mobile-bug1

Mobile Bug- Page updated


mobile-bug1

This is one of my most attracted circuit published in Electronics For You years back. But still it is in limelight .More than 200 students selected the circuit as their engineering project. It detects an active mobile phone even in the silent mode and beeps. It’s range is 2 meters radius. It is ideal to monitor Mobile phone restricted areas like Examination hall and Confidential rooms. It detects, Incoming and Outgoing calls, SMS, MMS, Video capturing, Photo capturing etc. I have slightly modified the circuit to increase its range. Check this updated page to get full details including the project report and video of the circuit.

https://dmohankumar.wordpress.com/most-used-circuits/

Alarm for Water Heater


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It was a big problem in my house that, sometimes the Water heater left on for many hours after the use. It has a Thermostat to cut off but when the water cools, again it switches on. This caused a hike in electricity bill. Finally I found a solution. Just connected a Timer based alarm with the heater AC socket so that it will also switches on when the heater turns on. After 30 minute, it gives a loud alarm to remind that the heater is On. Alarm continues for another 30 minutes or till the heater is switched off.
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TRANFORMERLESS-POWER-SUPPLY

Drawbacks of Transformerless power supply


Capacitor-Power-Supply

To reduce cost and size, Transformerless power supply is now widely used which uses an X-Rated Non-Polarized capacitor to reduce 230 volt AC to low volt AC. It is then rectified and used as low volt DC. But unlike the Transformer based power supply, the transformerless power supply has many disadvantages

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Alcohol Detector


MQ3_Sensor

Use this simple circuit to detect the presence of Alcohol. This kind circuit is used by Police officials to prevent drunk driving. It gives a beep when it detects the Alcohol vapour. MQ3 Alcohol sensor is now readily available and you can make the device very easily. When the Sensor detects alcohol vapour, it gives output voltage depending on the concentration of alcohol molecules in the air.
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QR Code and its uses


QR-Code

This image is familiar to you because it is now printed in the packing of many products including Mobile phone. It is the Quick Response code or QR code used as a Bar code for storing information about the product. It is a “Mobile readable” code that can be used to connect with the website of the manufacturer directly to get the details of the product. Users with a camera phone equipped with the correct reader application (QR Code decoding software) can scan the image of the QR code to display text, contact information or directly connect to the website. This mechanism of linking Physical world objects is called “Hard linking” or “Object hyper linking”.
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LPG Sensor Alarm


MQ6-GAS-SENSOR-MODULE2 LPG Sensor modules are available now at low cost and we can use it in the Kitchen as a Gas leakage Alarm. The Module has a MQ6 Gas sensor, an Op-Amp as comparator and a preset for adjusting the sensitivity. All we need is a load resistor at the output to connect with the alarm circuit. Module is very sensitive to LPG (Liquefied Petroleum Gas) which contains Propane and Butane. The MQ6 sensor detects the gas concentration between 200 to 10,000 ppm.
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2014 in review


The WordPress.com stats helper monkeys prepared a 2014 annual report for this blog.

Here’s an excerpt:

The Louvre Museum has 8.5 million visitors per year. This blog was viewed about 270,000 times in 2014. If it were an exhibit at the Louvre Museum, it would take about 12 days for that many people to see it.

Click here to see the complete report.

PIR Light Switch


PIR-1You can easily make a Burglar Alarm system using the PIR Sensor module. The PIR sensor module is readily available now and costs less than Rs.100. You can make the complete unit at the cost of less than Rs.200 but its use is worth. The PIR Sensor module has a circuit board with a timer. The timer circuit gives a time delay between 30 seconds to 3 minutes that can be adjusted using the present. It also has a sensitivity adjustment for adjusting the sensitivity from few centimeters to 10 meters. In some modules, an LDR is also provided for night time operation only.
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FM-TRANSMITTER2

Ultra simple FM Transmitter


FM-TRANSMITTER2

With this tiny FM transmitter , you can transmit your voice or audio to an FM Radio. Its range is 10-25 meters in the properly tuned condition.
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How to solve SSL Error


Sometimes when we open Facebook or Gmail, the page will not open and prompts as “SSL Error”. What is this SSL means? It is the “Secure Socket Layer” which is the security system used by browsers especially the Google Chrome for secure login. How this SSL error occurs? SSL works based on the Security certificates authenticated during the browser installation.  The browser works only if the date and time of the computer is up-to-date. Sometimes the date and time may change automatically if the computer is shutdown incorrectly. Switch off  through UPS, Power failure, Battery flat in Laptops etc causes this error. So what will do if the SSL error appears?
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