We have two poodle mixes, otherwise known as doodles. A golden-doodle, Lola and an old English sheep dog - poodle mix, also know an a sheep-a-doodle. Those with doodles know how smart they are and how much they love to "work". Because they love running so much my wife got them training collars, and trained them to return to us when they heard the tone. Because they enjoy "working" so much my wife has started to teach Casey (the sheep dog) how to herd sheep and Lola to find people. Traditionally in both cases you train the dogs to associate different behaviors to different whistles. Since neither of us are very good at whistling the thought came to me to built a training collar that could have multiple tones. So this Blog will be about the creation of such a device.