Battery power small electronic project CT related

[scarrier]

Hi,

Sorry for my english, it's not my first language.

I have made some micro-controller project before, mostly with Atmel. I am now starting a very small project. I am aiming at a low cost and long battery(more than 1 year).

The project itself as 3 current transformer input. and when any of them go below or higher than a programmable threshold 1 LED per channel will be open.

Obviously i need 3 ADC for the CT that and 3 output for the led all of that is possible with all the at tiny's almost. I would also need 3 input for the programmable threshold.

I have several question and most of them are power related.

How do I power the micro-controller?
Can I power it directly from coin-cells?
Should I use coin-cells or AA batteries? (which is most easy and offer the simplest electronic integration?)
If I do not have a voltage regulator I will need a voltage reference for the ADCs. What is the best kind of cheap voltage reference for low power application?
Can I power the LEDs directly from the CTs?
Is it a good practice to power things from a CT ? will it change the readed Value?
If I want to switch the led on from the CTs I need a switch. What is the easiest way for the witch to keep is position while the micro-controller is in sleep mode.


Thank You a lot in advance. I know this is a lot of question, feel free to help me on the subject you can. If you have any other advice I will happily listen to them.