Humans have been connecting around fire since the dawn of time. The fireplace is the focus of many houses and apartments, but our urban lifestyles don't always lend themselves to all the tending and feeding a fire requires. Many houses have antiquated fireplaces that no longer work, but are still designed to be the focal point of the room. 

In this project, we'll create an artistic LED fireplace insert for your fireplace. Laser-cut clear acrylic flames are placed above high-density LED strips controlled with WLED, a free, open-source control program that works over WiFi. The flames "disappear" when they're turned off, but can be started up with a click on your phone or a request to Alexa. Make your own custom flame animations in WLED, which gives you sliders and palettes and all sorts of controls. 

Take back your hearth.

Parts

You'll Also Need

• A laser cutter (Don't have one? Go join your local makerspace!)
• 3/4" Clear heat shrink tubing for sealing the ends of the strips
• Hot glue gun
• Soldering iron & accessories
• 1/4" plywood sheet for the base 
• 1/4" cast acrylic sheet for the flames
• Wood glue or CA glue

You can get the plywood and acrylic both at your local hardware store, or shop around online once you know your project's dimensions. My project used about 24" x 36" of each to make a fireplace that is about 20" wide and 15" deep, with a height of around 13".

The three wires from the light strand will connect to the three pins on the Mini Sparkle Motion as follows: 

• Red to +5v
• Green to 33
• Black to G

The NeoPixel strips will zig zag through the project. Take note of the arrows on each strip. Make sure the arrow is pointing away / downstream from the controller for each strip. Always connect DO (data out) on the previous strip to DI (data in) on the later strips.

The project will be powered through the USB port on the Sparkle Motion -- plug in your USB cable for power. 

This page will guide you through how to install WLED on the Mini Sparkle Motion.

The Mini Sparkle Motion has a USB to serial chip which may need a driver installed before you can install WLED. Head over to the How to Install Drivers for WCH USB to Serial Chips tutorial, and download and install the new driver.

Install WLED

These next steps require a Web Serial-compatible browser. As of this writing, that means Google Chrome, Microsoft Edge, Firefox 151 or Opera “desktop” browsers. Other browsers (Safari, older versions of Firefox, Explorer and anything mobile) won’t work.

Setup & Preferences

Enable AudioReactive Mode

Do this first before setting up your LED preferences with your GPIO number. 

LED Setup

Use It

Now you can use any computer or handheld device to control your LEDs. 

Make sure your device is on the same WiFi network as your board. Navigate to your custom URL (projectname.local/ ) in a web browser. You'll see a color picker above a whole bunch of color palette choices.

Choose a color, choose an effect, and watch your lights animate and glow!

Save your favorite combinations as presets, create playlists, control the speed and intensity of the animations, and lots more. This web app is incredibly intuitive and easy to use.

Head over to the WLED wiki at https://kno.wled.ge/ to delve into all the particulars.

Troubleshooting

If your lights didn't come on, here are a few things to try:

1. Head back to WLED and check your pinout configuration under LED Preferences. Be sure the pin number is the correct GPIO for the attachment point you used.
2. Check your wiring! Be sure you connected to the IN end of the LED strip. These strips can be inconsistent so this is a pretty common problem. Use an alligator clip to try connecting the data wire on the other end (the power and ground wires should work from either end).
3. Try re-uploading the WLED software. 
4. If the lights come on but you can't control them: i.e. you type in "projectname.local" into your browser and it won't connect, make sure you're on the correct WiFi network. If you're on a different network than the one you set up the sofware on, you won't see the WLED connection.
5. If your lights came on in blue or green instead of yellow, your color order is wrong. See below to fix.
6. If only half your lights came on, be sure you've got the correct number in the "length" field under LED preferences.
7. If your lights came on in a variety of weird colors and looking like a 1950s diner interior, you may have the wrong LED strip type selected. RGBW strips and RGB strips are not the same, so be sure you've got the correct strip type or you'll get very odd behavior.
8. If your microcontroller hangs or keeps rebooting, or gets really hot, you may have the power and ground lines switched. Unplug right away and check: this is a fast way to brick your controller.

Start by measuring your fireplace. Mine is trapezoidal. It measures about 20 inches wide at the back and 30 at the front, and about 18" deep.

