TREE

This Simple 5 Digit Alarm Control keypad Circuit Diagram switch will suit the Modular Burglar Alarm circuit.However, it also has other applications. The Keypad must be the kind with a common terminal and a separate connection for each key. On a 12-key pad, look for 13 terminals. The matrix type with7 terminals will NOT do. Choose the five keys you want as your code, and connect them to `A, B, C, D & E`. 5 Digit Alarm Control keypad Circuit Diagram Wire the common to R1 and all the remaining keys to `F`. Because your choice can include the non-numeric symbols, almost 100 000different codes are available. The Alarm is set using the first four of your five chosen keys. When `A, B, C & D` are press edin the right order and within the time set by C1 and R2 (about10 seconds), current through R11 switches Q6 on. The relay energizes, and then holds itself on by providing base current forQ6 through R12. The 12-volt output switches from the “off” to the “set ” terminal, and the LED lig...

The following display features eight 7-segment displays arranged in two rows of four digits. The on-board MAX7219 driver enables you to easily add eight 7-segment LED displays to your project using only 3 I/O pins of microcontroller. The major advantage of using this board is the time-division multiplexing operations required for continuous refreshing of the display digits are performed by the MAX7219 chip, thereby keeping the microcontroller free for doing other pressing tasks. It is suitable for displaying two variable values simultaneously in a project, such as displaying temperature and humidity, or current and voltage, etc. [ ]