I missed the earlier post, what is their u r l?
73
Butch Bussen
wa0vjr
open Node 3148
Las Vegas


On Mon, 20 Sep 2010, John 
Glass wrote:

> Hi,
>
> I just checked out their web site, and it looks like they still have a number of interesting devices, including a multi meter.
>
> I sure hope they are able to continue, as their company has helped many blind people with innovative solutions by supplying technical solutions over the years.
>
> John
>
>
> ----- Original Message -----
> From: Martin McCormick <[log in to unmask]>
> To:  [log in to unmask]
> Date: Monday, Sep 20, 2010 9:18:16
> Subject: Re: D-star?
>
>>
>>
>> I remember them. Their equipment modifications were
>> pretty good. They did have some kind of business-related problem
>> and I remember reading about a fire that destroyed a wear house
>> full of products, etc, so I am not sure if they exist today or
>> not, but whether or not they do, here's the problem and within
>> that problem is also the solution.
>>
>> As one who likes to build and tinker with stuff, I can
>> tell you that the kind of stuff that Science Products used to
>> put ports on just doesn't exist any more. I bought a used DVM in
>> the early eighties that I had the intention of making talk by
>> tapping in to the display lines that fed the digits in the
>> display. It would have been possible and this is the kind of
>> device that Science Products would have been modifying back
>> then.
>>
>> The display was on a board with the 7-segment LED chips
>> right there where one could solder ribbon cable to the back of
>> each chip or remove the chips and replace them with 16-pin DIP
>> headers if one wanted to sacrifice the display. One could have
>> then taken the 8 segment leads which were actually 7 segments
>> and a decimal point, anded that with the strobe which activated
>> each digit, and fed those leads to logic circuits or a
>> microprocessor to decode each actual digit. This could have all
>> been done in the eighties and while the result would have been a
>> little awkward, one could have had a talking DVM or a DVM that
>> sent CW.
>>
>> "QST" even had articles about how to modify DVM's and
>> frequency counters to make them accessible.
>>
>> It is all very different now in that the level of
>> integration in common electronic devices is so much greater than
>> in the Science Products era. You simply can't get to the display
>> drivers without totally destroying everything. Open up something
>> today and you may see a monster surface-mount IC that is the
>> whole device. The rest of the board is possibly hundreds of
>> traces going to the LCD display screen. You could have 500 or
>> 600 columns and another 500 or 600 rows to address each pixel on
>> the screen to make it possible to generate graphics, words and
>> numbers, and even whole pictures.
>>
>> I am not trying to be negative or explain why this or
>> that can't be done, but today, it must be done differently. You
>> just can't run 20 wires out from the display board any longer
>> and read the display. If there is a signal to read, it may be a
>> serial data channel consisting of a clock line plus at least one
>> more wire that goes high and low according to bits being sent
>> and received. You really need some kind of processor to decode
>> those data and that is a possibility, but the whole level of
>> complexity is way up there compared with how things used to be.
>>
>> In some ways, the possibilities are greater now but the
>> techniques for getting at the data are totally different now.
>> By the way, I was lazy and never got around to building that DVM
>> interface. I had one of the analog DC volt meters that AFB, I
>> think, sold in the early seventies that used a Wheatstone Bridge
>> and chopper modulator so I could read DC voltages and
>> resistances. I fooled around and procrastinated until the early
>> nineties when the Radio Shack Talking DMM came out and I just
>> never got around to finishing that project.
>>
>> Martin
>>
>> Tom Brennan writes:
>>> Actually, I wasn't even thinking about a computer.  In fact, ten or
>>> twenty years
>>> ago there was a move toward one of these systems as a universal access
>>> tool.  It
>>> wouldn't be much more than a speech synthesizer.  There used to be an
>>> outfit
>>> called Science for the Blind which became Science Products who would add
>>> speech
>>> output to any digital device that you had by just adding a port and
>>> supplying
>>> you with a voice box.
>
>