Basic Electronics/Electrical Projects & Kits

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Hit Switch Save Rs. 25.00
Rs. 150.00
Rs. 125.00

Hit Switch

Hit Switch

by KNS Pvt Ltd
Save Rs. 25.00
Rs. 150.00
Rs. 125.00

Summary

This versatile hit based switch is the electronic equivalent of a switch. This circuit serves as an on/ off control for incorporation in a wide variety of electronic design.The circuit uses a Piezo electric diaphragm which when pressurized produces a small potential between its plate. This small signal is amplified and used in combination with diodes to form a voltage controlled switch.

Learning

Things which you will Learn :
*Application and basics of Hex inverter with CD4069 IC.
*Implementation of the Bridge rectifier circuit for AC to DC conversions.
*Use of transistors as signal amplifiers.
*Inverter gates with IC CD4069 (IC1)

 

Product Description

This versatile hit switch is the electronic equivalent of a conventional switch. It can be used to control the switching of a variety of electronic devices.

The circuit of the hit switch uses a piezoelectric diaphragm (piezo buzzer) as the hit sensor. A piezoelectric material develops electric polarization when strained by an applied stress. The hit sensor makes use of this property.

Working:

When you hit or knock the piezo element (hit plate) with your fingertip, a small voltage developed by the piezo element is amplified by transistor BC547 (T1). The combination of transistor T1 and the bridge rectifier comprising diodes D1 through D4 acts as a voltage-control switch. The inverter gates of IC CD4069 (IC1) together with associated components form a bistable switch.

IC CD4069 is a CMOS hex inverter. Out of the six available inverter gates, only three are used here. IC1 operates at any voltage between 3V and 15V and offers a high immunity against noise. The recommended operating temperature range for this IC is –55°C to 125°C. This device is intended for all general-purpose inverter applications.

Initially, the input of gate N1 is low, while the input of gate N2 is high. Triggering the voltage-control switch by hitting the sensor pulls the input of gate N1 to a high level and causes the bistable to toggle. The capacitor gets charged via resistor R1 and the circuit changes its state. This latch continues until the bistable switch gets the next triggering input.
Every time the hit plate receives a hit, the voltage-control switch triggers the bistable circuit.

That means every subsequent hit at the sensor will toggle the state of the switch. The red LED (LED1) connected at the output of gate N3 indicates ‘on’/‘off’ position of the switch. Relay RL1 is activated by the hit switch to control the connected load.

The circuit works off 12V DC. It can be constructed on any general-purpose PCB. For the desired results, proper connections and installation of the hit sensor are necessary. Remove the cover of the piezo buzzer and connect its two leads to the circuit. Mount the plate such that it receives the hit properly. The piezoelectric material on the plate can easily get damaged, so hit the switch gently.

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Musical Hold On For Telephone Save Rs. 50.00
Rs. 200.00
Rs. 150.00

Musical Hold On For Telephone

Musical Hold On For Telephone

by KNS Pvt Ltd
Save Rs. 50.00
Rs. 200.00
Rs. 150.00

Summary

The Musical Hold On for Telephone is an add-on external circuit that can be attached to the telephone to generate a melodious tune on the telephone line. The circuit allows the person on the other end to enjoy this melodious tune during the hold-on interval. To resume talking, just a simple switch needs to be flicked into the OFF position. A Red LED included in the circuit indicates that phone line is on-hold and it automatically turns OFF when the music stops. No. of ICs used: 1

Learning

Things which you can learn:
*Application of the melody generator IC UM66.
*Application of diodes for rectification and voltage regulation.
*Application of transistors for amplification and switching purposes.

Product Description

Build a cool Musical Hold on a device using simple components and fascinate your friends when you put them on hold.The heart of the Musical Hold-On for Telephone is the melody generator IC UM66. This IC generates a melodious musical tone when continuous power is supplied to it.

Working:

The circuit utilizes the voltage supply present on the telephone line, which is further applied to the bridge rectifier formed by four diodes (D1-D4). 

In a normal state with a switch (S1) kept in OFF position, no voltage is applied to the base of the PNP transistor MPSA92 (T1) and it remains reverse biased. Thus, the red indicator LED (D5) and the melody generator IC UM66 (IC1) are OFF and the phone line is free for normal usage. However, while talking if the switch (S1) is closed, then a positive DC voltage (available across the telephone line) gets connected to the base of transistor T1.

This forward biases T1 which acts as an amplifier and an electro-switch. A regulator circuit (comprising of resistors, a capacitor, and a zener diode) regulates the voltage available at the collector of transistor T1. The red indicator LED glows and IC1 also begins generating music as voltage gets applied to its Pin2. The low-value output from Pin1 is amplified by the NPN transistor BC547 (T2). This is coupled to the telephone line using a capacitor and thus the musical tune is heard on both phone.

 

Smart Laptop Security Station Save Rs. 100.00
Rs. 700.00
Rs. 600.00

Smart Laptop Security Station

Smart Laptop Security Station

by KNS Pvt Ltd
Save Rs. 100.00
Rs. 700.00
Rs. 600.00

Summary

If someone tries to lift your laptop from the docking station, Then it will give you an alarm by audio and visual means to indicate that some one has stolen your laptop. Build this kit and prevent laptop theft.

Learning

Things which you can learn:


*Application of CD4060 as binary counter.
*Applicaion of opto sensor CYN70.
*Use of transistors as signal amplifiers.
*Implementation of the Bridge rectifier circuit for AC to DC conversions.

Product Description

Convert your ordinary docking station to smart docking station with this laptop security station kit. Laptops are very expensive and to prevent theft of it, employ this circuit and get informed whenever someone tries to steal your laptop.

Working:

Circuit is built around IC CNY70 (IC1) and IC CD4060 (IC2). 

IC CNY70 is an integrated reflective type opto-sensor that contains a phototransistor and an infrared LED. The LED emits infrared light and the transistor works as a receiver. The current flowing through the phototransistor depends on the intensity of the light detected.
IC CD4060 is a 14-stage ripple-carry binary counter. The counter is reset to zero by a gating positive voltage at the reset input independent of clock.

When the laptop is in the docking station, the phototransistor inside IC1 receives the IR light from the LED, reflected by the laptop surface. The phototransistor conducts to make
reset pin 12 of IC2 high, so IC2 does not oscillate.


When someone lifts up the laptop from the docking station, the phototransistor cuts off and pin 12 of IC2 goes low. As a result, IC2 starts oscillating. After a few seconds, delay pin 3 of IC2 goes high to drive transistor T1. The piezo buzzer starts beeping to raise an alert and the LED2 glows to indicate that someone has stolen the laptop from the dockyard.

 

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