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Periodically On Off Mosquito Repellent Save Rs. 20.00

Periodically On Off Mosquito Repellent

by KNS Pvt Ltd
Save Rs. 20.00
Rs. 119.99
Rs. 99.99

Summary

Some of the mosquito repellents available in the market use a toxic liquid to generate poisonous vapors in order to repel mosquitoes out of the room. Due to the continuous release of poisonous vapors into the room, after midnight the natural balance of the air composition for good health reaches or exceeds the critical level.

Mostly, these vapors attack the brain through the lungs and exert an anesthetic effect on mosquitoes as well as other living beings by small or greater percentage. Long exposure to these toxic vapors may cause neurological or related problems.Here is a circuit that automatically switches on and off the mosquito repellent after a preset time interval, thus controlling the release of toxic vapors into the room.

Learning

Things which you can learn:

*Application of NE 555 timer.
*Application of TRIAC BT136.
*Application of Zener diode as a voltage regulator.

Product Description

Here is a circuit that automatically switches on and off the mosquito repellent after the preset time interval, thus controlling the release of toxic vapours into the room. The circuit turns the mosquito repellent ‘on’ for approximately 20 minutes then process of 'on' and 'off' occurs repeatedly.So if you leave the mosquito repellent switched on from 10 pm to 6 am (eight hours), it will be ‘on’ for four hours and ‘off’ for four hours of the total duration. During ‘off’ time, the room air tries to balance its natural composition.

Another important feature is that the circuit switches to ‘on’/‘off’ operation without producing any noise or a sound click as in a relay and hence doesn’t disturb your sleep.

Working

The circuit consists of a timer section built around IC 555 (IC1) and an automatic switching section using Triac BT136 (triac1). Power supply to the circuit is derived from the AC mains by stepping it down to a required level and rectifying it. The elimination of the transformer saves on space as well as money. Zener diode ZD1 and capacitor C2 provide regulated 9V DC power supply to timer IC1.The timer section comprises resistors R1 and R2 and capacitor C1.

The output of timer IC 555 is fed to the gate terminal of BT136 through series LED1 and resistor R4. When the timer output goes high, it triggers the gate of Triac 1 and LED1 shows the ‘on’ period. During ‘off’ time, the output of IC1 goes low and hence Triac 1 is not fired and LED1 doesn’t glow. The circuit is very compact and can be assembled on a general-purpose PCB. Use an 8-pin IC base for timer IC LM555. After assembly, fit the unit inside the housing electric board where you plug in the mosquito repellent.

 

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Battery Low Indicator Save Rs. 75.00
Rs. 250.00
Rs. 175.00

Battery Low Indicator

Battery Low Indicator

by KNS Pvt Ltd
Save Rs. 75.00
Rs. 250.00
Rs. 175.00

The purpose of the battery low indicator is to give a visual indication when a battery has been discharged below a certain level. This is especially crucial for re-chargeable batteries that should not be discharged below a certain voltage level. This lower voltage limit depends upon the type of the battery. The battery low indicator circuit can be typically used for 12V batteries to give an indication of the battery voltage falling below the preset value. The indication is in the form of a flickering LED.

Learning from the project

  • Application of the LM319 dual comparator for level comparison.
  • Application of the NE555 timer in astable mode of operation.

Product description

The heart of the battery low indicator circuit is the dual comparator IC LM319 (denoted as IC1) which compares the battery’s voltage to a reference voltage level. Only one of the two independent comparators that are a part of the LM319 is used in the circuit. The two inputs to this comparator are:

  1. The reference voltage, which is applied to the non-inverting input pin (4). It is held constant at approximately 1.2V by the zener diode (D1).
  2. Battery’s voltage, which is applied via a potential divider arrangement built around resistors R2, R3, and preset VR1 and fed to the inverting input pin (5).

The corresponding output is generated at pin 12 of IC1. Preset VR1 is very important as it sets the voltage level at which a visual indication of the low battery level is generated. For example: If the battery under test is of 12 V and an indication is required as soon as the battery voltage falls below 10.5 V, the voltage at the inverting input (pin 5 of IC1) should be adjusted to 1.2 V using preset VR1.

