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Simple LED Emergency Lamp you can Build at Home

Updated on February 6, 2014

This is one evening project that any new electronic hobbyist can build at home using a few inexpensive components such as LEDs, relay and battery. Let's learn the whole procedure of making this simple automatic LED emergency lamp circuit.

Bill of Materials

You will require the following few components for making this useful emergency lamp circuit:

105/400V metalized capacitor - 1no.

100 ohm, 1 watt Resistor - 1no

1N4007 diode - 4nos.

1000uF/25V capacitor - 1no

12V relay, spdt, 400 ohm - 1no

general purpose PCB - 4 by 4 inches piece, 2 nos

mains cord 2-pin - 1no

White LEDs, 5mm, high bright type - 20 to 50 nos as per requirement

connecting wires, screws, solder wire, solder iron, suitable enclosure, snipper, etc.


The following procedure will comprehensively explain you regarding the making of the proposed automatic emergency light circuit at home

It's merely a matter of looking into the above diagram and connecting the parts as per the given connection details.

The 4 diodes are the first components which need to be inserted inside the procured general purpose PCB.

Next goes the resistor, and then follows the relay. All these should be soldered close to each other in such a manner that it facilitates the shown connections without much hassles or with minimum overlaps or jumpers.

Once the above components are fixed over the PCB, finally its time to solder the large 105/400V and the 1000uF capacitors which similarly must be arranged for facilitating easier interconnection as per the shown diagram.

As soon as you finish the above assembly and interconnections of the various components as per the instructions given in the diagram, the LEDs now needs to be fixed over another separate PCB.

Align them neatly such that the series connections become easier to implement. This again needs to be done as per the given instructions and layout of the diagram.

Once the LEDs are fixed, integrate the previously built control circuit output with the LED board.

Finally attach the rechargeable battery to the correct shown position.

After this you may connect the mains cord to the shown points and plug it in your house AC mains socket.

If everything is connected rightly you would find the relay clicking making sure that the LEDs are shut off.

Now switch of the mains power to the circuit, and you would find the relay once again restoring to its original position, however this time illuminating the connected LEDs with full brightness.

The above action would automatically trigger every time the mains power is disrupted ensuring an immediate emergency light illumination in your house, relieving you from the discomfort of having to look for candles or other inefficient lighting options.

The Enclosure

Once the above explained emergency lamp circuit is built you would want to enclose it inside a suitable box.

The best option is to look for a transparent acrylic box, which you could easily procure readymade from any local plastic fancy or kitchen ware shop.

Select a suitable box and enclose the entire assembly neatly inside, screw the circuit boards if possible with self-taping screws over the inner surface of the box.

Position the LED board such that it sticks snugly with the inner surface of the transparent cover of the box.

Also drill a suitable sized hole on the back of the box for terminating the mains wire out of the enclosure.

On the upper section of the same, carve out a keyhole so tat the box could be stuck on the wall over an existing nail.

That's it! Now You have your own homemade full fledged automatic emergency light unit that will never let you mess up in the darkness during blackouts or mains failures.


Be warned! The above discussed circuit design is not isolated from mains lethal AC, therefore be extremely careful while assembling or testing the circuit while power is plugged-in to the circuit.


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