet had time to test everything on version 3.x.x. I recently updated to the main branch and set up the Gdb debugger to try to figure it out.
4. Note that if the target is my raspberry pi or a server I have running on Digital Ocean, it always connects and succeeds. But if it's another 8266, it always fails, with the noted exception above.
5. If I use client.connect, the connection also fails.
6. Targets that fail include my code running a ESPAsyncWebServer server, a Tasmota smart switch. Both of them work with http messages sent from a browser.
And don't tell me to use MQTT because I'm building a product where I don't want that overhead, and I'm not sending the data anywhere. I just want to control a switch from my other 8266.
7. My sense is that somehow this "Elephant in the Room" example isn't well supported but the tcp transport layer should be quite independent of the radio connection mode. Once two devices are connected to the LAN they should be able to send bi-directional tcp messages, in this case with HTTP protocols running.
Code: Select all
/**
RealBasicHttp.ino
Created on: 24.05.2015
*/
#include <Arduino.h>
#include "Arduino_DebugUtils.h"
#include <ESP8266WiFi.h>
#include <WiFiUdp.h>
#include <WiFiClient.h>
#include <ESP8266HTTPClient.h>
#include <ESP8266Ping.h>
const char string_BSQ[] PROGMEM = "\"";
const char string_Host[] PROGMEM ="Host: ";
const char string_GET[] PROGMEM ="GET ";
const char string_switchCmd[] PROGMEM = "/cm?cmnd=Power";
const char string_ContentLen[] PROGMEM ="Content-Length: ";
const char string_ContentTypeTxt[] PROGMEM ="Content-Type: text/plain";
const char string_HTTP1P1[] PROGMEM =" HTTP/1.1";
const char string_urlBase[] PROGMEM = "http://";
//const char string_ipBase[] PROGMEM = "192.168.0.35"; //Raspberry Pi
const uint16_t serverPort = 80; //5000 for Rasp Pi, 80 for Ubuntu server
const char string_off[] PROGMEM = "off";
const char string_on[] PROGMEM = "On";
#define ipLen 17
#define HTTPport 80
#define MTempSize 160
char MTemp[MTempSize]; //General purpose buffer for many operations
char workBuffer[21]; //General purpose buffer when two are needed
const IPAddress test_ip(192,168,0,71);
bool RlyOnOff(bool OnOff, uint8_t relNo);
HTTPClient httpSW;
WiFiClient client;
char switchIP[ipLen];
int httpCode;
void setup() {
Serial.begin(115200);
establishContact();
Serial.println();
strcpy(switchIP, "191.168.0.28"); //ip address of the wireless switch
Serial.println("Connecting to wifi");
wifi_set_phy_mode (PHY_MODE_11G);
WiFi.mode(WIFI_STA);
WiFi.begin("TigerScout", "5415492012");
// wait for WiFi connection
if(WiFi.status() != WL_CONNECTED){
Serial.print(".");
delay(500);
}
Serial.println("Wifi Connected");
}
bool ONoff = true;
void loop() {
Serial.println("Begin loop");
if(Ping.ping(test_ip)){
Debug.print(DBG_INFO, F("ping succeeded"));
} else {
Debug.print(DBG_INFO, F("ping failed"));
}
// RlyOnOff(ONoff, 0);
ONoff = !ONoff;
delay (10000);
}
void establishContact() {
int counter = 0;
while ((Serial.available()<= 0)&&(counter<2)) {
Serial.println(F("0,0,0")); // send an initial string
delay(3000);
counter++;
}
}
bool RlyOnOff(bool OnOff, uint8_t relNo){
//relNo is for future expansion, requires multiple swtichIPs
int httpCode = 0;
httpSW.setReuse(false);
Debug.print(DBG_INFO, "RlyOnOff, Switch IP: %s", switchIP);
sprintf_P(MTemp, "%s%s:%d%s" ,string_urlBase,switchIP,HTTPport,string_switchCmd);
// sprintf_P(MTemp, "%s%s:%d%s" ,string_urlBase,srvIP,serverPort,string_switchCmd);
strcat(MTemp,"_"); //"%20" for Tasmota devices
if(OnOff){
strcat_P(MTemp, string_on);
} else {
strcat_P(MTemp,string_off);
}
Serial.println(MTemp);
httpSW.begin(client, MTemp);
httpCode = httpSW.GET();
if ((httpCode > 0)){
httpSW.writeToStream(&Serial);
Serial.println(" ");
Debug.print(DBG_INFO, F("HTTP %d"), httpCode);
httpSW.end();
return true;
} else {
Debug.print(DBG_ERROR, F("HTTP GET invalid response http code %d %s"),httpCode, httpSW.errorToString(httpCode).c_str());
// something wrong with connection
httpSW.end();
return false;
}
}