Initially, when the battery is fully charged, the voltage at the inverting input (pin 5) of IC1 is higher than the non-inverting input (pin 4- voltage level held constant at approximately 1.2 V by D1). This causes the output at pin 12 of IC1 to remain low. The reset pin (pin 4) of an NE555 timer (IC2) is connected to the output pin of IC1 and hence, a low gets applied to it correspondingly. Since the reset pin is “active low”, the NE555 is reset continuously and oscillations are not generated at its output (pin 3). As a result, LED1 does not blink.

Considering the example values, when the battery voltage falls below 10.5 V, the voltage at the inverting input (pin 4) of IC1 becomes lower than the non-inverting input (pin 5) and the output at pin 12 of IC1 goes high. This applies a “high” to the connected reset pin of IC2 (NE555 timer) and the astable multi-vibrator built around IC2 starts generating oscillations. LED1 is connected to the output pin (pin 3) of IC2 and hence blinks to indicate low battery voltage and the battery needs to be charged before further use.

 

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Variable Power Supply With Digital Control

Variable Power Supply With Digital Control

by KNS Pvt Ltd
Rs. 500.00

Summary

A Variable Power Supply with Digital Control is one of the most important and essential requirements in an electronics lab. The available power supply must provide variable outputs in steps. This circuit gives variable and fluctuation-free DC voltage as output in the range of 1.5V to 12V. No. of ICs used: 4

Learning

Things which you can learn:

*Application of the NE555 timer IC in the stable mode of operation.
*Application of the 3-terminal positive and negative voltage regulator ICs LM317 and LM7912 respectively.
*Use of the decade counter IC CD4017.
* Basics of Voltage and current control

Product Description

A variable power supply is a must for those who are looking forward to taking their project building to the next level. Armed with this system you can have a clean DC supply without spikes and it ranges from 1.5 V to 12 V. Get ready and build this kit and enjoy making projects.

Working:

The circuit of the Variable Power Supply with Digital Control is built around an adjustable 3-terminal positive voltage regulator IC LM317, CMOS decade counter IC CD4017, timer IC NE555 and 3-terminal fixed negative-voltage regulator LM7912. The AC mains supply is stepped down by transformer X1 to deliver a secondary output of 12V-0-12V AC, 1A. The output of the transformer is rectified by a full-wave rectifier comprising diodes D1 through D4.

Capacitors C1 through C4 are connected in parallel to rectifier diodes to bypass undesired spikes and provide smooth and fluctuation-free power. Capacitors C5 and C13 are used as filters to eliminate ripple. Here both negative and positive half cycles are used to obtain positive as well as negative DC output. LED1, along with current limiting resistor R1, is used for mains ‘on’ indication. Timer IC NE555 (IC1) is wired as an astable multi-vibrator. It generates clock pulses when switch S2 is pressed.

The output of IC1 is connected, via an RC network, to the clock input of counter IC CD4017 (IC2). IC CD4017 is a decade ring counter. Each of its ten outputs goes high one by one when a clock pulse is received. The outputs of IC CD4017 are connected to the bases of transistors T1 through T10, respectively. LED3 through LED11 is used here to indicate the voltage levels.

The collectors of transistors T2 through T10 are connected to presets VR1 through VR9, respectively, which are used to set the output voltage. Adjustable voltage regulator IC LM317 (IC4) develops 1.25V nominal reference voltage (VREF) between its output and the adjustable terminal. The reference voltage appears across resistor R16. When the voltage is constant, a constant current flows through one of the output-setting variable resistors (VRset, VR1 through VR9), giving an output voltage at pin 2 of IC4 as VOUT=1.25(1+VRset/R16). Presets VR1 through VR9 is adjusted to get the desired output voltage.

The collector of transistor T1 is directly connected to ADJ terminal (pin 1) of IC4, so the output voltage of IC4 will be the voltage across fixed resistor R16, which is equal to 1.25V. When switch S3 is pressed, pin3 of IC2 goes high and the output voltage becomes 1.2V. When switch S2 is pressed, the output of IC1 goes high.

As a result, the outputs of IC2 go high one by one as a ring counter. Since presets VR1 through VR9 are connected at the collectors of transistors T2 through T10, respectively, different output resistances appear between the adjustable and ground terminals of IC4, resulting in different output voltages. By using a properly calibrated digital multimeter you can easily adjust the presets to obtain 1.5V to 12V. A fixed, negative 12V DC can be obtained by using fixed, the negative-voltage regulator IC LM7912 (IC3). Thus the power supply unit can be used for circuits requiring both negative and positive DC voltages. When CD4017 is reset by pressing switch S3, the output voltage becomes 1.2V and all the voltage-indication LEDs turn off.

