Today we shall talk about a really amazing circuit that produces a sound of a siren. There are different types of circuits that produce different kinds of sounds. Here is a simple circuit that produces wailing siren. The main principle of this circuit is to produce a wailing siren. The 555 timer IC is operated in astable mode. When the switch is pressed, speaker produces high pitch siren and when it is released, its pitch decreases and is...
This is a very interesting hobby project which can detect active mobile phone or GSM communication in its proximity. Active mobile phone means there is some live communication is going on like calls, sms sending or receiving etc. This circuit can be used to prevent unauthorized use of mobile phones in examination halls, conference rooms etc. As you already know, today's mobile phones (2G, 2.5G, 3G, 4G, LTE) are operating in electromagnetic signals ranges from 700MHz to 3500MHz. Each countries will...
Here is a simple and interesting hobby circuit that can be made using the popular 555 timer IC. As you might already know, a 555 Timer can be easily wired as Astable, Monostable or Bistable multivibrator. This circuit can be used as rain sensor, water overflow sensor or as a water level sensor. This circuit make use the principle that normal water can conduct some amount of electricity (PURE water is not...
A simple electronic toy piano can be easily constructed using the popular 555 timer IC. 555 Timer can be easily wired as Astable, Monostable or Bistable multivibrator. We all know that Sound is a Mechanical Wave as it is produced by to and fro movement of particles of the medium. Displacement of particles are in the same direction as propagation of sound waves, so sound is a Longitudinal Wave. The to and fro motion of...
As the name indicates, a bistable multivibrator has 2 stable states. It can be switched from one state to another by providing an external trigger. It can be used for storing a binary digit (bit) as it has 2 stable states (0 or 1). So it is commonly used in digital circuits, where it is named as Flip Flop or Latches. A bistable multivibrator can be easily constructed using the most popular and low cost 555 Timer IC.
IR Remote Control for controlling home appliances can be easily made using Decade Counter CD4017, 555 Timer and TSOP1738 infrared receiver. By using this circuit you can easily control your home appliances using your TV, DVD Player remote control or using a remote control circuit described here.
IR Transmitter and Receiver pair can be easily made using 555 Timer, IR LED and TSOP1738 IR Receiver. This can be used for remote controls, burglar alarms etc. TSOP1738 is a very commonly used IR receiver for PCM remote control systems. It has only 3 pins, Vcc, GND and Output. It can be powered using a 5V power supply and its active low output can be directly connected to a microcontroller or microprocessor. It has high immunity against ambient light...
