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alarm keypad - enhanced 5 digit

2016-02-18 19:10  
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This article describes the enhanced keypad five alarm circuit. For your better understanding in the diagram, we recommend that you look at the text. Works as follows: the keyboard to that common terminal and a separate connection for each key. In a 12-key pad, look for 13 terminals. Matrix type with 7 terminals will not do. Select your desired five elements of your code, and connect them to the "A, B, C, D and E". The common thread R1 and all the remaining keys F. Because of your choice can include non-numeric symbols, almost 100 000 different code is available. Alarm setting of your choice using the first four five keys. When the "A, B, C and D in the correct order and the pressure within the time set in C1 and R2 (about 10 seconds), the current through the switch to R11 progress of excitation torch, and has its own by providing base current to pass R12 schedule 12 volt output switch from "off" to "Settings" terminal, and the LED lights. switch clock and necessary at A, B, C, D, and E in the correct order. IC is a four 2-input AND gate, a Cmos 4081. these doors only produce a high output when both inputs are high. Press "" to sell a high in the period of time set through C1 and R2. Such "make" gate 1, so when you press the "B ", the output will rise at pin 3 This output and tw1o work it locks itself high using it so that the door 2 R3 and to pin 5 high. remaining gates operate in different ways, and each lock through a resistor to make their own its successor. If you enter the correct code is in the time allowed, the pin 10 will switch, so even the Q5 Q6 base to the ground, which can lead to dropping out of school closures and the relay and any keys are not wired "A, B, C, D and E "Connecting to the base of the fourth quarter of R9. Whenever these" error "key is pressed, the fourth quarter off a low need, which eliminates the" Enable "from Gate 1, the code entry process fails if C, D and E in order of precedence, Q1, Q2, or a third-quarter sales will be lower, the same result you can change the  code  by changing the keyboard if you make a wrong password, just start again if you need more secure code You can use a larger keyboard and more "wrong" key to connect to F. a 16-key pad to more than one million different codes. lie down all the components shown in the plate; but some are actually mounted upright. this link bare copper wire assembly side. tw1o link must be installed in the IC. understand the principle that text, you can plug a high efficiency.

Pad enhanced 5 digit alarm keypad