While I have no Arduino experience, I've read this thread and watched the embedded tutorials and I'm going to try this DIY project. Please confirm that my list of parts is complete:

1. Speaker Lights Kit Type-12

2. Micro controller w/soldered pins and USB cables
ebay.com link: itm

3. Barrel power connector x 2 (It's not clear to me if these should be male or female.)
ebay.com link: itm

4. 5V 144/m RGB LED strip, 1m x 2 (OP doesn't specify length. Just "x2." Does he mean 1m x 2?)
ebay.com link: itm

I'll get the resistor from an operator friend and I have some spare, light-gauge wire.

Thanks.

Thanks, Scotty, for your help. I still don't know how I will replace the stock LED strip with the 144/m strip, but perhaps it will be intuitive when I get the kit and can inspect how it's made. Your thread and the clips address Arduino, but not cobbling together LED strips. I s'pose there are countless clips on YouTube for that.

In the first tutorial clip you post here, the author shows you how to visit Arduio CC and download free software. Looking at the website now, I'm seeing nothing free. Must I buy the "starter" kit for $92 just to get the basic software?

**update**

Hold on. It looks like I've found something. I'm assuming I need this IDE software:
https://www.arduino.cc/en/Main/Software_

Off to a terrible start.
My soldering iron's spade tip has destroyed the adjacent LEDS at the joint of the two strips.
Must start over, but can't salvage these strips as they are cut to 39 LED's each. If cut away the damaged LED's from the start of each strip, I will have 38 per side - too few! Once you cut the strips and then butt them together, there are at most four millimeters to work with when soldering. I can't get the solder to truly flow onto the LED's conduction pad. Do I need special solder? I'm using the same, ordinary lead operator's solder that I generally use for pinball projects. Mistake? Has it not got the right flux? I'm quickly feeling like I'm in over my head just because the soldering dexterity required seems exceedingly high.

A9E7D562-6F90-43A7-B446-89370CDC8E8C (resized).jpeg

1387C925-9437-417E-8D28-44941F138BA4 (resized).jpeg

83C992E5-7A64-460B-BA9E-218A4A327DBB (resized).jpeg

Thanks, LTG, for your input.
Lead solder shown is from you.
I have just the one tip.
Do you have a spare fine tip I could use?

Take two:

Thanks to all of you for your helpful comments.
I filed the tip of my iron into a true pointed tip and turned it down 40%.
I trimmed off the damaged LED's from the first effort and grafted a short strip onto each longer strip (repair visible). I also "cheated" the trim wherever I was making a butt joint to give me as much clearance as possible.
I did the work on a piece of stainless plate for ease of access. I will now transfer the completed unit to the frame.
The result is a bit ragged but perhaps it will suffice.
It will be exasperating if I get this into the game only to discover there's a break in either data or power. It will then come out I s'pose for take three!

DFBD2710-2440-48AD-865F-8C4C17EA8A7E (resized).jpeg

Oops!
Embarrassing mistake!
I cut out the blunder bridges with an X-acto knife.
Going to flash the code to the controller tonight and fire it up.
Odds are long that it will actually work, but I have to be optimistic!

85E4E554-88ED-4C24-B1FE-89D5722663BA (resized).jpeg

Question re: uploading code using Arduino IDE:

Okay, I have the software loaded and running. I have followed the link here to your code on github. Do I just capture/copy all the code and paste it into my Arduino IDE window, then upload it? I set my IDE software according to the tutorial so I'm assuming it will flash to my controller. Or do I ask IDE to search for a particular "Library"?

Developments, Good and Bad:

I cut/pasted the code into an empty IDE coding window, then saved and uploaded it to my Nano. IDE reported "Upload complete."

I plugged the stock Speaker Light Kits controller into the power supply and then a stock strip to the controller and it throbbed its way through the RBG gamut, so I knew I had power. I then substituted my Nano dongle for the stock controller and, rather than the throbbing, it appeared to be running the flame program on the stock strip. Very positive!

I then plugged my DIY kit connectors from each of the two speaker frames into the dongle using the supplied splitter.
Nothing. (Insert cartoon sound for deflation here.)

It looks like it's back to the drawing board for me. Perhaps I destroyed the functionality of the LED strips in my DIY frames when I surgically cut out the blunder bridges. I really don't want to have to start from scratch, but perhaps I do. I put about six hours into this effort so far, or the better part of my weekend. Oof!

Possible Short?

I had to use sandpaper vigorously to prep the backside of the strip. The solder was *very* resistant to flow there.
My worry is that I've created a short.
When I connect this frame/strip to power, the leads quickly start to get hot and the strip does *not* illuminate.
Do I somehow have power and ground reversed?
These strips are 5V on the "arrow" side and ground on the other, and my

29D7F8F3-EB65-4BD9-82AB-0A8CA1833C2B (resized).jpeg

Now I'm really confused.
Strip seems to revive if I peel a portion of it out the frame.

57559956-733A-469C-8ED3-0F3D914324D9 (resized).jpeg

It's very temperamental. The strip will illuminate, but then go dark with the slightest touch, and within seconds after going dark the leads are heating up and I have to scramble to unplug the power. This is *not* a situation I can work with after the panel is closed and the game is being played! Must be a short, but I can't see where it might be happening. I s'pose I will have to build a new strip pair for the shorted side.
I get low marks on this project. Lots of time invested and still no success. I'm bushed! Still, I have learned a few things.

Thanks, all, for your input.

The frames are painted aluminum with no interruptions in the paint.

Strips have adhesive on the bottom and only have exposed contacts where one strip ends and another begins - perhaps once every yard or so. I had to scratch away the adhesive and then sand vigorously to expose contacts to solder leads to the backside in one spot to deliver power to the strip. In this frame, there are NO contacts on the strip bottoms that could short on the frame. To further insulate the strips from the frame, I used a layer of double-sided tape to help them adhere.

I would like to use my multi-meter to help me here, but I've never used it to find a short. I can use it to check continuity though so I will do some testing.

One more thing: one of my frames is working. It doesn't short. It's no less hacked up than the temperamental frame. The only difference between the two frames is that I didn't have sand the heck out of the back of the strip on the working frame as I just took advantage of that joint I mentioned above with the exposed contacts on the backside.

Signs seem to be pointing to cobbling together a new strip pair for the shorting frame. It won't kill me, but I'm out of gas for sure.

98F41BC5-6229-4071-A152-943AE959E0C3 (resized).jpeg

4471940E-28C1-4C2E-B59D-D667C16C730C (resized).jpegAnother misstep.
I started fresh with new strips and made a new frame.
I used my multimeter to check continuity across power, ground, and data at all my soldering, back to the connector, and it is sound.
Is the left side not getting data or power?

A8E8F94F-0378-4C75-96B4-6A6F4BE2DA8C (resized).jpeg

...be a bridge between the jumper and the data out leg of the LED on that connection (green arrow points to the DOUT pin of the LED)...
[quoted image]
[quoted image]

Wow, Eagle Eyes!
You're right!
Another blunder bridge thanks to my clumsy soldering!
Don't have de-solder equipment, so it's on to attempt #4!

66D01874-EA77-4CE0-B428-D6C92CD7EDCE (resized).jpeg

Finish line reached!
Thanks, all of you, for your patience and assistance!
We did it!
I adjusted the code parameters as follows:
Number or LED's - 35
Brightness - 125
FPS - 50

That's great! You avoided the challenging soldering! Doug was right! It can be done with smarter code!
Any chance you can share a clip of your machine running this code, or is there no perceptible difference?