 

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RFID Based Attendance System Save Rs. 500.00
Rs. 6,000.00
Rs. 5,500.00

RFID Based Attendance System

RFID Based Attendance System

by KNS Pvt Ltd
Save Rs. 500.00
Rs. 6,000.00
Rs. 5,500.00

Product Description

The main objective of the system is to uniquely identify and to make attendance for a person. This requires a unique product, which has the capability of distinguishing a different person. This is possible by the new emerging technology RFID (Radio Frequency Identification). The main parts of a RFID system are RFID tag (with unique ID number) and RFID reader (for reading the RFID tag). In this system, RFID tag and RFID reader used are operating at 125KHz.

Click To View Circuit Diagram

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Temperature indicator using ATC microcontroller Save Rs. 200.00

Temperature indicator using ATC microcontroller

by KNS Pvt Ltd
Save Rs. 200.00
Rs. 1,400.00
Rs. 1,200.00

Summary

The Temperature Indicator using AT89C52 is a microcontroller based temperature indicator that displays the temperature in the range of –55 degree Celsius to 125 degree Celsius. Besides AT89C52 microcontroller, it uses a temperature sensor chip and an LCD module. The indicator outputs the calibrated data in digital form. No. of ICs used: 3

Learning

Things which you can learn:

*Learn interfacing of temperature sensing IC DS1621 with the microcontroller input.
*Learn designing of the bridge rectifier.
*Learn interfacing of LCD module with AT89C52.

Product Description

Build a cool micro controller based temperature indicator for detecting temperature in heat sensitive environment to prevent damage to certain appliance.

The circuit of the Temperature Indicator (using AT89C52) employs the voltage regulator IC 7805 to provide supply to different parts of the unit. The temperature sensor DS1621 senses the ambient temperature and the output of this chip is read by the microcontroller unit. The temperature data is compared with certain user-defined temperature values and processed inside the MCU as per the programmed then sent to the LCD for display.

Click To View Circuit Diagram

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Automatic Low Power Emergency Light Save Rs. 250.00

Automatic Low Power Emergency Light

by KNS Pvt Ltd
Save Rs. 250.00
Rs. 1,000.00
Rs. 750.00

The automatic low power emergency light is a white LED based emergency light that offers the following advantages:

  1. It is extremely bright due to the use of white LEDs.
  2. The light turns ON automatically when mains supply fails and turns OFF when mains power resumes.
  3. It has its own battery charger. When the battery is fully charged, charging stops automatically.

No. of ICs used: 1

Learning from this project

  • Application of the adjustable voltage regulator IC LM317.
  • Application of Zener diodes for voltage regulation.
  • Application of diodes in the bridge arrangement for rectification.
  • Application of NPN and PNP transistors.

Product Description

Build yourself a cool automatic low power emergency light which can be used during a power failure. An added bonus is that it charges automatically.

Circuit operation

This automatic low power emergency light comprises of two sections: charger power supply and LED driver.

The charger power supply section is built around the 3-terminal adjustable voltage regulator IC LM317 (IC1), while the LED driver section is built around the transistor BD140 (T2).
In the charger power supply section, input AC mains is stepped down by transformer X1 to deliver 9V, 500 mA to the bridge rectifier comprising of four diodes (D1 through D4). A filter capacitor (C1) eliminates ripples.

Unregulated DC voltage is fed to input pin 3 of IC1 and provides charging current through a diode (D5) and a limiting resistor (R16). By adjusting the preset (VR1), the output voltage can be adjusted to deliver the required charging current. When the battery gets charged to 6.8V, zener diode (ZD1) conducts and charging current from regulator IC1 finds a path through the NPN transistor T1 (BC548) to ground and it stops charging the battery.

The LED driver section uses a total of twelve 10mm white LEDs. All the LEDs are connected in parallel with a 100-ohm resistor in series with each. The common-anode junction of all the twelve LEDs is connected to the collector of the PNP transistor BD140 (T2) and the emitter of this transistor is directly connected to the positive terminal of the 6V battery. The unregulated DC voltage, produced at the cathode junction of diodes D1 and D3, is fed to the base of transistor T2 through a 1-kilo-ohm resistor.

