A rather cool pictorial guide to to tracking lunar and tidal states throughout the year.

This project features a novel design in which the phases of the moon and the ebb and flow of the tides are shown on a graphics liquid crystal display (GLCD), along with clock and calendar data. It also illustrates how a PS/2 PC keyboard can be interfaced to a PIC-controlled circuit which only infrequently needs to have its settings adjusted, thus saving on the cost of the pushbutton switches which would otherwise be required.

A detailed discussion of interfacing a PIC to a PS/2 keyboard, and also to a PS/2 mouse, was published in EPE August ’04 (PIC to PS/2 Mouse and Keyboard Interfacing).

In the application described in thsi project, the keyboard is basically only required to set the real-time factors for the Moon, tide, clock and calendar, after which it can be returned to the PC to which it belongs. It may be re-attached to the PIC circuit at a later date if required, to adjust clock timing accuracy, for example. The various factors to be set are selected by pressing given keyboard keys, such as “M” for minutes or “Y” for years etc, and then correcting the selected values up or down by the use of the “+” or “–” keys.

Current clock time is shown in 24-hour mode, calendar information is displayed as weekday, day of the month, month and year. It automatically corrects itself for different month lengths, and for leap years.

Moon status is displayed graphically, mimicking what you actually see in real life. Most Moon displays normally show only four or eight phases per month – this design provides a more detailed simulation, having 256 separate progressions from full Moon to full Moon. With this degree of resolution, you are unlikely to ever see the change from one phase to the next, unless you actually wait to see it, and that could mean a really long wait (around three hours)!

Tide display is in a form of bargraph. When the tide is rising, a black triangle slowly enlarges from nil near the bottom of the screen, expanding until its peak reaches the top of the screen. As the tide then starts to fall, the peak of the triangle is slowly flattened, the flatness progressively descending the screen, until the tide has fully receded, prior to rising again. Even from a distance you can see the current state of the tide and whether it is rising or falling.