Introduction: Fire Pit With Sound Reactive Flame, Bluetooth Speaker, and Animated LEDs

Nothing says summer time quite like relaxing out by the fire. But do you know what's better than fire? Fire AND Music! But we can go one step, no, two steps further...

Fire, Music, LED lights, Sound Reactive Flame!

It may sound ambitious, but this Instructable has all the information you'll need to make just that!

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This project was based on a physics experiment called a Rubens Tube. It's essentially a way to visualize pressure caused by vibrations in a tube. I'm not going to get into the science behind it but I encourage you to look it up right now if you've never seen one.




Full disclosure, this is not a cheap project. I spent somewhere between $300 and $400 on parts and the build took me about 20 hours over 6 days. It's well worth it, but you have been warned.

Parts: Use the affiliate links to support my content

Wood (white 1x6, 1x4, 1x2, ¼ inch plywood)

Bluetooth Speaker Amplifier -

Midrange speakers -

Subwoofer -

3 inch Galvanized steel Duct - Hardware Store

4 inch Cap -

Aluminum Tape -

Propane Adapter -

Refillable Propane Tank -

PTFE Tape -

Various Hardware Store Parts for Gas (See Video)

WS2812b LED strip -

Arduino Nano -

24 V power supply -

Power Cord -

24 V to 5 V adapter -

Speaker Mesh -

Acrylic -

Fire Rocks -


Miter Saw -

JigSaw -

Circular Saw -

Drill -

3D Printer -

Soldering Iron -

Hot glue gun -


Solder -

Hot Glue -

Screws -

Drill Bit Set -


Step 1: Cut Out the Walls

Start by building the frame that’s going to hold everything. The outer walls are cut out of the white MDF. The size of the box will be 12" x 24" x 22" on the inside. For the outer dimensions add the thickness of the wood you are using.

You'll need 8 long boards and 8 short boards. Use a miter saw to cut the boards at 45 degree angles so the edges sit flush together. The inside measurements will match the dimensions that i mentioned earlier so for the longer boards cut the inside to be 24 inches and the shorter boards will be 12 inches inside.

Now that the side walls are cut, you'll need to cut four lengths of 4 by to the 22" height of the Fire Pit. These then get screwed to the inner edge of the long white boards. We're going to wait to screw on the side walls until we have everything on the front and back done.

Now is also a good time to cut the base and LED tray out of the thin Plywood. The LED tray should be 12" x 24" and the Base should be that plus the thickness of your walls. These can also be set aside for now.

Step 2: Set Up Speakers

Speaker set up depends largely on the driver and speakers you are using. In my case, the mid range speakers I was using just needed to be connected to the driver in the left and right slots. My Sub woofer came with instructions on how to wire it for different impedance values so I just followed the instructions for 8 ohms.

At this point you should plug in your driver and try to play some music to make sure it's working.

Step 3: Build the Tube

This is where the fun begins. Start by cutting your galvanized steel tube down to size. The correct size depends on the speakers you're using because you want to cut your tube to be 24" - (the depth of the mid range speaker). This will ensure that they will fit together snugly in the box.

Use a piece of masking tape to mark a straight line and drill a 1/8" hole every inch along the length of the tube. Opposite from these holes, you'll need to drill a hole big enough for the 1/4 MIP to hose adapter.

Bend the two large washers to match the curve of the tube. Place one on the inside of the hole and the other on the outside. Stick the adapter through the holes and seal it generously with aluminum tape.

Close the pipe and seal the seam with aluminum tape. Place the 3" cap over one end of the pipe and wrap the seam with more aluminum foil. Cut the tail off the balloon, wrap the balloon over the opposite end, and seal it with aluminum tape as well.

Step 4: Build the Gas Connection

It's very important that all your parts fit together properly to ensure a seal. If any parts are incorrectly paired you could have a gas leak. Also remember to always use PTFE tape when screwing gas parts together.

The easiest way to understand this is to watch the video above. I couldn't get a good picture of the whole thing together.

The tank will connect to the 20 lb adapter that will screw into the flow regulator. This will then connect to the ⅜ flare ⅜ mip union that can be screwed into the ⅜ inch brass ball valve. The other end of the valve connects to the ⅜ mip to ¼ inch inner diameter hose adapter. This is where you’ll connect the ¼ inch inner diameter silicone hose. The other end of the hose will connect to the ¼ inch mip adapter that was screwed into the hole in the bottom of the tube.

Step 5: LED Lighting

Cut the LED strip into six segments of 15 LEDs. Solder them together end to end, making sure your arrows are always pointing in the right direction. The Data In pad of the first section can be connected to pin 4 of your Arduino Nano.

Flash the code found on my github to your board and test that your strips are working.


Now is the best time to get the Power Supply working. Screw the Positive, Neutral, and Ground wires of your extension plug into the correct terminals on the supply. Connect one output to the power input on the speaker driver and connect another to the 24V to 5V adapter. The output of the 5V adapter should go to the Vin pin of the Arduino as well as both ends of the LEDs.

Make sure everything shares a common ground and you should be ready to move on.

Step 6: Add the Base and Side Walls

Before putting the box together you'll want to screw everything into the sides first. Start by 3D printing the files from my Thingiverse.


While you're waiting for the prints to finish, cut out the holes for each speaker, the speaker driver, the ball valve, and the gas tanks. These can go anywhere you think they would look good, I put the ball valve handle on the back with the propane storage hole.

Once the prints are done, glue the speaker mesh to each speaker cover, then screw one of the midrange speakers and the subwoofer into the wall with their covers. Glue a piece of scrap would flush with the base of the hole for the speaker driver to help support it. Then screw the front panel on, add the dials, and glue it into place.

For the ball valve I just used aluminum tape to hold it in place but I will probably end up replacing it with a more permanent solution later.

Now that the front and back are done you can screw in the base. After this, work your way up, screwing in each side panel to the 1 x 4 on the back of the front and back panels.

If you haven't already, cut notches out of the corners of the acrylic and the LED board to fit in with the 1 x 4 frame (see picture).

Finally, you'll want to drill a hole in the acrylic and the LED board for the hose to pass through to get to the tube. Then you can glue support 1 x 2 pieces in place to hold the LED board and acrylic.

Step 7: Finishing Touches

Once everything is in place all that's left to do is add the tube and other speaker. I through together some scrap wood to give something for the tube to sit on to keep the acrylic from getting too hot and melting. I also glued some extra scraps to one side that I screwed the last speaker into.

Once this is in place you can pour the lava rocks in place and turn it on. Be sure to thoroughly check for any gas leaks before turning it on. Always be responsible with an open flame, all it takes is one bad choice for a fun night in the backyard to go wrong.

Lighting Challenge

Participated in the
Lighting Challenge