My plywood base ended up at around 19" wide and 11" deep - about the size of the little log-holder grate. My tallest flames are around 13" high. The whole thing fills about 2/3 of the space when I set it up on a 2x4.

Design

The base is made from 3 pieces of 1/4" plywood, stacked on top of each other. The bottom layer is a solid base layer, with a cutout to leave room for the USB port and Mini Sparkle Motion board. The middle layer holds the LED strips in place in a zig-zag channel, and the top layer has slots that will hold the acrylic flame pieces vertically, centered right over the LEDs.

The flames are cut from 1/4" cast acrylic. I used the DLM Spartan laser at my local maker space for all the cutting.

Download the LightBurn project file below, or an .svg file if you use other software for laser cutting.

Modifying

Base Layers

Resize the base pieces to fit your fireplace, but be careful to keep the slots for the LED strips about the same width they are now. The strips fit a little loosely in there, so downsizing by an inch or two should still work, but if you make it a lot bigger or smaller the LEDs won't fit anymore. Keep them the same width if you're resizing by a lot.

Also, if you resize, make sure the slots on the top layer still line up with the center of the LED strip slots on the middle layer, so the acrylic is perfectly positioned above the lights.

The USB port cutout can be modified to fit the cable you plan to use. I ended up cutting this out of the base layer as well as the middle layer because the cable and Mini Sparkle Motion are slightly taller than the plywood. This gave me a little more room to work with, but I had to add some tape to the very bottom to give the Mini Sparkle Motion something to sit on. If you're using thicker plywood for the middle section, you can get rid of this cutout.

Flame Layers

The flame images are copies of each other that are slightly modified in length and height to add variation to the final piece. Feel free to squish or stretch them until you're happy with the layout. Make sure their final lengths will fit into the three slots in your project.

Or if you want to draw your own flames, here are a few tips: 

• Don't make any super narrow "choke points" on the flames. The light needs a direct line to the tips to shine bright. I could have done better with this. The flames are also more likely to break at the choke points when you're popping them out.
• Leave about an inch of uninterrupted plastic at the bottom, to rest on the LEDs.
• A little variation goes a long way! Remember you can cut the same flame over again, and flip it horizontally to get a whole new shape.

Laser Settings

I used ChatGPT to help me figure out the best settings for cutting on my laser. Tell it what kind of laser and how many watts and it'll give you some good advice about what to try. For my makerspace's very powerful 1100W DLM Spartan laser:

• 1/4" Plywood: 12mm/s and 90% power, with air assist
• 1/4" Acrylic: 10mm/s and 75% power, with air assist

Your mileage will vary. It's really helpful to cut a small square out of the corner of your material to test your settings before bulling ahead. I also had varying results with different plastic sources, so take your time and do some tests first, or you may end up with more scorch-y flames than you intended. (Ask Me How I Know)

The light looks a little weak in bright daylight, but once this is inside my fireplace with a dark surround, the effect is really beautiful. 

I also tried placing a mirror behind the flames to add more depth, but it actually introduced a lot more light into the fireplace and made the piece less effective overall.

I recommend doing the laser cutting first, so you have something to measure your light strands against to get them the perfect length. 

These strips are cuttable at any point. I found it easiest to just place the long strip temporarily into the laser cut slot to get the exact length I needed. Leave a little room at the ends of the slots for the wires to wrap around.

Slide on some more clear heat shrink and then connect the OUT end of the previous strip back to the IN end of the newly cut strip, leaving an inch or two of wire -- enough to comfortably get around the bend in the laser cut base.

Connect the third strip the same way. Once you've tested and verified they all work, seal up the ends with a little squirt of hot glue inside the heat shrink.

A flaming fireplace has endless variety, with flickers and hot spots that move and change, and flames that create a mesmerising organic rhythm. WLED comes with a couple effects that mimic a fireplace, and do a pretty good job of it. But with the addition of layered effects in WLED 16, we can go a little further and make something with color variations and much more randomness to capture our subconscious primal mind, making a much more convincing fire.

Working with Segments in WLED

A segment is a defined range of LEDs that WLED can control independently. You can divide one long LED strip into separate zones, give each zone its own colors or effects, or—new in WLED 16—stack multiple segments on the same LEDs to combine effects together.