When mains power is available, the base of transistor T2 remains high and T2 does not conduct. Thus LEDs are off. On the other hand, when mains fails, the base of transistor T2 becomes low and it conducts. This makes all the LEDs (LED1 through LED12) glow. The mains power supply, when available, charges the battery and keeps the LEDs off as transistor T2 remains cut-off. During mains failure, the charging section stops working and the battery supply makes the LEDs glow.

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Intelligent Metro Train Save Rs. 600.00
Rs. 6,000.00
Rs. 5,400.00

Intelligent Metro Train

Intelligent Metro Train

by KNS Pvt Ltd
Save Rs. 600.00
Rs. 6,000.00
Rs. 5,400.00

Summary

Future era train which has very advanced features.

Product Description

This project is designed so that students can understand the technology used in the now a day’s drive less metro train which is used in most of the developed countries like Germany, France, and Japan etc. These trains are equipped with the CPU, which controls the train. The train is programmed for the specific path. Every station on the path is defined; stoppage timing of the train and distance between the two stations is predefined. This is a very wonderful project to control the working of the train without a driver.

Brand: HBeonLabs, Product assembled by HBeonLabs

 

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Versatile Power Supply

Versatile Power Supply

by KNS Pvt Ltd
Rs. 425.00

Summary

The Versatile Power Supply is a DC regulated variable power supply that is capable of delivering DC voltages ranging from 3.3 Volts to up to 15 Volts with 1Amp current output using a variable voltage regulator IC LM317. Build the kit and enjoy powering up your awesome project! No. of ICs used: 1

Learning

Things you can learn:

*Application of the voltage regulator IC LM317.
*Application of NPN transistors as switches.
*Basics of Voltage Step downing
*Concepts and implementation of bridge rectifiers

Product Description

A variable power supply is a must for those who are looking forward to taking their project building to the next level. Armed with this system you can have a clean DC supply without spikes.

Working:

In the Versatile Power Supply circuit, the AC mains is stepped down by a transformer (X1) to deliver the secondary output of 18V AC at a maximum current of 1A dependent upon the load. The transformer output is rectified by the bridge rectifier comprising of four diodes (D1 through D4), filtered by a capacitor (C1) and fed to the voltage regulator IC LM317 (denoted as IC1). IC1 is a 3-terminal positive regulator capable of providing 1.2V to 37 volts at 1.5A current to the load.


Resistor R13 and selected combinations of several other resistors (R1 through R12) are used to produce approximately 3.3V, 5V, 6V, 9V, 12V and 15V at the output. The desired resistors are selected by switching into conduction one of the six PNP transistorsBC558 (T1 through T6) by grounding the corresponding transistor base using a rotary switch (S1). For example, to get regulated 3.3V, simply rotate the knob of the rotary switch to the 3.3V position. Consequently, transistor T1 is forward biased to switch resistors R1 and R2 (in series) across Adj pin of LM317 and ground to produce 3.3V.


Other voltages can be produced in the same way by using rotary switch S1. Capacitor C2 bypasses any ripple in the output. Diode D5 is used as the protection diode. Use a heat-sink for dissipation of heat from IC LM317. The fuse-rated lamp provides protection against short circuit.

 

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RFID cum GSM Vehicle Tracking System Save Rs. 2,001.00
Rs. 12,000.00
Rs. 9,999.00

RFID cum GSM Vehicle Tracking System

RFID cum GSM Vehicle Tracking System

by KNS Pvt Ltd
Save Rs. 2,001.00
Rs. 12,000.00
Rs. 9,999.00

Summary

In this system, When the vehicle passes near the reader the TAG is detected and a message is received on the mobile with the position where it is traced.

Learning

Embedded System

Product Description

This system is designed to track vehicles if someone does not find his vehicle and seems that his vehicle is stolen. Vehicles have RFID TAG and RFID readers are fixed at different places. Here we use GSM modem to get information on mobile. When the vehicle passes near the reader the TAG is detected and a message is received on the mobile with the position where it is traced.




Brand: HBeonLabs, Product assembled by: HBeonLabs

 

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Electronic Circuit Breaker Save Rs. 500.00
Rs. 5,000.00
Rs. 4,500.00

Electronic Circuit Breaker

Electronic Circuit Breaker

by KNS Pvt Ltd
Save Rs. 500.00
Rs. 5,000.00
Rs. 4,500.00

A circuit breaker is an automatically-operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Its basic function is to detect a fault condition and, by interrupting continuity, to immediately discontinue electrical flow. Unlike a fuse, which operates once and then has to be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation.

