Help needed to interface a Chinese caliper to the Propeller

dazed&confused

· I'm Trying read the 24BIT·WORD from·the low cost chinese scales with the propeller, Its 24 BIT wording has me confused as how to program the Propeller,·· Struglling
·Any help with this would be greatly app.

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Post Edited By Moderator (Paul Baker (Parallax)) : 3/7/2008 7:02:07 PM GMT

Mike Green

You will need to provide more information. Datasheets for the scale would be helpful. There are all kinds of ways to read 24 bits from a device.

deSilva

I recall a long thread about this topic half a year ago... Because I had not the faintest idea what chinese scales could be (food?), I got interested. The thread was comprehensive - look for it!

Phil Pilgrim (PhiPi)

"Scales" may be a little misleading if you're thinking "weight". If "caliper" better fits the instrument, here is a thread that may inform.

-Phil

deSilva

Thank you Phil! No that was not the thread..... but may be this one
http://forums.parallax.com/showthread.php?p=650150

Nick Mueller

I have a lot of information about these Chinese Scales on my page.
<http://yadro.de/digital-scale/protocol.html&gt;

On the Propeller, that should be fairly easy to program (compared to an ATtiny <EG>). Wait on one pin for the clock and shift in the data on the other pin. ASM required.


Nick

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Never use force, just go for a bigger hammer!

The DIY Digital-Readout for mills, lathes etc.:
YADRO

Christof Eb.

Hello,

has anyone tried to interface the propeller to the calipers?

I would be interested in some input....

Christof

Richard S.

Yes, I have just recently successfully interfaced Chinese (caliper) scales to the Propeller.·

I use a 2n2222 to step up the output which also inverts the scale output.· I then push the scale output through a Schmidt inverter so that the scale output is crisp, clean and back to its normal orientation.· What I don't have configured yet is an interface to change the scale speed of updates (from 3x/sec to 50x/sec) or zero the scale electronically.· But that will be coming.

The software interface uses one cog to monitor 3 scales, selects only the 'relative' scale output and after proper massaging the data, dumps it into hub memory.· From there I have a routine to display data on a CRT using VGA.TEXT.SPIN.·· It is patterned after my quadrature encoder reader/display developed with Propeller detailed with s/w in a previous post ... search under 'QUAD DRO'.·

I will be posting the schematic and s/w hopefullly in the next week or two.



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Richard in Michigan