For this fireplace project, segments let you build a more layered, realistic flame. You might use one segment for a slow orange-and-red fire effect, then place a second segment over the same pixels for twinkles, sparks, or a soft yellow shimmer.

Open the Segments tab and expand a segment to see its settings. Segment 0 is the default segment and normally covers every LED in your project.

Segment Layout Controls

Start LED and Stop LED define which physical LEDs belong to the segment. Use separate, non-overlapping ranges when you want different parts of a project to behave independently.

Grouping makes multiple physical LEDs behave as one larger virtual pixel. For example, a grouping value of 2 makes every pair of LEDs display the same color. This makes effects look chunkier and slower-moving, which can be helpful on very dense LED strips.

Spacing leaves dark LEDs between the active virtual pixels. A spacing value of 1 lights every other LED; a grouping of 2 with spacing of 1 creates pairs of lit LEDs separated by one unlit LED. Spacing is useful for special physical layouts, but for this fireplace you will usually leave it at 0.

Offset shifts where an effect begins within the segment. It does not move the physical LEDs; it rotates the effect’s starting position. Use it when an effect almost lines up correctly but needs to start a few pixels farther to the left or right.

Reverse and Mirror

The Reverse checkbox changes the direction an effect travels through the segment. A chase that normally runs left to right will run right to left instead. This is especially useful when you have two strips wired in opposite directions or want two halves of a project to move toward each other.

The Mirror checkbox reflects the effect around the center of the segment. Instead of one flame or sparkle pattern traveling across the whole strip, the same pattern is created symmetrically on both sides. Mirror works well for designs with a strong centerline and actually looks pretty good on this project.

The Blend Mode dropdown determines how the upper segment combines with the layers beneath it.

Top / Default shows the upper segment normally and ignores the lower layer wherever the upper effect is drawing. This is the most straightforward setting, but it can make an overlay look opaque.

Bottom / None shows only the lower layer. This is mostly useful for temporarily hiding the upper segment without deleting it.

Add adds the colors together, making the result brighter. This is one of the best choices for sparks or glowing embers over a flame effect, though too much brightness can wash the colors toward white.

Subtract removes the upper layer’s color from the lower layer, darkening the result. It is more of an experimental or special-effects mode than a fireplace setting.

Difference compares the two layers. Similar colors become dark, while very different colors become bright. It creates dramatic, unusual color changes.

Average mixes both layers evenly. This can create a softer combined effect, though it may make your fire colors look muted.

Multiply darkens the lower layer based on the upper one. White allows the lower layer through, while black blocks it. It is useful for adding shadow, texture, or a masking effect.

Divide brightens the lower layer where the upper layer is dark. It creates a more intense, high-contrast result and is best saved for experimentation.

Lighten keeps whichever layer is brighter at each pixel. This is useful for placing bright sparks over a darker fire without adding too much extra color.

Darken keeps whichever layer is darker. It can create shadowy, smoky effects.

Screen is a brightening blend mode that treats black as neutral and lets white win. It is excellent for soft glows, fireflies, sparkles, and warm highlights.

Overlay increases contrast by darkening dark areas and brightening bright areas. It can make a fire effect feel richer, but use it gently because it can become intense quickly.

Hard Light is a stronger version of Overlay controlled more by the top layer. It creates punchy contrast and vivid color.

Soft Light is a subtle version of Overlay. It is a good choice when you want to add texture or movement while keeping the original fire effect recognizable.

Dodge brightens the lower layer based on the upper layer. Light pixels in the top effect create strong glowing highlights.

Burn darkens the lower layer based on the upper layer. It can add soot, shadows, or darker texture.

Stencil shows the top segment wherever it has color and reveals the bottom segment anywhere the top segment is black. This is useful when the upper effect acts like a moving cutout or mask.

It's a lot of fun to sit and toy with the fire, playing with brightnesses and colors and speeds. The possibilities are endless. 

Once you're happy with a combination, SAVE IT AS A PRESET IMMEDIATELY. A stray click can undo all your hard work as clicking on a different preset will reset all the segments and all your tweaks will be lost. 

You can always refine the presets using the "overwrite with state" checkbox, so save your work early and often. 

I played with my fire for quite a while and made a handful of different modes. This one is my favorite!