Circuit breakers are made in varying sizes, from small devices that protect an individual household appliance up to large switchgear designed to protect high voltage circuits feeding an entire city.

Brand: HBeonLabs, Product assembled by HBeonLabs

 

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Digital Voltmeter Save Rs. 100.00
Rs. 600.00
Rs. 500.00

Digital Voltmeter

Digital Voltmeter

by KNS Pvt Ltd
Save Rs. 100.00
Rs. 600.00
Rs. 500.00

Build yourself a digital voltmeter which you can use to measure and troubleshoot your projects. This is a great kit for those who are looking to learn analogue to digital conversion concepts. A voltmeter finds application wherever voltage is to be measured. This digital voltmeter is designed as a panel meter and can be used in DC power supply panels or where it is necessary to have an accurate indication of the voltage.

No. of ICs used: 3

Learning from the project

Things you will learn:

  • Application of positive and negative voltage regulator ICs.
  • Application of the analog to digital converter IC ICL7107.
  • Voltage measurements technique
  • Linear Integrator
  • Comparater

Product Description

The heart of this digital voltmeter circuit is an analogue to digital converter IC i.e. the ICL7107. This 40 pn IC encases all the circuitry necessary to convert an analogue signal into digital and can drive a series of four seven segment LED displays directly. The circuits built into the IC are analogue to digital converter (ADC), a comparator, a clock, a decoder and a seven segment LED display driver.
The circuit can display any DC voltage in the range of -1999 volts to +1999 volts. It operates off ±5 volts.

Project working

The operation of the circuit can be described in two stages. During the first stage, for a given period the input voltage is integrated, and the output of the integrator at the end of this period is a voltage which is directly proportional to the input voltage.

At the end of the preset period, the integrator is fed with an internal reference voltage and the output of the circuit is gradually reduced until it reaches the level of the zero reference voltage. This second phase is known as the negative slope period and its duration depends on the output of the integrator in the first period. As the duration of the first operation is fixed and the length of the second is variable, it is possible to compare the two and this way the input voltage is in fact compared to the internal reference voltage and the result is coded and sent to the display.

Basically, the voltage to be measured is applied across points ‘IN-L’ and ‘IN-H’ of pins 30 and 31 of IC1, respectively, through circuit resistors R5, R6, R7 or R8 and preset VR1. Resistor R2 together with C5 forms the RC circuit used to set the frequency of the oscillator (clock), which is set at 48 kHz approximately. At this clock rate, there are about three different readings per second. Capacitor C4, which is connected between pins 33 and 34 of IC1, compensates for the error caused by the internal reference voltage and also keeps the display steady. Capacitor C2 and resistor R1 together form the circuit that does the integration of the input voltage and at the same time prevents any division of the input voltage making the circuit faster and more reliable. Capacitor C1 forces the instrument to display zero when there is no voltage at its input. Resistor R3 together with reference control preset VR2 is used to adjust the instrument during set-up so that it displays ‘0’ when the input is zero. Resistor R4 controls the current that is allowed to flow through the displays (for decimal point) so that there is sufficient brightness without damaging them.

The IC, as mentioned earlier, is capable of driving four common-anode, seven segment displays. Displays DIS1 through DIS3 are connected such that they can display all the numbers from ‘0’ to ‘9,’ while display DIS4 can display only the digit ‘1’ (and ‘-’ sign when the voltage is negative). When TEST switch is pressed, test pin is pulled high (to V+) and all segments turn on to show ‘1888’ on the display. The TEST pin will sink about 15 mA under this condition. In the lamp test mode, the segments have a constant DC power supply. Pin 36 (REF HI) is made high through VR2 to adjust the reference voltage and pin 35 (REF LO) is connected to the negative terminal of the input. Preset VR1 is used to adjust the range of voltage divisions. Resistors R5, R6, R7, and R8 connected to pin 31 are used for range selection. Switch S2 is two-pole, four-position (each ganged) rotary switch. The decimal point is connected to resistor R4 via rotary switch S2 for different range selection.

Click To View Circuit Diagram

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