Introduction: Hydro-Lamp

"Water is a good conductor of electricity"; heard these lines before? yes, surely in your school days. We all know that water is good conductor of electricity. So, how about making a cool table lamp which works on this basic and simple principle of physics? So let's make the HYDRO-LAMP!

Another interesting fact about this Lamp is that I have not used any kind of Arduino chipset or resistors, potentiometer which make the circuit complex. This lamp uses a very simple circuit which can be constructed by DIY enthusiasts.

Let's divide process into 6 simple steps

  • Planning
  • Wooden Framing
  • water Container
  • LED light Housing
  • Circuitry
  • Assembly


  • LED BULBS 20W - 4nos
  • wires
  • AC DC adaptor
  • Adaptor female jack
  • Electric tape
  • White acrylic sheet 3mm thick- A3 size
  • clear acrylic sheet 3mm thick - A3 size
  • China-pine wood
  • Flexi quick glue
  • Araldite
  • Fevicol SH
  • Masking tape
  • Scissors
  • Water
  • Salt and water based pigments

Step 1: Planning

I'm designing this lamp in such a way that the lamp should turn on when it is kept in horizontal position, and turned off when it is kept upright. for this I'm going to use water as switch.

I'm choosing cuboidal form for this lamp, because the lamp will be stable both in vertical and horizontal position.

the second image shows the basic layout and dimensions of the lamp.

I've also made some 3D rendering just to visualise the final product.

Let's start making the lamp according to the above dimensions.

Step 2: Wooden Framing

The Predefined dimension of the wooden frame is 70x70x30 mm.

The wooden Frame will house the LED lights as well as the water container. The material used to make the frame is China pine.

I made the frame using the following simple steps.

  1. First, I took the wooden plank of thickness 10mm and cut down into the strips 30mm width using band saw.
  2. Now, I cut these wooden plank into a length of 70mm. Then by using angle cutting machine cut the edges into 45 degree such that you can make a square box easily. you will be needing 8 pieces to make two boxes.
  3. Now, using Fevicol SH glue join these pieces to form a box. wrap it with masking tape to ensure the firmness.
  4. Now Make an internal groove of approx 5mm depth on the centre of one of the edges of the box. This will help you in coming steps.
  5. once the glue gets dried, remove the masking tape.

Step 3: Water Container

For making the the water container, I'm using 3mm thick clear acrylic sheet. Cutting acrylic sheet manually is a tedious job. Hence I have used Laser cutting machine to ease the job.

I have uploaded the template of the container. Once the laser cutting is done, remove the protection films carefully and wipe the surface.

the top and bottom faces of the container has 2 tiny holes to insert the wires into it. insert the wires on both the sides and seal it with the help of Araldite.

Now start sticking the sides starting the any one of the side. Make sure all the sides are leak proof. Before sticking the last face fill the container with water. ( I have mixed table salt with water in the ratio of 1:1 to enhance the electric conductivity.) I have added blue colour to the water.

Now fix the final face and make it as a closed container.

Step 4: LED Light Housing

Again to house the LED lights I have used 3mm thick milky white Acrylic sheet. You can laser cut the acrylic sheets using the uploaded template file.

stick the acrylic sheets accordingly using Flexi quick. Before pasting the top cover, place and stick the LED lights in place and pull out the wires from the slot made. now close the housing with the top face.

Step 5: Circuitry

Now make the circuits according to the circuit diagram given. Link for the Circuit diagram

make the connections appropriately and check for loose connections if any.

leave some extra wires which your can trim and connect accordingly during the assembly.

Step 6: Assembly

first fix the LED light housing to the wooden frame using Araldite. follow the same step for the other end.

Now your connections should be as shown in the pic.4. This Should be the only visible wires so far. Now in order to hide these wires, connect them accordingly and pack them.

now use the wooden strip to cover them in such a way that the wires are completely hidden. Stick the wooden strip with araldite.

Now your Lamp is almost done. For Fine tuning, mask the acrylic parts of the lamp, sand the excess wood and varnish it using linseed oil.

Tadaa!! There you go! your HYDRO LAMP is READY!!


Here is a video clip to show the working of HYDRO-LAMP.

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    2 years ago

    2 thoughts about the project.

    1. if you wire it like showed in the diagram, its not goint to work. You will just shorten the AC adapter and probably just burn it out.

    2. DONT use ordinary salt in the water. When you add the current, you are going to set something called electolyte in motion and when you are using saltwater, one of the products of that is chlor. Its very toxic and NOT suited for a fun project like this!


    Reply 2 years ago

    Hi Allan, you said do not use ordinary salt in the water. Then what kind of salt should i use?


    Reply 2 years ago

    NaOH/KOH, or just tap water. The amount of chlorine produced will be extremely small and dilute. And if its water sealed, it should hold pretty air tight as well.


    2 years ago

    Hey Manvith:

    Nice Instructable. However, it turns out that PURE (i.e. distilled) water is a TERRIBLE conductor. It has a resistivity of about 18 million ohms/centimeter.

    However, water is a wonderful ionic solvent, so salts dissolve readily in it and will make an ionized water solution into a good conductor (as you rightly pointed out).

    NV1T Tom


    2 years ago

    How neat! What a great idea :)

    Manvith Subraya
    Manvith Subraya

    Reply 2 years ago

    Thanks Jessy!!.
    Check out my Instagram handle @manvith_us for some more pictures of the lamp