Introduction: Portable Modular Desktop Computer (PMDC)

About: I work in the Aerospace (Space) Industry as a Product Assurance Manager for Space hardware. I have creative ability that allows me to be able to construct a range of different things from bikes and computer sy…

The attached pdf document lists and illustrates the steps I took in making this Portable Modular Desktop Computer. I used a case, PC components and materials I had at home already. A few inexpensive things like double sided tape, aluminium tape, mains power socket, one 500mm x 500mm x 4mm sheet of perspex and two 400mm x 500mm x 3mm sheets of hobby-sheet material I had to buy from the local DIY Home Improvement Store (called OBI) and an electronics store similar to Radioshack and Maplin (called Conrad).

The case I used is pretty rare and came from a limited edition racing bike Shimano Dura Ace 25th Anniversary Groupset, but I checked the local DIY store (OBI) and they had a similar sized aluminium tool case available for 45 EUR (about 50 USD) which would work just as well.

I didn't open up the power supply and start soldering everything in sight to make it all integrated, as I thought the better build would be 'modular' so that all of the standard desktop PC components, including the PSU, could be easily swapped out or upgraded later... Portable, Modular and Upgradable that's what I wanted and that's what I've built. The only soldering I did was with the power cable connections from the display to a mains power socket which I built into the back of the case. Ok, ok, there was a little bit of soldering involved with the dismantling of the speakers from their plastic cases before I transferred them to this build, but I could have avoided that by cutting through the plastic and removing the speakers and volume control electronics in a more crude way.

There is a third fan, which I added to the back of the front panel (bottom left corner) and it's pretty silent running at about 16.5dB. The other two fans for cooling and airflow belong to the CPU and the PSU.

Under load (with a graphic intensive game running) the Graphics GPU was observed to be running at a temperature of 65°C (149°F) which is a little warm, whilst the CPU Temp. was at 48°C (118°F) and the System Temp. was at 38°C (100°F).

I wish you a lot of fun building one :-)

Step 1: Preparing the Case

The case was modified to accommodate the micro-ATX Motherboard interface plate and graphics card interface on the left side, followed by modifications on the right side for the power supply unit (PSU) connector and the optical disk drive (ODD) interface plate. I used a steel rule for measurements and a mini-drill (similar to a Dremmel 8200) with a cutting disc attachment for cutting and just swapped over to a drill bit when I needed to drill holes. Since the case is made of wood covered with a thin aluminium it was relatively light work, but I did take my time to try to keep it as tidy as possible. Bear in mid this is the first time I used such a tool to cut in this way so the cut-outs ended up being a little less than perfect.

Step 2: Base Plate Preparation

The intended base plate dimensions (495mm x 395mm) were measured using a tape measure, prepared using a band-saw and the holes and fixing posts were prepared with the mini-drill for the motherboard [2], relative to the motherboard interface plate position. Note that the corners of the base plate needed to be cut off in order to fit the shape of the case. The PSU was fitted temporarily for clarity of the spatial arrangement. The base plate fitted snuggly into the bottom of the case resting on the top corners of the 45° angle, which meant that there would be an air-gap of around 7mm between the bottom of the case and the bottom side of the base plate. The base plate was covered with a Self-adhesive fablon/Hobbycraft (SAF) material with a gray and black pattern and the holes in the base plate were located and poked through with a drill bit..

Step 3: PSU and Motherboard Cut-outs

The first image here shows the PSU connector and power switch visible through the case cut-out as well as the position of one of the two PSU fixing screws.

The second image shows the micro-ATX Motherboard interface plate. Since the micro-ATX motherboard dimensions are an Industry Standard, it means that the cut-out can accommodate further interface plates, should the motherboard be replaced in the future.

Step 4: Hard Disk Drive (HDD) and Optical Disk Drive (ODD) Mounting

The 3.5" HDD mounting frame was taken from an old 19“ PC rack mounting case. The HDD mounting block was cut to the same dimensions as the mounting frame from wood and then prepared with the self-adhesive fablon /Hobbycraft (SAF) material.

