This video is a New & Improved co2 Generator.
Easier to make then my last one.

What you need :
5 gallon bucket with a lid.
use the aquarium air pump, air hose & 1 air stone.
Incubator heating matt or an aquarium heater.
water, sugar yeast.
mix: dissolve 4-6 cups sugar into 2 gallons of warm water
then stir in 2 tablespoons of yeast.
Change mix about every 2 weeks.