Alan B Pearce wrote:
>
> >> You can buy digital verniers over here pretty cheap these days, I've seen a
> >> pair for as little as 35 UKP.
>
> >And mine even had a serial (TTL) data port hidden inside. 1200 Baud
>
> I take it that you bought a cheap version without interface, and found the
> expensive version is the same but at twice the price, with the only difference
> being the serial connector?

No. I just bought a cheap unit for $50.00 for general use around the
lab, and found that it had a PCB style edge connector hidden inside
(behind a sliding cover). Poking  around with a scope showed that it was
sending data every 180ms. Just dumb luck that it had an async port.

I have since found another no-name caliper that also has a port,
but it sends out 2 24bit SPI style words instead. Presumably for
an external dumb display (Shift register -> 7 segment decoder).
I haven't bother figuring out the format since the serial one
was easier to use.

I guess you just have to go down to your local tool shop and
take a look inside the case (battery compartment).

--
Robert.Rolf-AT-UAlberta.ca