Introduction: Split and Extend the Philips Hue Lightstrip
I've been adding more "smart home" type gadgets to my house, and one of the things I've been playing with is the Philips Hue Lightstrip. It's a strip of LED lights that can be controlled from an app or from a smart assistant like Alexa or Google Home. The starter kit that I got came with a 80 inch (2m) strip of lights that can do white or colored light with adjustable brightness.
I wanted to install these as under-cabinet lighting in my kitchen so that when my hands are busy cooking, I can yell at my Google Home to turn on the cabinet lights. My main problem was length. My cabinets aren't contiguous and they turn a corner, so I calculated that I'd need 4 shorter strips to cover everything. Philips sells extensions to make your light strip longer, but making them shorter was a problem. The officially supported method is to use scissors and trim the strip to the desired length, but the part that you cut off becomes unusable. I'd have to buy multiple kits and cut each of them down to size. That wasn't acceptable because it would be wasteful, extremely expensive, and would require a separate power outlet for each strip. Instead, I did the entire job with a single light strip by modifying it to work as several smaller strips connected by cables.
Step 1: Understanding the Hardware
The key to this project is understanding that the lightstrip is actually six smaller sub-strips connected together. These sub-strips can be separated and then re-connected using cables, which will allow our installation to span gaps and turn corners.
Locate the cut line marked on the lightstrip every 12 inches or so. This is where the manufacturer says to cut the strip to make it shorter. We aren't going to do that, though, because it prevents us from using the rest of the lights past that point. Instead, there's a soldered connection next to the cut line that we're going to remove and replace with a connector.
Thankfully, we don't have to invent a connector system to use here. The tail end of the lightstrip already has a connector that's used for connecting to an optional extension strip. Instead of having a single connector on the very end, we're going to replicate that connector on the end of each individual sub-strip. Using the same connector enables us to seamlessly add extension strips if needed.
Important Note: This project will almost certainly void your warranty, but that's true of most good projects.
Step 2: Supplies and Parts
Tools I used:
- Soldering iron and solder
- Solder sucker and/or solder braid
- X-Acto knife or similar
- Needlenose pliers or tweezers
- Electrical tape or heat-shrink tubing
- "Helping hands" tool (optional, but highly recommended)
- Philips Hue Lightstrip
- Female connectors (2mm pitch, 6 pin, surface mount - right angle)
- Male connectors (2mm pitch, 6 pin, through hole)
- Ribbon cable (28 AWG, 6+ conductors, rated for 300V)
- Foam mounting squares or double-sided tape
The ribbon cable was leftover from a previous project. I decided it was safe to use here because the lightstrip connects to the control module by a similar ribbon cable, and my cable was rated for voltages beyond what this lighting system would ever see (it's actually labeled for "appliance use"). You can substitute something easier to solder if you wish.
The connectors need 6 pins, but you can buy long strips and cut them to size. The male connectors are "through-hole" style (straight on both ends). The female connectors are "surface mount - right angle" style (note the zigzag on the metal pin). The important part about these connectors is that they are "machine pin" style, meaning that the pins and sockets are round. Typical pin headers have square pins. Round pins are harder to find, but I chose these specifically because they match the connectors that the lightstrip and extension kit already use. By using the same connector, we retain the ability to connect an extension. I tried a square pin header initially, but it didn't fit very well (your classic "square peg in a round hole" problem).
If you buy long connectors and cut them to size, don't try to cut in between two pins like you might do with a regular pin header. The spacing is so tight and the plastic so thin that attempting to cut between the pins is almost guaranteed to damage the neighboring pins. Instead, pull out the seventh pin and cut the header in the space where that pin used to be.
Step 3: Split the Sub-strips
Important: The first sub-strip is connected by a ribbon cable to the control unit. Leave this connection intact. Only split the connections between adjacent sub-strips.
Using a sharp knife, cut away the rubber casing to expose the solder joint between sub-strips. You want the entire length of the joint exposed, plus a bit extra to give you some room to work. Don't expose any of the electronic components, though.
