Digital Caliper Interface?
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Posts: 46,084
Anyone ever mess with interfacing a Stamp to some cheap digital calipers
with a computer / printer connection? Harbor Freight had some on sale
recently for $20 that have a printer output.
I ordered a couple several weeks ago -- they showed up today and I have
started hacking. Got a usable standard connector mounted and found a couple
of helpful web pages. It looks like the PC interface and printer are not
available though.
It looks like it communicates at 4800 baud, so a Stamp 2 is what I'll have
to use. So far I have identified the ground and data out pins -- it looks
like logical 1 is only about 1.3 volts though. Guess I'll need to build a
logic level shifter too. There are still two other pins unaccounted for --
one has 1.3 volts on it all the time and the other I have not checked with a
scope yet. They apparently have to do with sending commands to the calipers
to change measurement modes.
Here is the poop:
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=47257
http://www.sh.com/ie/meters/data_adaptor_&_microprinter.htm
http://www.longf.com/measuring2.htm
with a computer / printer connection? Harbor Freight had some on sale
recently for $20 that have a printer output.
I ordered a couple several weeks ago -- they showed up today and I have
started hacking. Got a usable standard connector mounted and found a couple
of helpful web pages. It looks like the PC interface and printer are not
available though.
It looks like it communicates at 4800 baud, so a Stamp 2 is what I'll have
to use. So far I have identified the ground and data out pins -- it looks
like logical 1 is only about 1.3 volts though. Guess I'll need to build a
logic level shifter too. There are still two other pins unaccounted for --
one has 1.3 volts on it all the time and the other I have not checked with a
scope yet. They apparently have to do with sending commands to the calipers
to change measurement modes.
Here is the poop:
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=47257
http://www.sh.com/ie/meters/data_adaptor_&_microprinter.htm
http://www.longf.com/measuring2.htm
Comments
don't know if everyone follows a standard.
O> Anyone ever mess with interfacing a Stamp to some cheap
digital calipers
> with a computer / printer connection? Harbor Freight had some on sale
> recently for $20 that have a printer output.
>
I suspect this is similar as these look like a knock-off of the Mitutoyo.
One document I found said it was a serial interface, 4800 baud, 8N1.
**********
> I have some BS2 code I found for a Mitutoyo Dial Indicator. I
> don't know if everyone follows a standard.
>
> O> Anyone ever mess with interfacing a Stamp to some cheap
> digital calipers
> > with a computer / printer connection? Harbor Freight had some on sale
> > recently for $20 that have a printer output.