The only things you need are metal cans with pull off lids. I'm using Alpo dog food cans.
An aluminum pop tab
some nylon fishing line
A yard stick and 2 push pins
Step 1: Step 1
Step 2: Drill Cans
Step 3: Make a Jig
I set the push pins 3.25" apart. I set my heavy tape dispenser on the yardstick just to make it a bit more stable, you can also clamp it down . You may have to play with the spacing of the push pins depending on your cans.
The object is to have the pull tab on the can lid to act as the clapper and the lid to act as the sail.
Step 4: Tie It Up
insert opposite end of tab over the left push pin.(Opposite if you are a southpaw)
Pull out 6" of line and cut. Place tab of can lid on right post and thread line through tab pulling tight with first loop and finish off knot and trim.
Step 5: Finish Up
I had a duh moment and realized that its easier and less wasteful to poke the nylon line down through the can the tie the tab with plenty of free line then pull the line back and trim for your hanging length. I left about a foot of line and secured it to the can with a piece of tape until I take them to the garden.