Just a quick way for your dogs to let you know when they have to go out.
Step 1: Supplies
You'll need a pair of sharp scissors, eight or so jingle bells and about three feet of string.
Step 2: Put it together
Start by tying the jingle bells onto the string about an inch to two inches apart. I tied four on one end. Now do the same for the other end of the string. Sorry for the blurry picture, camera phone.
Step 3: Measuring up.
Take your newly tied jingle bells over to the door. Hold them up to about nose height of your dog. You don't want it to have to jump up and scratch your door. Pinch the string with your fingers holding the correct length. Then tie it in a knot. Hang it over the door knob to check the length. If all is well tie a knot a couple of inches below the first knot so it can slip back over the knob.
If you have a new puppy, just jingle the bells every time you take them out. Before long you will hear the soft jingle when they ring for you on their own. Nothing is more satisfying than not cleaning up a mess. You'll be happier and so will they.
You can just make out where my dog had begun scratching to get out. Thankfully no more of that.