Megatimer is a (big) evolution of the “minitimer”. Basically it is a programmable timer with:

  • one cyclic output, programmable duty cycle (T_on, T_off);
  • one single end timer, which can go clocwise or contraclockwise;
  • the two timer can be linked together;
  • all intervals are programmable from 1 second to 10 hour with auto-ranging (see later).

All input is achieved with a scroll&push knob control.

All output is displayed in a common backlit 16×2 character LCD module.

Outputs are shown with two leds. Actually one of them is not connected to an output but can be easily done so.

Autoranging: To make user interaction simpler, time intervals are programmable with a +/-1 precision in the actual scale used. So if you want more than a minute you can only set +/-1 minute. If you want more than an hour you can only set +/-1 hour. You cannot set 1 hour and a half. An exception is made for the seconds scale. You can reach 89 seconds (which is 1 minute and a half) but then you pass to minutes scale.

Interaction: Scrolling the knob a blinking cursor shows which entry to select, once selected press the knob to edit the value of the timer or to navigate the menu. The menu lets you start, stop, reset, pass, or link timers. First three are self explaining. Pass means that you can skip the current duty on the cyclic timer. Link toggles on/off the link between the two timers. Link only works when the second timer is contraclockwise: when it reaches zero it stops the first cyclic timer. By the way, in the second timer menu “start>” and “start<” mean respectively “start clockwise (incremental timer)” and “start contraclockwise (decremental timer)”.

Note. This project has been committed by M.G., to whom goes also a thank for the photo.


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