Modifying Existing LED Lights

Originally, I designed a circuit for a battery powered Set of LEDs so that would provide some ambiance for the living room at night time. However, I did not have any battery terminal connectors on hand so I went to Lowe’s to try to find something cheap I could scavenge from. Instead I found a package of 3 remote controlled puck lights that were open box so ingot a discount on them. So I decided to buy them and just swap out the existing LEDs with my own blue LEDs. This project is a very simple example of using COTS items and modifying them for a specific use.

1) Puck lights with a remote
2) LEDs in the color of your choice.
3) Soldering iron and solder.

Make sure when you are disassembling that you don’t break anything and you remember how things are put together. Sometimes parts are glued together but in this case it was fairly simple. Analyzing the power source and circuit is the most important part here. My blue LEDs are 4 volts and can’t accept more than 25 mA but it’s sometimes difficult to determine what the LED requirements are in the original circuit. This case has 3, 1.5V AA batteries in series, which means the voltage adds making a 4.5V power source. This is important in looking at the circuit to identify whether the LEDs need to be in parallel or not. Often the boards are just a 2 sided board and you can follow the traces to verify the LEDs are in parallel AND where the positive and negative of the LEDs are. This is VERY important because LEDs can only operate in one direction where the positive lead is the longer one. Once this has all been determined you can move to the second step.

Now, to replace the original LEDs with your LEDs, you have to be careful not to overheat the circuit. The LEDs will likely be surface mounted and not through hole which can make it even more important that you don’t overheat the circuit or accidentally touch a trace with the iron because it could interrupt the trace. For this specific project I took the iron and heated up the LED itself “picking up” the LED itself and solder with the iron. Ensure that all the solder is off the connects and that the positive and negative pads are NOT connected.

Before soldering the Blue LEDs, I bent the leads gently in almost a C shaped form so that it would fit in the area of the light. You could also cut the leads shorter if needed but make sure you know which side is positive and which is negative. Again the positive side is longer in length. Then put some solder on your iron and coat the leads gently with the solder, then solder your LED leads to the appropriate positive and negative pads (or through holes depending on design of board). Again make sure that the leads are solid and not moving with no connection between positive and negative terminals. Test the light briefly by putting in the batteries and seeing if the LED properly works (issues of it not working in the test may happen if you try this if they are in series. Current is the same through a circuit in series and voltage differs so your current may be limited depending on combination of LEDs on the board). Repeat those steps with each of the LEDs until you have all soldered and tested.

Reassemble the light making sure everything goes back to the way it was originally meant to and test.

(Make sure your LEDs are not overheating and pulling more current than they should be during your testing phases),