Deterrent Light. Application Circuit 1


deterrent-light-circuit
Install this Deterrent Light in 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

Laptop Battery Power supply. Start Up Project 38


12ADon’t throw away old Laptop 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

Peltier Joule Thief. Start Up Project 37


13AYou know, we can light a 1 watt LED without a battery! Peltier will 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

USB Wall Socket. Start Up Project 34


15AI have many devices using USB Port for 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

Car Jump Starter. Start Up Project 31


9AImagine 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

Flame Sensor. Start Up Project 30


8AWhy 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

Servicing a Maintenance Free Battery. Start Up Project 29


6BI 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 volt 7 Ah (Ampere hour) Maintenance free Sealed LeadAcid battery (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.

Continue reading