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 →
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 →
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 →
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 →
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 →
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 →
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 →
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.Continue reading →
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 →
This is an excellent DC- DC Converter Module that can adjust the output voltage to any desired value, even fractions from 0 V to 17 V. It is a very good Variable Power supply Module. But pressing the switch we can adjust the output voltage. It can handle a Peak current of 3 Amps. The output voltage and current are displayed in an LCD Screen that has back light. If the input voltage is from a Battery, the LCD display shows the Battery Level also. Input voltage can be between 5V and 23 V but the best voltage is 20 V. It has 95% conversion efficiency and 1% LCD accuracy. It is available with a transparent casing. You can fix it in the case provided along with the Module.It can be connected to the Bread board so that we can determine the current consumed by the project. Its cost is just Rs.350. Continue reading →
Here is a simple tester to test the IR Sensor TSOP 1738. It is a highly sensitive device that damage easily if its input voltage rises above 5V. This Tester can be used to test TSOP 1738 before using in a circuit. It confirms the condition of the Sensor, whether it is functioning properly or not. It can also be used to check the IR Sensors kept in your junk box so that you can keep only the good one for use.
We make Infrared Transmitter circuits to generate Pulsed Infrared rays to use with IR Sensor based receivers. The IR Transmitter circuit based on IC 555 generates IR rays pulsating in the frequency typically at 38KHz. The IR Sensor used in the receiver is TSOP 1738 which also works in the same frequency. So here is a simple IR Transmitter Tester to check whether the IR Transmitter is emitting 38 KHz frequency or not. Continue reading →
We construct different types of Infrared Receiver LED ( Rx) or IR Sensor ( TSOP 1738 ) based circuits. To test, the working of the circuit we have to use an IR Transmitter. Usually we use IC 555 based IR transmitter for this. But the frequency of the IR from the Transmitter should match with that of the Sensor, otherwise the circuit will not respond. Here is a simple solution to test the IR based circuits. Simply Hack a Mini Remote obtained along with low cost FM radio,Toys etc. You have such Remotes in your Junk box. Let us Hack one such Remote to make a Tester. Continue reading →
IR Rays are invisible to human eye, so it is very difficult to check the working of IR LED. Usually we use a Mobile camera to test IR LED since the pink light from the IR LED becomes visible in digital camera. We can make a simple IR LED tester so that, before using it in the project, we can confirm whether it is good or not. Lot of IR LEDs are also in our Junk box. So we can check all IR LEDs and discard the damaged ones. The same tester can be used to check all ordinary LEDs, Photo diodes, Silicon and Germanium diodes etc.
Install this Deterrent Lightin your Home backyard and Porch to thwart the attempt of Burglary. This PIR Motion Sensor based light switches on instantly when it detects a Human movement from a distance of ten meters. The light turns on for 3 minutes and then turns off. It Re triggers again if the movement continues. Relay is used to drive the load, so any kind of lights can be used. Continue reading →
So many types of Car USB chargers are available which step down the 12 volt DC from the Car battery to 5V DC for charging devices like Mobile phone, Tablets, MP3 player etc. These are usually connected to the Lighter socket to get 12V. The low cost chargers do not have a circuit inside but simply providing 12V DC directly. Only a fuse is present in it. This is dangerous because, the Car battery is a high current one which can damage the gadgets. Here is a simple solution for this. We can make a Voltage and Current regulated Car Charger using the IC MC 34063. It is a Step down DC – DC Converter IC with many features. The output from the circuit will be 5 V at 500 mA.
