This device captures the IP address of your network and it publish on site DynDNS.com. All without PC. It allow a remote access to your LAN even if the IP address of the connections changes.
For logistics reasons the provider can not assign a IP fixed for all users, so many users, especially private, work with a dynamic IP or public IP: in practice when they connect modem or router, to their connection is assigned an IP address that, when the connection will’be closed, can be used by other users. This makes impossible to contact a remote computer or device connected to a LAN Internet.
Step 1: Schematics
Our device is essentially a publisher of IP address. Everything is made from a circuit that incorporates an Ethernet interface WIZnet WIZ811MJ, managed by an Atmega328 microcontroller programmed with the Arduino bootloader, so it all works like an Arduino and you can use the Arduino IDE. The Atmega I/O PB2, PB3, PB4 and PB5 are dedicated to dialogue with the Ethernet module and provide a full four-wire SPI bus. The microcontroller is programmed using the special interface TTL / USB from SparkFun.
R1, R2: 470 ohm
R3: 10 kohm
C1: 100 nF
C2: 470 μF 25 VL
C3: 100 nF
C4: 470 μF 16 VL
U2: ATMEGA328P (with Arduino bootloader)
LD1: LED 3 mm yellow
LD2: LED 3 mm red
Dip socket 14+14
Break away headers male 6 via
Break away headers female 2×10 via (2 pz)
Step 2: How Works
The main program sends the request to the IP address http://checkip.dyndns.com/ site. Now prepare the process of submitting to the site www.dyndns.com, which provides for the opening of a session onthe web page on, where will send data strings containing user name and password, thena string containing the Current IP connection. Cyclically the microcontroller check the IP to see if the address is changed, then, if it’s true, sends the new IP to www.dyndns.com
We use a dedicated circuit but the project can be replicated using an Arduino UNO and a Ethernet Shield.
Step 3: The Arduino Sketch
This is the complete sketch.
You can download the source code from open-electronics.org or in this page.