Laminar Flow Water Jet Part 2- the Lights




As I said in my first instructable i was planning on adding lights, but i wasn't able to get the results wanted because i didn't have access to the bigger, brighter LEDs so I just used what I had laying around.

Here is a link to my other instructable:

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Step 1: Supplies


1) at least one 10mm high brightness LED's (you can have as many as you want)(radioshack has the ones)
2) Some small gauge wire such as 18-22 gauge.
3) Epoxy or similar glue
4) Superglue
5) 6 volt lantern battery.


1) Wire connectors
2) Solder
3) Soldering Iron


Step 2: Main Body Modifications

First you will need to drill a hole, about an inch below the caps bottom end, large enough for your wires to fit through (you can drill two small ones too) next you will want to pull enough wire to work with, out of the tube you will want at least 4 inches to work with.

Step 3: Wiring the LEDS

First cut the insulation just where it comes out of the top of the tube, you then want to slide it about 1/4 inch and expose the bare wire(don't completely remove it!) do the same with the other wire. Now it should look like the picture. Next use a small pointed object to make a small hole in the bare section of wire, now slide one end of the LED into the hole and fold the lead around the bare wire, and then twist the power wire to close the hole around the LED now you can use either solder or superglue to secure the LED lead in place. Now repeat this step with the other side of the LED. After that you are ready to cut a new strip into the wire for your next LED jus follow this step and you can finish the LEDs, you want to put them about an inch apart. 

Step 4: Inserting LEDs Into the Tube

Now that your finished with the LED wiring you can snipp off the excess wire, then you want to take the slack out of the wire so it pulls the LEDs into the pipe now arrange them in a circle around the inside of the tube and try to aim them at the nozzle. Once done you can glue them to the side walls of the pipe but since I only used one I will let it hang free as seen.

Also i know it sounds crazy but the wires need no insulation between the terminals!!! That is because normal water does not conduct electricity as show in the second picture it requires salt water to conduct electricity efficiently enough to short it. 

Step 5: Wires

Now mix some epoxy and thouroughly coat the wires on the outside of the holes to seal them in as pictured. (if you use superglue the water pressure will force it out)

This is optional but you can put a conector on the wires for the battery or you can leave them bare and wrap it around the battery terminals.

Step 6: Wrap Up

Finally put the nozzle cap on and test the lights you should get a bright concentrated dot out the end as seen. Be sure you DO NOT LEAVE THEM ON WHILE DRY!!!! The lights  get very hot when being driven at this voltage but when the water is running you have your own water cooling system so you can use them till the battery goes dead!!! The light looks purple in the picture but it is actually a 5mm ultraviolet LED, i would not recommend them as they are not as bright as the bigger 10mm bulbs such as the blue ones, if you can find big ultraviolet ones then you can use them. The light wasn't as bright as I thought so it only illuminated the beam when it got an air bubble in it or it started to break up, but brighter lights would solve this.

Step 7: Fin.

So now you have a functioning illuminated Laminar Flow Water Jet. This be my last laminar flow instructable for a while as I have to make a cutter and possibly multicolored- fading LEDs. I am planning on using an arduino to controll everything, I am open to any suggestions, but until next time happy instructable-ing.

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    24 Discussions


    6 months ago

    Can you tell me how to make a nozzle cutter?


    3 years ago

    Since water is going through LED and wires, I expect that it's the cleanliness of water that has saved from a short-circuit.


    4 years ago

    Dear You !

    My name is Hoang Nhat. I am 27 years old . I am from Viet Nam.

    Your clip that instructs how to make a Laminar Jet Construction. It is interesting. My group decided to make it to decorate for the local church and bring joy to children for free.

    But we got the problem that when the water came out from the nozzel, the water line was not focused, gathered on one line. It is just foucused, garthered on one line when it goes far about one meter. If we try to make the water line goes higher and farther, the water line will be divided a lot before it is landed.

    What is the problem with it ? about pressure or something ?

    Please, help us to do as soon as possible because the chrismas is coming soon.

    If you need to get more information about parameter, picture .etc you can contact with me by this email

    Hoang Nhat! Best regards to you !

    1 reply

    Reply 4 years ago

    Hello, I think what you are saying is that the water breaks up into drops rather than staying a "beam" if that is so then a larger diameter nozzle will help, usually if you try and increase the pressure with a small nozzle you lose the laminar beam and just get a normal hose stream, (I hope that makes sense) definitely try a little bigger nozzle then you can add a little more water pressure and have a larger, longer/higher beam. Hope this helps.


    7 years ago on Introduction

    i have made a jet and i put 5 high brightness leds in them but the flow doesnt light up, when you touch de flow it becomes light up what did i wrong?

