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 →