[font=Georgia:]"clamshell" yaobls case "-v1" update
The "-v1" design "clamshell" yaobls prototype case parts ordered 12Sep11 arrived back from Shapeways yesterday (27Sep11). Keeping in mind that the intent of the "-v1" design was just to prototype some new features, the prototype parts turned out pretty much okay. See 13Sep11 posting for more details. In particular, the lip detail and the new dimensional model worked out well.
[hr:][/hr:] clamshell-yaobls-case-bottom-dsm-v1 Proposed changes for "-v2" design include the following:
Continue to use two 5.0 mm mounting hole bosses that are the same length as the bottom case support ribs. The proximity of the Wing connector and the WingPwr connectors to the mounting hole bosses is an problem. The best long term solution is to provide corner mounting hole locations like the newer Bus Pirate layouts (with enough space for mounting hole bosses) when the OBLS board is updated.
Extend two 2.1 mm diameter [1] mounting holes through the bottom of the case.
Add 3.5 mm diameter [2] screw head wells in the bottom of the case.
Move two of the support ribs so they are centered between the two push-buttons.
Reduce the space under the board slightly from 2.0 mm to 1.8 mm.
Reduce the size of the holes in the bottom of the case somewhat. Defer for now.
Refine the USB-connector-lip-detail slightly.
Refine the logic-connector-lip-detail slightly.
clamshell-yaobls-case-top-dsm-v1 Proposed changes for "-v2" design include the following:
Eliminate the two mounting holes that passed through the top of the case.
Eliminate the long top case board capture rib. Replace this detail with top case support ribs opposite the bottom case support ribs.
While the LED light pipe hole locations were correct, resize the holes slightly and reposition the text.
While the push-button plunger scheme worked and the locations were correct, something better is needed. arhi proposed a solution which I will implement.
While the Wing and WingPwr connector opening locations and opening margins were correct, the length of the openings are tight if the connector lengths are longer than typical 0.1" grid female headers. For example, the Pololu headers I used were slightly longer than I expected. Use 0.2 mm for the top connector opening side margin. Use 0.4 mm for the top connector opening end margin.
Add openings for the other connectors - JP1 to JP6 and JP9 (JP7 and JP8 are the logic connectors).
Add two 5.0 mm mounting hole bosses that are the same length as the top case support ribs.
Add two 1.5 mm diameter [3] mounting holes.
Thanks for your time.
dsm
[1] Clearance fit for a 2.0 mm diameter plastite screw. [2] 3.25 mm diameter Torx screw head. [3] 80% thread engagement fit for a 2.0 mm diameter plastite screw.[/font:]
Thanks for getting back to me about the Bus Pirate board layout even though the board geometry scheme chosen was different than I had hoped. The locations of board geometry features and components that affect the case design for v4.0a are shown in the attached spreadsheet.
[attachment=0] In the "no good deed goes unpunished" category, your response raises a couple short questions:
What screw size were you assuming for the mounting holes? English or metric? 3.0 mm is 0.118", but after plating the mounting holes will probably be closer to 2.8 mm or 0.110. Plastic pins pins that are part of the case to position the board might be a possibility if you use snap fingers to hold the case together.
Who is supplying the 12-pin shrouded header that you plan to use? As far as I can tell, 10-pin, 14-pin, 16-pin, and 20-pin shrouded headers are readily available, but the 12-pin variant seems to be fairly rare. I would prefer to not guess about the header dimensions if at all possible.
Is there a larger (about an inch high or so) DP-LOGO image or source available?
[quote author="ian"]We (Seeed and I) are trying really hard to get everything in a nice case, starting with the Bus Pirate, so I keep changing the size for cases that are then no longer available. Everything will be changed again soon too.[/quote] Perhaps working with Seeed to get several standard injection-molded cases fabricated would be worthwhile. How about three or four cases designed to fit roughly golden-ratio-sized boards up to the maximum dimensions allowed by the free version of Eagle PCB layout? Seeed could suggest what board sizes would maximize their yield from whatever panel size they use. For example, the typical spreadsheet board yield model specifies
I'll finish designing a couple yabp cases (even though this seems like a redundant activity if you're working with Seeed to get new cases designed and built) after the "-v1" clamshell yaobls case prototypes arrive back from Shapeways in couple days. From my viewpoint, I still want to figure out how to use the "draft angle" feature of the tool I've been using for the clamshell yaobls case designs.
