Abstract: A speedometer is provided for determining speed by providing a sound signal at a first frequency, receiving a second signal which is the reflection of the first signal, and determining difference in frequency between the first and second signals created by the Doppler Effect. A speech synthesis chip within the speedometer provides a verbal indication of velocity. In this way, a person using the provided speedometer does not have to look at a dial or other visual indicator.Provided within the speedometer is a heat-sensitive transducer for measuring the air temperature. In this way, the speedometer can take into account the change in the speed of sound with respect to temperature when calculating velocity.

Abstract: A puzzle of the type having an array of movable tiles enclosed and supported by a frame structure includes circuitry for producing sound to identify each of the tiles. Each tile is formed with contact terminals formed on a surface that confronts a support surface of the frame. The support surface defines a number of predetermined locations at which the tiles can be positioned, each location being provided with contact terminals connected to the sound-producing circuitry. Each of the tiles is equipped with spring biasing so that when a tile is properly positioned at one of the predetermined locations and depressed, the contact terminals of the tile and the location are brought together. Each tile is provided with some electrical characteristic that causes a tone to be produced, identifying the tile.