|Re: Can we make'em like Bill and David? An open RPN?|
Message #21 Posted by uhmgawa on 18 Sept 2011, 8:43 p.m.,
in response to message #20 by Garth Wilson
1. Off-the-shelf LCDs are in the $5-$10 range even in singles.
You can certainly find lcd modules in surplus for that
price -- mostly COB text modules. But they aren't typically
suitable for this application due to footprint bulk,
excessive current consumption, incompatible voltage rail,
and being of less than preferable transreflective design.
Text only modules IMHO are somewhat of an unenthusiastic
compromise as, well you're limited to that rigid format.
The last point may be workable as the lower
polarizer could be retrofitted. Even the current consumption
could be managed if due to a brute force resistive voltage divider
by removing the chain and substituting a high
impedance equivalent feeding ultra-low current voltage
followers. But the form factor bulk of typical modules
tends to be the impasse.
In any case if substantial resources are expended
on an enclosure design, the display supply needs to be
Custom LCDs, when we looked into them in the late 1980's, were a couple thousand dollars to tool up for.
I wouldn't assume too much from that data point given the
intervening time and changes in technology. Also
price varies with topology, form factor, controller,
etc.. so that figure by itself doesn't offer much guidance.
I sent a quote request out last week for custom/semi-custom
32x160 and 32x192 STN reflective formats in COG, COF, and bare glass. Unfortunately
a bundled glass + controller unit may be
a practical non-negotiable
here as contemporary controllers able to support these
densities are not really feasible to provide in reflowable
2. We just this year looked into a custom enclosure requiring molds to be made, with a lot of complex curves-- not a simple design at all. The quote was $50,000.
3. Along with #1 above, we looked into a set of double-shot keys similar to the HP-71's. NRE was a few thousand-- I don't remember exactly, but it was under $5,000.
Was the 55K up-front simply NRE or was some production volume included in this cost?
4. We made a lexan panel with dead-front annunciators in 1994 and the tool-up was $2,000.
I investigated UV resistant polyester recently and IIRC the tooling
cost was around US$500. Lexan/polycarbonate besides being more
expensive was actually claimed to be less durable in this service.
But I do like the durable under-printed matte-upper surface design
of these panels for legend use.
All together, it's well under $100,000, and the custom case takes most of it. For low volumes, if you can be satisfied with an off-the-shelf case from a company like PacTec and get them custom machined, the per-piece cost will be much higher but there will be almost no up-front cost.
I wasn't even considering use of such utility enclosures.
For an initial prototype nearly anything will do. But I
doubt a pocket calculator sporting pactec aesthetics would
attract much of a following. I'd even speculate a professionally
3D printed enclosure would do better in this respect.
CNC milling may also be feasible for limited production
and opens up the possibility of using a cast aluminum
If someone takes up the project again, let's give them our encouragement (and help if we have something to offer).
To be clear, I'm certainly not discouraging the effort.
Far from it -- I'd encourage it and would be interested
to contribute assuming the direction appeals to me.
But if we're looking at a design which can compare functionally
and aesthetically with say, a legacy HP product,
there will be substantial NRE involved. Leveraging funding and
patience of interested parties needs to happen in the
context of some type of business model and have a realistic
execution strategy and schedule.
I'm not saying it can't be done, but rather substantial
engineering and logistical challenges exist on the
path to getting there. No one would be happier than I for
this assumption to be proven wrong.
[edited for clarity]
Edited: 19 Sept 2011, 8:54 a.m. after one or more responses were posted