Simple 6 Input Alarm

This simple alarm circuit was designed for use in a combined garage and rumpus room. It can be assembled on Veroboard and uses just one IC plus a handful of cheap components. The circuit is based on a straightforward 555 timer circuit (IC1). This is wired as a monostable and sets the siren period which is adjustable up to about three minutes using potentiometer VR1. In operation, IC1s pin 2 input monitors the detector circuit for negative-going signals. When a switch is closed, a brief negative-going pulse is applied to pin 2 via a 10µF capacitor and its corresponding series diode (D2-D7). This triggers IC1 which switches its pin 3 output high and switches off relay RLY1 (ie, RLY1 is normally on).

As a result, the piezo siren sounds for the duration of the monostable period. In addition, relay RLY2 is turned on via diode D9 and latches on via D10. This means that the strobe light (which is wired to the normally open contact) will continue to flash until the alarm is switched off (via the keyswitch). At the end of the monostable period, RLY1 turns off and this turns off the piezo siren. The circuit can then be retriggered by any further trigger inputs from the switches. A variety of detectors with normally open contacts can be used for the switches, including reed switches, pressure mats, IR detectors and glass breakage detectors. All switches must be open before the alarm is switched on.

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water tank Alarm to stop over flowing

This circuit is so simple concept.But by using this circuit you can prevent overflowing your water tank.After water touching sensors the circuit will give a sound.then you can switch off the mot er.


Note

# fix your circuit near by the water tank.Unless it will not work properly due to less power supply.

# This circuit operates with 9V power supply

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4 Digit Alarm Control Keypad

4-Digit Alarm Control Keypad Circuit Diagram

The 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.

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VFD Talking Alarm Clock

Are you having a bothersome time waking your hubby from sleeping? And when you go away the house for work, are you unsure that he has not gotten out of bed? One thing with the intention to cease your issues is to use this clock that does not simply tell time but in addition “swears”.

This is an All-in-one alarm clock. It shows an alphanumeric character, it has a calendar, temperature, and a gentle sensor to keep watch over its brightness. You can plug it on to your energy supply or use a battery. Although that is cool, It’s now not adequate being round kids. We don’t want young youngsters to examine to swear or say dangerous things, right?

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