If It Doesn’t Exist, Make It!

From time to time, you may find yourself in a situation where something you want or need just can’t be found. 

There are various ways to deal with the problem. You can do without. You can use something similar. You can come up with a different way to accomplish the task. 

But sometimes, in the right circumstances, you can build what you need and get the precise solution you desired.

Here’s an example that arose during recent studio renovations at WETA. In an effort to modernize and streamline, we elected to install some StudioHub panels: a headphone amp (P/N SH-HPB), a two-button panel to switch between the “Live” and “Auto” modes of our automation system (P/N SH-2BUTRJ), and a three-button panel to control our EAS device (P/N SH-3BUTRJ). 

StudioHub panels adhere to the Decora standard, and to that end they also sell a 19-inch rack panel (P/N SH-RACK4) that allows the user to mount up to four devices. Similar mounts are available from other manufacturers such as Middle Atlantic, RDL, Lowell, Strong and others, and in various configurations such as 1-4 devices horizontally in a single RU, or up to nine devices vertically in three rack units, so there are plenty of options.

We also needed a small USB hub in the room so that peripherals could be more easily connected removed from a computer, which was located out of the way and not convenient for physical access to the ports. 

Normally this would be a separate device on the counter, or mounted to a rack shelf; but with that one unused space in the aforementioned rack mount, I set about looking for a USB hub that mounts in a Decora opening. After all, Decora is a common standard in conference rooms and home theatre systems, so it must exist, right? 

Well, maybe. If it does, I haven’t found it. I spent way too much time looking. And while I found numerous small USB hubs that could have worked if mounted elsewhere, this didn’t provide the elegant solution I envisioned. 

Designing a USB hub solution

So I set about making my own.

In truth, I did not design and manufacture a USB hub from scratch. While I’m certain I could do so, the quicker and far simpler thing would be to adapt an existing hub into the Decora form factor. 

The “standard” size of a Decora device is 2.62 by 1.3 inches, at least according to Google, so the ports on the hub had to fit within that rectangle. While there were a few that met this requirement, I ended up choosing the CoolGear Model No. CG-3510S4-Board, a four-port USB 3.1 hub module. 

I chose it for three reasons:

1. It did not have an enclosure, which I wasn’t likely to use anyway.
2. Since it is a module, you could clearly see there were mounting holes in the circuit board that I could take advantage of.
3. CoolGear offers a technical drawing on its website that allowed me to confirm it would fit in the space I had available.

Once I received the board, I set about making a few measurements and sketches as to how to mount it in the Decora opening. 

Realistically the technical drawing could have allowed me to start prior to receiving the hub, but I find it best to work with a part in my hand to prevent unforeseen issues from cropping up. 

Since I wasn’t concerned about matching the depth of the cutout, I chose to use a simple flat rectangular plate with two holes to allow it to mount to the rack panel, and four rectangular cutouts for the USB ports. 

This left only the task of how to mount the hub to it. Since the mounting holes in the hub were horizontal and the panel I wanted to mount it to was vertical, I settled on using two small nylon 90-degree mounting blocks (Essentra PCB-MB-01) along with some No. 4 stainless machine screws and locknuts.

For the panel itself, I turned to a company called Front Panel Express, which I’ve dealt with previously. They offer free design software to allow you to create custom panels of any kind, from rack panels to AV outlet covers to complete enclosures, milled parts, signs, etc. Drawing the panel in their software took little time, as their software is intuitive and simple to use. 

While I could have made the panel myself with a piece of aluminum, a drill and some files, I knew I was going to need more than one, and I wanted them all to look good and be interchangeable. 

Had I chosen, I also could have had them engraved or printed with text, the station’s logo, etc. 

The price quoted for my panel, in black anodized aluminum of 2 mm thickness, was just under $30, which seemed reasonable. Price per panel goes down with quantity, so bear that in mind if you decide to use their services.

Once everything was in hand, assembly was a matter of a few minutes. All the parts fit together as intended, and indeed the finished product was quite sturdy and up to the task of folks plugging and unplugging repeatedly.

All in all, a success. And now others who might need to find a USB hub to mount in a Decora panel can also accomplish the task, should they choose to do so.

Costs involved

Here’s the parts list for this project, with approximate costs:

• CoolGear CG-3510S4 Hub: $40
• Essentra PCB-MB-01: 36 cents each, need two
• Custom panel: $30
• Misc. hardware: $2
• TOTAL: ~$75

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