4-Digit Alarm Control Keypad Circuit DiagramThe Keypad charge be the affectionate with one accepted terminal - and a abstracted affiliation for anniversary key. On a 12-key pad - attending for 13 terminals. The cast blazon with 7 or 8 terminals will NOT do. On the Support Page youll acquisition capacity of how to Accomplish Your Own Keypad.
The broadcast is activated by acute a distinct key. Choose the key you appetite to use - and affix it to terminal "E". Choose the four keys you appetite to use for your aegis cipher - and affix them to "A B C & D". Wire the accepted advance to R1- and all the actual keys to "F".
When you columnist "E" the broadcast energizes - and the 12-volt achievement moves from the "off" to the "set" terminal. The blooming LED additionally lights. It provides a beheld adumbration that the anxiety is set.
When you columnist keys "A B C & D" in the appropriate adjustment - the broadcast de-energizes - and the 12-volt achievement allotment to the "off" terminal. The blooming LED is additionally abolished - to announce that the anxiety is switched off.
The actual keys - those not active to "A B C D & E" - are affiliated to "F". Whenever one of these "Wrong" keys is apprenticed - the attempted cipher access fails - and the cipher access arrangement is reset.
The aforementioned affair happens if "C" or "D" is apprenticed out of sequence. If "C" is apprenticed afore "B" - or "D" is apprenticed afore "C" - the attempted cipher access will fail. And the cipher access arrangement will reset.
With a 12-key pad - over 10 000 altered codes are available. If you charge a added defended cipher - you could artlessly use a bigger keypad with added "Wrong" keys active to "F". A 16-key pad gives over 40 000 altered codes. If you accomplish a aberration while entering the cipher - artlessly alpha again.
The Support Material for this circuit includes a step-by-step adviser to the architecture of the ambit lath - a genitalia account - a abundant ambit description - and more.
