You could use a 5v volt regulator, and thus get a steady 5v supply.

You could also yank the crystal of the arduinos and use the internal oscillator, which brings the arduino down to 8mhz, and then provide it with 3v3 on the vin pin, this essentially makes it an 3v3 8mhz arduino.

If you power it with 4 batteries and you disable the power led you should get fairly long battery life, regardless of the required voltage of your setup.

If you are uncomfortable with modding your arduinos, I suggest you look in to low dropout volt regulators.

@John
well I am not all that familiar with anycast, is that the same as the segment's broadcast address ?

@John
But in anycase, I have only 1190 bytes left, and this is with debugging disabled.

I was hoping I could get a simplified serial library going to show the ip on a lcd aswell, but I am guessing this is more or less a no go.

@nneeoo
I am well aware of this, but it requires you to actually know the broadcast address of your segment.

In multicast you choose the multicast address you want to use, and this is regardless of your segment, which actually makes it abit easier.

@daulagari
I am all for a standard way of doing this, but as present Ethernet Library implementation we have to alter our libraries to support multicast broadcasts, and therefore it is not possible to do a standardized implementation, since it wont be compatible with the current Ethernet Libraray.

We have to wait for the library to include this functionality, or come up with a way to do this without multicast and still keep it small.

@daulagari
Never really fooled around with that, and in my oppinion it is a not a so smart Network feature, I dont want any application to cause my router to open a port into my Network, even tho it simplifies Things from a user perspective, I just dont care for it.

But that dont mean you can't implement it

There is also limited Space left in the chip after the mysensors library and Ethernet library is loaded in, so I am not even sure you have Space enough to implement a UPnP protocol.

@John
I would be happy to share my code with you, infact the sketch modifications can be found on http://wiki.zennet.dk

My udp broadcast listener is just a simple test code build in c#. its less then 15 lines of code, and it Works well.

@John
no its not in the library, it even requires you to add a function to the EthernetUdp.cpp file in your arduino libraries, to support multicast.

At least thats my findings.

I also found a couple of issues with this, thats the main reason why I only do one broadcast on setup.

I cant make it broadcast once per 10 seconds (simply because the gateway goes to sleep) the millis() does not update

Second, I did manage to get it to broadcast continously but I found that it doubled the message each time,.

I already modified the sketch to do a udp multicast broadcast on setup, this will allow you to listen on the broadcast address and get the gateways ip, after it has aquired a dhcp issued address.