Cheap Idea for a DRO

[irving2008]

That sounds like a good approach and one I would take re the balanced tranceiver at the read head. Is your small pic down there doing the timing and stripping the word off for transmission. I take it your I2c is bi directional for reset and imperial/metric mode selection as down-link commands?

The PIC will do all the decoding and sampling and filtering and will upload a value on request from the display processor. It is fronted by a dual comparator to do the level shift and generates a PWM output to drive the -1.5v charge pump. The output will be in native format (note that the reader always outputs in imperial, metric conversion is done by the display processor)

If all you will end up needing is the reader PCB assembly have you found an import source just to buy these boards on their own?

No, not looked but doubt you will find one...

Have you mounted these readers on your own machined bar that replaces the caliper bar they come with? If so, was there any particular features that you had to
accurately emulate to make the capacitive sensor work reliably and accurately. I'm still mystified as to how these things work as a sensor. When I first opened one up I was surprised when I did not find an optical encoder rolling on the bar or other optical solution. Its certainly a neat non contact sensor.

The 'machined bar' is a PCB, under the graduated label... see here for more info. This makes it hard to extend, but easy to cut down...