Most of the low cost LED Emergency lamps do not have LED indicators to show charging and load on conditions. This simple circuit solves the problem. It can be hooked in the Emergency lamp. A Green LED lights when the charging is going on and turns off when the charger is disconnected or power fails. It gives a good indication that current is flowing to the battery. A Red LED lights when the load turns on. It also indicates that charging process stopped. Continue reading →
Don’t throw away oldLaptop battery; it can be reused for other purposes. I hacked one Laptop battery and salvaged six high efficient Samsung Lithium Ion batteries each rated 3.6V, 4300 mAh. It is worth Rs. 1000. Few days before, I found that, my Laptop is not getting enough back up and shutdown immediately when the charger is removed. So I replaced the battery at the cost of Rs.1200. Due to curiosity, I just opened the case of the old battery pack and found that, the batteries inside can be reused. After testing, I found that only one battery out of the six is damaged. All the other five are in good condition. That damaged battery created the problem in the battery pack and prevented the remaining five batteries from their work. So actually this is happening in our Laptop. If one battery fails, we have to replace the battery pack. If the good batteries are salvaged from the old pack, we can reuse them for many different applications like LED lighting, Mobile charging, making power supply etc. So I spend Rs.1200 for the new battery pack but I salvaged 5 good batteries worth Rs. 1000 from the old battery pack. So my actual expense is only Rs.200. So do not discard the old Laptop battery. Tear it, salvage the individual batteries and reuse. You can save money and can reduce the e-waste. Continue reading →
You know, we can light a 1 watt LED without a battery! Peltierwill give “Free Electricity” for that. When we heat the Peltier with flame, hot water or a hot object, it starts to generate current. Its voltage can be around 1.5V when the heat is above 60 degree. But this 1.5V is not sufficient to light even an ordinary LED that requires 1.8V minimum. 1 watt White LED requires 3.6V. Then how? We can add a Joule Thief circuit for that. A Joule Thief circuit is a self oscillating circuit that increases the input voltage as low as 700 mV to 4-5V. So if the Peltier is connected to a Joule Thief and heated, Joule thief will amplify the voltage to light the 1 watt LED. Let us check this. Continue reading →
Peltier is the Fantastic device used to make cooling devices. When a current of more than 500 mA passes through the Peltier, its one side cools while the other side turns hot. This is due to the transfer of heat from one side of the Peltier semiconductor to the other. As the current increases above 1 Amps , the cooling effect increases and the temperature of the cold side of Peltier drops below 0 degree. But if we reverse the function of Peltier, it generates electricity. For example, if we heat one side of Peltier above 60 degree using a hot object, hot water or flame, Peltier generates around 1.6V DC and around 350mA current. Let us make one circuit of “Free energy “generation using a Peltier Module. Since the 1.5V from the Peltier is not sufficient for lighting an LED, we have to add a voltage booster to increase the Peltier voltage sufficient to light the LED. If 5 Peltier are serially connected, we can even charge our Mobile phone using a Candle flame.
Keep this Match box size Mobile Scannerin your pocket. It will Scan around you and beeps loudly when a Mobile phone turns active in your vicinity. It can detect the activation of Mobile phone around 2Meters radius. It beeps during incoming call, outgoing call and when somebody tries to take your Photo. It is an ideal device to detect Mobile phone use in examinations halls, confidential rooms, hospitals etc where Mobile phone is strictly prohibited. Its range can be from 50 cm to 3 meters depending on the type of the active Mobile phone. With Smart phones, its range is less than 1 meter because there is a mechanism in it to prevent excess radiation. But in ordinary Mobile phones, its range can be up to three meters. Try this nice weekend project. Continue reading →
I have many devices using USB Portfor charging. For this, I purchased one USB Hub to connect 4 devices at a time. But the result was disappointing . The devices are not charging and even a Pen drive is not opening in the Hub. Analyzed the reason and found that the USB port of Laptop is not giving sufficient current to the devices for charging. The USB.2.0 Port can give maximum 200 mA current and USB.3.0 can give maximum 400 mA current. Then how all these 4 devices in the Hub charge normally. The 200 mA current from the Laptop port is sharing to all devices, so no one is charging. Moreover, the Laptop gave a warning that, “USB Port over loaded and shutting down”. Remembered that famous saying “Every problem born with its own solution”. Got the remedy. If the current to the USB Hub is increased, all devices will charge normally. But in that case, Laptop is not useful and I have to make a separate power supply. So made a USB Wall socket. It has an AC socket for charging Laptop, and a 5V, 1 Amps SMPS power supply to power the USB hub. Thus the problem solved. The USB Wall socket is fixed on the wall and powered from Mains. SMPS has well AC-DC isolation, so no shock hazard while charging the USB devices. I found the same type of USB Wall socket in the Online shop but its cost is Rs.2500. I made it at the cost of Rs.250. Let us check it. Continue reading →
