Digital caliper LCD display
After buying my metal milling machine I immediately mounted digital calipers in order to get precise position readings.
Reading 3 different displays is not handy. So I wanted a central display where I can read the 3 positions at once.
Most cheap digital calipers have a 4 pin connection for reading the position: 0V, -1.5V, DATA and CLOCK. The signal however is very specific for these calipers.
I made my first central display with three PIC 16F628 microcontrollers programmed with machine language for speed.
Later I turned to a Parallax Propeller multicore controller. Three processors read out the signal and a fourth displays the readings on a lcd. Another processor is used to reset the calipers on startup or by manual pushbuttons. Part of the programming was done with spin, a specific language for the Propeller, and part in machine language.