Thanks for your time.
dsm
[1] Unless the boards are scored and snapped - and Seeed doesn't look like they do that.[/font:]
When I looked at the various Bus Pirate source files, there seem to be three groupings:
BusPirate-SMPS.brd 20Apr11 ~ no mounting holes
BusPirate-v3.5-SOIC.brd 19Apr11 ~ MH3 @ 2434.055", 1449.803" ~ other components not on an obvious grid BusPirate-v3.5-SSOP.brd 19Apr11 BusPirate-v3.5a-SSOP.brd 17May11 BusPirate-v4a.brd 06May11 BusPirate-v4b.brd 17May11
BusPirate-v4.brd 06May11 ~ MH3 @ 2.45", 1.3" ~ other components on an obvious grid BusPirate-v4.1.brd 06May11
So when you say [quote author="ian"]BTW: a first batch of v4 is in production. It will probably be ready in a few weeks.[/quote] I still don't know which board dimensions to use since there are two "version 4" layouts!! As you might imagine, I would prefer to not put a lot of time and effort into the wrong Bus Pirate case design. Any idea which "version 4" layout is going into production? Is there any simple way to get a bare "version 4" production board so that I can have something concrete to play with?
Thanks for your time.
dsm [hr:][/hr:] ian, [quote author="ian"]It's pretty much just me on the design side :) I am trying hard to get someone full time to help out with engineering, but it will be a while. Your points are all valid, and any non-sense in the design is entirely my fault ;) I appreciate your investigation and feedback and will certainly add these updates to the routing queue. I'll also try to follow best practices in the future.[/quote] I can imagine that what you are doing is a lot of fun part of the time and a lot of cruft the rest of the time. Lately I've been asking you and arhi a bunch of questions in order to get around roadblocks that I'm running into that other people might also be encountering. I apologize for taking up so much of your time. I wish I could be more helpful.
ian, [quote author="ian"]The files should be at the Gadget factory: http://www.gadgetfactory.net/logicsniff ... r.Download[/quote] The page on the site you referenced does not appear to be for OBLS board-level documentation (board layout, schematics, gerbers, etc.).
The
Download page on the same site ~ points at the page you referenced. The Getting Started page on the same site ~ asks for password if you next select Introduction!!! The Learning page on the same site ~ looks slightly interesting. The Hardware page on the same site ~ only has a description of the hardware. The Forum page on the same site ~ points back to the Dangerous Prototypes OBLS forum. The Playground page on the same site ~ looks slightly interesting.[/list] I've been looking around quite a bit for the latest OBLS board-level documentation and I have yet to find it anywhere obvious. I am a newbie, so I might be making some obvious error (see next section). Any suggestions you might have would be very welcome.
Thanks for your time.
dsm
[hr:][/hr:] arhi,
You are absolutely correct about the source of the 27May11 version of LogicSniffer-v1rev3.brd board layout I am using. That was the latest documentation I was able to find.
You are also absolutely correct about what was needed to make the GND ground plane appear in Eagle for the LogicSniffer-v1rev3.brd board layout. I usually use another schematic entry / PCB layout program (Altium Designer) and I am obviously not as familiar with Eagle as I should be. Thanks very much for the tip.
