Esp8266

notes on esp8266

Hi Mitul,

My best esp8266 code is in https://github.com/mckennatim/demiot. A couple of notes on it.

You can always get it online by hard coding your SSID info ala...

   #include <ESP8266WiFi.h>
   #include <ESP8266WebServer.h>
   
   const char *ssid = "street_no_vale2";
   const char *pwd = "jjjjjjjj";
   
   ESP8266WebServer server(80);
   
   void handleRoot() {
     server.send(200, "text/html", "h1 root of espAPsb AP server /h1");
   }
   
   void getOnline(){
     WiFi.begin(ssid, pwd);
     int tries =0;
     int success=1;
     while (WiFi.status() != WL_CONNECTED ) {
       delay(500);
       Serial.print(".");
       tries++;
       if (tries==15){
         success=0;
         scan();
         setupAP();
         break;
       }
     }
     if (success){
       Serial.println("");
       Serial.println("WiFi connected");
       Serial.print("IP address: ");
       Serial.println(WiFi.localIP());    
     }   
   }

   void setup(){
     Serial.begin(115200);
     Serial.println();
     Serial.println("--------------------------");
     Serial.println("ESP8266 webconfig");
     Serial.println("--------------------------");
     getOnline();
   }

   void loop(){
     server.handleClient();
   }

but that is not at all interesting for a couple of reasons

1. you shouldn't have to be reconnect and upload over USB every time you move to a new SSID
2. this sets you up as a server instead of client. There are lots of downsides to that. (your customers have to open ports on their routers ala xbox, an outside server&clients needs to keep track of its IP...)

So you need to be able to webconfig the thing and then run it as a client.

In denmiot/essp8266/mqttall I broke out webconfig in `#include "config.h"` (excuse the `extern` globals).

setup calls getOnline() which reads a config from the EEPROM and connects but if that fails it jumps into webconfig mode, turning itself into and access point server with an SSID of `espAPsb` and an ip of 192.168.4.1 where you can send it a get string like

  http://192.168.4.1/config?ssid=street_no_vale2&pwd=jjjjjjjj&devid=CYURD001&ip=10.0.1.100&port=3332

once you send it that it reboots itself (sometimes you need to hit the reset or powerdown) as a client on your local wifi.

mqtt

mqtt is a very cool pu/sub/ protocol. For some reason though it won't automatically reconnect when you do a webconfig. You have to power down first

tls on esp8266

{"pid":5768,"hostname":"tim-hp","name":"mosca","level":40,"time":1484804098536,"msg":"101057795:error:14094410:SSL routines:ssl3_read_bytes:sslv3 alert handshake failure:openssl\\ssl\\s3_pkt.c:1472:SSL alert number 40\n","type":"Error","stack":"Error: 101057795:error:14094410:SSL routines:ssl3_read_bytes:sslv3 alert handshake failure:openssl\\ssl\\s3_pkt.c:1472:SSL alert number 40\n\n at Error (native)","client":"ESP8266Client-e1e","v":1}

openssl s_client -connect sslvh.tm:8883 -tls1

http://security.stackexchange.com/questions/119505/how-to-speed-up-slow-tls-handshake-on-esp8266-running-mbed-tls

https://www.bountysource.com/issues/28368887-compatibility-with-arduino-and-esp8266

• http://iot-playground.com/2-uncategorised/40-esp8266-wifi-relay-switch-arduino-ide
• web based configuration

debug

• https://github.com/me-no-dev/EspExceptionDecoder

sparkfun thing dev

http://frightanic.com/iot/comparison-of-esp8266-nodemcu-development-boards/

:back to breakout boards

wifi breakout board

• ESP8266-as-Arduino

wiring

http://www.forward.com.au/pfod/ESP8266/GPIOpins/index.html

https://github.com/esp8266/Arduino/issues/1243

current sensing

http://www.esp8266-projects.com/2015/06/mailbag-arrival-acs712-current-sensor.html