Very sensitive. Detects Fire from a distance of 2 meters in a dark room. Beeps loudly till Fire ceases. Since it is detecting Infrared rays, it can be also used as a TV Remote tester.
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Save water .This simple circuit beeps loudly when the water tank becomes full.No more wastage of water.
Continue reading “Water Tank over flow Alarm”
Turns on a White LED for 3 minutes and turns off when a human move in front of it. Uses Passive Infra Red (PIR) motion sensor.
Continue reading “Motion Sensor Light”
The Op Amp comparators sometimes works well under some conditions but not always. If there is a slow wave form or some noise on it, sometimes the output switch back and forth many times. So for stable operation, Op Amp comparator can be designed as a Schmitt trigger.
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Comparator is a circuit that compare two voltages. When one voltage is higher than the other, the output of comparator is in one state, either high or low. If the input conditions are reversed, output of the comparator switches to the other state.
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Two LEDs indicate the power on and off status of bread board power . So it helps to confirm whether the positive and negative rails of the bread board are getting power. Green LED lights at power on and turns off after 3 seconds. Red LED turns on at power off and turns off after 3 seconds. Let us see the circuit
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It is easy to light an LED by directly connected to 220 volt AC. It can be indicator in AC devices or Bed lamp if White LED is used. If used as a Bed lamp, the circuit can be enclosed in a plug with LED projecting out. Caution : The circuit is directly connected to high voltage that can give a fatal shock if handled … Continue reading LED in AC
This circuit can protect AC appliances. When the AC voltage in the mains increases above the set level , say 220 volts, relay triggers and breaks power from the appliance. Reconnects the appliance when the power returns normal.
Beep once when power fails. 12 volt relay is used as a switch. When power is available, relay pulls and capacitor charges via diode D1 and NO and Common contacts of relay. When power fails, relay turns off and capacitor discharges via Common and NC contacts and buzzer. Buzzer gives a short beep at that time. If more timing for beep is needed, connect one … Continue reading Simple Power Failure Alarm
The Project implementing is a Gas leakage alarm system that senses the leakage of LPG from Gas cylinder or Gas stove and gives a warning alarm. Its further modification can be automatic cut off the electricity system in the home and also a battery operated exhaust fan to remove the leaked gas from the room.
This project is based on the PIR Motion sensor to detect human movement and alarm generation as a surveillance system for home and office. The circuit sends the alarm sound wirelessly to the interior of home and also switches on the outdoor lights when it detects a human movement. Continue reading “PIR sensor based home surveillance system”
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 causes 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. So that alarm reminds to switch off the water heater. This can be used for Electric Iron also.
Make this simple White LED emergency lamp using few components. It can be plugged into the AC socket and it turns on at the moment when power failures. It emits cool white light in the room which is sufficient even for reading purpose. It is powered by a 4.5 volt rechargeable battery and uses 1 watt White LED.
When we use Triac and LDR to make Automatic Lights, a major problem arises . Lamp starts flickering during the light transition period in the evening and morning. Lamp fully turns on only when there is complete darkness and turns off only when day light is full. This simple design solves the problem. Light instantly turns on / off without any flickering. You can drive CFL, LED bulb etc which turns on automatically around 6 pm and turns off around 6 am. See the simple design. Continue reading “Flicker Free Automatic Light”
It is very easy to convert 220 Volt AC to DC for powering electronic circuits. Any DC voltage from 3 volt to 36 volt can be generated from 220 volt AC using appropriate value of X rated capacitor and Zener diodes. The X rated capacitor drops 220 V AC to low volt AC. This can be rectified to DC by a Rectifier diode and smoothed by a Filter capacitor. By selecting a required value Zener, regulated DC can be obtained. But the only drawback of the Tranformerless power supply is its low current, so only light loads can be used. Here explains the design of a 4.7 Volt 4.6 Milli Ampere Tranformerless power supply to power PIR sensor .
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A Simple design of PIR Light using Tranformerless Power Supply and Triac for driving the load. Too compact and can be enclosed in a small case. The light turns on when the PIR sensor detects human movement and turns off after the preset time. Re triggers in another movement. Its range is 30 cm to 10 meters and time delay, 30 seconds to 3 minutes both can be adjusted using the presets in the PIR sensor Module.
Continue reading “AC Powered PIR Light”
Here is an efficient Car battery charger for fast charging the Car battery. It is a 5 Ampere charger with Digital Volt and Ampere Meter to display the charging voltage and current. Since the charger provides maximum 5 Amps current, battery can take high current it needs to charge very fast. As the charging process completes, current flow reduces to zero and will be displayed in the meter. So it is easy to confirm whether the battery is fully charged or not.
