| 摘要 |
A sound producing device producing different notes when rotated. Three orthagonally mounted gravity switches produce signals corresponding to their orientation to a reference. A multiplexer or programmable counter coupled to the switches selects one output line for each combination of states of the switches. Each output is passed through different values of resistance so that unique frequencies result. The output of the multiplexer is coupled through an oscillator to a speaker and a tone corresponding to the frequency of the output selected is produced. Multivibrators are coupled to the switches and to the oscillator to shut off the production of sound when the device has been left at rest for a certain time period.
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