Picture of UV Glass Hanging Nightlight/Whiteboard ( From Mobile Charger )
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Today i Bought some Ultraviolet lights and i wanted to make something attractive. So i made another glass hanging nightlight! (I am still a beginner so sorry for the glass joint to wire)
My first Nightlight (with brightness control) :-

Step 1: List Of Parts

Picture of List Of Parts
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Parts Needed :-
(1) Ultraviolet(UV) Led
(2) USB Charger
(3) 100 Ohms
(4) Plastic Small Container
(5) Highter (Optional)
(6) Some Wires

That's all! :P
rajath1 year ago

Hi there! Awesome project. I am doing a similar project with LEDs.

I don't know much about electronics (Mechanical Engg) so please bear with me. Last week I went to the electronics market and some guy there told me to use a 47k ohm resistor in series with one LED and hook it up to a 220V AC supply (from the wall). I did that and it works!!! But unfortunately it works only for 3 LEDs max (in series).

Now I want to use the AC power supply to light up about 40 LEDs and I don't want to use a transformer. Can you give me a minimalist circuit diagram and if possible parts list to get this done.

Please can you tell me what values of resistors I am supposed to use so that I can light up all the 40 LEDs brightly.

Thank you for your instructable and thanks in advance for all replies

Ayush Sharma (author)  rajath1 year ago
Tell me the colour of led which you are using?...because different colors have different voltage.

First of all thanks for the very quick reply.

1.) Red LED (2V and 30mA I guess) in series on one circuit.

2.) Blue LED (4.5V and 30mA I guess) on another circuit.

40 LEDs of each. i.e. 40 red and 40 blue.

Ayush Sharma (author)  rajath1 year ago
Hi Bro,
For Red Leds :- Try a 6.6 kilo Ohms resistor( hight brightness or 6.8 kilo resistor (low brightness) and they should be of 3.5/4 Watt rating. And it gets extremly hot while dropping the voltage.so you should add a heatsink stick to resistor. This is for 40 red leds connected in series
( Donot use anyother value lower than these Valuses, burn the leds)

(Less brightness - Longer life of leds
High Brightness - Less Life
It's now upon you choose high or low)
For Blue Leds :- Try a 4k Ohms resistor ( high brightness) or 4.7k Ohms (.And same they should be 3.5/4 Watt rating resistor and added with good heatsink.
Good Luck for your Project..

But transformer is the best choice for me.... ( Not Much Heat and No Heatsink :D)
Donot forget rectifier diode at end (1N 4007)
I Hope there are no problems.. But if incase you got any problem.Reply/message me :)

Thanks Killerwhale!! Exactly what I needed..

And I can hook this up to the wall directly right?

And IF POSSIBLE, keyword "IF". Can u upload a two rough handwritten circuit diagrams for it? One with transformer and other for the what u have mentioned.

Ayush Sharma (author)  rajath1 year ago
First of all "yeah" you can hook it directly to Wall
And i will draw the diagrams tomorrow. :)

Sure no prob.. Thanks a LOT!! I mean it

Ayush Sharma (author)  rajath1 year ago
Hey bro! Here are your diagrams...

Hope you mention my name if you are making a instructable of this :)

Sure bro!! I'd HAVE to put your name and I will! Thanks a lot again!

Ayush Sharma (author)  rajath1 year ago
I have sent you a Private message. Please see it :P

Very cool! I like that you can use it as a whiteboard too!

Thanks :)