Using msp430 Launchpad to Connect Digital Caliper to RS232 serial port
|Caliper and Launchpad|
You can get digital caliper from ebay.com from about 7$ with shipping. I bought it from this seller, but you can search for Digital Vernier Caliper to find many more. Most of them have small digital port on side, with 4 pins. You could connect data port to microcontroller and use digital caliper as precise position sensor, for instance.
Taking it Apart
What I discovered or maybe more correct to say, proved to myself as I have been reading other articles that was talked about this, was that "capacitance" was used to sense movement. PCB that has display had small strips of copper. Similar pattern is on calipers part that moves, the one with units and digits. Basically both of those parts form series of capacitors and when caliper inside part is moved, all those "capacitors" are changing capacitance and from the sequence in what it changes, MCU inside caliper calculates by how far it has moved.