Case modding / construction

[dhicks]

Hello All,

 

With the Raspberry Pi being released in a week or two, I'm looking at making some kind of case or enclosure to fit round it to make a usable computer. My plan is to come up with something that can be put together by school pupils. I'm thinking of something along the lines of a Commodore 64-style case, with an all-in-one keyboard and main computer that you can plug in to a screen, adding a mouse and maybe a CD drive via USB ports along the back of the case. The Raspberry Pi is, of course, much smaller than the average keyboard, so there should be plenty of space inside to lead cables and so on. I'm thinking of constructing the basic shell out of balsa wood and/or plywood and covering it with fiberglass. To add various ports to the back of the case I was thinking of using keystone snap-in modules and simply leading short extension cables from the Raspberry Pi to a snap-in module at the back of the case - no soldering required.

 

Can anyone with any case modding or similar experience tell me:

 

Where can I get a cheap, UK-layout USB keyboard that easy to strip the plastic shell off? I was looking at maybe Cherry keyboards but all the suppliers I could find on eBay seemed to be providing US layout keyboards.

 

Are keystone snap-in modules going to work in balsa wood, or do I need to reinforce them with a metal plate of some sort? Is the keystone "standard" fitting simply a square hole of a particular size? Would I do better using case-mount extension cables that I can fix to the case with screws?

 

Edit: do these look about right?:

 

http://www.ebay.co.uk/itm/BLACK-PVC-Single-Gang-Faceplate-face-plate-Module-50-x-50mm-Keystone-/110813692764?pt=UK_Computing_NetworkingTools_Accessories_SM&hash=item19cd02c35c

http://www.ebay.co.uk/itm/Excel-Single-Gang-Faceplate-25x50mm-Module-/270886200480?_trksid=p4340.m185&_trkparms=algo%3DDLSL%252BSIC.NPJS%26its%3DI%26itu%3DUCI%252BUA%26otn%3D10%26pmod%3D110815985926%252B110815985926%26po%3D%26ps%3D63%26clkid%3D5931488229514187310

 

Does anywhere sell USB hubs with 4A power supplies that are, again, easy to strip the plastic shell off? I'm planning to put the USB hub inside the case along with the Raspberry Pi and power the Pi via one of the USB ports, leaving the rest of the USB ports and the power connector to be connected to the outside of the case via short extension cables. Does that sound like a workable plan?

 

Is balsa / fiberglass easy enouge to work with, or would sheet metal be more practical?

Edited January 28, 2012 by dhicks

[sted]

might it be easier to use the wall mount brackets on the back of a monitor and mount it there

[glennda]

Talk to your DT Dept - Make something from acrylic - blow mold or something - could make some cool shaped devices!

[Arthur]

Acrylic would look cool, especially if it's the clear variety.

 

You probably already know this, but the first run of Raspberry Pi's do not have mounting holes...

 

There are a few things to be aware of with the first batch of boards, Upton warned, including the fact that the initial production run of 10,000 will be limited to Model B units. "Mounting holes were sacrificed for the first run of boards", he added; a move which could make things difficult for modders looking to build custom cases for the bare PCBs. "What we will have is a kind of point release of the design which adds mounting holes back in. Until then, people are going to have to come up with clever ways of holding on to the board: you can come up with a case which will hold the board, it just has to be carefully designed to hold on to the board around the edges of the board, where there's space." (Source)

[glennda]

You probably already know this, but the first run of Raspberry Pi's do not have mounting holes...

 

Thats a shame - going to try and order a couple of play with but will wait for them to have half decent mounting holes first!

[dhicks]

might it be easier to use the wall mount brackets on the back of a monitor and mount it there

 

There's plenty of other people making cases like that - ther's even a company selling adaptors to fit the Raspberry Pi inside a standard mini ITX case, so you can probably use any VESA-mountable case you like.

[dhicks]

Talk to your DT Dept - Make something from acrylic - blow mold or something - could make some cool shaped devices!

 

We're a primary school with limited space, unfortunatly we don't have a DT department. I don't know what a blow mold is - I've used a vaccume former before, if that's any help? I get how I could vaccume-form a basic box shape, but how do I cut holes in the sides and top and screw something to the bottom?

[dhicks]

Acrylic would look cool

 

How do I work with it, though - how do I go about cutting holes in an acrylic box to fit a keyboard and ports round the side? The advantage of balsa is that I can accuratly trim it with a craft knife. Is acrylic easy enough to work with a Dremel or similar?

 

You probably already know this, but the first run of Raspberry Pi's do not have mounting holes...

 

Indeed - I was thinking to simply rest the Raspberry Pi on a chunk of balsa and tie it down via its plugged-in cables with cable ties.

[dhicks]

Talk to your DT Dept - Make something from acrylic - blow mold or something - could make some cool shaped devices!

 

I looked up blow molding on Wikipedia over the weekend - it seems to be mostly used for hollow plastic bottles and similar. I'm aiming for an open-sided box with appropriate holes cut in the side somehow. From DT at school I remember using a vacuum former - can I combine that with die-cutting holes in the side of the formed shape while the plastic is still soft?

[Pyroman]

I looked up blow molding on Wikipedia over the weekend - it seems to be mostly used for hollow plastic bottles and similar. I'm aiming for an open-sided box with appropriate holes cut in the side somehow. From DT at school I remember using a vacuum former - can I combine that with die-cutting holes in the side of the formed shape while the plastic is still soft?

 

You need to vac form not blow mold and you could use a dremel to cut holes

[dhicks]

You need to vac form not blow mold and you could use a dremel to cut holes

 

I figured using a Dremel would result in holes that were a little bit wobbly around the edges, which might not work so well if I'm aiming for something that can take keystone snap-in modules. It would also tend to cut slightly rough edges, so I figured using a die to cut the plastic while it was still warm would give me nice smooth, consistant edges to my holes. I only remember forming a plastic sheet around a wooden block at school, though, so I don't know if die-cutting is possible at the same time.

[glennda]

You need to vac form not blow mold and you could use a dremel to cut holes

 

Yeah my bad - it is what I meant just wrong name!!

[dhicks]

I'm aiming for an open-sided box with appropriate holes cut in the side somehow. From DT at school I remember using a vacuum former - can I combine that with die-cutting holes in the side of the formed shape while the plastic is still soft?

 

Ahh - found instructions on how to make your own vacuum former on YouTube:

 

 

That looks quite do-able for small production runs. I'm guessing I can vacuum form the top of a computer shell with plastic, then die-cut an area for the keyboard out of the top while it's still warm - a steel-rule die seems to be the thing to use. I could then fit the top shell over some kind of base - vacuum-formed plastic again, or maybe some kind of metal plate bent up into shape?