Emergency Light

The first post that I wanted to make was the Emergency light, it is an important creation for me cause this was my first ever board that I designed completely by myself.This might be of use to everyone due to the frequent power cuts these days.

The list of Components and their ratings:

1. Diodes : 1N4007 -  6 nos
2. Capacitors : 470uF, 16V -1 nos
3. Regulator : MC7805- 1nos
4. Battery : 4V, 4.5Ah - 1nos
5. Relay : 5V DC, single pole, I used Hongfa relay  1nos
6. Resistors: 1kohm,1/2W  2nos
7. LED's: Green , Red - 5mm
8. Transformer: 0-6V, 500mA secondary
9. 2 Pin male and female connectors: 4nos
10. White LED: half cut , 5V  - Quantity can be as per required..I used about 40 of them in mine.
11. Mechanical casing to fit in all the components firmly.

I have used acrylic box to fit the PCB, the red light when the power is not there can be seen in the above image.

The operation of the circuit is very simple. The diodes convert the input AC voltages to DC , the capacitors remove and regulate the ripple, the regulator takes care of the voltage step down in case of surges.The regulator is connected to the battery such that it only gives power to the battery.The relay inputs the ac power and keeps itself on whenever there is power.In case of power loss, the relay deactivates itself letting the battery power the led's. 

The PCB layout for my design has been attached to this post.

Emergency light by Dheeraj Sonnenahalli

Upgrades :

Changes in battery can be made , if in case higher voltage battery is used then connection of led's in series would help.Also dont forget to replace the voltage regulator [7805] with the battery rated one (remember to use the regulator about 2V higher voltage rated than in battery) and also the transformer with rated voltage and current.