Green LED USB Bulb




About: I am a University of Edinburgh electronics engineering student.

This instructable will gude you to the process of modifying a regular 220VAC bulb to a USB plugged LED bulb.

It it a nice touch around your PC or anywhere in your room. It won't be able to light your room fully, though you may use such a bulb to see the keyboard keys in darkness or just add it to the interiour.

The process is relatively easy and there are no special components that you need.


Step 1: Components & Tools

What you need is:

  1. Bulb
  2. Green LED
  3. 330 Ohm resistor
  4. USB Cable
  1. Multimeter
  2. Soldering iron
  3. Soldering wire
  4. Desoldering Pump
  5. Hot glue
  6. Cable nippers and pliers
  7. * You may need a breadbord to do the prototype and test the if the resistor you use is right but you can skip this step
There is a little idea from me. I found it very nice to have the bulbs blown. I just had them at home already blown and have no idea how you can do it manually. Anyway, you could use a regular working bulb for the project - it is not so essential. I have used small bulbs that are for desk reading lamps.

Step 2: The Bulb

You wil have to fit the LED in the base of the bulb, so you have to detatch the metal part from the glass.

NOTE! This step includes working with glass, which is dangerous and you can injure yourself. Take care and be patient when going over the process.

Start by applying some soldering wire to the soldering iron. This will make the desoldering much easier.
  1. Heat the solder dot at the end of the bulb.
  2. If it doesn't melt add more soldering wire.
  3. Tap the bulb downwards and the melted solder will fall. You can use the pump as well to clean the solder.
  4. Do not try to remove the solder 100%, just get to the point where you see a hole with a metal wire in the centre.
  5. Using a thin screwdriver for example break the wire link as you do not want it to link the metal part to the bulb anymore.

Step 3: Detach the Metal Part From the Glass

NOTE! This step includes working with glass, which is dangerous and you can injure yourself. Take care and be patient when going over the process.

First of all grab a piece of fabric and sprinkle some water on it. Then grab the glass part of bulb with the fabric in your palm. This will protect your hand if the glass breaks.

Now grab the metal part of the bulb close to the glass with the pliers and apply little pressure on the pliers. You do not want to smash the glass! Continue working on the metal twisting the bulb a little bit and applying pressure again. You want to go over the whole edge so rotate the bulb a bit after each squeezing.

The metal part will eventually fall off, but if you struggle a lot try heat the edge with the soldering iron. The heat will make the edge expand and crack the glue underneath.

Picture 4 shows what should not happen. I applied too much force with the pliers and it all went wrong.

If you are lucky the metal part will detach as you can see on the next pictures.

Step 4: Fit the USB Cable

Using the pliers grab the top of the bulb and remove the small metal cap which you desoldered earlier. Then using something sharp break the black glass and widen the hole. Protect your eyes!

Get the cable you want to use and cut whatever is hanging on the non-USB end. Fit it through the hole and tight a knot, then make sure the knot goes into the metal part deep enough.

Step 5: Get Ready to Connect!

Here is the idea how to fit the LED in the bulb.

There are the LED and the resistor that have to be hidden. You can see how i soldered them to each other fitting them close to each enough so they don't take a lot of space.

Next comes the cable. The USB2.0 standart cables have four wires in them - Red, Black, White and Green. Red and Black are the 5V power lines and the other two are the data lines. The data lines can be shortened at different lenghts, then isolated with a piece of shrink tube and then you can put them in the knot facing backwards. This wil make more spae for the LED connections.

Fit the knot in the metal part. Your project should look like on the 5th pic.

Step 6: Connect!

One thing I should have mentioned earlier:
  • Measure the current flowing through the LED and the resistor. It depends on the LED, but in most cases this current should NOT exceed 15mA. How to measure it? Connect one leg of the LED to 0V, the other leg is connected to the resistor. The free resistor leg goes to one of your multimeter's plugs (does not matter the color) and the second plug is connected to +5 V. So the current flows like in a pipe constructed of the LED, the resistor and the multimeter.
  • Now switch your multimeter to the mA (DC) measuring function and check whether you have to move the cable plugs or not (depends on the multimeter you use). After connecting the power, the LED should start emitting light and you will see how many miliamps flow though the circuit.
  • If nothing happens reverse the LED's legs as it does matter. You can reed more here.
  • In my case the current was 6.29mA which is normal.
Now if you are happy with the current measurement results, solder the Black and Red cable to the LED and the resisor. Do not forget to put some shrinking tube to isolate the connections!

At this point I tested the LED plugged into the USB and it works! Beautiful!

Step 7: Fit, Glue & Enjoy

You can see how the LED and all the cabling fits into the metal part.

Now apply hot glue around the connections and to the edge where the glass was originally held. Try to apply a thin layer of glue and then press firmly.

Lastly, the point where the cable goes out of the bulb should be gued. Apply some hot glue while turning the bulb around at constand speed.

You are ready! Now sit back and enjoy!

+ You can even plug the LED bulb into most mobile device chargers that have a USB connector.



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    18 Discussions


    6 years ago on Introduction

    Would it be possible to make something like this work in reverse? What I mean is, would it be possible to have the light powered by plugging it into an iPhone?

    2 replies

    7 years ago on Introduction

    Poundland has almost every LED requirement you could need, including colour changing ones!

    This is a Great idea! I love the LEDS worked into other things.

    I think I might be able to help you skip a step: There's really no need to remove the glass from the base. Have a look at this instructable...

    ...I've make a lot of these, with the concrete, and to use the LEDs you'dmhave to simply not pounch out the center glass stem inside the bulb. Remove the glass end on the base and clean it out, as you would in both of these instructibles, and carry on with the LED and Resistor.

    I'll be giving it a try myself! :)

    1 reply

    This is a better way, for sure! You can still fit the LED and the resistor with the solderings inside and so it makes no point to deal with removing the glass and then glueing it again.

    Hobby Lobby, and other craft stores, often have fake glass light bulbs for projects. That would make things a lot easier for the more casual crafter. (And they're only $1.50 as well.)

    1 reply

    Of course buying them defeats the whole purpose of this site :) This is a great instructable and a great project for a beginners class on electronics!


    Reply 7 years ago on Introduction

    I am glad that you like it. I would like to see some variations of the LED bulb so if you make one, please share it!