While constructing circuits on Bread board, sometimes we need a well regulated power supply. For this, we use Voltage Regulator IC. But, its needs some components and take some space in the bread board. For an easy project making, we can make a Permanent Regulated power supply board that can be hooked in the bread board. The power supply board has a 3 pin socket, so any Voltage regulator of the 78XX series can be connected in it. The power supply board has noise and transient filtering capacitors, a buffer capacitor and input and output indicators. So by plugging the power supply board in the bread board, we save time and save much space in the bread board for the circuit assembly. Easy project building makes the circuit perfect. Continue reading →
How can we confirm the voltage level from the Solar panel ? A 12 Volt Solar panel generates around 20 V DC Open circuit voltage in bright sunlight. The voltage gradually increases from 6 am and peaks in the mid noon between 11 am and 3 pm. Then the voltage from the Solar panel drops to zero around 6 p.m. So we get sufficient voltage for charging the battery for 4-5 hours only in a day. The 12 V battery requires more than 14 V for proper charging. Its current should be above 500 mA. The current rating of the Solar panel is represented in terms of Watts. As a general rule, for each watt, the current will be 80 mA. So a 10 watt Solar panel gives 800 mA current. This depends on the availability of sufficient voltage from the Solar panel. Many factors like corrosion of contacts, loose contacts in connections, dust on the panel etc will affect the current flow from the panel. So how can we monitor the voltage level from the Solar panel. A volt meter can do but we can make a simple LED Meter for this. Its cost is less than Rs.80. It has three LEDs. The Green LED lights, if the voltage from the Solar panel is above13 V. Yellow LED lights if the voltage is between 9V and 11 V and Red LED lights, if the voltage is below9V. Remember, the Solar panel is efficient only when the Green LED lights between 11 am and 3 pm. Continue reading →
Imagine a situation. We are going for a night drive and stopped the car in a place for some purpose. Then we see that the car is not starting because the battery is flat. It is a totally confusing situation. We will be trapped if this happens in an isolated place. The only way is to leave the car there or wait till morning to purchase a new battery. Don’t worry. Keep a ‘Jump Starter’ always in the car. It will start the car in 5 minutes. Many Jump starters are available in the market but the cost is too high. We can easily make a Jump Starter using a UPS battery. How the Jump starter starts a car if its battery is flat? Actually, the Jump starter has a 12 volt battery inside. When we connect this new 12V battery across the flat car battery, the new battery shares its current to the flat battery. After 5-10 minutes, the terminal voltage of the flat car battery increases to 12.6 volts. It is sufficient to start the car. Jump starter is the improvisation of the conventional technique of connecting the flat battery of one car across the battery of another car using battery clips and wires .That is why the technique is called as “Jumper starting” or simply “Jump starting”. Now light weight Power bank type Jump starters are available with 10,000 to 15000 mAh Lithium Ion battery. These have provisions like Mobile charger, LED light, Distress signal light etc. But the cost is very high around Rs.6000- 10,000. Let us make one Jump Starter with the same provisions like Mobile charger and LED light. The Jump starter can be charged from the Lighter socket of the Car. Its cost is less than Rs.800. Continue reading →
Why going for a costly Fire Alarm system? Some of the Fire alarm systems cost more than Rs.2000. You can make an efficient Fire warning system for just Rs.20. It uses only a few components and is a very efficient Flame sensor. The Thermister based commercial Flame sensors have a drawback because, the alarm sounds only when the Thermister turns hot by the nearby flame. That means, the alarm sounds only after the room is full of fire. But this tiny circuit overrides that drawback. It uses a Photodiode as Fire sensor. It sounds the alarm even if the flame is far away . Interestingly, the spark of the first fire burst can activates the alarm. It can be installed in Home, Commercial shops etc. It will not activate in the ambient light of the room like that of Fluorescent light. It sounds the alarm only when it detects a light similar to a flame, sunlight or incandescent bulb. It is battery operated and in the standby state the current consumption is as low as 5 mA. So Simple, Efficient, and Low cost. Build it. Continue reading →
I found that my UPS is not giving sufficient back up as expected for 20 minutes. I thought that I have to spend Rs. 800 to replace the battery. But I was not in a hurry. Want to find out the reason. After 5 minutes, the PC shutdowns. Why so? The UPS battery is not giving sufficient power (Ampere Hour) to run the load. The UPS battery is a 12 volt7 Ah (Ampere hour) Maintenance free Sealed Lead – Acidbattery (SLA). That means, it is “Maintenance free” and can be used for long time without any attention. But what happens is, the cells dry out due to heat generation. This happens after 6 months to 1 year of use . It is a Lead Acid battery that requires Electrolyte in the cells. So water is necessary inside. It has 6 individual cells giving 2V each. After removing the battery from the UPS, I found that it is very easy to rejuvenate the battery through “Hydration”. The battery will become top, if the dry cells are filled with battery water. Hydrated the battery and charged. Well, now it is giving more than 15 minutes back up. Saved Rs. 800 and reduced an e-waste. You can also rejuvenate the 6V Emergency lamp battery like this. So do it yourself. It is only a 10 minutes job.
