Introduction: Build Your Own Portable COB LED Desk Lamp!

About: An electronics enthusiast with eternal curiosity!

In this Instructables, I am going to teach you how to make a gorgeous looking, very powerful and most importantly, a portable desk lamp!

Disclaimer:This project is not sponsored by any brand.

• Modern and elegant design
• Portable and rechargeable
• Mini USB charging port
• 5200 mAh battery
• Bright, Filtered and soft focused light
• Warm white illumination

The story of...
Well, I started making this lamp 2 years ago when I just completed 11th std in 2018. I started and almost completed it within 15 days and I captured photos too, because I was planning to publish an Instructables after completion of the project… but that COB LED strip, which I ordered from an international website, didn't arrive unfortunately. It was so sad. I temporarily used some cheap LED strips from a local store, which was not that bad. But, still I was not satisfied and was feeling like an incomplete project. Recently, (in 2020) I had to order some modules from an international website again, and just remembered about this project. So I ordered that same COB LED again. And It actually arrived! I was so happy to finish my ‘incomplete project’. But, we know that we always crave for better. So, my task was not only to remove that cheap LED and install the fresh COB LED, but it also included some improvements like applying some awesome black radium stickers on white oil painted body, using ‘advanced’ filter technology from LCD monitors, adding indicator LED (Because the existing RGB LED was accidentally blown by me)...etc. Adding up this all, it surprisingly took me another 10 days to finally ‘complete’ the project! The final result is truly fabulous as you can see!

Excited? Well, stick with this Instructables till the end and I am pretty sure that you will learn a lot! Also, you will be able to make one of your own!

Before proceeding, consider the following:
Step 1—>For Designing
Step 2 to Step 4—>For Body
Step 5 to Step 9—>For Electronics Stuff
Step 10—>Cover for the bottom of the base
Step 11—>Adding reflectors
Step 12—>Experimenting with LCD screen diffusion layers
Step 13—>Installing diffusion layers on LED
Step 14—>Final Touch
Step 15—>Test
Step 16—>Some modifications

Ready to go?
LeT’s gEt sTaRtEd!


Materials you will need to make this project:
• PVC pipe (inner dia 28mm and outer dia 37mm)
• COB LED strip 12v 10w
• Copper wire 14 gauge
• Lid of a plastic container
• Buck-boost converter
• Li-ion battery charger module
• 5mm RGB LED
• SPDT or SPST Toggle switch
• Double sided tape
• Plastic tape
• Light Diffusion sheets (Simply get a useless LCD monitor display, even broken screen will work)
• M-seal
• 2x 18650 batteries(usually found in old laptop battery)
• Wires
• Cardboard
• Matte black and silver radium stickers
• Glue
• M-Seal
• Super glue
• Solid cardboard

Tools you will require:
• Saw
• Soldering iron
• Soldering wire
• Wire cutter and stripper
• Paper cutter (to cut white radium stickers)
• Sand paper
• Hot air gun or hair dryer

Step 1: Design

You can skip this step if you want to follow my design.

In this step I am going to tell you how to design.You can think and develop a mental image and/or make a sketch on paper. You can get inspiration from various things/sources around you (I got inspiration from Nobita's desk lamp. FYI, Nobita is a character of my favourite cartoon series: Doraemon!). Include materials that you have or you can buy. Make a final image/sketch after thinking about every physical aspect like weight, durability etc. Your final image/sketch should contain all the measurements. If you are not sure about some measurements, you can decide it while making it actually. You can start making once the final image is ready.

Step 2: Cutting PVC Pipe

As you might have guessed the use of PVC pipe, but still I would like to tell you that It will be used for making outer cover for LED strip.

First, cut the pipe in length 18 cm. Then, cut it in half lengthwise. You got two pieces. Put one of them apart, because we are going to use only one. Now, cut from both sides to create slope. Then mark mid point of length and mark a point 0.7 cm apart from midpoint. Do the same on the opposite side of midpoint (we are doing this to make holes for two copper wires that will serve the function of electrical connection as well as the arm to hold the upper part of the lamp). Now, drill holes equal to the thickness of copper wire you have. Now, sand sharp edges of this part to make them smooth.

Step 3: Modification of Lid

Take a lid off the container as shown in image. We will use it as an enclosure for Electronics stuff. First off, we need to remove the logo on top of the lid, because it is slightly embossed in my case. So it will appear even when we colour it, which I certainly don’t like and probably you too. So, grab a sandpaper, and sand the lid until the logo disappears. When You are satisfied with it, we have to make some holes for the switch, LED, charging port and copper wires (Please note that two holes for copper wire should be 1.4 cm apart from each other.) Do it according to the size of each. Refer images. From now on, we will call this part ‘base’.

Step 4: Copper Wire Connection

Take two copper wires of thickness 14 gauge and length 30 cm. Now insert those in the premade 2 holes in the base about 2 cm and bend it. Apply M-seal to fix it rigidly. Now, in the similar manner, do exactly the same with the PVC part. Next, bend copper wires from base to 90 degree to create lamp shape. Refer images to get an idea how to and how much M-seal to apply.