Two ODD mounting brackets were fabricated from wood using a band saw and a router before being prepared with the SAF material and screwed to the top of the base-plate from the under side of the base plate. Screw holes were measured and drilled in the the mounting brackets for securing of the ODD. This was a bit tricky so take your time with this step to get screw-hole alignment right first time.

Step 5: Fitting the HDD

The HDD was fitted to its mounting bracket with standard HDD mounting screws. A gap is left between the HDD top side and the mounting frame in order that the Solid State Drive (SSD) mounting plate may be inserted there later.

Step 6: Fitting the PSU and Monitor Power Socket | Caution: Mains Voltage !!

Caution! Mains voltage can give you a serious electric shock if not handled correctly and therefore you must be certain that you are qualified and/or experienced enough to set up wires, cables and sockets which are to be connected to the mains voltage! If you live in another country it could be higher or lower voltage and could be potentially more dangerous! Under no circumstances whatsoever will I be made responsible for any electric shocks or physical injury if you build one of these PMDC systems - you build it at your own risk and with the understanding that you the builder of such a project/system are responsible for how the wires, cables and sockets are connected to the mains power! If you are unsure seek professional or experienced advice and help rather than taking any risks which may or may not cause physical injury.

The power supply unit (PSU) was then fitted to the case in its intended position and secured using standard PC PSU screws.


A further case-cutout was necessary at the back of the case in order to accommodate a second 230V power socket for the display power. This socket was built directly into the case and the cable connections from the display power were soldered to the socket pins for Live, Neutral and Earth connections. All three soldered mains power connections were covered using heat-shrink electrical wire safety tubing for isolation.

Step 7: Fitting the Micro-ATX Motherboard

The micro-ATX motherboard was fitted to the standard motherboard mounting posts on the base plate using standard PC motherboard screws and care was taken to ensure that the interface connections fitted correctly to the interface plate. Note that the low-profile graphics card and the CPU Fan were pre-mounted to the motherboard. I used mounting posts I got from the old 19" racking case but you can also buy these from an electronics shop or PC hardware store for pennies.Take care to align the screw holes in the motherboard with the mounting posts and ensure the motherboard connections align snuggly and accurately with the interface plate on the side of the case.

Step 8: Fitting the Optical Disk Drive (ODD)

The PSU was temporarily removed and the ODD was fitted by sliding it through the case cut-out and aligning it with the ODD mounting brackets. It was then secured using standard ODD mounting screws. The PSU was then re-fitted and secured.

Step 9: Fitting the Solid State Drive (SSD)

The SSD drive was fitted to its mounting plate which was crafted out of 3mm thick Hobbycraft material and then fitted to its place in the HDD mounting bracket. The power and data interface cables were then connected between the motherboard and the components. The cables were then routed and tidied up using cable ties.

Step 10: Preparing and Fitting the Front Panel

Four mounting rails were cut from thin pieces of wood (10mm x 15mm x 95mm) and covered with aluminium tape before being fitted to the front and sides of the case in positions which would best accommodate the front panel The front panel was then prepared from 3mm Hobbycraft material with fan cut-outs and the front panel power, reset switch, audio and USB connections. I used a craft knife/stanley knife free-hand to cut these out. I took my time in order that it would not look bad as it was quite tricky to cut circles out free-hand. I also left a gap on the back edge of the front panel with a view to leaving some space at the back of the case for cables.

The front-panel connections (power button, reset switch, line-in, line-out and 2xUSB connectors) were then glued in place on under side of the front panel using a glue gun and all-purpose glue stick. The connections were then connected to the motherboard front-panel connector. I tidied up the front panel wires using a cable wrap.

The front panel was then mounted and secured to the mounting rails on the case using 3.0x12mm screws.

Step 11: Fitting the Display, Audio Speakers and Display Panel

The 19“ display was fitted to the lid of the case by 4 standard M4x15mm screws after drilling the holes in the lid of the case. The screws simply secured the the case to the back of the display with screw holes which already existed on the display case for a wall mounting bracket.

I dismantled some small USB audio speakers from their plastic cases and kept the audio and power cables attached to the electronics board along with the speakers themselves. The amplifier and volume control electronics were on a small PCB and I just drilled 3 holes large enough for the volume control knob, on/off LED and the headphone output socket. I used the glue-gun to secure the PCB to the back side of the display panel.