One Damaged Mosquito Swatterwas in my home with full of dust. So, decided to salvage its parts to reuse for other purposes. Just to avoid e –waste and to do some kind of Recycling. Well, it has a good 2.4VRechargeable Battery and a circuit board. The problem is in its circuit board that generates highvolt AC to burn the Mosquito. But the charger is still working. So decided to use the charger part to make a High power Rechargeable LED Flash light. The Mosquito Swatter generates a high voltage between 400- 1000 volts from the 2.4 V battery. For this, there is an oscillator circuit and an Inverter transformer. The Inverter transformer converts the 2.4 V DC from the battery to around 200V AC. The oscillator circuit makes the AC waveform. The 200 V AC thus produced is then boosted by a Voltage Multiplier comprising some high volt capacitors and diodes. This boosted AC appears in a High volt Capacitor which then passes it to the Nets of the Swatter. The middle net of the Swatter is Positive while the outside nets are Negative. When we press the switch, the High volt capacitor discharges high volt AC to the nets. When the Mosquito passes through the net, it explodes due to high voltage. Even though the AC voltage is very high around 1KV, Current is negligible. Let us see how that Swatter turned into a Rechargeable Flash light. Continue reading →
Wow! We can make a cup of cold water in 5 minutes without a Fridge. You need only a Peltier Element, a 12 volt high current battery and a Computer cooling fan. Peltier element is a semiconductor plate like device with Cold and Hot sides. When we provide 12 -18V, 1 amps power to it, one side of the Peltier suddenly cools and the other side turns hot. The cool side temperature goes down below 0 degree and the hot side becomes around 100 degree. So to transfer that much heat, the Peltier should be placed over a large Heat sink. A Computer cooling fan with heat sink is the best choice. Fan will remove the heat from the Peltier and heat sink. At the same time, the cold side turns too cool in minutes. Without a heat sink, the Peltier will be damaged. If we reverse the Polarity (+ and –) of the power supply to Peltier, the sides reverses. That means, cool side becomes hot side and vice versa. Let us make one Peltier Fridge to get some cold water. Later we can change it as a heater to drink hot water. Peltier costs around Rs.200. Continue reading →
Thwart the attempt of a Bag snatching during journey. Keep this Tiny Alarm in your bag and it will beep loudly when somebody attempts to snatch your bag. It can protect your Laptop bag, Mobile pouch, Luggage etc during the journey. It is essentially a “Vibration Alarm” using ultra sensitive Vibration sensor SW 18020 P. So even a mild shake can activate the alarm. Build it and its cost is just Rs.50. Continue reading →
You can make a beautiful Rainbow display to decorate your show case to give a “Visual Treat “to the visitors. It emits all the colours of the Rainbow (VIBGYOR) one by one and finally flashes rapidly. This is a kind of simple “Mood Lamp” to elevate the mind of viewers. You can fix it in an empty Jam pot so that it appears like a “Rainbow pillar”. A Multi colour Flashing LED and Glue stick can do this Magic. Multicolour LED has three chips to generate Red, Blue and Green (RBG LED) lights. Due to the fast transition of colours from one to another, the colour mixes and gives the Rainbow display. The Gluestick commonly used with the Glue gun transmits this light to its entire length giving a good visual effect. So try it, you need only Rs.25 for this. Continue reading →
We see lot of LED Panel Lights flooding cool light in commercial buildings, offices, banks etc. I love LED Panel lights because these are high efficient and economic lights. They also not cause any eye strain. Unlike LED Bulbs, the efficiency of LED panel lights is very high and gives the Lumen, K and Power as per the specifications provided because of the use of LED Driver with constant current output .The use of LED driver increases efficiency because the input AC fluctuations will not reflects in the output. So the LED Driver gives constant voltage and current for the LEDs inside the Panel. The result is uniform light throughout the life period of the Lamp as high as 1 lack hours. The only problem in the LED Panel lights is that the Driver may fail if there is a high voltage surge in AC lines that may occur during unexpected lightning or other reasons. But we can easily replace the Driver because it is externally connected. The cost of the Driver is between Rs.50 and Rs.100. Let us analyse one LED Panel light to see its interior and efficiency. Continue reading →