Step 5: The Circuit

It’s time to understand the circuit. The first image shows the connection diagram. It’s fairly simple. Let’s understand its elements one by one.

Battery: I used two 18650 cells in parallel, 2600mAh capacity each, so total 5200mAh capacity with 3.7V nominal voltage.

Battery charger module: It is a li-ion battery charger module with over charge protection circuit. I removed the pre soldered indicator LEDs and added a 5mm RGB LED with wires extended.

Boost converter: This is the magical component of the project. This module converts low voltage to high voltage(Actually I used a Buck-Boost converter which can convert input voltage to either lower or higher voltage).
The reason to use a boost converter is that the LED strip operates at around 12V, and our battery has a nominal voltage of 3.7V. So, we need to increase voltage from 3.7V to 12V, otherwise COB LED strip won’t work.

Toggle switch: As you might have guessed, this switch is used to turn the lamp on or off.

COB LED strip: I have used COB LED strip of 17cm length. It has 10W power and operates at 12V. The colour is warm white.

Step 6: Preparing the Battery

As I tried to keep the overall cost of the project as low as possible, I decided to use a couple of 18650 batteries from an old laptop battery. If the battery shows voltage above 3.7V, we can conclude that the battery is working.(If battery shows voltage below 3.7V, then the battery is said to be ‘dead’. However, if the battery is dead but voltage is not too low, then there are some techniques to revive a battery. search google to know more.) Take two of these batteries, and connect them in parallel.

WARNING: Do not put solder tip on battery terminal for too long as overheating batteries for a long time can be hazardous.

Once connected in parallel, solder the terminal wires. Then use some double sided tape to cover the battery terminals, and finally wrap it with plastic tape completely.

Step 7: Test Circuit Setup

Before fixing components permanently, It is always a good practice to check whether the circuit is functioning properly or not.

So now, create the circuit as shown in diagram, but don’t connect the LED strip, because we will need to adjust the voltage of the boost converter first.
For a beginner, the most complex part can be to remove red and blue indicator LEDs on the battery charger module and connect an external RGB LED using wires. But wait! that is completely optional and if you like it as it is and your design is different, you are good to skip that. So, why did I do that? Just because the LEDs on the charger module will be covered inside the base. So we need to extend it to mount in the hole in the base. Although I used RGB LED as extended LED, I used only two colours: RED and GREEN. Another important thing according to the configuration of my charger module is that if we are using RGB LED as extended LED, we can only use common anode RGB LED because common cathode will not work.

Once the circuit is complete (without LED strip of course), get your multimeter and set the output voltage of the boost converter to 11V. Now, connect the LED strip. It should light up. To increase the brightness, increase the voltage of the boost converter by trimming slowly. As the voltage increases, the brightness will also increase, but the boost converter will heat up more as well. So, make sure that the voltage is somewhere between 11V to 12V.

Test the circuit functions thoroughly, like charging, LED indicators, temperature of all components etc. Once you are happy with that, we are good to go.

Step 8: Installing Components in the Base

We are now ready to fix components in the base.
Start with the switch, fix it tightly.Then fix the RGB LED in its hole using super glue. For battery, use double sided tape.Now, connect all the components including charger module and boost converter, not LED strip.
Fix boost converter and charger module as shown, use plastic tape to make sure that nothing gets shorted! Next, connect output terminals of the boost converter to those thick copper wires using normal wires.

Step 9: Installing the LED Strip

On the top part, connect the LED strip to thick copper wire using normal wires. Insulate open terminals of thick copper wire using plastic tape, because the LED strip has a metallic heat sink, which is totally conducive, and able to do short circuits. Use double sided tape to stick the LED strip to the PVC part.

Good to go!

Step 10: Cover for the Bottom of the Base

Once the LED is working as expected and temperature is not high, you are all okay. You can finally cover the bottom.
Cut a circle out of solid cardboard, diameter equal to the diameter of the open part of the base. Now close the bottom of the base with it using super glue. (My cardboard was not that tough, so I cut two circles and sticked both to make a rigid circular shape.)

Step 11: Adding White Reflector Strips

As there is a bit of space besides the LED strip, It would be a good idea to add a light reflector. I got one white plastic reflector from an old LCD monitor screen. You can use some similar things too. Measure the space available for the reflector and draw two rectangular strips, cut it and stick it using double sided tape. Now, still both ends are open, we need to cut two semi circular shapes, diameter equal to the outer diameter of the PVC pipe. Use the same white reflector. Finally stick it using a few drops of super glue.

Step 12: Experiment With Different Layers of an LCD Screen

Probably, the most interesting part of the project. This is the secret of not only the modern look, but also focused light. Yeah! Let’s start the experiment!

