While shopping online for something else, I saw
where a lot of people were looking for some type
of clicker device to train birds, dogs, rabbits and
other pets. It seems most want a clicker which
costs as near nothing as possible. This might be
it if the sound works for their pet.

Step 1: Three Parts, Plus Glue, Is What You Need.

You will need a length of cord long enough to span your
hand three times. Once across, once back and once more
for the "tail". A flat lace from a sports shoe works good for
this, and the lace tips keep everything neat. I didn't have
it on hand for making this one. The clothes pin or laundry
pin you choose should have a smooth body with no grooves
near the end that you pinch. This will save wear on your
fingers later. The small black item is a spring loaded string
keeper from a jacket or hoodie. They are available at
sewing supply places. Those are the three parts....now
add glue.

Step 2: Prepare Your Cord or Shoelace

Put a simple overhand loop knot in one end of the
cord or lace....keeping the hole as small as you can.
Thread the opposite end through the hole and feed
it through the spring loaded cord keeper. Mark the
cord to the measure of the width of your hand as
a guide for placing glue when you add the laundry
pin.

Step 3: Now Glue the Laundry Pin to the Cord or Lace

Before you add any glue....put your hand in the
adjustable loop you have created and see if it
is comfortable. Adjust it. See if it feels right.
You have the choice at this point to have the
knot up toward your thumb or down toward the
heel of your hand. Decide which feels better
for you... remembering that in order to operate
the clicking motion with your thumb... the end
of the pin which is pinched....must be toward
the thumb.
Decisions made....glue the cord/lace to the
laundry pin.

Step 4: Test Your Clicker

Your finished product should look something like
this.
With the cord lock firmly adjusted you can open
and close your hand to make a hand command
or button your jacket.
I don't know one thing about training pets but
someone was hunting something like this and
maybe this will fill the bill.

Note: a more comfortable band around the hand
can be made with a wide band of elastic sewed
to the right length or a band of cloth webbing and
a couple of pieces of salvaged hook & loop fastener.