Project completed, but...

[lunobili]

Hi,
my project is mostly completed, see the low res picture taken with my phone.

This is meant to be kept in my mother's in law garden (in Fukushima - Japan) and generate a feed in Pachube, just like this other feed that I am generating (https://pachube.com/feeds/41012).

My other Geiger device is an over the counter piece of equipment that lasts over a month with a 9 Volt battery. I erroneously assumed that this one would do the same or at least last a couple of weeks. Unfortunately I realized that it uses about 7.7 mA (notice that I am using a custom firmware that logs every ten minutes and not every second like the original) which I reckon it will drain batteries in about three days or less.

I clearly have to find a hack for this; and here it comes my question: on what voltage range can I expect the kit to work? Can you give me a min and max value?

Of course any suggestion on how to extend battery life is very welcome. At the moment I am considering solar power (but seems expensive and I am not sure I have got the skills to get the charging circuit right) or simply lot of chargeable batteries in parallel (lame, not cheap, and I am not sure how easy is to damage them if, for any reason, they are not charged all at the same level) or to use the voltage regulator on board of the XBEE breakout and draw power from the AA batteries (but I doubt it will make much of a difference).

Thanks,
Luca

[mightyohm]

The kit will run on 2 - 3.3V as-is, probably a bit higher with no component changes. You can extend the operating range to 5V pretty easily, with only 2-3 component changes. If you're interested in this, I can provide component values, but I need to do some testing first.