Ronja is the author’s dog, a beagle-mongrel, who seems increasingly often to need to be called to heel either with a shout or with a whistle. And so the idea came about for an electronic dog whistle that could produce two alternating high-frequency tones. A design like this has several advantages over conventional whistles or calling. Dog Whistle for Ronja Circuit Diagram Dog Whistle for Ronja Circuit Diagram You can continue to carry on a conversation with your friends without having to stop to whistle or call to your dog. Using high frequencies means that the whistle sound is barely audible to (especially older) humans and so is less annoying to other people than conventional whistles or calls. As is well known, dogs have rather better hearing than we do and can hear frequencies of up to 40 kHz. The two alternating pitches mean that the dog can more easily distinguish it from...