Category: alarm / sound generator

Various sound generating project is posted in Alarm and Sound Generation Section. Now here is very simple an easy to construct electronic project called Toy Siren using CD7400 (IC1). Circuit Description of Toy Siren Circuit Using CD7400 The heart of the project toy siren circuit is quad-2-input NAND gate IC CD7400 (IC1). IC1 (CD7400) is a cheap easily available IC and it consist four NAND gate. Two NAND gate out of four is configured as low frequency oscillator and another two NAND gate as high frequency oscillator. When output of…

Here one another sound generator project is added is section of alarm and sound generator projects. We have tested and posted dozens of sound or tone generator projects. Now, here is multi-tone generator circuit which produces eight different types of tones. The tones produced by the circuit multi tone generator are of Bell, Ambulance Siren, Whistle, Machine gun Sound, Jingle, Police siren, Birds and Dual sound. Circuit Description of Multi Tone Generator Circuit The heart of the circuit multi tone generator is UM5561 IC (IC1) and the entire circuit is…

Various types of alarm and sound generator circuit is already published in bestengineeringprojects.com. Now here is a alarm circuit which draws very low quiescent current and also does not need any type of power on off switch because this offers automatic switch-off after fixed time. Circuit Description of Low Power Alarm with Automatic Timer The heart of the circuit low power alarm circuit is 4060 IC, which is here configured as timer. The advantage of using IC 4060 (IC1) is the wide music range instead of UM series musical IC.…

When the battery is kept in the discharge state for a long period, irreversible chemical reaction takes place reducing the capacity of the battery so that eventually the battery becomes useless. No protection circuit can stop self discharge of the battery and only trickle charging on compensate for it. Here is a circuit charging reminder for emergency light to inform the user that the battery has discharged itself below the safe level. The discharge characteristics of a dry battery, as supplied by its manufacturer indicate that the battery should not…

Here is a circuit for an miniature IC organ using 3-volt AF amplifier IC TDA2822. Frequency of the AF sound generated depends on the capacitor between pin 1 and pin 7 of IC. When switch SW1 to SW10 are pressed, different audio tones are heard from the speaker. SW1 to SW10 are small push-to-on switches. Pin 2 of IC is connected to positive terminal of 3-volt battery. Two pen cells connected in series can be used to power this circuit. Satisfactory loud sound will obtained at 3-volt supply. Note: Capacitors…

The novel circuit light and touch operated music bell used a photo transistor (T1) with an npn transistor in emitter-follower mode to increase sensitivity of the circuit. So even if very little light fall on the photo transistor, it gives a triggering pulse to SCR gate and the SCR starts conducting. Circuit Description of Light and Touch Operated Music Bell When SCR conducts, IC UM66 starts producing music. After the music has halted, no current flows through the SCR and the SCR switches off till the light falls again on…

Every day addiction of people towards technology is growing deeper and deeper, even before entering into someone’s house we press doorbell which is a clear example to support our belief. Listening same doorbell always might be boring, this circuit 12 tones doorbell help us to avoid this dull situation. Music doorbells, music horns, touch-sensitive doorbells, etc are not new projects electronics hobbyists, especially for BEP readers. But, this music producer (twelve popular tones in sequences) gives a new dimension to musical doorbells. Whenever a switch is pressed, a popular tone…

Here is an inexpensive electronic siren circuit built around the most popular and low-cost IC 741. The circuit is basically a square wave generator that is used here to produce the tone of a siren. Circuit Description of Electronic Siren Circuit using OP-Amp 741 The IC1 is used as a low-frequency multivibrator, the output of which modulates the high-frequency tone produced by the IC2 multivibrator. The final output is amplified and converted into a loud siren by transistor T1 and the speaker. Various interesting tones can be obtained by changing the…