arduino digimatic interface

Ooooh, that's interesting. Is it a special connector on the micrometer? I have a digital caliper, it has a four pin interface but I can't find the mating connector. It's a kind of high speed (Well, faster than 2400 baud) synchronous serial interface that constantly pumps out data. The interface is specced in the instruction manual. Two things come to mind wrt to interfacing to a microcontroller:

1) The caliper, and I assume your micrometer is powered by a single button cell. That means the voltage swings of the digital signal is quite low, lower than a 3.3V microcontroller could easily read, I think. Maybe if it ran at 1.8V it might be closer. So you need some hardware to interface. My caliper specs its 0 at 1.3V. I suppose that's with a fresh battery. 2) It's not a RS-232 style serial interface; you're going to need to see if your Arduino's uC supports the serial protocol. My caliper says its a 90KHz clock on one pin, and 24 bit data on the data. It also says it bursts out two readings every 300ms. That's a basic shift register.

Do you have a scope? A logic analyzer? If so, can it go that low for its 1 threshold?

Linky link to your stuff, please.