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…
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…
Clock Controlled Relay
You can switch on a load such as Water pump automatically at the required time through this Clock Controlled Relay. It uses an ordinary clock to trigger the circuit to switch on the load. The load remains on till it is switched off manually. The triggering signal is obtained from the DC voltage that…
High Bright LED Emergency Lamp
Emergency Lamps is one of those circuits which are fairly commercialized and are also popular in the DIY section. Keeping aside the feature of finished product and simple use, DIY circuits provide flexibility measures to circuit designing. DIY LED Circuit A typical…
String LED
String LEDs are now very popular as decorative lights which are available in different colors at very low cost. It gives very brilliant colour display sequencing in four channels. The blinking pattern is controlled by a programmed chip and the switching is achieved by a high volt SCR .String LEDs show automatic Multi pattern changing…
Web Feeds
Web feed is the data format providing frequently updated contents to the users. The content distributors syndicate a web feed to allow the users to subscribe the contents. Web feed is also known as the Syndicate feed or News feed. To access a collection of web feeds, Aggregation is used so that the user can…
PWM Inverter
PWM or Pulse Width Modulation is the technology to generate a steady output voltage from inverters. When compared to the conventional Semi Sine wave and Pure sine wave inverters, PWM Inverter offers superior quality. PWM Inverters use MOSFET technology at the output stage, so that any type of loads can be connected to the inverter.…
Voice Recorder and Playback Circuit
With this circuit, you can record your voice and play back the same for 20 seconds. The voice recorder circuit is ideal for door phones, automatic answering devices etc. APR 9301 is used in the circuit which is a data storage and retrieval IC without any micro controller programming. The IC requires minimum components…
Simple Door Alarm
You can use this Simple Alarm to protect the door or Window. It gives a loud beep and switch on the room light when an intruder/burglar attempts to breaks the door lock. The alarm functions only after 5 minutes to confuse the intruder. Working of this burglar alarm circuit is simple. IC1 is used…
Diode Pump
Diode Pump is a rectifier circuit that makes a varying AC signal output to a DC voltage relative to the peak-to-peak voltage across the AC waveform. Diode pump can be used to switch on a driver transistor or to give in digital or analog circuits for DC measurements. The design note given here explains the…
Bluetooth Technology
The Bluetooth technology offers wireless access to LANs, PSTN, Mobile network and portable handheld devices. The Bluetooth enabled devices communicate wirelessly through short range network called”Piconets”. The Piconets establish connection with the Bluetooth automatically as the Bluetooth device enters the proximity of the radio communication. The technology of Bluetooth was named after Harald Blaatand Bluetooth…
Heat Sensor using Thermister
This is the circuit of a Heat sensor that beeps when it detects heat. It is an ideal add on circuit in heat generating devices like Inverter and Amplifier. Thermister is a special kind of resistor and its resistance depends on the temperature in its vicinity, Depending on its working, thermistors are divided into two types:…
Cell Phone Spying
Mobile phone Spywares were introduced as a measure of Parental control and for tracking purpose to locate the mobile phone in emergency situations. These are mainly used for child safety to watch the online activities of children and to prevent Sexting (Sending or receiving sexually explicit messages).But now the Cell phone spywares are becoming 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…
Ultra Wide Band Technology
Ultra wide band is a carrier free base band technology used in wireless communications especially in Radar applications. It can provide high data transfer in multi-user network. The technology uses the carrier free band without RF carrier to prevent signal interferences. The technology is highly reliable since it has very high resolution within centimeters. It…
Trick to Save a Battery Life
Save your spare batteries from self discharge due to improper charge- discharge cycles. If you forget to charge the sealed lead acid battery for long period, it will not accept full charge during charging and its performance deteriorates. A solar panel can solve the problem and since it charges only during day time, over charging…