Although I'm still waiting for my clamshell-yaobls-case-botom-dsm-v1 and clamshell-yaobls-case-top-dsm-v1 prototype parts to arrive back from Shapeways, I decided to update my OBLS geometry spreadsheet (see attached) in order to add the connector locations that arhi suggested should be added to the v2 clamshell prototype design. [quote author="arhi"]...there is a 2x2 header. I for e.g. use that header a lot (it allow external triggering etc etc) and for me for e.g. that header is way more important then the unbuffered pins on the bottom of the device. [/quote] I used a 27May11 version of LogicSniffer-v1rev3.brd as the basis for updating the spreadsheet. So far, so good.
In the process of updating the spreadsheet, however, I noticed that GND seems to be missing from the board layout (even when all layers were turned on). I suppose that means that either
(a) This board layout was not the released version, or (b) I have a defective copy of the board layout, or (b) GND has been scrubbed for some reason from this version of the board layout.
This brings up a question about where the released version of the OBLS board-level documentation (board layout, schematics, gerbers, etc.) is kept. As far as I can tell, the current OBLS board-level documentation is not on
Dangerous Prototypes OBLS hardware
docs Dangerous Prototypes Open Hardware documentation on Google code svn or downloads Gadget Factory old site Gadget Factory new site Gadget Factory on GitHub site Papilio site alternate Logic Sniffer client site [/list] Since the OBLS design was a joint effort between Ian Lesnet (at Dangerous Prototypes) and Jack Gassett (at Gadget Factory), perhaps documenting this open source hardware effort may have fallen through the cracks. Perhaps the documentation is really there and I'm not seeing it. Any suggestions?
Someone asked whether I could design a Bus Pirate case similar to the "clamshell" version of the yaobls (Yet Another Open Bench Logic Sniffer) case (thread). I assume they meant Bus Pirate v3.x or Bus Pirate v4.x, but I'm starting to realize that these boards are not the same size. I am interested in the board geometry (board outline, mounting holes, keepout areas, etc.) and the locations of components that might interact with or affect the case design (connectors, jumpers, LEDs, push-buttons, etc.). Where do I go to find the latest version of the Eagle layout files for these designs?
Thanks for your time.
dsm
Private Message edited slightly for clarity. [hr:][/hr:] [quote author="ian"]v3.5 and v4 are in the Dangerous Prototypes SVn at google code. They are the same size but that will probably change. The headers are in about the same place, but they are not exactly the same.[/quote] [hr:][/hr:] Bus Pirate board geometry
ian,
I downloaded the Eagle brd and sch files for the Bus Pirate v4.0, v4.0a, v4.0b, v4.1, and v3.5 revisions from source and downloads and measured various board geometry features and certain component locations.
For the Bus Pirate v4.0 and v4.1 layouts, the board geometry and the component locations are exactly on a 25 mil grid (except for the USB connector which is shifted left 12.5 mils for rational reasons) (except for the push-buttons which are exactly on a 5 mil grid). So far, so good. But the "history.txt" file in the downloads directory says these boards don't fit the Seeed Studio case. Is this an existing or currently unannounced new case?
For the Bus Pirate v4.0a, v4.0b, and v3.5 layouts, the board geometry (board edges are exactly on a 1.0 mm grid) (mounting holes are exactly on a 0.025 mm grid) seems clear, but the component locations don't appear to be on any obvious "mil" or "mm" grid. What is the story here?
What I am trying to do is determine are the locations of any board geometry or components that would affect a case design. For example, for Bus Pirate v3.5
board ~ lower left corner ~ nominal 0.000, 0.000 ~ mm board ~ upper left corner ~ nominal 0.000, 40.000 ~ mm board ~ upper right corner ~ nominal 65.000, 40.000 ~ mm board ~ lower right corner ~ nominal 65.000, 0.000 ~ mm
mounting hole ~ lower left ~ nominal 3.175, 3.175 ~ mm mounting hole ~ upper left ~ nominal 3.175, 36.825 ~ mm mounting hole ~ upper right ~ nominal 61.825, 36.825 ~ mm mounting hole ~ lower right ~ nominal 61.825, 3.175 ~ mm
Since 0.1 mm is roughly 0.0039 inches, specifying these dimensions to 0.005 mm is like specifying a board feature to 0.000196 inches accuracy. This level of accuracy doesn't seem commensurate to the problem.
connector ~ ExtPwr ~ pin one or center ~ ??? connector ~ ICSP ~ pin one or center ~ ??? connector ~ IO ~ pin one or center ~ ??? connector ~ USB ~ center ~ ???
push-button ~ Normal ~ center ~ ??? push-button ~ Reset ~ center ~ ???
LED ~ pwr ~ center ~ ??? LED ~ usb ~ center ~ ??? LED ~ mode ~ center ~ ??? LED ~ vreg ~ center ~ ??? [/list] In the past, board designs often used a "mil" grid (usually because of 0.1" grid connectors and 0.1" grid through-hole device packages) while package designers often used a "mm" grid. Given the number of high pin count metric device packages there is probably less of a need for boards to be on a "mil" grid any more, but it is useful to have some grid scheme to locate components (so locations are not arbitrary measurements that have to be specified at the highest resolution). I can work with either scheme, but currently the Bus Pirate board seems to use a hybrid design grid that I'm having considerable difficulty figuring out.
I realize that this a fairly minor issue and you have a lot on your plate. Do you have anyone available to answer this type of question? Am I missing something obvious? Or is there a short, simple answer?
Thanks for your time.
dsm
[attachment=0] Private Message edited slightly for clarity. [hr:][/hr:] [quote author="arhi"]Ian should correct me if I'm wrong but BP4.x ain't final yet hence not in production so changes are still very possible. I think it would be very useful if the pcb can be modified a bit to be more "case friendly".
Maybe it would be best if you, David, can give some pointers to what you think would be a best changes in 4.x pcb design to make it more case friendly, both for a custom case and for existing abs cases, and then Ian can implement those changes in Eagle pcb layout.
The BP I have (3.5b I think) is case friendly - the 4 mounting holes are ok, the usb is ok, only the connector I replaces with 90 degree headers but going from top is also more then ok.
The BP 4.1 comes with buttons, that is the major difference ... but they are not problematic imho ... the only changes I'd make on 4.1 are - for ICSP connector I'd use the layout that is not 100% in line but every second pin to be with a little offset (like for e.g. on arduino) so that you can use icsp holes without actually soldering a header. - I'd add a 1mm border of clean pcb on the top edge (where the led's are) so that it can easy slide in a tray case or can be easily clamped without blocking light from leds.[/quote] [hr:][/hr:] Bus Pirate board layout suggestions
ian, arhi,
Okay, I'll add my $0.02 worth...
Use a "mil" layout grid (imperial) for the board design. Use a "mm" layout grid (metric) for the package design.
Use a relatively coarse grid (100 mil or 50 mil or 25 mil) for all board geometry features (board outline, mounting holes, keepout areas, etc.) and the locations of all components that might interact with or affect the case design (connectors, jumpers, LEDs, push-buttons, etc.). Lock these parts down so that they don't accidentally get moved later.
Position most 0.1" grid through-hole components so that their pins are centered on the coarse grid.
Place 80 mil (minimum) mounting holes 125 mils (both X and Y) (minimum) from the corners of the board. 80 mils will allow a 2 mm self-tapping screw.
If you use larger mounting holes, place them proportionally further away from the corners of the board.
Make the board slightly larger than necessary so you don't have to redesign the case if the board design changes slightly.
Come up with a standard case that is the right size for a variety of Dangerous Prototype designs. Design boards to fit this case. Worry about connectors later in the process - they can often be cut with a laser as needed. For example, how about a smaller case that fits boards roughly 1.5" by 2.5" for a Bus Pirate product? For example, how about a larger case that fits boards roughly 2.0" by 3.5" (the size of a standard business card in US)?
arhi makes a good suggestion about offsetting the pins for the ICSP connector. Sparkfun once ran an article about the optimum offset of pins in a staggered array for this application. The reverse scheme is to place the ICSP holes directly on grid in the normal manner, but offset the pins in the connector that temporarily plugs into this array of holes.
arhi makes a good suggestion about leaving a keepout area on the edge of the board. Use 50 mils for this keepout area.
Move the LEDs slightly further away from the edge of the board to allow more room for lightpipes.
Position the USB connector to slightly hang over the edge of the board to allow for a maximum wall thickness of 1.5 mm plus a small margin of error.
Other than the right-angle USB connector, use vertical 4-wall shell connectors for everything else. These other connectors should exit from the top of the case.
[font=Georgia:]"clamshell" yaobls case push-button plunger
arhi,
[quote author="arhi"]For some reason shapeways 3d look don't work for me...[/quote] Well that explains a few things! Attached is an image of the push-button-plunger-on-a-nylon-hinge scheme used for the clamshell-yaobls-case-top-dsm-v1 prototype (which is probably not a good scheme for a variety of reasons).
I've been trying to think of ways to provide a captured push-button plunger that is compatible with inexpensive injection molding processes. People who do this sort of packaging design for a living probably have lots of ways of accomplishing this goal, but as you probably know, packaging design is really not my area of expertise.
I did have a push-button plunger idea using
separate plastic plunger parts top guide via hole in case plunger shaft captured using an ordinary metal "C" clip return action using a spring from a cheap ball point pen bottom guide near target push-button (also braces the spring)
[font=Georgia:]"clamshell" yaobls case fastening schemes
arhi,
The Developer use case is fairly simple - use two short self-tapping screws to hold the OBLS board in the bottom case.
The User use case is more difficult, but I've got several ideas to prototype:
Use two somewhat longer self-tapping screws that go through the top case into the bottom case. The OBLS board is sandwiched between the top and bottom cases. This is an ugly solution that is visible from the top.
Use two somewhat longer self-tapping screws that go through the bottom case into the top case. The OBLS board is sandwiched between the top and bottom cases. The bottom case would have to be countersunk - which might screw up the Developer use case.
Use snap fingers in the top case and and little indentations in the bottom case. This is the most common solution for high volume products. This was the scheme used by the little Seeed Studio Bus Pirate case that is no longer available.
Use two neodymium magnets that pull at the heads of the two short self-tapping screws used to secure the OBLS board for the Developer use case. Just attach the top case when you are through developing for the day. I ordered some 3mm x 3mm cylindrical neodymium magnets to prototype this scheme. The general problem with magnetic schemes is that they attract little bits of conductive metal.
I put off ordering initial prototype case parts until I realized I needed at least some case parts to prototype case fastening schemes.
[quote author="arhi"]... but what could be interesting is, as nylon is bendable, to design the buttons into the cover itself.[/quote] In that case, you should be happy with clamshell-yaobls-case-top-dsm-v1 design since the push-button plungers are part of the top case and supported by nylon hinges. Go to the Shapeways site and rotate the top case in 3D to see how the push-button plungers are attached.
I updated the "clamshell" yaobls case design and finally sent off for some initial prototype parts from Shapeways. Sorry about the delay, but I had some other projects that had higher priority.
The case-bottom (link) can be used by itself to support the Developer use case. This part looks a lot like the yaobls-tray-dsm-v5 design. Updated - see 18Oct11 posting. Features include the following:
The OBLS board is attached from the top.
Lip detail matches top "chamshell" case.
Two mounting bosses under the Wing connector.
Ribs to provide support elsewhere.
Revised dimensional model to reduce error budget.
Thinner walls for lower cost.
Openings in bottom for lower cost.
Feet wells in bottom for rubber feet.
The case-top (link) can be used with the case-bottom to support the User use case. Updated - see 18Oct11 posting. Features include the following:
The OBLS board can be held in place by two ridges along the long axis of the case.
Lip detail matches the bottom "clamshell" case.
0.2 mm reveal where the top can bottom cases come together.
Push-button plunger on hinge over "Reset" and "Update" push-buttons.
Two openings for commercial light pipes over "Trig" and "Arm" LEDs.
Raised text for "Reset", "Update, "Trig", and "Arm" functions.
Opening in case for Wing connector and two Wing power connectors.
Other than the push-button plunger detail and the long top case board capture rib, the design can be injection-molded without any any special mold "pull" features after some "draft" angle is added. Any suggestions or thoughts you have for the "clamshell" yaobls case design would be greatly appreciated.
[quote author="ian"]... you've done a ton of great work here. I'm having a hard time summarizing it for a blog post. Could you please give 3-4 sentences about the most important parts of your work? I'll put it on the blog and link to your designs at shapeways.[/quote] I'm not sure that there really is much direct importance to the current yaobls case effort, but I had a lot of fun and learned some new skills.
I'm interested in releasing some open source board designs under the Creative Commons license. Some of these board designs would benefit from having a small case, so I've been looking into various options for getting custom cases built. One of the approaches I investigated was using the Shapeways online SLS (selective laser sintering) 3D fabrication service. In order to gain some experience with the tool chain that I wanted to use to fabricate case prototypes, I decided to design a simple case for the OBLS board in which the OBLS board slides in from the side (so I would only have to design one case part instead of the two case parts I would need for a "clamshell" case design). This became the "-v3" yaobls case series.
After the "-v3" prototype came back, I generated eight updated variants as an experiment in partially automated parametric case design. These became the "-v4" yaobls case series and my initial posting to this forum was about this effort. You posted an article (link) to the blog about "-v4" design. arhi was kind enough to comment about the "-v4" design and out of our subsequent exchanges came the following positive results:
An improved understanding of the User and Developer OBLS board use cases.
An improved understanding of the advantages and disadvantages of FDM and SLS 3D printing technologies.
An improved understanding of open source CAD and CAE tools.
An improved understanding of which Creative Commons license to use and where to release an open source design.
An improved appreciation about how my access to materials and services in California compares to elsewhere in the world.
Convinced me to order a 3D printer kit as background for designing my own 3D printer.
After the "-v4" prototypes ("-v4" top) ("-v4" bottom) came back, I updated the design to include
a yaobls-tray-dsm-v5 design (link) to support the Developer OBLS board use case (top) (bottom).
a yaobls-case-dsm-v5 design (link) to support the User OBLS board use case (top) (cover) (bottom).
I sent some "-v5" samples to arhi so he would have some concrete SLS examples in front of him.
I released the "-v5" yaobls series cases under Creative Commons license CC-BY-SA 3.0 via Thingiverse (tray) (case). See 28Aug11 "yaobls design release" posting for more details.
I quit any further development on cases where the board slides in from the side. I found that this approach has a surprisingly large number of drawbacks compared to more conventional "clamshell" cases (see below).
My next steps include
Creating a partially automated parametric "clamshell" case design tool chain that allows me to generate design files suitable for either injection molding or SLS 3D printing. See 16Jul11 "parametric case design" posting for more details.
Design an inexpensive, easy-to-assemble FDM 3D printer. A few selected CNC parts would make it much easier to build an FDM 3D printer at a lower price point.
Finish designing and release some open source hardware designs.
I truly appreciate the effort you and Jack put into the OBLS design. When it finally comes time to update or refactor the design, perhaps I could help out in some small way.
You're absolutely correct about your measurements of the yaobls-case-dsm-v5 case. The space between the top-of-the-bottom-slot and the bottom-of-the-top-slot is 5.7 mm. The original intent was to make the top of a 8.5 mm high wing connector [2] protrude 1.0 mm above the acrylic top window [1] and 1.0 mm below the top surface of the case [3]. As you point out, this means that the wing connector (and any other components taller than 7.5 mm) will interfere with the right side of the top window frame. That was by design. You may recall that half of the eight "-v4" cases in my original posting were so-called "partial" cases missing the right side of the top window frame. These cases were intended to allow taller components to slide in from the side. Even with these "partial" cases, in the case of components taller that 5.7 mm, the acrylic top window and the OBLS board would have to be merged before the combined assembly was slid into the case.
[quote author="dsm"]Partial ~ top frame border on three sides. Makes it easier to slide tall components into the case.[/quote]
When I updated the "-v4" design to the "-v5" design, I eliminated these "partial" cases since I figured that Developers would want the "-v5" tray design and Users would want the "-v5" case design. I assumed that people who needed a case design with an open right side of the top window frame could easily modify the yaobls-case-dsm-v5 design as needed.
[quote author="dsm"]chamfer top frame border ~ The inside edge of the "-v4" series top frame had a 1.0 mm radius. The inside edge of the "-v5" series top frame has a 1.0 mm chamfer (which provides a handy guide for modifying the top frame at the open end of the case with a razor blade).[/quote]
My assumptions notwithstanding, I didn't state the implications of eliminating the "partial" cases very clearly. I'm sorry about that and I hope this issue didn't cause you too many problems. I suspect the best solutions are as follows:
use the yaobls-tray-dsm-v5 design.
modify the right side of the top window frame of the yaobls-case-dsm-v5 design.
move on to the clamshell yaobls case design or what I've been calling a typeB case.
[quote author="dsm"]typeA versus typeB ~ Although I believe that typeB cases (where the board is held between top and bottom case shells) provide a better solution in most situations than typeA cases (where the board slides in from the side), I want to finish up my typeA efforts first.[/quote]
I've made an initial pass at the typeB or clamshell yaobls case design and plan to order initial parts from Shapeways later this week. I've been trying to make the bottom of the clamshell look something like the yaobls-tray-dsm-v5 design to support the Developer use case. The top of the clamshell could then be an optional part that matches the bottom of the clamshell to support the User use case.
Any suggestions or thoughts you have for the clamshell yaobls case design would be greatly appreciated.
Thanks for your time.
dsm
[1] top of OBLS board to top of acrylic window = 7.5 mm = 5.7 mm + 1.8 mm (slot) [2] height of wing connector = 8.5 mm [3] top of OBLS board to top of case = 9.5 mm = top of acrylic window + 2.0 mm (top wall thickness)[/font:]
Canadian Cory Doctorow (link) was the keynote speaker (link) at ACM Siggraph 2011 (link) in Vancouver, British Columbia. The conference bookstore carried autographed copies of Cory's science fiction novel Makers and I thought that you might enjoy a copy. When I saw the SCAD Bag provided to Siggraph attendees by Savannah College of Art and Design (link), I immediately thought of your comments about OpenSCAD.
The red samples (case and tray) are what Shapeways calls RSF (red strong & flexible SLS nylon) (link). The grey sample (tray) is what Shapeways calls alumide (white strong & flexible SLS nylon combined with aluminum dust) (link). Shapeways also provides a tumble-polished WSFP (white strong & flexible polished SLS nylon) that is more smooth. This SLS nylon material can also be dyed various colors (link). Isopropyl alcohol works pretty well to clean the acrylic top window when you take the blue protection film off. I'll laser etch names for the ARM and TRIG LEDs on the future versions of the acrylic top window. The little rubber feet should fit the feet wells in the bottom of the case and the trays.
As I've mentioned before, I believe that many Dangerous Prototype designs and other open source hardware designs would benefit from a little more thought about the overall packaging scheme during the specification, component selection, initial design, and board layout processes. For example, designing a new open source hardware board (e.g.OBLS) to fit an existing case (either off-the-shelf or slightly modified) is probably a better approach than having to design a new custom case (e.g.yaobls) after the fact to fit a new open source hardware board design. My $0.02 worth.
I'm glad you liked the stuff I sent. Thanks again for your help.
[font=Georgia:]where to post and which Creative Commons license
Ian,
Any suggestions about where to post the design and which Creative Commons license to use would be greatly appreciated. I've never released a design though this process before and, although willing, I am somewhat uncertain about how to proceed. See 28Aug11 posting for more details.
