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Quiet Media PC made from Junk

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Edward McKeating’s project started not as an exercise in reuse and recycle but because he wanted to move his media PC into the living room to watch TV and videos more comfortably. The problem was that the PC was ugly and very noisy. He decided instead to modify what he had with some of the junk cluttering his garage. The end result is a unique and successful DIY media PC that cost only a can of paint and some time and effort.

April 24, 2007 by Edward McKeating

Edward McKeating is a retired construction worker who likes tinkering with things. His favourite saying: "When all else fails, read the instructions." He thinks that says a lot about him. Edward’s project started not as an exercise in reusing and recycling junk but because he wanted to move his media PC into the living room to watch TV and videos more comfortably. The problem was that the PC was ugly and very noisy. He thought about upgrading with quiet components but decided instead to modify what he had with junk cluttering his garage. The end result is a unique and successful DIY media PC case/system that cost only a can of paint, some time, and rid Edward’s garage of a bunch of junk.

Mike Chin, Editor

This article is intended for people like me who already have a noisy
system they want to make quieter. For someone shopping
for components to build a media center from scratch, the part about fan
control is irrelevant as most decent mobos already have thermal fan
control built in, as do modern PSUs. In general, the cooler you
can keep your PSU and components, the slower the fans will run and the
quieter it will be. So this style of box is still worth thinking about.

I believe that many of the people who assemble their own
computers are already fairly handy and able to make what is really just a wooden box. That’s
carpentry 101. So this won’t be a set of step by step instructions on
how to make a box. The pictures should be self- explanatory.

Pic1
The finished HTPC.

I decided to use the wooden
surround of an old TV set and
other junk cluttering up my garage as the basis of a wooden case for a HTPC. There is a
lot of junk in my garage, while my car lives outside at the mercy of
the Irish weather. Besides the old TV, I had….

  • an obsolete AT case
  • an old stereo amplifier with nice knobs and buttons and an array of handy switches. One of the switches was a double pull double throw that I used as a
    toggle for switching voltage to the fans.
  • a pair of aluminium door
    plates adapted for the front panel
  • an old spark guard provided a fine
    mesh to cover the fan openings
  • other bits and pieces that I’ll
    describe in time.

I regret not taking a photo of the
assembled junk before I started. But the idea of writing an article about it only came to
me after I had begun.

The bits to be housed were:

  • Shuttle AV49n motherboard
  • Intel Northwood 2.4Ghz 533FSB CPU with stock heatsink fan
  • 512Mbs crucial DDR ram PC400
  • nVidia GeForce MX400 video card
  • Hauppauge PVR 350 TV card
  • Codegen 300W power supply
  • Lite-On DVD burner

These were the basic assumptions I started with:

1.  Wood is better at dampening sound than metal

2. My old noisy PSU could be isolated in its own chamber, and
only having to cool itself, it could safely have its fan connected to the
5V line.

3. A fan with a given output will completely change the air in a
small compartment much more quickly than in a large one, especially one
with lots of nooks and crannies.

A mention here of what kind of wood to use: I would stay away
from solid timber. The reason being that if you build the box correctly, you
will basically have a wind tunnel with a heat source in the centre.Because of the heat and airflow, humidity and moisture content on inside of the board will
be zero, while on the outside it will be normal. This would
probably result in cracking and warping over time. Plywood or block board should resist
the cracking; I’d go with veneered chipboard or
fibreboard.  They are much more stable. The old TV surround was veneered chipboard and it stood up to similar
conditions for many years.

DESIGN & CONSTRUCTION

pic2
In the beginning…

I didn’t put a lot of thought into the design.
Making a box to fit the components was about the extent of it. One of the goals was for it to be set under a TV. I
winged it, putting in supports, etc. where needed.

What size? I was constrained by the TV cabinet’s 600mm width and
225mm depth. With the standard mobo and expansion
cards, it would be difficult to make it under 175mm high.  The
depth suited my Shuttle AV49n, which was 305mm by 190mm. Width was about right to take the mobo, PSU and one hard drive
mounted on edge. I cut the cabinet down to about 140mm, keeping
the base, and the top to 35mm. The thing is that if you are making your
own case, you can tailor it to suit what you want.

pic3
As you see I cut the old AT case chassis down leaving only the expansion slots and base for the mobo.

pic4
I used an old PII board as a template.

pic5
If I had had an ATX case to play with, I would have kept the I/O slot.

The next step was to install a bulkhead to isolate the PSU from the main
compartment. Just in front of the PSU, I cut a 70mm hole in the bottom. As the rubber feet on the bottom of the case are about 20mm thick, plenty of air is available for cooling the PSU. The same space was used for the DVD drive as well. I created a space the width of the DVD drive plus the
thickness of two strips of rubber with brass pins. These
would replace the screws in the drive. The rubber comes from a sheet, about
200mm square used by shoe menders to replace worn heels. I used the
same method to mount the hardrive to the floor. Woodscrews then fixed
the rubber strips to the bulkheads.

newpic
Strips of rubber to help damp the vibrations from the DVD drive.

Working aluminium needs care, as it is so easily scratched. I
cut out holes in the aluminum door pushes, for USB and audio
sockets and a “display” made from a glass microscope slide and backed by a
piece of green plastic bag. Holes were also made for the power switch, reset
switch, 5V/12V toggle switch, the big knob from the stereo (which is a dummy
but looks nice). Then there was the hole for the DVD drive as well. Finally,
a new facia for the DVD drive was made; if the stock one wasn’t beige, it would have
been a lot less trouble.

pic6
Before all the other holes were cut in the front panel aluminum.

