Years ago when we had the gun shop we needed a Milling Machine and long story short I was under the effects of Cancer and Chemo at the time and someone else went to look at a machine and bought it without really asking any questions... it was a 1.5HP Mill/Drill it had a lot of issues, won't run on the slowest speed without tripping the breaker, won't run on the highest speed without tripping the breaker but in between it will run...
Little to no tooling available, it has a 3MT spindle, so after many moons I was finally able to score some collets that will work with it. The Dial Collars on the X-Y and Z were useless... the X axis was seized and immovable, the Y axis would not lock.. the Z would not move...
So no good way of knowing where you were on the machine... I recently got it moved to my home garage... instead of having it reside somewhere else.
Well I decided I wanted it to be useable for SOMETHING other than a fancy drill press... So I would need to know for sure where I was...
I looked into DRO... Everything I could find cost more than the machine was worth...
Then Thumbing through the Grizzly Catalog I spotted some IGaging Remote Display Digital Scales... They have a nice little LCD display on each one that are magnetic so you can stick them on the machine and stack several up for each axis...
Nice but the displays are tough to see in a hurry, are not backlit, etc. etc...
So I started looking at Open DRO from Shumatec and while researching that I stumbled upon "Touch DRO" an app for an android tablet... for a display with a small controller built from an Arduino UNO micro processor... with simple coding... Hmmm Says I ... this could work...
Arduino DRO DIY Build Instructions | Yuriy's Toys
I built the Controller using his instructions from his Blog
Arduino UNO micro processor board...
$25 Shipped (could probably be had cheaper) on Amazon
Prototype Shield Arduino UNO $6.50 shipped this is a piggyback board for the UNO that is unpopulated allowing custom circuits to be built...
A Grand total of 5 resistors, some wires and some USB Mini "B" jacks on breakout boards to solder too.
and last but not least a $10 Bluetooth transceiver Board...
A little soldering later and Voila! Works FINE! Once Calibrated
Got a much maligned Pyle Audio Astro 9" Tablet for $40 Shipped off Amazon...
About $210 total cost...
Needed a nice custom Plate to go on the front of the Z Scale cover...