Adjustments

The main adjustment you will want to make is the gain on the microphone breakout. This is a tiny silver potentiometer on the back of the board. Use a small phillips screwdriver to make small adjustments while you make sounds or play music with both some loud and soft passages. This might take a bit of patience.

You may want to rearrange your pixels to produce colors in a pattern that you like.

You can change some of the constants at the beginning of the program to also adjust the behavior.

Finally, the brightness potentiometer is optional - in a cabinet you may want maximum brightness although in a dark room, it is beneficial to tone down the light a bit.

Here is the circuit without a cabinet, the Neopixels brightness was reduced to allow for photographing without oversaturating the camera:

Mounting

The typical color organ cabinet of the 1970s has a wood grain or black plastic box and a clear diffuser. Of course the wood grain was typically faux.

To create your own cabinet, you can chose nearly anything. A clear plastic case works well but the light will not diffuse through a clear lid, it will go straight through and you will not get that fuzzy light look.

You may select a cabinet size to suit your decor. Repurposing a box made of nearly any material is ideal. To give it that faux wood grain look, there are a number of contact papers available marketed as shelf liners that would do nicely. To make an inexpensive diffuser, a replacement fluorescent light fixture plastic cover is ideal and inexpensive.

Supplies may be found at home stores. In the US, Home Depot has the following:

• OPTIX 23.75 in. x 47.75 in. Prismatic Clear Acrylic Light Panel

For the faux wood look, optionally you may chose:

• Con-Tact Creative Covering 18 in. x 75 ft. Light Oak Multipurpose Shelf Liner, roll

Cover your box in the self adhesive liner and cut a section of diffuser to cover the open end of the box, allowing the LED lights to shine through.

If you want a more professional look, a well made wood cabinet is hard to beat.

Place your electronics in the back of the box, spacing your LEDs to suit your desired pattern. Test the project before securing the LEDs to the back of the box to ensure you like the light pattern when sound is made. If you find the sketch is not producing the ideal light pattern, you can change some of the parameters to get a reaction more suitable to your taste. Ensure you adjust the microphone gain to pick up the sound at the levels you want. When done, cover the front with the diffuser, and place in an area to add that special ambiance.