MAKING AN economical DRO

[Andrew] wanted a digital readout (DRO) for his tiny lathe and tiny mill, but found that buying even one DRO cost as much as either of his machines. The solution? You guessed it, he built his own for cheap, using economical digital calipers purchased off eBay.

The DRO he created features a touch screen with a menu system running on an LPCXpresso, while smaller OLED screens serve as labels for the 7-segment displays to the right. The DRO switches back and forth between the lathe and mill, and while the software isn’t done, [Andrew] hopes to be able to transfer measurements from one maker to the other.

In a very sweet touch, [Andrew] hacked cheap digital calipers to supply measurements for each axis, where they supply a resolution of 0.01mm. There are six daughter boards, one for each caliper, and each has a pic that converts from serial to I2C, freeing the main firmware from dealing with six separate data streams.

The DRO doesn’t have a case, [Andrew] has it positioned out of chip-range from either machine.

A previous DRO we featured in 2012 used an Android tablet as its display.