Peripheral Box

by WalkerYYJ in Circuits > USB

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Peripheral Box

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So I spent the last few months traveling for work, and found I was getting frustrated lugging around cables and all the various peripheral boxes for my laptop, so I decided as a weekend project to build an all in one solution to holding all the various bits in one slightly more convenient container.


I started the project with an old Pelican 1050 transparent case, which had served me well over the years, I decided to use a larger case than necessary so I could also carry my laptop power supply and a few more goodies as well. The basic idea was to integrate all the components in to the bottom half of the case, while leaving the top half free for any other items that had to be carried about.

Basic Materials used:
-Pelican 1050
-Amphenol environmental through bulkhead USB connector (Newark)
-4 port Logiix USB hub (LGX-10015)
-Alfa Networks 500mw WIFI card (AWUS036H) {Has more juice than standard laptop card}
-No name USB multi format card reader/writer
-Small sheet of 3/16 Lexan
- 6 pin dipswitch
-Assorted shop supplies


I also recommended downloading a USB pin out diagram

Cut Cut Cut!

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The first step was to measure and cut the lexan, alas I did this by hand and did a rather poor job with keeping the edges straight (however most of this was cleaned up later.) The first chunk I wanted to form a new flat deck for the box, elevated with its bottom starting ~ 14mm from the original case bottom. Because the Pelican case is slightly tapered I was having trouble getting accurate measurements, so I filled it with water to the desired height and tossed it in the freezer to get a positive mold of ice in the correct dimensions.

After the water was nice and solid I popped out the ice cube and quickly traced it on the Lexan before It melted. After that it was time for some elbow grease!
After the main floor plate was cut I repeated the process with the case on its side to form a sheet that would act as a support/shield for the CF reader.

(If anyone goes to recreate this project I HIGHLY suggest building a jig first as I think you would get a much better result and solve a lot of other clearance issues later on down the road.)

I then cut the floor plate to make it ~20mm shorter than original, At this point the CF side support was then cut at the bottom to agree with the ~14mm base height restriction, the two pieces were then cemented together with a small support strip for reinforcement.

Pop the Box

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I then started taking the peripherals out of their cases to establish proper alignment;

As I had suspected when I was first gathering supplies the CF reader was going to be the closest fit; After getting the board out of its case I was able to see how the fitment was going to play out. The taper in the case prevented the card from being fully inserted, after having a peak at the board it appeared there was a bit of unused space I could shave off to help make things fit.
After deciding on the cut point I taped the area to be removed, and covered the components, then removed the the dead chunk of board.
I made a point to test all the components after each major modification just to be sure I didn't miss anything.

Crack the Hub

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After the CF reader was figured out, I went to work on the hub;
I decided I was going to hardwired three of the components and leave an open plug for future additions (Wimax/3G/IronKey etc.)
So that meant I needed to remove three of the plugs on the hub (as well as on the other components.) So i figured this would be a good excuse to go buy a desoldering Iron, the 808 series by Hakko is a very high quality unit under $250.
After pulling the now superfluous plugs I marked and cut the excess parts of the hub. This time I used a rotary tool and as you can see this is differentially a "hand made" unit.

I also at this time took the Amphenol plug apart with the Hakko and Dremel, as well as a small $8 thumb drive (I plan to put a bigger/faster one in at a later point)

Pulling the Plug

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I decided to retain two removable plugs, The first making it a bit easier to get into the box in the future, and the second because I still may use the card in another project.
1) Originating at a solder joint from the bulkhead connector ending in a 5 pin mini to the hub

2) Originating at a solder joint from one of the now liberated ports on the hub ending in another 5 pin mini going to the wifi card

The big problem was the strain relief on standard 5 pin mini USB cables is too long to allow things to fit, so I decided to go buy the cheapest garbage USB cable I could find (cheep= poorly built connectors; poorly built connectors = a LOT less hassle when pulling them apart.)

Putting It Together (rough Fit)

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At this point I had enough components far enough along to start putting things together and drilling mounting holes.
I found a small interference problem with the bulkhead connector because of the case taper it sits at a slight angle, but it was simple enough to remedy with a small grinding stone and buffing pad.

I also at this time cut a hole for the dipswitch. The use of the switch is to be able to disable/enable components, in case you don't want a device powering on either for software issues or if later a 3G card (or something else with large power draw) is to be added. This way if there was insufficient bus power to run all the devices you could power down certain components; It may also have a small benefit for running a laptop off battery power.
To kill power I wired pin 1 (+5V) of all devices into the switch, I went searching for the recommended pin to kill but was unable to find any concises opinion on the matter, but this way does appear to work.
(As a side note on power, the specific hub I chose to use also has the ability to be powered, there is enough room in the box to later mount a battery and small 5 volt regulator if a large draw device is ever added.)


I also at this point pulled the 5 pin connector off the CF reader and soldered in its lines. After that nonsense was done I measured and mounted the reader on the lexan

Pull Out the Solder!

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After basic fitment was finished, I started connecting the devices to one another. For the most part I tried to use ribbon cable to keep things organized, considering these are such short runs shielding/twisting/and abnormal line lengths from pin to pin I am told are no issue.

Finishing Up!

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After all the electrics checked out I finalized the support locations and cemented them to the case. After witch I drilled/tapped pilot holes through the new floor plate and supports to hold the whole assembly together. I was originally going to just use the little 1/2" 4-40 Taiwanese screws I used at all the other points in this project, but when mounting things I managed to snap off a few heads, so I decided to stop messing about and use some 316 stainless North American made hardware (we DO know how to make good stuff in this part of the world, we've just gotten lazy over the last 30 years.)



After everything mounted well, I pulled everything apart one last time, cleaned all the components, hit everything with conformal coating to add to water resistance, removed all the pen marks, and buffed all the marks on the plastic.
I then took the original rubber insert that came with the peli case and cut it to shape. It extends to be flush with the bottom of the new floor, and avoids the CF area. Considering the insert also acts as the cases gasket I made sure to keep the top section intact.

After which I mounted the bulkhead connector for the last time, being sure to silicone everything and use stainless hardware.


One final clean, and its done!
ENJOY!


I'll probably pull the 4GB module in the future adding a high speed 64GB chip, and I wouldn't mind getting a GPS in here as well, perhaps for the next project...
Any comments or suggestions would be greatly appreciated!

-Walker