The Button Code is a system that allows a single button to act as a keypad. The user enters a 4 digit code into the system using button taps. The button can be placed where the public can access it since like a keypad there are many combinations to keep guessers from activation the system. When the correct code is entered a form-C relay is activated (Normally Open and Normally Closed relay contacts). When activated it can either activate for a programmed time or simply toggle the output whenever the correct code is entered.
This simple circuit allow for simple control of things such as:
Garage Door Openers Pulse the door open button for a second to operate.
Lighting Toggle to turn on, toggle to turn off.
Door Access Pulse the door lock for 3 or 4 seconds.
Simple Security System Toggle alarm power on or off.
The heart of the button code project is a PIC 16f628A microcontroller (PDF). This microcontroller monitors user input using a single button that is connected to the button terminals. The controller provides visual feedback to the user over the same button terminals, this means that only 2 wires are needed to be run to the button location. A relay is controlled by the system, it is only activated when the correct code has been entered.
Modes
The button code system has two operating modes. One is normal running mode where it is waiting for a code to be entered and reacts as programmed when the correct code is entered. The second running mode is program mode, this mode is used to configure the system to operate is as you desire.
Changing Running Modes
There is a program jumper that is used to change the running mode. When the jumper is out the mode is the normal running mode, when the jumper is in the system is in program mode.
Please note that the state of the jumper is only checked when power is applied. This means that if the system is in program mode and the jumper is removed, the mode will not change until power...
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