    4 replies

    The stream should light up only a little it won't be super bright as it will act as a fiber optic and the light will bounce around in the beam and not leave the beam until something disturbs the beam such as touching it or it hitting an object. I've been working on adding little bubbles into the stream to try and scatter the light but if you take some rough sand paper and try to gouge the edges of the nozzle just a bit it can disrupt it enough to allow some light to leave but still look laminar in nature.

    i have put a needle in the flow just a bit and now it lights up a bit, i think i use some high power leds sinds its already cooled with water

    Can you expand on the "needle"?

    Is it just a pin poking into the flow, or a hypodermic that allows bubbles to be sucked into the flow.

    Where, how is it placed?

    My water jet is in our pond right now and since its winter i am not able to take it out of the pond for pictures. The needle is just a thin piece of metal poking into the flow mounted on a servo just outside the jet housing, The servo allows it to disturb the flow only when i put the high power RGB led on. This makes for a highly visible coloured flow, it only isn't super laminar any more)


    9 years ago on Introduction

    A few comments: First, cool build -- I'd love to see it working; Constructive criticisim: While it won't inherently short circuit with clean water, if its for a fountain it probably has lots of other gunk getting in the water, and will eventually conduct and steal your precious electrons. The soldered connections will release lead into the water over time, so you want to insulate that, and the metals will corrode n the slightest conductivity while electrified -- as such, I HIGHLY recommend dolloping some silicone on the connections

    4 replies

    Reply 9 years ago on Introduction

    **also, its a good idea to run a series resistor so the led *doesnt* heat up. Under regular operation a 5 or 10mm led should *never* get hotter than 'barely noticable warm'.

    LEDs are inherently non-linear conductors.

    Above their rated voltage, they will draw as much current as is available and quickly burn out. They have a rated current, say 20ma.

    You can make a current source (so you can vary the intensity, high it's probably better to PWM them), but the usual way is to use a dropping resistor.

    The blue LED is probably around 3V vfe, so we need to drop from your 6v to 3v at 20mA. A 150 ohm resistor will do the trick. It's less than an 1/8 watt, so any resistor will do.

    Note - resist the urge to put two 3v LEDs in series and run them from 6v. Nothing is exact.

    Note 2 - running LEDs in parallel with one resistor has some risk as thevLEDs won't be exactly the same and on might draw much more current than the rest. Poof.

    Thank you for the ideas I mainly didn't insulate them beacause I didn't have any silicon on hand but i will definitly do that, and the resistors are also a good idea i just planned on using mulitple LEDs and I wanted them to be as bright as possible, but I will try adding a resistor and see how much it effects the brightness. Also I don't currently have a video because the single small LED just wasn't bright enough to see even in the night, you can just see a faint glow when a bubble goes through it and as it hits the ground it makes an ultraviolet dot. When I get the new LEDs I will make a video. Also for the fountain idea a pump filter would help solve the build up problem, plus in the one I made there are sponge/scrubber pads in it to hold the straws and to break up any bubbles in the flow.

    Good deal! Again if you want the led to last, even with water cooling it -- you want that resistor in there. It will cost hardly anything and won't make the led even noticably less bright.


    8 years ago on Step 6

    I think the issue you're likely facing isn't that you don't have enough light, but that the light is reflecting off the sides of the water "beam" if you will. A fiber optic cable does the same thing - reflects the light off the sides and carries the light beam with a near perfect light signal to the end. That would explain why it only appears when there's air bubbles - because otherwise it is just reflecting back. If you put a white surface at the end of the beam, I suspect you'll see the light showing up there. I'd be curious to hear what happens!

    Does the addition of the LED free floating in the water stream interrupt the laminar flow of the water? I'm assuming the placement of the LED is between the aperture and the straws.

    1 reply

    Reply to HadMatter,

    Hope you had good luck building the jet, as for the LED's you want them down in the tube some and as close to the center of the opening as possible, what I did was put them in and gently set the top on, power it up and point it at a wall and look at the beam it shines, if using more than one LED you can take the top off the jet and move them around until they shine through the nozzle and onto the wall at close to the same spot, instead of multiple spread out beams, the LEDs do need to be pretty bright if you want it to be seen well, I used 3 10mm 3 volt radioshack blue LED's run at 6 volts and they light up the beam well at the point it hits something and the beam has a slight blue glow to it, but brighter lights would make it glow better and it would transfer more light to the impact point. As for mounting the LEDs I just used the wire to hold them but building a small frame would be a much better idea and then they wouldn't move in the tube. Hope this helps you.


    9 years ago on Step 4

    It may not conduct enough to short out, but it will drain your power source more (it's not huge, but it's there.) and it can't help the wires. The corrosion will increase do to the voltage leaking as it aids in ion transfer.

    1 reply

    Reply 9 years ago on Step 4

    Yeah when I did it I just kinda threw it together but now I put Silicone Glue on the connections so they no longer contact the water.