Once the joint is exposed, remove the solder from the joint and separate the two strips. Once separated, clean up any remaining solder and make sure that you haven't accidentally created any solder bridges.
The desoldering work was the hardest part of this project for me. I melted the solder using a soldering iron and used a solder sucker to remove the solder from the top of the connection. There is also solder between the strips and running through the holes in the connection pads, so I used some solder braid to remove most of this. Even with no visible solder the strips were still stuck together. I had to heat up each individual pad with the iron while using an X-Acto knife to gently pry the two strips apart (it's easy to tear/cut the strips while doing this). I suspect that my cheapo soldering iron was not hot enough to melt this particular solder effectively. A proper desoldering tool - or even a temperature-controlled soldering iron - would likely have fewer problems with this.
Note: While strictly optional, my helping hands tool was invaluable here. It's much easier if you can hold the strip level and flat while you're working on it. Some alligator clips are strong enough to bite completely through the rubber casing, though, so you might want to add a little padding (I wrapped a strip of paper towel around the strip).
Step 4: Add Connectors
Soldering the connectors is a bit tricky. You have to hold the strip and the connector in place, plus have free hands to hold the solder and soldering iron. If you're an octopus or if you have an assistant, you can probably solder these the traditional way.
If you're doing this by yourself, solder the connector in two steps to minimize the amount of hands you need at any given time. Use a helping hands tool to hold the strip (grip it close to the area where you're working) and apply a blob of solder to each of the pads. Hold the connector using needle-nose pliers or tweezers and gently press the connector down onto the pads while heating the solder blobs. Once the blobs melt and the connector sinks in, remove the soldering iron and everything will solidify in place.
Double-check that you haven't bridged any of the pads. If that happens, remove a little bit of the solder and re-heat the joint to clean it up.
After you've added connectors to all the sub-strips, give them a quick test before continuing. Use a male connector to connect one of the sub-strips to the first sub-strip (the one that's still connected to the control unit). If you can power it up and both sub-strips light up, then everything should be working.
Step 5: Make Cables
Make some cables to run between the sub-strips. Cut the cables to whatever length you need, strip the ends, and solder them onto a six-pin male connector. Since the original connections were soldered directly together, your cables should be wired straight through (top pin to top pin, second pin to second pin, etc).
Make sure you attach the wire to the side of the connector that has the barrel-shaped protrusion. The open side of the connector should be flat. It will still work if you get it backwards, but the connectors won't sit flush while mated.
If you're using ribbon cable like I was, be very careful when splitting the strands and stripping them. This isn't what these cables were designed to do, and it's easy to expose part of the wire that you weren't trying to expose. If that happens, cover it with electrical tape or cut the end off of the cable and try again.
Step 6: Safety
Both your light strips and your cables have exposed solder connections. We need to insulate these connections to protect your equipment against accidental shorts and to protect your humans against accidental shocks.
I wrapped mine with electrical tape, which worked well enough. Heat shrink tubing would have been a better option, but I didn't have any that would work on a connection this size and shape.
Step 7: Install
Decide where you want to mount each of the strips. The first strip is connected to the control unit and must be near a power outlet. It works best to place this one first.
The light strips come with an adhesive strip on the back. Simply peel off the paper backing and stick them wherever you want them to go. The control unit also mounts this way and is short enough to hide behind the lower lip of the cabinet.
After the strips are up, use your cables to connect them together. Take extra care to ensure that you're connecting to the correct end of the strips. One side of the connection must have a visible "cut here" line nearby (looks like a pair of scissors), and the other side must not have this line. Also make sure that your cables are connected straight-through. My ribbon cable has a red line indicating which side is "pin 1". I made sure that my cables always had that red line facing the back wall. If one side of the cable showed a red line and the other didn't, I knew the cable was twisted.
To keep the cables nice and neat, I stuck them to the underside of the cabinets with foam mounting squares. I cut the squares into thirds to get get long, thin strips that were roughly the same width as the cable. Double-sided tape may also an option.
Step 8: Enjoy
Congratulations! Enjoy your new lighting system. If you like, you can connect it to a virtual assistant for hands-free control.
Participated in the
LED Strip Speed Challenge