ECE | Electronics Mini Project

    Simple Smoke Detector.      This simple smoke detector is highly sensitive but inexpensive. It uses a Darlington-pair amplifier employing two npn transistors and an infrared photo-interrupter module as the sensor. The circuit gives audio-visual alarm whenever thick smoke is present in the environment.      The photo-interrupter module (H21A1) consists of a gallium-arsenide infrared LED coupled to a silicon phototransistor in a plastic housing. The slot (gap) between the infrared diode and the transistor (see Fig. 1) allows interruption of the signal with smoke, switching the module output from ‘on’ to ‘off’ state.  Fig 1: Top and Bottom view of Photo interrupter module.   The circuit of the smoke detector is shown in Fig. 2.      When the smoke enters the gap, the IR rays falling on the photo-transistor are obstructed. As a result, the photo transistor stops conducting and the Darlington-pair transistors conduct to activate the buzzer and light up LED1.  Fig 2: schematic of Smoke d

 Microcontroller-Based Tachometer             A tachometer is nothing but a simple electronic digital transducer. Normally, it is used for measuring the speed of a rotating shaft. The number of revolutions per minute (rpm) is valuable information for understanding any rotational system. For example, there is an optimum speed for drilling a particular-size hole in a particular metal piece; there is an ideal sanding disk speed that depends on the material being finished. You may also want to measure the speed of fans you use. / . / Electronics mini project. Tachometer using microcontroller mini project. How to make Tachometer using microcontroller. Tachnometer mini project circuit. Electronics mini project using microcontroller. Microcontroller based mini project. Microcontroller AT89C51 mini project. Microcontroller using Tachometer.

 How to make Electronics mini project?: Micro converter. A simple low-power inverter circuit is described here, which converts 12V DC into 230V AC. It can be used to power very light loads like night lamps and cordless telephones,but can be modified into a powerful inverter by adding more MOSFETs. This circuit has two stages-battery charger with cut-off, and battery level indicator and inverter circuit.Charging circuit is built around IC1 (LM317) as shown in Fig. 1. When mains 230V AC is available, IC1 provides gate voltage to SCR1 (TYN616) through diode D3 (1N4007). SCR1 starts charging the battery. For output voltage setting preset VR1 may be used. //Keywords / . / how to makemini inverter mini inverter circuit best electronics mini project how to make small mini inverter project mini inverter circuit diagram how to make mini inverter at home mini inverter diagram small inverter circuit how to make a mini inverter at home small inverter circuit diagram

Audio Amplifier for personal stereo         In the output stages of most broadcast receivers and some amplifiers, there is a limit up to which maximum power can be developed without distortion. In the widely accepted output circuit, two output transistors are connected in series between the positive and ground and biasing is adjusted so that each transistor gets half the supply voltage.        The circuit presented here is a simple audio amplifier for a personal stereo system. In this, supply voltage to each transistor can be enhanced to produce a larger output. The audio driver transformer drives the transistors adequately.        A 9V-0-9V, 300mA transformer has been used in the set-up. Out of the four diodes (D1 through D4), two are used for developing the positive voltage rail (+9V) and the other two are used for developing the negative voltage rail (–9V). In the this pushpull amplifier, each transistor (T2 or T3) gets double the voltage when activated.     Connect the low audio si

 Triple-Mode Tone Generator  Here is a simple circuit that generates three different tones. You can use it as a call bell, burglar alarm or any other security alarm using ic LM556 . Another circuit.  Now, here is unique tone generator circuit which produces three different type of sound according to input three different logic levels (i.e. 0&1, 1&0 and 1&1).  Circuit description: This circuit is designed around digital IC 7400 which is NAND gate. The working of the circuit is like the working principle of oscillator circuit, where frequency depends upon capacitors C1 and C2. The duty cycle of this circuit is 50%. The output is given to power amplifier circuit which further drive loudspeaker or head phone. For low frequency value of capacitor C1 and C2 must be high and vice-versa. / . / How to make Electronics mini project. How to make Triple Mode tone generator circuit. Electronics mini project. Triple mode tone generator circuit diagram. Electronics mini project using IC 

 IR-Based light Control This circuit turns on the lights at the portico, car parking or other areas when a motorbike or car enters through the gate to cross the sensing area. It can also be used as an electronic watchdog for your house, by activating an alarm simultaneously. // How to make ir based light Control circuit. Electronics mini project

  TACHOMETER   A tachometer is an instrument that measures the rotational speed of a shaft or disk in a motor or other machine. Here we present the basic version of the tachometer that shows the revolutions per second (RPS) on a digital display.

   This infrared object counter can be installed at the entry gate to count the total number of people entering any venue. For example, it can be used at the railway stations or bus stands to count the People arriving per day or week.

This multiutility flash light consists of three sections: a flasher, a sound-to-light display and a white LED-based flashlight. / . / Electronics mini project using ic ne555

 

How to make IR sensors (infrared LEDs)  object-detection circuit.       There are various applications of IR sensors such as TV remote controllers, burglar alarms and object counters. Here we have used IR sensors (infrared LEDs) to make an object-detection circuit and also a proximity sensor for path-tracking robots. The basic idea is to transmit the infrared light through an IR LED, which is then reflected by any obstacle ahead and sensed by the receiving LED. Another circuit :-       Infrared (IR) remote controller comprises the transmitter and receiver sections. The range of the transmitter can be increased up to 5 meter by using convex lens. Circuit Description of infrared (IR) remote controller       Transmitter section: – The transmitter circuit of infrared (IR) remote controller is built around IC 741 (IC1) wired as frequency square wave oscillator. Gate pulse from pin no 6 of IC1 is given to gate of SCR1 to drive IR LED1. Variable resistor VR1 is used to vary the generated

 Periodically on-off Mosquito repellents circuit using IC LM 555          Some of the mosquito repellents available in the market use a toxic liquid to generate poisonous vapours in order to repel mosquitoes out of the room. Due to the continuous release of poisonous vapours into the room, after midnight the natural balance of the air composition for good health reaches or exceeds the critical level. Mostly, these vapours attack the brain through lungs and exert an anaesthetic effect on mosquitoes as well as other living beings by small or greater percentage. Long exposure to these toxic vapours may cause neurological or related problems  / . / How to make Periodically on-off Mosquito repellents circuit. Electronics mini project using ic lm555. Electronics mini project using Triac. How to make Electronics mini project. Mosquito repellents circuit Diagram.

How To Make DC To DC converter mini projects (chopper Circuit) This simple circuit lets you run a 1W LED from the battery of your car. IC MC34063 is used here as a buck converter. It is a monolithic switching regulator sub-system intended for use as a DC-DC converter. The device consists of an internal temperature-compensated reference, a comparator, a controlled duty-cycle oscillator with an active current-limit circuit, a driver and a high-current output switch. These functions are contained in an 8-pin dual in-line package. Another major advantage of the switching regulator is that it allows increased application flexibility of the output voltage. Another circuit: Conversion of AC to AC is quite simple as in compare to DC to DC converter because it only implies a transformer which converts AC from one voltage level to another voltage level But conversion of DC to DC is quite tedious work without transformer and more power losses. Here is simple, low-cost, high precision circuit whic