Programmable Timer, 99 minutes and 59 seconds. It is an unit of decreasing counting with 15 count´s kept in memory, no volatile.

The unit still has an exited N.O. for relé, to control potency loads.

Being the control of all of the based functions in a microcontroler, PIC16F84, the whole circuit is very simple, being just necessary some extra components.

Basic Functions:

All of the references the letters 'E' 'M' and 'D' they follow the represented drawing.

Main menu from where breaks for all the remaining functions. We can choose the part of the counting that we intended or we can go to the menu of adjustment of the 15 existent countings in the memory.

Leaving of the I begin that the key was pressed 'E', we have three opcções now: The key 'E' it selects one of the fifteen countings in memory, the key 'M' he gives begin the selected counting, and the key 'D' it is going to the menu of adjustment of the selected counting.

Being in the menu to alter the timer, we came in the following way, with the keys 'E' and 'D' we selected the number that we want to get right and we selected with the key 'M' following we passed for the following image.

Being back to the selection menu, now we can carry in the key 'M', and starting from here the timer has begin. During the timer the rele is activated. At the end of each timer an acoustic alarm appears indicating the end.

In the end to return to the I begin is only to carry the key 'M.'

Designs of the presented circuit: