Emriver Em2 model. After many hours of meetings, emails, CAD work, research on materials and methods, and prototype building, I think we have the basic design figured out.
The first design, based on twenty years of tweaking, has been wonderfully received, but now we can see the Em2 will be built in hundreds, if not thousands of copies, so now is the time to refine the design.
I want to keep these models accessible (to conservation groups and others who don't have much money) by keeping them simple, locally repairable, and adaptable to user-made parts and repairs. I hope to keep the models inexpensive, open source, and supported by grant-funded curriculum development.
I had visions of a sleek Euro design, but what's emerged is elegant in a less obvious way, like the old Coleman stoves I mentioned here two years ago.
This work will also make the Em2 shippable via UPS. A big deal for our users and for export.
Lab time is precious. Our users really appreciate simple, obvious assembly and operation because they have better things to do than fuss with equipment.
We're working on legs that will replace the aluminum "horses" we now use. The horses are great, but a bit bulky and very expensive to build, so we've designed attachable legs that will be lighter, easier to use, and less expensive.
It's one thing to build an instrument that will work, and another to create something that's mass producible, needs little maintenance, and is safe, shippable, and obvious to operate.
Here are some of the constraints and parameters we considered, and these are just for the legs!
1. Manufacturablity/cost; minimum weight and parts count, welds, etc.
2. Robustness; long-term indestructible; very high margin of safety.
3. Safe from thoughtless use ("idiot proof," I don't like that term);
5. Redundant safety with near-zero chance of catastrophic collapse;
6. Usability with laminated wooden legs or other open source things users can build
7. Easy user assembly on initial ship; legs cannot be attached for UPS shipping;
8. Very simple, obvious, and satisfying in assembly and operation;
9. Very solid with little/no flex in use.
10. Elegant, engineered appearance; strong; attractive.
11. Box will be carried (i.e in a pickup), bottom cannot have sensitive components, box should have zero parts that stick out and snag.
12. Buildable without exotic extrusions or parts, locally repairable if damaged.
13. Locally and easily repairable with off the shelf parts.
Photos of my messy workbench (per request of my wife) and of a design that didn't make the cut.