PIC16F877A Astro Clock

  
It has 16 timers that can be independently paused and restarted, and can run forward or backward. There are 16 alarms with configurable sounds and actions. Timers can show Earth, Mars, Jupiter, etc. times at the same time. How about sidereal time, Moon phase, Jupiter's Great Red Spot transit time, and anything periodic in general? Simultaneous 24-hour and Julian-time decimal display. All changes in configuration can be done from the device's keyboard - no computer necessary. External AC power with built-in rechargeable battery, so you can take the clock around. High on the geekness scale.
PIC16F877A Astro Clock - schematic

The 5V Power Supply block contains the voltage stabilizer and filtering capacitors from the power supply on the modem board. The Speaker Amplifier block is the LM386-based amplifier circuit that was on the original modem board. The speaker is the internal modem speaker. The PICkit 2 Programmer port is intended for reprogramming the microcontroller without disassembling the clock. The DB25 to 6-pin adapter (see the picture) is not shown. If your keyboard has different layout than the one shown, refer to Using Different Keyboard in the Code section. I used a Techstar 16 characters * 2 lines LCD Module with backlight. These modules are pretty standard, so almost any 16x2 LCD module will work. Backlight is a plus, but it is not mandatory.



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