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

http://security.stackexchange.com/questions/105766/openssl-generate-self-signed-certificates-with-different-cipher-suites

{"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

CONNECTED(00000003)
depth=0 /C=US/ST=MA/L=Boston/O=sitebuilt.net/OU=dog/CN=sslvh.tm/emailAddress=mckenna.tim@gmail.com
verify error:num=18:self signed certificate
verify return:1
depth=0 /C=US/ST=MA/L=Boston/O=sitebuilt.net/OU=dog/CN=sslvh.tm/emailAddress=mckenna.tim@gmail.com
verify return:1
---
Certificate chain
 0 s:/C=US/ST=MA/L=Boston/O=sitebuilt.net/OU=dog/CN=sslvh.tm/emailAddress=mckenna.tim@gmail.com
   i:/C=US/ST=MA/L=Boston/O=sitebuilt.net/OU=dog/CN=sslvh.tm/emailAddress=mckenna.tim@gmail.com
---
Server certificate
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
subject=/C=US/ST=MA/L=Boston/O=sitebuilt.net/OU=dog/CN=sslvh.tm/emailAddress=mckenna.tim@gmail.com
issuer=/C=US/ST=MA/L=Boston/O=sitebuilt.net/OU=dog/CN=sslvh.tm/emailAddress=mckenna.tim@gmail.com
---
No client certificate CA names sent
---
SSL handshake has read 1080 bytes and written 412 bytes
---
New, TLSv1/SSLv3, Cipher is AES256-SHA
Server public key is 2048 bit
Compression: NONE
Expansion: NONE
SSL-Session:
    Protocol  : TLSv1
    Cipher    : AES256-SHA
    Session-ID: EB450D46B951B96AB6D8F3B10762772F05D8D9E65998FEC796EAA852A335FFD2
    Session-ID-ctx:
    Master-Key: 6F9AA7D47D1E352283BC6D7715A4664E184E4B565B14F6288350E117D3D9F6FD6869F28E66481822B1B37CC35E252BE0
    Key-Arg   : None
    Start Time: 1484812097
    Timeout   : 7200 (sec)
    Verify return code: 18 (self signed certificate)

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://superuser.com/questions/882638/sslciphersuite-settings-in-apache-for-supporting-tls-1-0-1-1-and-1-2

• 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