Joule Thief Nightlight




Introduction: Joule Thief Nightlight

About: Ever since i was little i've love fixing electronics or just taking them apart to see how they work. I prefer machines that have a purpose (move something, etc.). Currently i'm saving up for a Printrbot Simp...

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Step 1: Intro

Hey, instructable users! You ever needed a flashlight to get around your messy room at night? Or a nightlight for your girlfriend that's still afraid of the dark?-_- Well let me tell you, i've got just the thing for you! It's a joule thief circuit packed inside of a Tic-Tac bottle! All it uses is a single AA battery, and can last for hours on end! If you're still reading this, you must be interested, so lets get started and i'll show you how to put this together yourself!

Step 2: Parts List

1- AA battery
1- battery holder
1- switch( slider or pushbutton)
1- capacitor (optional- I added this capacitor just incase of any spurts of electricity(highly unlikely))
1- 2N2222 Transistor
1- Toroid Transformer
1 to 6 LED's or 1- high brightness LED
1- 820 ohm resistor (Gray- Red- Brown)
1- TicTac Bottle
1- PCB

Soldering iron
Hot glue glun
X-acto knife or razor blade helps with small cuts
Continuity tester(comes in handy!)
Wire snips

Step 3: Schematic

So I found this schematic on another instructable(if you're the one with this schematic, I'm very sorry, i cant remember who's it was so I can't reference you). Anyways, this is a very simple setup. It only includes the necessities, which makes it very handy on our part!

Step 4: Prototyping

I, myself, learn much better from pictures so I took lots of them for this step! So start off with the transistor(no particular reason), i have heard of people using the 2N3904? And other transistors but I kept hearing that the 2N2222 has 30% more efficiency than others, but don't take my word for it! Now after I got the transistor set up, next I placed one end of the resistor in the socket parallel to the middle pin(2nd) of the transistor and the other in another blank slot. After that I added my switch off to the side. Now here's the toroid, I found it in an old DVD player, I think.... So notice the two different wires(if you can tell from the picture) one is yellow and the other is a smooth light brown color. The left and right sides of the toroid each have its own two ends of the wire. Take the yellow wire from the right side and the brown wire from the left side and twist them together, these two wires will be added to the positive end on the proto board. Next, take the loose yellow wire and put it in the slot parallel to the right pin(3rd) of the transistor. The other loose brown wire goes to the other end of the resistor. Now, take a wire and put one end in the left pin(1st) of the transistor and the other end in a blank slot on the board. Take another wire and put one end in the parallel port of the right pin(3rd) of the transistor and the other end in the slot next to the first blank wire. Now another will go to the left pin(1st) but let the other end just hang because that will go to the negative side of the battery. Then another wite to one side of the switch and the other end is left alone because it connects to the positive side of the battery. Now the last wire goes to the other side of the switch and the other end of the wire goes to the two twisted wires from the toroid. Now put the LED in its correct slot according to those two wires you plugged in to the board off to the side. Last step, attach your battery pack(just for demonstration) to the wires designated for the battery and press the switch, your light should light up!

Step 5: Playing With the Prototype

Step 6: Setup

So i forgot to take a few pictures, but its fine, you get the idea from the pictures that i did take! I started by putting the cap of the bottle on my pcb and then tracing it with a sharpie. Then i cut it out with my snips(heavy duty electricians scissors) and trimmed down to size and test fit until I got it right. Then i took some battery contacts( from the battery compartment in an old r/c car) and cut them in half and soldered them in place and tested the fit with my AA battery. Now on to the switch, I decided a slider switch would be easiest to use and cut a hole in the top with my knife. I originally had plans to use the push switch from the prototype so that it would turn on when lid was closed and off when lid was opened, but the TicTac bottle had other plans for me.

Step 7: Skip Ahead...

So follow the prototype design and the schematic(depending on how you want yours to look or how many leds you used, yours will look different so thats why I skipped those pictures and setup). I have my board setup and functioning, i used a different toroid because the smaller one from the prototype, i'm going to use in another project in a flashlight. I showed you fro the picture, how to place the switch, then I glued it into place and the door shut since i wasnt going to use it anymore. And lastly, i glued the board into place.

Step 8: Finishing Touches!

Just to spread the light evenly and give the light a little direction( like a flashlight instead of a lantern) I glued a small piece of foil inside the body, which you can see in the pictures. Now all there is to do is to close it up and turn it on!

Step 9: Closing

Thankyou for taking the time to look at my first instructable! Thankyou again, and don't forget to vote!:)

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    10 Discussions


    9 months ago

    Here is my version, has a ultrasonic sensor to turn the light on, and a timer to turn the LED off after a set time. Also, uses joule thief type circuit so that on single AA battery needed.


    Question 1 year ago

    I expected a night lite that would turn on at night?

    Dark Bottle
    Dark Bottle

    5 years ago on Introduction

    hey what's the toroid transformer for? I'm new to electronics: curious


    Reply 1 year ago

    It's for amplifying the power to the LED.


    Question 1 year ago

    Where did you get the solderable breadboard?


    5 years ago

    @Dark Bottle, The toroid resonates when electricity is sent through it, and amps the current instead of the voltage so you're able to power an led or other small electronic.


    5 years ago

    though this is very common circuit..nice explanation and good pictures