In this I will show you how to make a solar rechargeable automatic led night light. I made mine for outside use but hey you could do whatever with yours! :)
How did this idea come about? first I have been meaning to get some sort of light fixture in our back yard, I was going to install an outside light but that fell short once I saw the ratherr poor wiring in the garage. Now the light I wanted shouldnt be so bright but just enough light to see the table and surroundings so I decided to use leds, so I finaly came up with this product. Its a 2l bottle turned into a table light. but its more than that, Its solar rechargeable, and turns on by its own at night. I used a 3.7v lithium ion battery and a charge controller to properly charge the battery, an npn and a LDR circuit. now if you are not familiar with these types of batteries and how dangerous they can be then I recommend using normal batteries such as 4 double As, rechargeable of course. If you charge lithium ions inproperly it could end bad. That being said, do this at your own risk.
before starting give the video a watch :)
it lights at night and charges in the day time
Step 1: Things Needed.
npn switching transistor (2n3904)
5 white leds
5 volt power supply (needs to be rechargeable ((4xAA batteries should work just fine)) )
If you change the value of the resistor you can alter the sensitivity of the on/off action. dont change the value by alot because you could fry the npn.
Step 2: Schematics.
take a look at the schematics, try to bread board everything first to get a feel of the position of the componets. bread boarding is widely recommended.It helps pin point potential issues.
the first picture is the npn/ldr circuit. If you feel your leds are too bright or even slightly blue you can add an optional resistor where I pointed it out in the picture. A ten ohm should do the trick.
The second picture is the battery charger using a solar panel. pretty easy stuff.
Step 3: Moving It to the Bottle Part 1
first cut a slit in the bottle and fill it with rocks, it adds weight to the bottle so it wont be easily blown off any surface, also if adds an out door look. (CAMPING)
Step 4: Moving to the Bottle Part 2
now move all the componets to the pop bottle. Place the leds at the mouth of the bottle facing in, mount the LDR on the cap, solar panel on the top at a small angle and the battery source whereever seems fit.
The npn is hidden behind the panel. forgot to take a pic of it.
Step 5: Finished!
Enjoy the light you have created! :) leave me comments or questions. hope you enjoyed!