Turtle Art is programmed to produce two different frequency sounds. The headphone output of the XO is connected to a pair of LM567 tone decoders, each of which lights a LED when its input signal frequency is present. With this principle we could control any device based on the frequency emitted by the XO. | Turtle Art is programmed to produce two different frequency sounds. The headphone output of the XO is connected to a pair of LM567 tone decoders, each of which lights a LED when its input signal frequency is present. With this principle we could control any device based on the frequency emitted by the XO. |