Timer Countdown Circuit with PIC
Project Specifications
- PIC:PIC16F84A
- Processor Frequency:10MHz
- Range:1 to 99 minutes
- Timer Set:BCD switches
- Display:Minute:00-99 Seconds:00-59
Timer countdown every second controled bt hardware.
Time adjust with 2 BCD switches.
In countdown, control voltage value contact.
Led lights up in final countdown and relay turn ON/OFF external circuit.
Timer Display | ![]() |
Circuit Diagram, PCB
Electronic circuit diagram - Timer countdown
![Timer circuit Diagram](/circuitos/gif/timer-diagram.gif)
X1=10Mhz resonator.
Pattern drawing (component side)
![PCB timer](/circuitos/gif/pcb-timer.gif)
Pattern drawing (wiring side)
![PCB wiring timer](/circuitos/gif/pcb-timer-wiring.gif)
Green lines show wiring connections at component side.
Source code files - LED flasher
Timer source Code (ZIP) Timer HEX (ZIP)
Flowchart - Led Flasher
Flow chart showing software processing outline.
Processing can be understood read only source code list.
LED Flasher Board Pictures
Components
![component side PCB](/circuitos/picture/timer-pcb.jpg)
Wiring
![wiring side PCB](/circuitos/picture/timer-wiring-pcb.jpg)
Original Author: Seiichi Inoue (Japan)