The Juicy Lemon Light Pod

This Instructable will show you how to make your own Juicy Lemon Light Pod!
It is based upon the idea of the classic 'Lemon Battery', only this one's just a bit more special!

The main features include:
> 3x Refillable Juice containers
> Use of the Joule Thief Circuit
> LED Extension / Flexible arm
> Recycled Aluminium Cans

/// Add some juice to each container and let there be light! ///

How does it work?
When two different metals come into contact with citric acid, an electrochemical reaction occurs. This reaction generates a small potential difference or voltage. In this project, the copper coin is acting as the positive electrode and the aluminium can becomes the electron-producing negative electrode or anode. When constructing a traditional lemon battery, you can connect multiple lemons or cells in series for more energy. The one problem I've seen with directly wiring electrodes into a lemon is that after a while the lemon dries up and becomes discoloured. This inspired me to design an object with 'pods' made from aluminium cans which you could use, empty and refill.

What is this 'Joule Thief'?
For those who haven't heard of this before, the Joule Thief is a self-oscillating voltage booster circuit. The circuit is actually quite simple to make, the few components are affordable and readily available. Basically, this little circuit is going boost the energy obtained from the reaction of citric acid with the different metals into something useful to power for example a light emitting diode.

Step 1: Tools & Components

Here's what you're gonna need...

Tools & Preparation
> Soldering Iron (+ Solder)
> Power Drill (+5mm bit)
> Glue Gun
> Wire Cutters
> Scissors
> Junior Hacksaw
> Metal Polish
> Adhesive Insulation Tape
> Voltmeter
> Marker Pen

Materials & Components
> A fresh lemon!
> 4x Aluminium Cans
> PVC tubing (5mm dia.)
> Thin wire (2mm dia.)
> 3x Copper Coins / Copper Sheet

For the Joule Thief Circuit
> Standard Ferrite Toroid Core (+thin, enamelled wire)
> 1k Resistor (Brown-Black-Red)
> Optional 10uF Electrolytic Capacitor
> NPN Transistor (2N3904)
> 5mm White LED

Now that we've got everything, let's get going >>>

Comments

[Tron man]

Is the Joule Thief necessary to the whole project?

[Alexdlp]

The Joule Thief circuit is used to provide enough voltage for the LED. You may find that your LED doesn't work properly without it.

[Tron man]

Can you do the project without the plastic tubes?

[Alexdlp]

Yes, they are only used to add support and protect the thin wires.

[P0rt4L TOO]

But the real question is, Are the lemons combustable?

[tech458]

this is epic

[jexter]

Nice fun project, and well written and illustrated! My only constructive criticism, and it's a minor point considering how clear your written instructions are, is that you could put more notes on the images to identify what the image is meant to show. (This would be even more helpful for your very cool wireless bike computer instructable!)

Nice job!

[telharmonium]

Have you tried using coke? Softdrinks are pretty acidic too.

[jdougherty2]

I'm curious if you can use lemon juice purchased from the store instead of fresh lemons. Is it just the citric acid in the juice that makes this work, or is there something in the rind that helps, too?

[Alexdlp]

As far as i'm aware, it's just the citric acid reacting with the different metals.. I actually tried lemon juice from the store before to see how it compared to fresh lemons. To be honest there wasn't much of a noticeable difference in light intensity or anything though (:

[ernestocfernandez]

that first image is very cool!!! it kinda looks like the flux capasitor (BttF) LOL!!!

[Alexdlp]

Update 19th April:
>> It's been about 3 days now since I last added any lemon juice to the "flux capacitor" lol... but hey, the LED is still going strong!! :D Admittedly some of the lemon has started to evaporate but I kept some fresh juice (3/4 of original lemon) in a jar in the fridge so that I can top it up later :)

[icsnerdics]

awesome!
that's the flux capacitor of back to the future! :D

[Alexdlp]

How is it possible that hadn't yet crossed my mind?? Haha :)

[scraptopower]

If you're looking for a ready made joule thief, look for emergency phone chargers like I used in my thermoelectric generator.

[XOIIO]

So it's basically 4 "baghdad batteries" wired together.

[Biggsy]

I think this will be a GREAT experiment for my Scouts on science night :D thanks :)

[terlitz]

Good instructable :D. Could you tell me what program is shown in the first picture of step 7 ?

[Alexdlp]

Thanks, the software is actually Microsoft Word (2008 for Mac) and it's the interactive notebook template. It's got a feature to annotate, write on notes type of thing.. :)

[sageserver]

Nice, but will an air tight lid prolong battery life by not letting the lemon juice evaporate?