Get yourself a broken or useless LCD display. Disassemble it carefully. Behind black screen, you will find an LED strip and a number of plastic sheet layers. All of them do different jobs, yet the overall function of them is to spread light of LED strip evenly all over the screen and ‘to push’ the light towards the perpendicular direction of the screen. We will use both of these functions. Here is why.

1. We need to diffuse the light in order to make it softer.

2. We need to push the light in a perpendicular direction because that will reduce the brightness of light in surroundings and will just focus on the object in front. Perfect for reading at night.

Back to the experiment. You will find several plastic layers and those are fresnel layers(one with horizontal orientation and another with vertical orientation), diffusion layer (one highly diffusive and another lightly diffusive.). There will also be an acrylic sheet with a dot pattern on it, which we are not going to use here. So, to understand the function of diffusion sheet and fresnel sheet, just put them one by one on the LED strip, turn it on, and observe the difference in light output. Also, if it is a fresnel layer, then rotate it to make different angles with the LED strip and observe what changes.

You may observe the following:

1. When you put the diffusion layer on the LED strip, obviously, the light gets diffused as the word suggests.

2. When you put the fresnel layer on the LED strip, crazy things start happening.

Turns out that we need to understand the fresnel layer.

The function of the fresnel layer is to ‘double’ the things. If you put that on the LED strip, you will see two LED strips! But that also depends on the angle at which you put it on the LED strip. Try to adjust by rotating the layer to get the perfect effect. Another fact about that layer is that if you flip it, the effect will not be the same.

Step 13: Installing Diffusion Layers Over LED Strip

In this project, we are going to use two fresnel layers (one horizontal and one vertical) and one diffusion sheet(one mostly white).
Cut all the sheets in the same size, size equal to the open part of the PVC part(i.e.length equal to the length of PVC part. And width equal to the diameter of PVC pipe). Next, arrange the cut pieces in the following order.

The Order: One ‘mostly white’ diffusion layer at bottom, a vertical fresnel layer on it and finally, horizontal fresnel layer on it.

Next, place it on the PVC part, and apply a drop of super glue on two diagonal corners to fix it temporarily(It will be fixed permanently by applying radium stickers).

Tip: Before sticking diffusion layers, clean the LED strip and reflectors with diluted acetone (Nail polish remover) to remove any kind of stickiness. But don't use acetone on the area of the part on which you are going to apply glue.

Step 14: The Final Touch

In this step, we will do the magic of giving our lamp a premium look and feel by adding some matte black radium stickers! (As you might have noticed in the pictures, I initially used white oil paint when I build it 2 years ago, but it didn't look much appealing and white colour turned a bit more creamy after long time. So, recently I decided to use matte black radium stickers.)

This step heavily depends upon your skills, so it may happen that you may not get it perfect at first, but practice will make you perfect.

Get an A3 sized matte black radium sticker sheet. We have to cover the whole thing with it except the bottom. So plan accordingly and start applying stickers. Use a hot air gun or a hair dryer to soften the sticker. Refer Images. Once done, It’s awesome idea to add some decorative touches. I used silver radium stickers strips and applied them on the base, which looked unbelievably awesome! And that means our project is complete! I would rather call it a ‘product’ instead of a ‘project’!

Step 15: Test!

Great! This is the time to test your project. Just switch it on! You can see the final result in images. Also check whether it charges properly and the charging indicator is working correctly.

Enjoy the fruit of your efforts.

Step 16: Some Modifications (Optional)

The project is completed, but when I tested it, I felt to do some further modifications to make it even better. So, consider the following when you are making this project.

The PVC part was a bit heavy, so if I bend the lamp beyond a certain point, the center of mass of the lamp slips out of the base and the lamp falls down.
—> Solution: Increase the weight of the base by adding any extra weight like metal and fill the cavity inside the base.

• The toggle switch was not functioning very well, and because of that, sometimes when I turn it on, the brightness of the LED was a bit lower than usual because of some resistance. You can see it in some pictures in the previous steps.
—>Solution: Use DPDT or DPST toggle switch with parallel pins soldered together to reduce resistance and thus to avoid such problems.

• (This is what I had to modify, but I won’t really recommend you to do unless you are also in the same situation as me lol) I accidentally blown the charging indicator RGB LED while soldering, and could not find another of the same type (common anode), So I did a hack. As I need only 2 colours of light as an indicator (Red=charging; Green=fully charged), So I got one red LED and another green LED, did some sanding to make it thinner, and finally used a drop of clear super glue to join both LEDs. Again, sanded it from the top to get it done. Soldered anode of both LEDs together and that’s how I got dual colour LED! Finally, I replaced the blown LED with that.

With that, I am concluding this Instructable. I hope you enjoyed reading it! If so, please consider giving your feedback/suggestions about this project and ask questions if any :)

Feel free to connect with me on Instagram and Linkedin to get the latest updates about upcoming projects!

kEEp mAkiNg, kEEp sHaRiNg!

Thank you!

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