Fluorescent Oil Lava Lamp

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Today I will guide you through the steps of building a new sort of lava lamp based on fluorescence.

It looks similar to a lava lamp, however the lights you get out of it are really beautiful and look even unreal (or radioactive like in movies, much cooler than a lava lamp ;) ). Don't worry, it is not a dangerous project (even if you shouldn't inhale the powder nor drink the mixture...).

We will be using water, fluorescein (pouder that reacts to light) aaand a bunch of oil. The oil makes the "lava lamp" effect since it won't mix with water, and being lighter than water will "float" on it.

I bought fluorescein a couple of years ago for some tests I conducted in the frame of my masters thesis. I was fascinated by the beautiful lights you could get out of it, and wanted since that moment to build something out of it (similar to a lamp, even if at that point it wasn't clear).

Warning :

Choose a bottle that is stable and do not put it somewhere where it could be knocked over (so basically anywhere you have kids). You do not want 4 liters of oil spreading on your floor… You have been warned ^^.

Cost :

If you have to buy everything it can add up to about 50 euros. Since I already had most of the components, it did cost me about 20€ (mainly the pump).

Time :

This is not a very time consuming Project. It can easily be done within an afternoon if you already have the components.

Complexity :

This is a pretty easy project, apart from soldering the LED no particular skill is needed.

Supplies:

Step 1: Working Principle

The working principle is here different from traditional lava lamp. The lighting effect is based on fluorescence (instead of normal lighting), and the movement is generated by a fluid pump (instead of heat).

Fluorescence is the ability of a material when it is excited with a specific wavelength to emit light with a different wavelength (longer).

In our case we will be exciting water mixed with fluorescein with 450 nm wavelength (blue), which is close enough to the "excitation wavelength" (494 nm). The emission wavelength is 521 nm, which corresponds to a greenish yellow.

By filtering out the emission wavelength (so the blue light) with an orange light filter, we will only see the yellow light due to the emission.

Step 2: Components and Tools

Components:

  • 1x canister / bottle for the lamp. In my case it was coloured with a colour that filters the light away the way I need it. You can use any transparent one you just need the light filter described next.
  • 1x Light filter: must absorb wavelength near to 450 nm (blue) and let wavelength above 500/550 pass through. In germany you could buy this here, in other countries maybe online, on website for music equipment for example (since they are used for lighting purposes in shows).
  • 1x LED 450 nm (often called royal blue). In my case I had an array of 8 LEDs working with 24V (therefore 2 power supplies in the pictures). I recommend going for 12V so at best 4 LEDs or lower it down with a resistor (small resistor should be built in anyway if not on the LEDs themselves). You need quite powerfull LEDs since the oil tends to dim the light intensity. An example i found on ebay: this.

  • 1x LED controller for 12 V LEDs

  • 1x water pump 12 V. I bought mine in an electronic shop, online you can go for a cheaper solution (the link is to a german website, but the same pump can be found through the reference on other websites). However it is important to get a LOW flowrate since you want to pump small amount of water. My pump is 0,6L/min, I would recommend something similar (or even less if you find). Warning, the pump must allow to pump oil.

  • 1x 12 V power supply

  • 1x flexible tube (once again german website, but can be found everywhere)

  • A teaspoonful of fluorescein

  • 4L Oil or less depending on your canister (at best an oil as clear as possible, since oil tend to be yellowish, they can therefore absorb some of the blue light before it reaches the fluorescent water). I went for « purified sunflower oil » that I could find at my local superstore.

  • 1L water to mix with fluorescein

  • Electrical components (cables, electrical connecting strips, black electrical tape, heat Shrink tubing, zip tie)

  • A push button (if you want to manually control the pump which i did)

Tools:

  • Various standard tools (cutting pliers, scissors…)

  • A soldering iron

Step 3: Connecting the Components

The main step is to connect the components. It’s quickly explained, but takes a bit of time.

In the schema you can see all necessary connections. I made it for someone using LED and pump working on 12 V, which wasn’t my case. If like me you need different voltages then just power up pump and LED controller separately (problem is, that you'll need 2 outlets).

You can use a cable with 4 wires to get the LED and pump hooked up in one go (also easier to hide afterwards). You can either solder everything and use heat shrink tubing or use electrical connecting strips.

Concerning the LED controller, it has 3 output (for red green blue), you can use independently one of the three. Just watch out if they have common GND or common 12V (look up the datasheet or measure it with a multimeter).

In my case, I used a small heat sink in order to cool the LED which tends to heat quickly when high light intensity is used.

Step 4: Preparing the Bottle

First thing to do with the bottle is to cover it with the light filter. I didn’t have to do it, since the bottle I used was originally somewhat orange and therefore filtered the blue light good enough. Alternatively you could try some translucid orange paint… Basically you need to make sure, that the whole surface filters the light.

So this is it, we are getting those bottles popping.

First of all in a plastic bottle full of water, put in a bit of fluorescein. You do not need too much, it is amazing how little of this powder can colour the water (when under excitement light). For a liter I used about a teaspoon of fluorescein.

Close the plastic bottle and mix it for about 2-3 mins. It must be very well mixed, otherwise some powder could mix with the oil (I didn’t test it but don’t take any chances).

You are ready to fill the bottle (the lamp bottle).It doesn’t really matter with what you begin. I recommend putting the Lamp bottle in a bathtub before pouring those mixtures into it.

I poured about 1/5 in height with water with fluorescein, and the rest with oil.

Step 5: Preparing the Pump and Tubes

Then you need to attach the tubes to the pump. Be careful to watch which one is the input and which one the output (some pump can both directions depending on current, some can’t).

The input tube must be long enough to reach the bottom of the lamp (and pump only water not oil). The input tube should be covered in black electrical tape (or any opaque tape), so that you won’t see the luminescent water going up (looks better imo.). I secured the tape around the hose with small black zip ties.

The output tube must be rather short, in order to spill the water in the higher part of the lamp, allowing it to slowly get back down due to the higher density of water.

Step 6: Final Build

You are now ready to build the lamp. Important is, that the LED(s) illuminates at maximum the Fluid, so that the water lights up. I secured everything on top of the bottle with hot glue / electrical tape.

Make sure the Pump is held in place (zip ties).

Then proceed to (if necessary) cover any open spot on the top of the bottle, through which blue light could come out. You only want to see light coming from the water.

Once everything is secured, plug it in and you are ready to go. You can control the light over the IR remote control (on, off, intensity or fade programs…).

This is a project I wanted to do for a long time (had 5 bottles of oil for about a year before I used them), and I think it looks gorgeous. The light is very special. It is not bright enough to light up the room. But as a mood light it is perfect.

I hope you enjoyed this instructable =).

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