New Long period Timer

In order to form a protracted period timer the 556 IC teamed up with a binary divider will give delays the maximum amount as sixteen times that set by the time constant of the primary timer. You'll be able to use 2 555 ICs rather than the 556.

The first timer provides a delay of seven. 5 minutes and therefore the divided outputs provide a delay of fifteen min, 30 min, one hour and a pair of hours severally. The second timer is employed to get the required output pulse length. extra dividers is also added  to relinquish longer delays.

If you would like an extended period, for up to ten hours you'll be able to use this circuit

New Long period Timer

New Window or Door Alarm

Economical circuit of Associate in Nursing electronic alarm, notifies you once your door or window is open, is given here. This circuit wired round the Quad 2-input NAND Schmitt trigger IC 4093 (IC1) often power  from a typical 9V battery. Here, a normally-closed (N/C) push switch (S1) is employed to observe the door/window activity. For satisfactory operation, it is crucial to mend S1 within the door/window frame specified once the door/window is closed, S1 remains in open state.

When the door/window is opened, electrical condenser C1 charges through R1 (and S1) till it reaches the purpose wherever the output of IC1A switches from high to low. Once this slight delay, the output of IC1B then goes high to change the gated astable complete victimization IC1C. Elements C2 and R3 set the astablefrequency. Note that here IC1D is employed as inverting buffer/amplifier that provides single-ended drive to the 30mm piezo-ceramic electrical device (electric-to-acoustic converter) BZ1. The monotone once IC1C is in “on” mode is, gated by a high input at pin twelve of IC1D. The signal reaches the piezo-ceramic part BZ1 may be a sq. Wave with peak-to peak amplitude up to the provision voltage.

Ambient lightweight sensing element mechanism, engineered round the 150K predetermined pot (VR1) and also the 5mm LDR, ensures that the alarm sounds only if close lightweight is incredibly low (IE night time). VR1 are often wanting to fine-tune the detection sensitivity of this lightweight sensing element. Just in case of no interest you'll take away this feature by commutation the LDR with a 100K resistance, and connecting pin twelve of IC1 to the positive rail via a 10K resistance.

This simple circuit works well with multiple switches. Simply add desired variety of N/C push switches in parallel with S1 (through low-tension cabling) to hide all the entry and exit points.

New Window or Door Alarm

New Kojak siren circuit

Here could be a terribly easy Kojak siren that's designed with two 555 timer ICs and has a pair of linear potentiometers that permits the management of sound speed and tone.

IC2 produces a sound that may be adjusted with P2 so drives a little speaker.

The amplitude of the signal is modulated by IC1 with an occasional frequency signal.

The modulation speed will be adjusted with P1.

By victimization each potentiometers you'll get a siren that produces a sound that's almost like the Yankee police cars. The whole circuit is tiny enough to be created within a little box in conjunction with the battery and speaker. You'll use a 8Ω speaker asynchronous with a 47Ω electrical device rather than the 150Ω one. You'll use it as a push too.

New Kojak siren circuit