Pic16f84 Circuit Diagram | Electronic Project Circuits

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Combination lock using PIC16F84

This is my electronic combination lock to use with an outdoor gate. The functionality is implemented in software. It turns on a relay (usually to open a door) for a few seconds if someone enters the valid code. Alternatively, it works as an ON/OFF switch, which toggles the relay each time the code is entered. This relay can operate a power-to-open type electric strike with a shorting contact or a power-to-hold type electromagnetic lock with a breaking contact (we need the relay because these locks usually work with AC, not DC). The code can be changed any time after entering the current code. Current consumption of the circuit is low, because the PIC sleeps most of the time, and wakes up only for processing key presses. If you don’t have a crystal, you can use the RC oscillator of the PIC16F84 as well, just check the PIC datasheets for details on oscillator configurations. The 16F628 already contains an internal RC oscillator, so no crystal is needed…
Read more source: http://jap.hu/electronic/combination_lock.html

Be the first to comment - What do you think? Posted by admin - September 25, 2011 at 9:55 pm

Categories: Alarm systems, Microcontroller Tags: combination lock circuit, Electronic lock switch, pic16f84 circuit diagram

Multiple Servomotors by PIC16F84

Using a modified version of the last program, we can control as many servomotors as we have I/O lines on port B. In the next listing, we will control two servos in the same manner as we controlled a single servo in the previous program. The circuit is shown in figure 4 (below). The program uses two pulsewidth variables, pw1 and pw2; and two sets of routines, left1 and left2, right1 and right2; one for each motor. As you can see in the schematic, the first servo is wired as per the previous circuit. The second servo is now using B3 as it’s pulse out, and B4 and B5 for the SPDT switch.

Read more original source:http://www.imagesco.com/articles/picservo/04.html

Be the first to comment - What do you think? Posted by admin - July 27, 2008 at 12:59 am

Categories: Electronic Control, Microcontroller, Motor controller Tags: pic16f84 circuit diagram, servo driver schematic, servo motor circuit diagram

First Servomotor Control Program by PIC16F84

In our first program , we will simply sweep the servomotor from CCW to CW and then sweep back. The program will be kept simple as to demonstrate the priniciples of controlling a servo with a the PIC Basic language. The schematic can be seen in figure 2 (below). The variable pw controls the pulsewidth, and is started at 100 (extreme left, -45 degrees). The program sends the pulse out to the servo, and then is increased by a value of 1 until it reaches 200 (extreme right, 45 degrees), at which point it will reverese the rotation.

Read more original source:http://www.imagesco.com/articles/picservo/02.html