| That's pretty good actually, I wasn't able to get over 1 month with all the (software) power saving techniques that I found. For me it made more sense, because using just 3 x AA I get about 5V so I don't have to use a voltage regulator (less power used). That way I can also use the attiny's internal voltage reference to measure remaining battery life without any additional circuitry. Plus the smaller package, no annoying red lights everywhere, etc. > I would like to the next level and use ATTiny's directly but I have no real electronics experience, how did you get started ? I started with zero experience as well. I bought an Arduino, did the LED example and put it away for a year. Then I found a 37 sensor kit[1], together with a breadboard[2] and some wires[3] and this wonderful wiki[4] and... everything was different, because I was doing real practical (albeit simple) things with it. The rest was just experimentation and reading about it, which was easy once I've found my "spark". See @gh02t's answer for the attiny part, I went the lowest friction way with using an existing Arduino to program the attiny84. [1] https://www.amazon.com/Elegoo-Sensor-Module-Arduino-MEGA/dp/... [2] http://eud.dx.com/product/solderless-breadboard-with-400-tie... [3] http://eud.dx.com/product/chuangzhuo-male-to-male-male-to-fe... [4] https://tkkrlab.nl/wiki/Arduino_37_sensors |