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Digital Volt Ampere Meters are now available which can be used in Battery chargers to monitor voltage and current. One section of the Meter displays 0 to 100 V DC and the second section displays current 0 to 10 Amperes. The Meter works off 4 to 30 V DC. Let us see how it can be used in a charger….
Continue reading “How to connect Panel Meter in Battery Charger”
This 5 Amps charger automatically stops charging when the terminal voltage of battery rises to 13.7 V thus preventing over charging. If the battery voltage drops below 11 V, Charger turns on and starts charging. Check it……….
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Wireless Electricity Generator
Here is a High Efficiency Wireless Electricity Generator project. Usually we make a simple wireless electricity generator to light 1.8 volt Red LED. But here the efficiency of the Wireless Electricity Generator is increased to light 1 Watt White LED Bulb that requires 3.6V. It generates voltage and current even to light a Strip LED. Try it and see the wonder of LED lighting without a battery connection.
PIR Sensor Alarm
This simple alarm can be used to detect the movement of human beings at a distance of 10 meters. It works both day and night and beeps shortly when there is a human movement through its detecting range. It is ideal to monitor the entry passages, stair case, corridors etc. It is highly useful to monitor the human movements in Flats, Multi storied buildings, Shops etc. A relay can also be connected for activating lights, electric alarms etc. It can be used as a Personal alarm during journey to protect luggage.
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How  to connect Digital Volt Ampere Meter
Digital Volt Ampere meters are now available to measure DC voltage and Current. It can be connected to the output of the Power supply. So the output voltage and current to the load is displayed in the meter. If a battery is connected to the power supply for charging, we can see the current consuming by the battery during charging. When the battery is fully charged, current drops to zero which indicates the termination of charging. If project is connected, the voltage and current to the project is displayed. 
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Ultrasonic Pest Chaser
Here is an efficient Electronic Pest Repellent to chase Pests from home. It emits Ultrasound in the frequency 9 to 96 kHz which can be set for each Pest. Human can’t here the Ultrasound since it is out of human sound detection range. But most animals can hear Ultrasound.The circuit emits powerful Ultrasound to repel pests.
Mosquitoes are usually repelled between 20 and 40 kHz, Rats around 56 kHz, Cockroaches around 36 kHz and Flies around 30 kHz. Out put power of the circuit is 2 watts 1.3 dB. It can repel Mosquitoes, Rats, Cockroaches, Wall Lizards , House flies etc from home. Made and found effective.
Voltage regulation through Fixed Voltage Regulator IC is the most suitable method.78xx series positive and negative regulators are widely used to get fixed voltage to drive loads. Here explains a circuit design to get regulated voltage from a 12 volt 500 mA power supply .This circuit can deliver 5 volts at 300 mA for driving a load.
The circuit is Voltage and Current regulated and with Polarity and Surge protection components.
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1 Watt LEDs are widely used in Emergency lights and LED lights. Most of the circuits use 4 volt battery having 0.5 to 4 Ah capacity. The 1 watt LED is rated 3.6 volts maximum so we need the correct value resistor for LED to get maximum brightness. Let us see how the LED resistor value is determined.
Continue reading “How to select resistor for 1 watt LED”
Solar Garden Light
Make a lighting path in the garden using this simple Solar LED light. It automatically turns on in the evening and gives light in the garden. LED light turns off in the morning. You can select any colour LED like Green, White or Yellow as per the choice.
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Automatic Solar Outdoor Light
Very simple to construct an Automatic Garden light using Solar Panel and LED light. ON in the evening and OFF in the morning. No switching needed and it light the premises of home even if inmates are not there. No circuit complication is here instead only a Relay and few components are used to make this efficient Solar light. It is very well lighting my home.
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It charges 12 V Lead Acid battery with 5 Amps current and Automatically stops charging when the battery voltage increases above 13.8 V to prevent over charging. Charger starts charging when the battery voltage is below 11.8 V and stops charging at 13.8 V.
Continue reading “Efficient Car Battery Charger”
Here is an efficient battery charger for Car battery and Inverter battery. It quick charges the battery with 5 Ampere current and cut off charging when the battery attains 13.8 V which is the full charge condition of the Lead Acid battery. Red LED indicates charging process while Green LED indicates full charge and charger cut off status.
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CD 4060 is the Binary counter IC used in Timer circuits. It has 10 outputs that turns on one by one based on the timing components. Let us check its working
Continue reading “How to find out the Timing in CD 4060 IC”
High volt X rated capacitors are used to make Transformerless power supply. But the current delivering capacity of such power supply is very low generally less than 100 mA. Let us see how to select a Capacitor to get required current
Continue reading “How to determine the current in X rated capacitors”
Disc capacitors have an EIA Code to show its value. Let us see how to decode that
Continue reading “How to read the EIA code in Capacitor”
In Disc capacitors, an Alphabet is shown after its EIA code or value. It indicates its tolerance. Let us check
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In X rated capacitors a letter like J, K etc is printed after the EIA code.It is the tolerance of the capacitor. Let us check
Continue reading “How to check the Tolerance in capacitors”
EIA code is present in Disc capacitors to show its value. Let us decode to get the capacitance.
