Inside those inexpensive digital calipers is a data output. The guys from NerdKits has sent this data to a NerdKit to make an inexpensive DRO (Digital Read Out) for their new metal mill. As usual they have provided a great tutorial so you can also make your own or just learn from the process.

Thanks Humberto.

“These calipers output a synchronous (clocked) digital signal. The caliper periodically outputs a group of 48 bits, with a bit period of about 12μs. The first 24 bits are a signed integer representation of distance, with 20480 bits per inch. The relative timings are important because, although it is a synchronous protocol and each data bit is aligned with a clock edge, the relative times between clock edges (idle times) indicate when a new group of data starts. In particular, we wait for at least ~50μs of quiet in order to indicate that a new set of data is about to begin.”