To make your own LED lights, you choose an LED strip, match it to the correct power supply and wire gauge, and solder or connect it into your project — the most common first build is an LED tube light. The part people get wrong is the electrical sizing, not the assembly: the strip's voltage (usually 12 V or 24 V), its current draw per metre, the wire gauge for the run, and a current-limiting resistor only if you are wiring bare LEDs rather than a ready-made strip. Get those right and the build itself is straightforward.
This guide walks through a complete DIY LED tube light, then custom taillights and a Christmas-light fix, with the free calculators to size each step so nothing runs hot.
LED strip electrical basics (size this first)
Before you cut anything, know what your strip draws. A strip's power adds up fast over a few metres, and that decides both the power supply and the wire you can safely use. These are typical figures for common single-colour and RGB strips — always confirm against your strip's own datasheet:
| Strip type | Voltage | Typical power | Typical draw | Notes |
|---|---|---|---|---|
| Standard single-colour | 12 V | ~5 W/m | ~0.4 A/m | Cheapest; more voltage drop over length |
| Standard single-colour | 24 V | ~5 W/m | ~0.2 A/m | Half the current, less voltage drop |
| RGB / RGBW | 12 V | ~7–14 W/m | ~0.6–1.2 A/m | All channels on draws the most |
| High-density | 12/24 V | ~15–20 W/m | up to ~1.6 A/m | Needs heavier wire and power injection |
Work out your total load before buying parts: multiply the watts-per-metre by your length, then size the supply with some headroom. The LED strip calculator does this for you, and for anything over a few metres the voltage drop calculator shows when a 12 V run will dim at the far end (a 24 V strip or power injection fixes it). Note that LEDs are genuinely efficient — the US Department of Energy puts quality LED lighting at roughly 75% less energy use than incandescent — which is why a whole tube runs off a small adapter.
How to Make an LED Light Tube
What is an LED Strip Light?
An LED strip light is a series of LEDs on a flexible ribbon circuit board, powered as one line rather than as separate parallel LEDs. You will find strips used in art displays, building outlines, signage, subtle lighting near handrails and walkways, and cabinet and kitchen lighting.
You can buy strips from a hardware store or build the fixture yourself — which is what we cover below.
How Do LED Lights Work
LED stands for light-emitting diode. At a microscopic level it is a semiconductor doped with two different impurities, one on each side. When electricity flows across the junction at the correct polarity, electrons drop to a lower energy state, and that step down releases the excess energy as light.
Because the light comes out at a very narrow wavelength, each LED emits a single colour, which the manufacturer sets from red to blue by choosing different semiconductor materials. If you are ever wiring bare LEDs instead of a strip, that single colour also has a fixed forward voltage — use the LED resistor calculator to pick the right series resistor so the LED does not burn out.
Prerequisites for Building a LED Tube Light
Before building an LED tube light, make sure you have the right equipment and materials. Here are the critical components for this project:
- Half-inch (1.27 cm) wooden dowel rod
- End caps
- 5 m LED strip lights (8 mm white PCB flexible ribbon strip with solderless connector)
- 20-gauge two-pin extension wire (confirm the gauge with the wire gauge calculator for your strip's current and run length)
- Frosted acrylic round tube (1-1/2" diameter, 36" length)
- 12 V power adapter with a four-way cable split (sized to your total strip load)
- Soldering iron and solder
- Wire cutters
- Hot glue gun
- Saw (optional)
- File or sandpaper (optional)
- Drill
- Masking tape
- M1.2 screws
How to Make an LED Tube Light
Step 1
Cut the wooden dowel rod down until it matches your acrylic tube. You may have to shorten the acrylic tube too. Make sure the tube and rod end up the same length.
Step 2
Drill two small pilot holes on both ends of the rod.
Step 3
Cut the extension wire a few inches longer than the dowel rod. Tape one end of the wire to the end of the rod, leaving some excess hanging off. Keep the wire tight and flat against the rod: tape it down one side, then the other, so it runs straight across and sticks to the rod.
Step 4
Peel the LED strip from its backing and stick it to the rod, leaving at least half an inch of the rod exposed at the end.
Step 5
Strip one end of the extension wire and solder it to the end of the LED strip — red to positive, black to negative.
Step 6
Strip the excess wire on the other end and connect it to the power adapter for your LED strip.
Step 7
Drill two small holes in the centre of your end caps, small enough for M1.2 screws. Then, on one end cap, drill a larger hole near the edge with a quarter-inch bit for the adapter cable.
Step 8
Insert the LED-wrapped dowel into the frosted acrylic tube. Attach the end caps, feeding the adapter cable through the larger hole, and screw the caps to the holes in the dowel.
That is it — you should now have a fluorescent-style tube made of LED lights.
How to Make Colours on an LED Light Tube
To make the project more colourful, use a colour strip instead of a plain warm-white one. An RGB colour-changing LED strip can be controlled with an infrared remote, or you can program it by wiring it to a Raspberry Pi. Because an RGB strip draws more current with all channels lit, re-check your power supply and wire against the table above.
How to Make Custom LED Tail Lights
You can build custom LED taillights for a car. First, remove the taillight housing with a flat-head screwdriver. Then mould ABS plastic into custom plates with a heat gun.
Lay out an LED grid on the plates, drill holes, and fit the LED bulbs or strips into them. Because taillights use bare LEDs rather than a regulated strip, wire each LED through a correctly sized series resistor — size it with the LED resistor calculator — then solder the connections, wire the LEDs to the car, and secure the ABS plates.
How to Fix Christmas Lights
A string of Christmas lights usually fails at one point in the series circuit. Use a voltage detector to trace the fault while the lights are on. Once you find the failed LED, remove it and reconnect the wires with two pieces of heat-shrink tubing: solder the wires, then shrink the tubing over the joint.
What to Pay Attention to When Working With DIY LED Lights?
As you can tell, DIY LED projects involve a fair bit of soldering. If you have never soldered, plenty of books and videos will bring you up to speed. When you make a mistake, do not rip the wire out — de-solder it instead, using a desoldering pump (solder sucker), desoldering braid, or desoldering tweezers.
On addressable strips, watch the Data-In and Data-Out pins and the arrows printed on the strip: they show the signal's flow direction, and every segment must face the same way. Finally, double-check polarity before you power up — do not mix up the positive and negative pads.
Conclusion
LEDs are efficient, cheap, and easy to work with, which makes them ideal for DIY projects — from an LED tube light to custom taillights to a Christmas-light repair. The assembly is simple; the part worth doing carefully is the electrical sizing. Before you build, run your strip length through the LED strip calculator and wire gauge calculator, and browse the rest of the free LED calculators to size any project safely.
Jack Shi
Founder & editor, LEDaskJack Shi builds and writes LEDask, an independent LED-lighting tools project operated by clooms. He designs the calculators, checks their formulas and reference values against published engineering data, and writes the guides across the site.
