Digital Read Out (DRO) on Digital Calipers

Overview

The project utilizes a cheap digital caliper and a microcontroller kit to create the digital read out that uses the information from the calipers to display the current position of the cutting toll on the LCD.

Details

The caliper needs to be held parallel to the quill and couple their movement rigidly in order to measure the vertical movement of the quill while the potential for misalignment and binding are avoided. The calipers were held together to the quill and millhead casting by manufacturing 6 aluminum pieces using the lathe and mill. The two bored inner diameters include the innermost bore diameter as a clearance bore for the rotating spindle and the larger bore as a press-fit for the quill’s outer diameter.

The radial adjustment is allowed on a slot that was cut into the arm while the end of the caliper beams connects to a radial tapped hole. The end of the caliper rod is made secured by a clamped that is formed in two pieces. The elements of the DRO user interface involve the use of one pushbutton and one switch. A voltage is read by the microcontroller’s input pin.