Yet another caliper DRO

Hi Thunderbear,

Thanks for the kind words. The part number of the caliper I used is 62569. Look for the ones that say "Pittsburgh". I buy them when they are $10 with a coupon. I don't know if their other calipers use the same bit-stream. Go to the website http://www.shumatech.com/support/chinese_scales.htm for the pin connections on the caliper. This was the primary website I used for my research. Even at that, it took a bit of experimentation to get the bit-stream properly decoded.

You surely could use one Arduino do handle multiple calipers, but my software is interrupt-based using the caliper's clock as the interrupt. Arduino Nano's are so cheap (about $4 when you buy them in lots of 3) that the extra time to hack the software probably isn't worth it. Also, you'll probably need 2 displays. My version uses both lines of the 2 line display. One Nano can support multiple displays, but again the software gets a bit (slightly) more complicated.

I'm more than happy to answer any questions you've got as you go along. I know that taking someone's software isn't easy. We each have our own ways of doing things.

Glen
 
Thanks Glen,

I have a digital caliper of another brand that looks identical to yours (Mastercraft from Canadian Tire). Time to do some testing!

I had a look at the code, I found it really clear and well written. I think (hope) I understand what's going on.

The nano board has hardware support for two external interrupts and there are libraries to add additional interrupts that may be fast enough to read the 90kHz signal. I already have a multi-line display. Unnecessary, but would make for a fun experiment!

Torbjorn
 
Hey Glen, thanks for posting this. Just got done building it for my mini lathe. I was in the middle of writing my own but was having problems(not the best at programming in C++) and loosing interest. This enabled me to just get it done and move on to other projects. I did notice an error in your schematic, the pins for the caliper doesn't match your code though it was an easy fix. Also, PWM.h is not a common library, I just commented out the references to it. Other than those two simple things, it works perfect. Thanks again!
 
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