Introduction: Convert Cheap LED Bulb to IR Bulb
This project came out of the need for a IR LED Bulb. I found a few exotic IR LED Bulbs online but they were from vendors I had never heard of and appeared to be specialized ($$$). Recognizing the LEDs in the LED Bulbs could be replaced with IR LEDs I gave it a try with great success - and now you have an instructable!
For this project I purchased 2 LED bulbs from Amazon. To achieve IR light I purchased a small quantity of SMD IR (Infrared) LEDs from Aliexpress. To complete this project I used the following tools and supples:
- Temperature controlled soldering iron
- Fine straight-edge screw driver
- Box knife or Xacto knife
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Step 1: Open Your Bulb
These bulbs are a little challenging to open so take your time. I cut a notch in the side of my bulb where the plastic dome meets the body of the bulb which I used to pry the dome off, but in retrospect I don't think it is necessary.
Take a narrow flat-head screw driver and force it into the small gap between the bulb body and bulb dome. Slowly run this along the inside edge of the gap with light pressure. If you are careful I believe this process can be performed without leaving marks in the body of the bulb.
Step 2: Prep the Board
Now that the dome is separated from the body of the LED bulb you must prepare the board for IR LEDs. In order to prepare your board for new LEDs there are two basic procedures which must be preformed:
Slice Away the Plastic LEDs
Using your Xacto knife of box knife, cut the plastic body and lens from the individual LEDs. The goal here is to cut down to the metal LED pads. Imagine this like cutting the eraser off the top of a pencil - you want to place the blade flush with the board and cut the top of the LED off.
In this process you may find the metal LED pads are raised slightly from the surface of the board - simply raise your blade in order to pass the top of the metal LED pads.
Once the top is cleaned cut down to the pads use the tip of your knife to lift away any fragments of the plastic LED body which may remain.
Desolder The LED Metal Pads
I recommend removing the old LED pads entirely, but this may be optional. In order to complete this process I performed the following steps:
- Heat soldering iron to 750° Fahrenheit
- Touch the tip of the soldering iron to your solder until the solder begins to flow - remove immediately
- Touch the solder on the top of your iron to the metal LED pad, applying heat for approximately 1 - 2 seconds
- The pad may begin to move with light pressure from your soldering iron. Once the pad begins to move carefully use the surface tension of the solder on the tip of your iron to lift / pull the metal LED pad away from the circuit board
- Repeat process for both the anode / cathode side of the remaining LEDs
Step 3: Solder Your IR LEDs in Place
With the board prepared, you're now ready to move on two last items and finally soldering the LEDs. The steps below will help ensure a strong reliable solder connection - saving you from coming back to fix it later.
- The first item will be ensuring the pads you prepared in the previous step have good clean solder on them. This means removing excess solder or applying additional solder where necessary. A good pad should have a very slight dome on it - one rule of thumb here is that it's very easy to apply too much solder and in fact more difficult to get it right. In this case, the lower the dome's slope the better.
- The second item will be to apply flux to your prepared pads. If you do not have flux I would recommend buying it. I have previously purchased this flux and found it useful for this project because it has a precise applicator. A light coat of flux will suffice - again, in this application you want to apply the thinnest film of flux you can.
Now that the pads are cleaned and fluxed you can proceed to place your LEDs and solder them to the board. In order to align the IR LEDs I used curved needle nose tweezers, like these. Be sure to align the corner-indicator with the dot on the circuit board.
With the IR LED aligned take your soldering iron and apply the smallest dab of solder you can catch. Apply the small dab of solder on the tip of your iron to the metal frame of the IR LED's pad. The flux you applied above will help draw the solder into the joint.
You will know if you're applying too much solder because your joint will look like the connection in my photo. A good joint should look clean and shiny. If you see yellow or brown marks around your solder joint it is just left over flux - this can be cleaned later with 90% or more Isopropyl Alcohol.
Repeat these steps for each of the IR LEDs on your bulb.
Step 4: Test Your Bulb
I recommend you test your bulb in a simple on / off lamp - preferably one with a longer cord / switch you can turn on and off from a safe distance. If an IR LED bulb were to pop or the board sparked you want to be at a safe distance.
My reason for creating this was a home security camera. In the first photo attached you can see the room is clearly lit up, this is with the IR LED bulb enabled.
In the second photo you can see the room has dark patches, this is without the IR LED bulb.
This is a photo I snapped with my iPhone while standing in front of the "ON" IR LED. With the naked eye there is a very feint red glow (barely noticeable). The camera couldn't catch anything except the blurry green light of my WiFi extended in the background.
In order to better establish the performance of this modified LED bulb, I left it running under constant supervision for 5 hours. At the end of the 5 hours I recorded the following information:
- Room 72.9F / 22.8C
- Lamp Exterior 77.8F / 25.5C
- Bulb Exterior 81.6F / 27.6C