The display front panel was then measured and prepared then drilled with small holes for the sound to come out and fitted with the small audio speakers using the glue-gun then all of the power, audio and VGA cables were routed down the right side and tidied up using a cable wrap. Some small holes were also drilled on the lower edge of the panel just large enough to be able to access the buttons for display settings (Brightness, Contrast, Power On/Off, etc.) with a thin pen or stylus The empty space around the display was filled with foam pieces before being mounted to the display and case using double-sided tape. The double sided tape was simply applied to the metal front rim of the display and then the front panel attached to that in its correct position. I used some aluminium tape to secure the panel to the case around the outside edge, which also gave it an Industrial style finish.

Finally the volume knob was fitted to the volume control.

Step 12: The Completed Portable Modular Desktop Computer (PMDC)

After securing the front panel to the case I added a couple of PC stickers from ASUS and Sapphire to the front panel for a professional finishing touch. I plugged in the two power cables and switched on the machine at the PSU power switch and the front panel power switch. The machine started up first time very quietly and booted Windows 8.1 without any problems.

Step 13: Specification Review and Windows 10 Update

Specification:

OK, so I want to let you in on the 'secret' specification, which is running really well considering it is a bit out of date. Firstly the PSU is a 530W one I paid little money for, maybe about 50 EUR (about 55 USD), about 5 years ago but it is running cool and quiet. The motherboard is an ASUS PG41T-MLX fitted with an Intel Pentium D Dual Core CPU running at 2x2500MHz. The Graphics card is an NVIDIA GeForce GT 610 with 1GB and the GPU running at 540MHz. Originally I wanted to use the Sapphire HD5450 Graphics card I had, but when I tested it in this build it was faulty, showing a red coloured screen, so I replaced it with the Nvidia card which I had in my box of PC components from previous machines. In the memory department I've got a Corsair Vengeance 8GB(2x4GB) DDR3 1600MHz DIMM module fitted, which I took from another computer and unfortunately it will only run at 1333MHz, because this is the motherboard maximum BUS speed. Then we have a SanDisk SDSSDP128G 128GB SSD for the operating system and a Samsung HD502HJ 512GB 7200rpm 16MB Cache HDD for storage and applications. Finally I have a Samsung SH-222 SuperWriteMaster DVD-RW ODD fitted for the rare occasion when I might need to access a CD/DVD Software or to write a data backup DVD.

OS and Boot times:

Initially I had Windows 8.1 installed and it booted up in 25 secs. I have now installed Windows 10 (see image) and it boots up in 17 secs. I think this is a mighty quick boot time considering I am only using a cheap 128GB SanDisk SSD drive!

Step 14: 4K UHD Graphics Version (theoretical Upgrade Specification)

Hi all, I've been looking into how this could be made into a powerful 4K graphics system by exploiting the latest technology and I've found some pretty cool PC components which would really take this to the next level and beyond! I've kept in mind space availability, power consumption and cooling, so the following specification should work well but will cost a bit:

Motherboard: ASUS X99-M WS/SE; micro-ATX form factor for Socket 2011 CPU

CPU: Intel Core i7 4930K with support for upto 64GB DDR3 RAM

GPU: NVIDIAGeForce GTX 970 ITX 4GB up to 4096 x 2160 UHD digital output/resolution

Riser Card: PCI-E 16X 90 Degree Right Angle Riser Card

PSU: BeQuiet 530W L8

Display: Viewsonic 23.6" 4K 3840x2160p Monitor VX2475

Memory/RAM: [2]ADATA XPG V2 DDR3 2400MHz (PC3 19200) 8GB (4GBx2)

SSD: Samsung SM951 512GB NVMe SSD

NVMe Adaptor for NVMe SSD: Lycom DT-120 M.2 PCIe to PCIe 3.0 x4 adapter

I didn't go for the most expensive components like the newest core i7 CPU as they are just too expensive and you don't really 'need' them for a 4K UHD build. All of the components listed above are available on Amazon.com | .de | .co.uk | so they're available wherever you live in Europe or the USA/Canada.

I hope somebody finds this useful :-)