Behind the display are power and HDD LEDs, the remote
control sensor for the Hauppauge PVR 350 card and a homemade sensor
designed by a guy called Igor Cesko connected to a serial port and
using Girder 3.3 software. (http://www.cesko.host.sk/girderplugin.htm) There is a guy who makes them up and sells them on
ebay for a few GBPs. He even includes a freeware copy of Girder. This
is also activated by the Hauppauge remote (or any old remote) and
allows me to control VLC player, Media Player, and Winamp, or indeed
any other windows application. These sensors always seem to end up on
the floor, so having them built in was a plus. Also it was two less
wires for the tangle at the back.

The top was supported on all four sides, this was important as it
will have to bear the weight of a heavy CRT television. I decided to
paint the whole thing black as it would be more in keeping with modern
AV equipment and here was my only outlay, on an aerosol can of black
paint. The wood veneer was not wasted as the wood grain can still be
seen, giving it a very attractive texture.
The complete article is actually quite light, I could nearly put a handle on top and call it a portable.

pic9
All the components in place, ready for the top cover.

The hard drive is held
vertical by a rubber strip fixed to the floor on bottom and a piece
of angle screwed to both the drive and the bulkhead on top.  Last
thing to be connected up were the fans. The bottle-shaped
black object in the top left-hand corner of the photo above is a 12V to 7.5V 600mA
adapter made to plug into a car cigarette lighter socket. This was
connected to the DPDT switch, scavenged from the old stereo, to
control the fan speed. I disassembled the adapter, removed the end connectors
and soldered the wires to the 12V (yellow wire) and neutral line
of a molex plug.  I also soldered a second live wire to the 12V
pin of the molex plug. This one would bypass the adaptor and go to pin
1 of the switch. The one going through the adaptor would go to pin 3 of
the switch. I would only be using one side of the switch to
switch the fan voltage between 12V and 7.5V. The other side of the switch will be used to connect a bi-polar
LED, as soon as I find one.

Including the stock CPU cooler and cheap noisy PSU fan, there are four
fans. The CPU and one of the case fans had sensor wires. These I left
intact, attached to the motherboard fan headers. I cut all the
live and neutral wires from their various connectors. The neutrals I
bundled together and connected to the neutral coming from the adapter. The
live wires I also bundled together and connected to the central
pin of the DPDT switch. Pushing the button once will establish a
circuit between the central pin and pin 1, 12V. Pushing it again will
break that circuit and make a circuit with pin 3, 7.5V. Later I’ll
try different combinations of fans, but for now I want to have the same
setup as in my orignal computer case to compare the noise level.  I started
up the system with 12V going to the fans and the lid off. Putting the
lid on did result in a slight diminution of the sound level.  I
don’t think such was ever noticeable when putting the side back on a
metal case. 

There are other cheap ways of doing this, using the 5V and 12V lines to get not only 5V and 12V but also 7V. Check out Cliff Anderson’s Fanbus page or Silent PC Review’s Get 12V, 7V or 5V for your Fans article.

FINAL RESULTS

It doesn’t look too bad sitting under the big TV, but as you can see
from the blurry desktop, to use it as a computer I still need to
use a monitor.  My Nvidia series 4 video card will only handle a single
display, which is why I bought the Hauppauge 350PVR, as it, having a
video out, can output to TV and monitor simultaneously, though it will
only play MPGs. I use VLC and
the Girder plugin for remote control for playing everything else. The
case definitelys blend into a living room better than a tower. It’s
also very handy, sitting beneath my monitor, which does not have height
adjustment.  It brings the level of the monitor for me to a much
more comfortable level. And taking it off the floor will limit
the intake of dust.

Functiionally, the system works well for me. The single hard drive is
120GB. With a small partition for the OS, it leaves 100Gbs to store
video. That is about 70 hours of recording. If it get too full, I
will either burn the overflow to DVD or move to a removable drive. If I need to flash the BIOS, I can simply remove the
lid and attach a floppy drive.

pic12

Not having any noise measuring equipment, I could only use the rough
and ready method of using a piece of music. I set the volume control on
the TV to its default setting, sat the same distance away and played
the same music file. I then turned up the volume slider in Windows
Media Player until the noise from the fans became drowned out. There
was a decrease mostly from the heatsink fan, but as
most of the noise is coming from the fans mounted on the outside walls,
soundproofing could only be of limited benefit here. Turning the fans
down to 7.5V was truly amazing. The 40% drop in voltage was
not reflected in the drop in sound level; it was very much
greater subjectively.  Now I started taking the project seriously. Again
without measuring equipment I can only use my own perception, but
sitting three meters away and equidistant from a battery-operated
clock, I could hear the clock tock; if I concentrated, I could also
hear it tick.

Next I wanted to find out what the reduced airflow was doing to the
temperatures. I installed Motherboard Monitor 5. The ambient temperature was 25°C.  I used DIVX to
start converting an MPG file, pushing the CPU to 100% load.  The top
screengrab is taken at 12V, the bottom, at 7.5V, taken after
ten-minutes. My expectation was that I would use the lower
voltage when idle but have to turn it up when under a heavy load. The
difference in temperature though, as you can see, is negligible. Comparing the case temperatures with the ambient temperature shows that the ventilation in this case could hardly be bettered. Sensor 3, by the way, is the hard drive.

pic10
Fans at 12V.

pic11
Fans at 7.5V.

I had so much fun with this project that I am already thinking about a new
improved model. Lots of ideas have occurred to me, mostly for restyling
the front. I’ll probably be cannibalizing this one for parts.

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Articles of Related Interest

Bill’s Recycled, Fanless, Silent Woodbox Computer
Jani’s Big Quiet Wood Case PC
Doug’s Quiet Wood Case PC

Fanless Heatpipe CPU Cooling System by FMAH

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