One of my LED Bulbsshowed some unusual behaviour during the Peak hours. Unusual dimming, flickering, lighting faintly after switch off etc. It is a 15 watts LED bulb purchased for Rs.300. Checked its specifications. It is 980 Lm and 6500 K . That showed that there is something related to Watts, Lm and the K. The manufactures say that, instead of Watts, look the Lm before purchasing the LED bulb because “Watts” is an obsolete term for the LED bulb. Then what are the Lm and K? Lm is the short form of “Lumen” which is the measure of total amount of light from a source. As a general rule, a 100 watts ordinary bulb gives 1500lumen light. K is the short form of “Kelvin” which is the measure of “Colour Temperature “of light. For example, the day light has 5000K and a White LED Bulb gives around 6000 K . As the Colour temperature value increases, the light turns more and more white then turns to blue. Lower values of K shows Yellow to Red light. So as per the specification, the LED bulb should give 980 Lumens and 6500 K light. Ideal its specifications. Then what is happening in it. Analysed thoroughly. Continue reading →
LED Driversare used to drive High Power LEDs that require more than 100 mA current. A typical 1 watt LED consumes around 100-300 mA current while a 10 watt LED consumes 600 mA to 1 Amps current. So a resistor to drop the current is not sufficient since it heats up when high current passes. Moreover, the high power LEDs require a Constant Current to give steady brightness. So LED Drivers are used for this purpose. A typical LED driver has two sections. An SMPS converts 220V AC to DC and a Constant Current Generator Circuit provides Constant current to LED. But LED Drivers are costly units and the cost range from Rs. 150- Rs.600. We can make a Low cost LED driver just for Rs.15. Try it. Continue reading →
You can carry this Portable bread board power supplyto do electronics work outdoor. Keep this in your bag along with some components so that you can enjoy the holidays with the fun of electronics. This Mini bread board is powered by a 3 volt Lithium cell. A DC-DC booster Module converts the 3V to 5.1V for the Bread board. You can also enjoy Music from MP3 player, or even charge your Mobile Phone from the Power supply. So make this three in one power supply. Its cost is Rs.150. Continue reading →
No wonder, technology is that much advanced. You can charge your Mobile phone from a single Pen cell or even from a watch battery. The Mobile battery needs 5V for charging and the Pen cell has only 1.5volt. How it is possible? There comes the help of DC-DC Booster Module with USB. It converts a voltage as low as 0.9V (900 mV) to 5.1 Volt. Its input voltage can be between 0.9V to 5V so it provides 5.1-5.2 V out put through the USB socket. So you can connect any USB device that requires 5V. Irrespective of the low input voltage, the output remains constant as 5.1V. The Module that works on 1.5V AA cell provides 200 mA current while two AA cells give 600 mA current. Let us build one Pocket Mobile charger. It is too small and costs only Rs.100 Continue reading →
Once I purchased a 10 watts LED Flood lightfor Rs. 450. The Ad was so attractive that it is capable of giving light similar to 40 watts Tube light with low current consumption. But the result was disappointing. So hacked it to see the power, current and voltage consumption. It is a 12Volt 10 WattsLED Flood light as mentioned in the pack. The result was very interesting. Nothing matches with theory, specification and real measurements. Generally, the 10 Watt White LED works on 12 V DC and requires 500 mA to 1 Amps current to get full brightness and Flood light effect. It has around 10VForward voltage. It is usually powered by a high current LED driver that delivers 500 mA to 1 Amps current. Here comes the reality. Many LED flood lights use low current LED drivers or Capacitor powersupply. LED Driver is a small SMPS with an output current rating. It must match with the current requirement of the LED. Cheap Capacitor power supply can give only 75 mA current per uF. So we purchase the lights by looking the specifications on the package and not realizing the actual condition of the light. To experiment with that Flood light, opened it to see what is happening inside.Secret revealed. Continue reading →