Making an Automatic Emergency Lamp Using SMD LEDs

The following post explains a simple circuit diagram of an automatic emergency lamp using 36 nos. SMD LEDs. The circuit has been presented in response to the following request sent by Mr.Ali Adnan.

"Hi,

How r u Bro?? I Hope you are enjoying Good and Healthy life.
Bro I've 36 SMD LEDs(Side View Type), I Extracted them from my Broken Laptop's LED LCD screen. I tested them with multimeter and found all LEDs in working condition. 

Now I want to make some useful from them like an emergency LED lite. I'll remove all 36 LEDs from strip and mount them on a PCB (will be Tough JoB Mounting SMD's) once you will design a circuit for me to drive them. 

I don't know much about SMD LEDs so that's why I am bothering you. I googled for data sheet for that type of LEDs and I think I found right data sheet for this LED, please also compare the pictures of LEDs and data sheet. 

I am attaching actual pictures of LEDs that I have and also attaching data sheet, please check and help me with a simple circuit with simple parts. and just for information I've not found the IC ZXSC310 (that you used in your 1 watt LED circuit) here in Lahore Pakistan :( and I am too sad for this.

Waiting for your Reply.

Best Regards,

Ali Adnan Khan"

"Hi Bro,

What kind of emergency light do you want to make? Automatic AC/Dc operated or just direct on battery? 

The datasheet  and the pics are OK.

Best Regards,
Swagatam"

"Hi, thanks for your reply bro. Automatic AC/DC operated with battery backup."

OK, here's an automatic ac/dc emergency light circuit using the proposed 36 SMD LED lights which is easy to build, cheap and yet reliable.

CAUTION - THE CIRCUIT IS NOT ISOLATED FROM AC MAINS, UTMOST CARE MUST BE OBSERVED WHILE TESTING THIS CIRCUIT IN UNCOVERED POSITION.

ALTERNATIVELY YOU MAY INCORPORATE A 12V, 500MA DC ADAPTER ACROSS THE ZENER DIODE INSTEAD OF THE SHOWN TRANSFORMERLESS POWER SUPPLY FOR AVOIDING THE ABOVE CAUTION.

Parts List

All resistors are 1/4 watt, 5%,

R1 = 1M

R2 = 1K,

R3---R14 = 56 Ohms

C1 = 2uF/400V PP Capacitor

C2 = 100uF/ 25V

D1, D2 = 1N4007,

D3, D4 = 1N5402

T1 = TIP127

Z1 = 15V 1 watt zener diode

Battery = 12V/2AH

LEDs = SMD, 3V white, 20 mA

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