Here is a simple Solar Night lamp that turns on automatically at sunset and stays on till morning. It uses 1 Watt High Bright White LEDs to illuminate a confined area. 6 Volt 150 mA Solar panel is used to charge the battery during day time. This mini solar panel cost around Rs.300. Its positive…
Mosquito Swatter or Mosquito Racket
Definitely, mosquitoes are annoying and it can spread diseases also. The best way to destroy mosquito is electronic killing using Swatter. It eliminates the use of toxic chemicals. The mosquito coils and liquids do not kill mosquito but they repel them only. Mosquitoes will return back when the chemical disappears from the atmosphere. The swatter is…
Inverter Battery Charger with Cut Off
This Battery charger can replenish any kind of 12 V Inverter battery or Car battery and keep it in top condition. The charger never allows the battery to Over charge or Deep discharge. It automatically charges the battery when its terminal voltage drops below 12 volts and switch off the charging process when the terminal…
PIR Sensor based Alarm
This Passive InfraRed Alarm system (PIR alarm) can switch on a Lamp or Alarm when it detects the heat from an object like moving person. The name PIR (Passive Infrared) is given to the sensor because it receives the infrared rays passively and do not emit any infrared ray. The lamp or alarm remains on few…
Introduction to SMPS (Switched Mode Power Supply)
Switched Mode Power Supply uses a switching regulator to convert electric power efficiently. SMPS transfers electric power from a source ( AC mains) to the load by converting the characteristics of current and voltage. SMPS always provide a well regulated power to the load irrespective of the input variations. SMPS incorporates a Pass transistor that switches very fast typically at 50Hz and 1 MHz between the…
Battery Charger using Solar & Electrical Power
This Dual Power Source battery charger can utilize two power sources like Solar energy as well as electrical energy to charge a Lead Acid battery. Its charging is voltage and current controlled and can be used as a portable charger in places where AC is not accessible. It also has an LED indicator to show…
Locker Guard or Locker Security Alarm
This tiny circuit can protect your Locker or Almirah from a burglary. If the locker opens in the armed state, the circuit generates a loud police siren to thwart the attempt of burglary. The siren stops only when the locker door closes again. The circuit is too compact and can be powered by 3 volt…
Long Duration Timer
This Timer can give a time delay from 10 minutes to 12 hours. The time delay can be selected using a Rotary switch and when the timing cycle completes, relay energizes and remains latched till the circuit resets. This circuit finds various applications like battery charging or to control lab equipments. Timing cycle is not…
Mini Emergency Lamp
Emergency lighting systems for specific purposes do tend to get less common as the applications become more and more precise. This DIY details with an interesting low power consuming emergency lighting system. It charges from the main power supply and gets activated as soon as the mains supply is turned off. This Mini Emergency…
Beeper
Several electrical appliances we come across make a small “beeping” sound at various times while they are switched. Devices such as computers, heaters, LCD televisions, microwaves etc. are commonly found to make a small beeping sound. These small sound signals are heard either during the time when they are switched ON or OFF or…
Lead Acid Battery
A lead acid battery is composed of series of plates immersed in a solution of Sulphuric acid. Each plate has a Grid on which the active material is attached. In the negative plate, lead oxide is attached as the active material while on the positive plate, pure lead is attached. All the negative plates are connected together. Similarly all the positive…
Internet Safety
Internet and Mobile phone related Cybercrimes includes traditional activities such as fraud, theft or forgery, whenever a telecommunication system is involved .The word Cyber is derived from the Greek word Kubernetes meaning Steersman. It is used in the terms cybersex, cybernetics, cyberspace, cyberpunk, cyber homes and cyber hate, but has been largely surpassed by e- .It is used in the computer or electronic context to denote the control of the thing represented by the word…
Heat Sensor
For proper functioning of a circuit, its ambient conditions are to be maintained in an optimized manner. There shouldn’t be much of a mess with the temperature, neither humid condition are acceptable. Tackling out the heat factor of a circuit is this heat sensing circuit which alerts the user whenever the circuit tends to get…
Computer Borne Illness
Living in the modern digital world has benefits but along with the benefits of computer and mobile technology, we are also acquiring permanent health problems. Just like Air borne and Water borne diseases, computer and mobile phone related illness is also increasing. Actually, the term computer borne illness is not in use , but it…
TV Tuner Cards
TV Tuner card helps to see the Television programs in a Computer or Laptop. TV tuner card is basically a video capture circuit allowing the user to see the TV programs in PC monitor and to record the same in hard disk.TV tuner cards may be the PC1 expansion bus card that can be inserted…
Charger with Current Flow Indicator
While charging gadgets, we often come across those scenarios where the user plugs in the device but forgets to switch the electricity ON. Worse scenario is that where the user doesn’t plug up the gadget properly and leaves it, hoping it to get charged in quick succession of time. Solving these few and more…
Capacitor Power Supply Design
Circuit designers are now experimenting with capacitor based power supply due to its low cost and light weight features. Unlike resistive type power supply, heat generation and power loss is negligible in capacitor power supply. But there are many limitations in capacitor power supply. It cannot give much current to drive inductive loads and since…
Electronic Guard
Inrush current at power on or power resumption after a power failure is the major cause of data loss and errors in Microcontroller based electronic circuits. Even the SMPS based power supply is vulnerable, if the inrush current is too heavy. This circuit gives atime delay of 2 minutes to stabilize the power before the…
Battery Charging Reminder
Just as convenient as an interchangeable long running power source a battery is, it is as important to keep a good care of the battery. Maintenance of a battery is no longer a tough job as now they are good on their own and doesn’t need frequent user assistance in making the system work. However,…
Galvanic Skin Response
Human skin offers resistance to electric current just like a resistor do in electronic circuits. This transient change in the electrical conductivity of the skin followed by an arousal or oriented response is referred to as Galvanic skin response or GSR. In a fully relaxed person, the skin offers very high resistance and the skin’s…