John Knoll had added a set of iGaging DROs (Digital Read Outs) to his old manual lathe, but was starting to feel their limitations. They rely on coin cells and are too laggy for precision work.

Inspired by a video of a digital caliper being read by an Arduino, John went on to discover the Touch DRO project, which documented how to talk to several types of iGaging scales. This soon led to the creation of John’s own Teensy LC-based DIY DRO.

From spare parts, John soldered together a protoboard with two 7-segment 8-digit LED displays, two 4-character 14-segment displays, a shift register with 8 LEDs connected, a 4×6 button keypad for input, and a piezo buzzer for audio feedback. John then developed custom firmware and a nice enclosure, and is very pleased with the improvements over the prior budget system. Read more, plus find the source in the original forum thread.