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Because I have not tested all electronic circuits mentioned on this pages, I cannot attest to their accuracy; therefore, I do not provide a warranty of any kind and cannot be held responsible in any manner.
PIC Countdown timer
7. May 2008 - 20:35 — admin
Here is a PIC16F84 countdown timer for PCB exposure unit
Author says: The purpose of this timer is to provide a countdown time from 1 second to 99 minutes & 59 seconds. I use it to control the lighting for the Ultra-Violet exposure of photosensitive PCB material. The project provides also an audible alarm at the end of the countdown time and switches the UV lights by means of a relay. It is based on a Microchip microcontroller, the 18 pin PIC16F84(A). This microcontroller contains 1Kbyte of flash memory for program code, 64bytes of static RAM memory, and 64bytes of EEPROM memory which are used here to store up to 15 different (user-programmable) countdown times.
Link: PIC Countdown timer