Some months before the current millennium I thought it might be funny to watch the time count down. So I built this little device and wrote its first software: down2000.
Several years later (exactly 2009) the idea to have a countdown to the 18th birthday (to come of age) of my step daughters seems to be funny, too. The old software was massaged until it could be built on Linux and then changed to have an editable destination date.
10ssg.zip Archive with schematic as Eagle file and PDF, 189KB.
10ssg_hds.zip Archive with Hades design file, 6KB.
down2000.zip Archive with source and binary for down2000, 5KB.
d_timer.zip Archive with source and binary for d_timer, 6KB.
This software simply counts down to the 31st, december 2000. Today this doesn't make that much sense. ;-)
To enter the current date and time, you press the sole button. The display changes to show 2 digits of each the year, the month, the day, the hour (24-hour-mode), and the minute. While the button is released, the current field decrements once per second, starting with the year. To switch to the next field, you press the button. After adjusting the current minute, press and release the button and the countdown starts.
This software has a editable destination date. Starting from the countdown mode, you press the button and the display changes to show 2 digits of each the year, the month, and the day. The last 4 digits show "0000" and can't be edited. The current field is indicated with both decimal points lit. After entering the destination date, the current date and time has to be entered. Data entry works like in down2000.
To keep the entry of the year simple, only numbers from "19" down to "00" are used. If you like to use the timer after 2019, simply use the remainder of the division by 20.
Both softwares have no checks on the number of days in a month while in enter mode. However, the number of days calculated from the entered dates is aware of the correct numbers and of leap years.
|Well, it had to be rather dark to take this picture. But it shows what this little thing is about. The left 3 digits show the days left, the next 2 digits the hours, then minutes, seconds, and finally the tenth of seconds left until the destination date.
|This thumbnail is just for the quick peek on the schematic. It's quite simple, isn't it? Click on it and the download of the compressed schematic starts...
|Because I only needed one specimen, it was built "free-standing." The high resolution picture (622KB) can be downloaded through the thumbnail.
|Right before I started to develop d_timer, I found Hades, the Hamburg Design System, a framework for interactive simulation written in Java. It can be used for digital simulations and it contains a well working PIC 16C84 circuit. So I thought I'd give it a try - and it worked out so well!
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