Sound Operated Intruder Alarm with extra features like a flashlight, circuit diagram, description with working principle, and parts list. Introduction to Sound Operated Intruder Alarm with Flash If you have already gone through the previous project Op-amp 741 Based Sound operated Light on our website, then for you this project is a transformation of that generalized project into a specialized intruder’s alarm project. Why should one invest much effort, time, and money to recreate a new circuit when a slight modification to the existing project works fine? This is the core…
Introduction to Cell Phone Jammer Circuit: Our addiction to technological development has made it so that it is almost impossible to imagine a day without those amazing inventions. Cell phones popular as mobile phones are the ones we cannot separate from the essential list. By now, they have become an inseparable part of our lives. Talking about a country like Nepal which has a low population (approx. 5 million), mainly two categories of cell phone carriers are available namely; NTC and Ncell. They use GSM 900 or 1800 systems. The…
Various types of security-based projects are already available on bestengineeringprojects.com. Now here is sound operated light and alarm that is used as an intruder alarm, activated when any sound is detected (like the opening of doors, knocking, or door opening) and starts flashing with a sound that alerts you of an intruder. After the second sound pulse is turned off. Circuit Description of Sound Operated Light and Alarm The circuit of sound-operated light and alarm is designed using a pair of timer IC (NE555), a dual JK flip flop IC…
There are various types of voice processing chip (IC) with various features for speech compression and processing is readily available. Here is projects called Voice recording and play back using chip (APR9600). An APR9600 is a single chip voice recorder and playback device from Aplus integrated circuits. This chip used flash non volatile memory to store up to 256 voltage levels. i.e. for 32 to 60 seconds. This chip have many features like, one can select sample rates with consequent quality and recording times. Microphone amplifier, automatic gain control (AGC)…
Here is one another basic project call bass booster using op-amp 741 IC. The circuit bass booster increases beat frequency without affecting high frequency. Description of Bass Booster Circuit using Op-Amp 741 IC The circuit of bass booster shown in figure 1 is divided into two main section i.e. bypass high frequency and boost section. The input of this circuit is connected to the output of pre-amplifier circuit and it’s output to input of power amplifier circuit. When audio signal is given to the input, high frequency is passed through…
Here is a simple circuit using op-amp 741 called “Battery voltage state indicator using 741” used to indicate whether the battery is charged or not. The circuit shows three states of battery voltage i.e. charged, discharged, and normal using three different color LEDs (LED1, LED2, and LED3). you may also like other battery state indicator circuit Battery level state indicator (Designed using general-purpose NPN transistor 2N2222, indicate two states of battery i.e. undercharged and overcharged). 10 Level battery Charge Indicator Circuit (Designed using comparator IC LM3914, used to indicate the…
A speech filter circuit is a broadband filter and is also called a wide bandpass filter circuit because its bandwidth is restricted to the speech frequency. It can be formed by simple cascading high pass and low pass section and is generally the choice for simplicity of design and performance through such a circuit can be realized by a number of the possible circuits. The butter-worth filter is generally used in audio systems which are characterized by a maximally flat-flat filter. Description of Speech Filter Circuit: A speech filter using…
A single semiconductor chip, typically silicon, or a single insulating substrate, such as glass, ceramic or sapphire used to realize a complete electronic circuit is termed as integrated circuits or simply ICs. Different ICs have been produced to cope with multiple electronics circuits advancing day by day. Among them, we have enlisted some integrated circuits in this category. This list includes all those ICs made accessible by the manufacturers for use in equipment, generally classified as consumer electronics. And, therefore without a doubt, the ICs used in digital wristwatches, smoke…
No matter how far we try to escape from pest’s trap or we attempt to clean the surrounding around us, we get eventually bothered being followed everywhere from kitchen to every corners of our house. Different pest repeller circuits have been developed claiming to escort people through this problem. However, pest repeller circuits thus built are found to have low power output resulting poor effectiveness. And, this error gives no solution to our trouble. With this point as our main concern, we have presented a powerful pest repeller circuit that…
An electric filter or simply a filter is an electric network that passes or allows without loss, the transmission of electric signal within a certain frequency range but stops or disallows transmission of electric signal outside this frequency range. The three most-popular filters found in audio equipment are the High Pass Filter (rumble filter), Low pass filter (scratch filter), and speech filters. The rumble filter is a high-pass filter, used to suppress the low-frequency rumbling sound associated with old and worn-out turntable and tape deck mechanisms. Here we explain to…
