Arduino Ethernet Shield
Ethernet Shield
May 14, 2015
Part of Tinker.it!'s Internet of Things master class at dconstruct 9, covering networking using the Arduino ethernet shield.
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Arduino Ethernet Shield
Arduino + Ethernet
Twittering plant
Capabilities
★Wiznet W5100 ethernet chip★Client★Server★TCP★UDP★Four channels
The Ethernet library
★All looks like a serial port
★Ethernet: initialise network★Client: connect to a port on a server, then read() and write()★Server: waits for a connection on a port
Ethernet limitations
★DHCP needs 3rd-party library★No DNS★DIY for high-level protocols (no HTTP library, etc) - lots of print() statements★Library memory footprint
Practical 1: on the network
Practical 1: on the network
Example file:ChatServer
Configuration
byte mac[] = { 0xDE,0xAD,0xBE,0xEF,0xFE,0xED };byte ip[] = { 10, 0, 0, 177 };byte gateway[] = { 10, 0, 0, 1 };byte subnet[] = { 255, 255, 0, 0 };
...
Ethernet.begin(mac,ip,gateway,subnet);
Talking HTTP
Talking HTTP
$ curl -v http://www.example.com
Talking HTTP: the request
$ curl -v http://www.example.com* About to connect() to www.example.com port 80 (#0)* Trying 208.77.188.166... connected* Connected to www.example.com (208.77.188.166) port 80 (#0)
Talking HTTP: the request
$ curl -v http://www.example.com* About to connect() to www.example.com port 80 (#0)* Trying 208.77.188.166... connected* Connected to www.example.com (208.77.188.166) port 80 (#0)> GET / HTTP/1.1> User-Agent: curl/7.16.3> Host: www.example.com> Accept: */*>
Talking HTTP: the response
$ curl -v http://www.example.com* About to connect() to www.example.com port 80 (#0)* Trying 208.77.188.166... connected* Connected to www.example.com (208.77.188.166) port 80 (#0)> GET / HTTP/1.1> User-Agent: curl/7.16.3> Host: www.example.com> Accept: */*> < HTTP/1.1 200 OK< Date: Sun, 16 Aug 2009 16:05:42 GMT< Server: Apache/2.2.3 (Red Hat)< Last-Modified: Tue, 15 Nov 2005 13:24:10 GMT< ETag: "b80f4-1b6-80bfd280"< Accept-Ranges: bytes< Content-Length: 438< Connection: close< Content-Type: text/html; charset=UTF-8
Talking HTTP: the document
$ curl -v http://www.example.com* About to connect() to www.example.com port 80 (#0)* Trying 208.77.188.166... connected* Connected to www.example.com (208.77.188.166) port 80 (#0)> GET / HTTP/1.1> User-Agent: curl/7.16.3> Host: www.example.com> Accept: */*> < HTTP/1.1 200 OK< Date: Sun, 16 Aug 2009 16:05:42 GMT< Server: Apache/2.2.3 (Red Hat)< Last-Modified: Tue, 15 Nov 2005 13:24:10 GMT< ETag: "b80f4-1b6-80bfd280"< Accept-Ranges: bytes< Content-Length: 438< Connection: close< Content-Type: text/html; charset=UTF-8< <HTML>..........
The most important bits
> GET / HTTP/1.1> Host: www.example.com> < HTTP/1.1 200 OK< Content-Type: text/html; charset=UTF-8< <HTML>..........
Practical 2: retrieving data
Practical 2: retrieving data
Example file:WebClient
Web APIs
★It’s just HTTP★At least, the good ones are
Web API challenges
★HTTPS★Crypto (e.g. OAuth)★XML parsing★JSON parsing★Large documents
Practical 3: serving data
Practical 3: serving data
Example file:WebServer
Related Documents
