Lathe DRO Redux – Part 2

It’s finished!

I’ve completed the software, built the circuitry on protoboard, packaged it up and installed it.

The software – since the Z axis used an iGaging scale and the X axis used a Harbor Freight caliper, I had to mash up two different Arudino sketches to deal with two different protocols, making sure that they did not fight. I used the iGaging TouchDRO sketch as the base. It managed the bluetooth interface to the tablet and the iGaging stuff. I replaced the iGaging code for the X-axis with the Harbor Freight code. The only issue is that the Harbor Freight code blocks if it is not receiving a data stream from the caliper, so both axes need to be hooked up for it to work. Initially the response from the iGaging side was slow – readout lagging, but once the circuit was properly soldered up that went away, and bluetooth reliability went up, so it was probably a noise problem when the circuit was on the plugboard.

The circuit – I’m using a better quality protoboard, so building the circuit was pretty easy. First time I used surface mount resistors. 1206, about rice grain size. Easier to solder up than I expected.

After that it was a matter of getting the circuit in a box and hooking stuff up. I had originally installed the X axis scale I(the caliper) on the tailstock side of the crossslide, but it was interfering with the chuck, so I moved it to the tailstock side. That required a fairly hinky linkage, with some backlash, so I should probably rebuild that some day.