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Don’t throw away the old Mobile battery. The high efficiency Lithium Ion battery can be reused to make a Mini Power bank useful as a Travel Mobile charger. For this, you needs a Lithium battery charger Module and a Mobile charger module in addition to the battery. Both modules will cost around Rs.100.
Continue reading “How to make a Mini Power Bank”
Transistor is used to drive relay to connect AC loads. For efficient working, it is important to connect the relay correctly in NPN and PNP transistors. See the way of connection. Continue reading “How to connect Relay with NPN and PNP transistors”
7 segment display is used in Counter circuits, Temperature sensing circuits, Timers, Clock circuits etc. Let us see its pins and way of connection Continue reading “How to connect 7 segment display in circuits”
CD 4060 is the versatile Binary counter IC that can be used in Timer applications.When a resistor is connected to its pin 10 and a capacitor in its pin 9, it forms an oscillator that gives pulses to its pin 11.According to the timing cycle, each output goes high one by one. Output gives around 10 mA current and a voltage near to the supply voltage. Timer oscillates only when its Reset pin 12 is grounded. Continue reading “How to set CD 4060 IC as Timer”
Lithium Ion batteries are now widely used in Mobile phones, Power banks, Digital cameras and other devices that requires 3.6 V . Lithium Ion batteries are long lasting since its current rating is very high above 2300 mAh.It is very important to maintain Lithium Ion batteries since, both over charging and poor charging may completely destroy the battery.Some have the habit of plugging the Mobile phone in charger overnight. Mobile battery needs to be charged only when its charge goes below 50 %.Proper charging and discharging increases the life of Mobile battery and its efficiency. Let us see its voltage levels
Continue reading “How to determine the voltage level in Lithium Ion battery”
PIR sensor is the ideal device to use as Surveillance systems that operates by sensing human body heat. It triggers the alarm from a distance of 10 meters when a human passes. It operates both day and night. Let us see how to fix it on the wall
Continue reading “How to fix PIR sensor Alarm”
The PIR sensor module has a Jumper arrangement to select single trigger and re trigger modes. Let us see how it works Continue reading “How to set the Re trigger Jumper in PIR sensor Module”
It is important to know the connections of PIR sensor module. It is easy to connect it with alarms, relay to drive AC load etc. Let us see Continue reading “How to connect PIR sensor Module”
PIR sensor module is an ideal device to make efficient alarm systems and save energy lights. Let us see how it works?
Most simple Transformerless power supply that can convert 220 V AC to DC. Out put DC depends on the value of the Zener used. Output current is 60-80 mA.
See the step wise procedure
Continue reading “How to make a simple Transformerless Power supply”
Don’t throw away the SMPS power supply when the Computer damges. SMPS is a high current device that gives different regulated voltages from the output wires. It has numerous wires to give different voltages . So you can make a good Multi voltage power supply for the Projects or use as battery charger for different types of batteries. It has total isolation from Mains and output is safe DC.
Continue reading “How to Convert SMPS to Bench Power supply cum charger”
This Power supply box can be used to interface with the High current Bench power supply made from the SMPS of Computer. The Power supply box has a DC-DC Converter cum Booster module, A Volt Meter and an Ammeter to show output voltage and current consumed by the load. Continue reading “Power Supply Box”
Suppose the Laptop crashes and is irrecoverably damaged .Its Hard disk has full of valuable data. What will do to recover that? SATA to USB device will help. Its cost is just Rs.170 and available in Computer sellers. Open the small window on the back of laptop. You can see the Hard Disk there. Unplug from its socket. Connect it to the SATA-USB socket. Connect the USB cable to PC or Laptop. It will detect the removed Hard Disk. You can open the folders and copy the data. It can be a good external hard disk in future.
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Suppose the computer mother board crashes and the PC is irrecoverably damaged .Its Hard disk has full of valuable data. What will do to recover that? SATA to USB device will help. Just plug in its power supply and data cables to the Hard disk removed from the PC. Connect the USB cable of SATA- USB unit to a computer or laptop. The PC will detect the hard disk and you can copy the files to the computer. You can also use this Hard disk as an external hard disk. 
Don’t throw away the SMPS power supply when the Computer fails. It is a high current device that gives different regulated voltages from the output wires. It has numerous wires to give different voltages . So you can make a good Multi voltage power supply for the Projects or use as battery charger for different types of batteries. It has total isolation from Mains and output is safe DC.
Continue reading “How to convert SMPS Power Supply to Bench Power supply”
