Too lazy I spose, I like the arduino ide.
I got a pic 12f683 to work on something similar, a solar cell without a battery, and it was fine, I dont know for sure however I think I'd be ablet= to get it to work Ok on a fluctuating power source.
Actually the system will have a battery, but the idea is to get the processor to flash some Led's for a while after the push hog has stopped then go to sleep mode and save power, switching from batts to alty is still going to make a unstable power rail, theres every chance the chip will lock up.
And thinking about the i/o, I'll have 2 x 5mm leds and a 10w led in the rear, and a 10w led in the front, a pushbutton and an i/p for alty making power, that allready exceeds the 5 i/o's the attiny has, so it looks like it'll be a 'duino mini 168 I got a load cheap.