The last time I wrote about my suitcase computer (the one I started back in December), it wasn’t quite finished. As I had feared, the single slot-fan was not able to keep up with the heat. I thought about adding another slot-fan, however the first one was noisy and it would have been tough to fit a second one in. So I decided that my plans to leave the top of the case intact for the “clean” look were going to have to be scrapped in order to install 2 tried and true 80mm fans.

These axial fans turned out to be quieter than the radial slot fan, and push about 10x the air through the case. I had thought about just going with one 80mm fan, but decided that I didn’t want to spend another night after that installing yet another fan when the first wasn’t enough. With the addition of the second fan, I also added a second intake vent, and got 2 filter covers to take care of the dust.

At the same time, I decided to install the ¼” audio jacks that would enable the live guitar effects processing that I originally wanted this machine for. I also bought a distribution block so that I could change around the connections internally if needed. There are a total of four ¼” jacks, two mono, and two stereo. The mono are also switched, and tied to the ring on the stereo jack. This gives 2 jacks for input and 2 for output, for two audio signals each. If I have a stereo signal, I can plug it into the stereo jack. If I have a mono signal, I can plug it into the mono jack, and it switches off the ring of the stereo, essentially turning the stereo plug into a mono plug. This means I can either use 1 stereo, or 2 mono cables for both input and output.

On the inside, in order to wire the ¼” jacks to the sound card, I took a six foot 1/8″ stereo extender and cut it in half. I then wired it to the other side of the distribution block, making it essentially an internal hard-wired patch bay. The 1/8″ plug simply plugs into whatever sound card port I want to use. The only thing that I am still missing is a mic input for when I play games online. While writing this, I came up with a great way to remedy that. Next chance I get, I’ll simply wire another 1/8″ plug to the input (which is on line in at the moment) which will send the signal to both the line in and mic in on the sound card. This will enable me to select which one to use in software without having to manually open and swap plugs, or install another jack on the case for just a mic.

With the computer now 99.99% complete (I never know when I’ll want to add something to it) I am quite happy with how it turned out. It is a highly portable, power-packed, multi-purpose computer – exactly what I intended to make when I started. It serves up flawless 1080p HD video to my TV, plays the latest games, processes live music at high quality, and doesn’t sound like I have a hurricane in my living room. If I were to do this again, I would remove the video game requirement. I don’t play video games that often, and it really killed me on several issues. Without that requirement, I could have a super-low power, compact system that would give me all the HD and audio processing I need. Oh well, next time. For now, I’m calling this project a success. For real this time.

Enjoy the entire gallery of pictures from the project HERE.

 

So tonight I forged ahead with my weeks-neglected suitcase computer build. It is not as nicely finished on the exterior as I would like, but it appears to work. When I fastened everything into the case I ran into a few issues with cable placement. The 90 deg DVI-I connectors covered the onboard sound and back panel USB ports. I was using all the USB ports prior to connecting the DVI cable, but with the cable in place I was only able to use 4 of the 6 plugs. To mitigate this I simply plugged in a dual-USB back panel plate. This finished it off. My only concern is that the single fan I have won’t be able to keep up with the heat. 

Currently it is hooked up to my TV and running like a champ… but with the case open. I’ll have to recap more later, but for now I just had to post the successful near-end.

So over break I was working on my suitcase computer and had a moment (which actually was more like a span of a day) where I experienced what can really only be described as a rapid divergance between a cost-effective self-manufactured parts, and a time-saving purchased part. This is an uncommon failure on my part, but I digress.

This particular failure started out as an effort to make a DVI-I extension cable that will plug in to the video card and extend the DVI-I ports to the edge of the case. For this cable I knew that making my own cables would be painfull and time-consuming, however a search for a usefull commercial product turned up nothing (initially).

The first thing I tried was to take a DVI-D cable that I bought, use a dremmel to cut off the plastic casing around the end connectors, cut the wire and solder it back together shorter. Bad idea. I stopped halfway through the plastic casing realizing I would never get the wires free enough to solder back together.

So I bought a pair each of solder-on DVI-I male and female connectors. This was my first mistake: the DVI cable was DVI-D, not DVI-I. At the time of purchase I did not research the difference, but upon splaying the cable open I discovered that it was 6 wires short of the needed 29 wires for DVI-I.

