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      Coo Coo Clock for the Visually Impaired     1968    Designed and constructed by Jerry

Beeps and tones announce the time of day. Pressing the left yellow button asks the clock to beep the number of five-minute intervals since the last hour. Pressing the right yellow button asks the clock to Coo Coo the present hour of the day. These annunciations are also sounded out automatically every five minutes and on the hour. The case is solid walnut pieces. Front and top pieces of glass are held in place by groves to seal the clock from dust.

The one-pulse-per-second (1PPS) ticks can be advanced or retarded to synchronize the clock to an external 1PPS reference.

Power supply board including a time domain filter for the 60Hz. The black paint was added to help dissipate the heat from the rectifying diodes.

Oscillator board containing the five note generators (Gb, F, E, Eb, D from high to low) and the control logic to turn these notes on and off. The Coo Coo sound is generated using Gb & D and each minute the “Tick” note stays on the same pitch (Gb) while the “Tock” note is lowered one half step at the beginning of each minute (Gb, F, E, EB, D).

Dual toggle flip-flop board. Each flip-flop is capable of dividing a frequency by 2. The toggle inputs are falling-level-triggered. Each flip-flop has its own set and reset input.

The logic cards for this Coo Coo clock were originally part of an Air Force flight simulator computer at Wright-Patterson AFB. When the Air force updated to a better computer these cards were discarded. Each card is 3.5 inches by 5 inches and contains the same amount of logic units (i.e., two flip-flops, four 2-input gates, two four-input gates, 6 inverters) found on later integrated circuit families such as RTL, DTL, TTL, CMOS, and etc. What is surprising is that though it appears that these cards copied the population concepts of the RTL, DTL, TTL, and CMOS families, the truth is that these cards were built over a decade prior to when the later families came into existence. It appears that these cards set the example for all future logic unit concepts. Each logic unit on these cards is composed of discrete resistors, capacitors, and transistors. Oddly enough, the transistors are very crude germanium, PNP, high speed switching, point junction transistors type 2N393 in a T0-24 package. (6 volt, 50 mA) The power supply is minus 5 volts where a "high" is zero volts and a “low” is minus 5 volts. (minus logic)

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