The LED Ball is a fun project based on the electrical property of saline water. First put the cathode of the LED into a cup with salty water, connect the anode to the positive pole of a battery and also connect a wire to the negative pole of the battery. If you put the loose end of the wire into the saline water, the LED will glow. So the salty water works as a conductor.

Instead of using one LED and a cup of saline water, we decided to make a LED Ball with some salty water in it. So if you shake the ball, the LEDs will flash, because the saline water connects and disconnects the LEDs from the battery.

To learn how to make your own LED Ball, follow the instruction step by step.


Der LED Ball ist ein spaßiges Projekt, welches auf dem Prinzip basiert, dass Salzlösungen Strom leiten. Zuerst steckt man die Kathode einer LED in einen Becher mit einer Salzlösung und die Anode wird mit dem positiven Pol einer Batterie verbunden. Nun müssen wir nur noch einen Draht mit dem negativen Pol der Batterie verbinden. Wenn wir jetzt das freie Ende des Drahtes in die Lösung tauchen, wird die LED leuchten. Die Salzlösung fungiert als Leiter.

Statt aber eine LED und einen Becher mit der Salzlösung zu benutzen, haben wir uns dazu entschieden einen LED Ball mit der Salzlösung darin zu bauen. Die LEDs blinken beim Schütteln des Balles, weil die Salzlösung nur für eine zeitweilige Verbindung sorgt.

Step 1: Parts list

You need:

- epoxy resin
- soda (sodium (hydrogen) carbonate), e.g. wash soda
- LEDs (I used: 12 green, 12 yellow, 14 red )
- a transparent plastic bauble with a diameter of 80 mm
- a transparent plastic bauble with a diameter of 60 mm
- a cup of warm water
- a 3 Volt button cell
- two copper plates or copper foil the size of the button cell
- uninsulated wire
- soldering tin
- a small switch
- a resistor, around 150 ohm or higher
- an elastic band
- food colouring (optional)


Man braucht:

- Epoxidharz
- Soda (Natrium(-hydrogen-)carbonat), z.B. Waschsoda
- LEDs (Ich habe 38 Stück benutzt: 12 grün, 12 gelb, 14 rot)
- eine größere transparente Weihnachtskugel aus Plastik (80 mm Durchmesser)
- eine kleinere transparente Weihnachtskugel aus Plastik (60 mm Durchmesser)
- ein Glas mit warmem Wasser
- eine 3 Volt Knopfzelle
- zwei Kupferbleche oder Kupferfolien in Größe der Knopfzelle
- nicht isolierter Draht
- Lötzinn
- einen kleinen Schalter
- einen Widerstand, ungefähr 150 Ohm oder mehr
- ein Gummiband
- Lebensmittelfarbe (optional)

This is a wonderful project. <br>I mean no offense, but I think you wrote &quot;bauble&quot; when you meant &quot;bubble.&quot; <br>And it would make a great educational kit that you could sell to teach about conductivity and soldering. <br>Great work.
In my dictionary there it says a bauble is a decoration for Christmas and a bubble something you do with soap. So I mean a clear bauble which you can buy in an art supplies shop. Normally you paint them and hang them up on the Christmas tree. :D <br>Thanks for your comment, I will think about it! :D
If it hangs on a Christmas tree, it's usually called an ornament. A bauble is an old word that is very rarely used. And although it looks like a bubble, it's more correctly called a bauble. Except you won't hang it on a Christmas tree. Nevertheless, you are correct in calling it a bauble.
Oh ok :) Thank you for your explanation :D
I love it! Thank you for sharing!
How did you ever think of doing this? I love it.
Thank you :D
And I don't why I have sometimes crazy ideas like this ^^ <br>I just remembered how good saline water conducts electricity and I asked myself what I could do with it?
Very cool! Nice idea! Like the music too.
Thank you :D <br>

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