DVI comes in 3 basic types – DVI-D, DVI-A, and DVI-I – with an option for “Dual Link” in “D” and “I”. The D stands for Digital, and carries the video signal in 3 sets of LVDS (Low-Voltage Differential Signaling) wires, and 8 other signaling and shield wires. The A stands for analog, and uses another 6 wires, using the “+” on the connector and the 4 pins around it, along with the unused pin remaining on the grid of pins and shares a few of the signaling pins. The I stands for integrated, and is a combination of both D and A in one cable. 

Now that we know the types, there’s the Dual-Link option. From what I’ve read, if you don’t know what it is… you don’t need it. Just skip to the next paragraph. It’s not worth your time. Ok, if you insist… Dual link adds 6 more pins carrying 3 more LVDS channels in order to increase the amount of data that can be sent. If you simply say that’s twice the data that can be sent, you would be mistaken. This is twice the data channels. From what I can tell, LVDS is bit-wise signaling, so that means that you increase the information from 2^3 parallel bits, to 2^6 parallel bits. 2^3 = 8, and 2^6 = 64. That’s 8 times the data capability. Not that it uses it. In reality,  the largest resolution possible at 60 Hz is 2.75 megapixels (including blanking interval). For practical purposes, this allows a maximum screen resolution at 60 Hz of 1915 x 1436 pixels (standard 4:3 ratio), 1854 x 1483 pixels (5:4 ratio) or 2098 x 1311 (widescreen 8:5 ratio). -wikipedia on DVI  If you want higher resolution than this, you will need dual-link. Since I don’t know anyone who can afford a monitor with resolution better than this… you just wasted your time reading… congratulations. Next paragraph.

Back to the topic of me failing. So as I sat there looking at the lack of wires needed to make a DVI-I extension cable, I decided to go ahead and try to solder it on, and maybe find some extra wires to make the analog connections. This was my second mistake. I spent a good 2 hours soldering on 24 connectors (D-Dual link). When I finished, I looked at the soldering connections, and realized that there was a better chance of a 1 legged rat making it across a 4 lane highway alive than my solder points having resistance within tolerance. 

So I went back to the internet and started searching again. I found various sites that offered cables that I could probably rig up to work, but not exactly what I was looking for. So I went back to the mess of solder. I thought I still need the “A” connections, so I sacrificed a VGA cable that I had and removed the 3 component shielded cables to get the 6 necessary connections. I prepared to solder them on and simply gave up. I knew that there had to be an alternative. 

So I went back online and searched some more. I finally found a solution. One site offered a panel mount DVI-I extension cable in lengths starting at 1 foot and up. Great! I now have a 1.5′ extension cable, but I have another problem: the distance between the video card and the side of the case is less than the length of the connector plus the minimum bend radius of the wire. NOW WHAT! 

I went back to my combobulation of splayed wires and half cut up DVI-D cable and tried to weigh the chances of being able to cut enough of the panel mount extension plug away to get the bend radius needed to clear the case. Five minutes of holding the butchered connector and I was convinced there had to be a COTS part for this. (commercial off the shelf). So back to the interwebnet!

I finally landed on a site that sold 90 degree connectors for the exact purpose I needed. PHEW! Now the trouble was that the combined price of the 2 panel mount connectors and the 2 90 degree connectors was upwards of $90. One last look at the mess I made with a dremmel and soldering iron and I gladly laid down the cash. 

Today the 90 degree connectors showed up in my mail, and I rejoyced. Success! …at a price.

I usually have no problem manufacturing something for less than the COTS alternative, but this is one case where I will pay the cash over the sweat. What made this such an epic event is the obscurity of the parts to complete this project, and their high price when I found them. So instead of simply finding them and buying them, I sunk time into making the part, knowing that there was more than a good chance it wouldn’t work, and in the end the time cost was too high to justify over the money cost. Fail. Success.

(clicking the picture should take you to the full gallery.) More pictures to come later!

This is the preliminary layout for my new Portable HTPC. It is being built in an aluminum tool box that i picked up from Home Depot for 20 bones. Not bad considering the cheapest computer cases are barely that cheap and not even as close to being this rugged. 

The purpose for this project is to have a computer that will do the following:

• Live music effects processing- plug in a guitar and pedals
• Live music multi-track recording
• Blu-ray Home Theater PC
• DX10 gaming PC

This is quite a lot to ask of a computer, but I think I managed to put together the hardware that will do it:

• mATX board
• Core 2 Duo 7300
• 4GB OCZ ram
• Radeon HD4850
• 160 GB hard drive
• HD/Blu-ray combo drive
• 500 W power supply
• 19″ touch screen
• Custom case