DRO Interface Pin Functions for MSP430 LaunchPad

Last week, after posting the “Roadmap for the DRO project”, I received a few emails from different people who were working on developing a custom PCB for the controller that can use the firmware I created. During one of the conversations it dawned on me that I never explained what my intentions for the Launchpad Interface are. At this point a lot of the controller functionality is still “vaporware” (i.e. I’m still working on it). Fortunately, when selecting the platform for the DRO controller I planned out the connections. I wanted to be sure that MSP430G2553 that come with the “Value Line” LaunchPad kit, so I carefully mapped out the future needs. In this post I will try to explain how the pins are currently used, and which pins will be used for future expansion.

Connecting Glass DRO Scales to The Controller

After the two posts describing the DRO setup for my Sieg X3 mill, I’ve received a ton of emails asking for more details. It appears that a number of people are having issues with the glass scales. Additionally, there has been a lot of interest in the simplified version of the interface board. I think a more detailed follow up is in order.

DRO Project Roadmap for Early 2014

Well, first of all, Happy New Year! I hope 2014 will be a great year for everyone. There is a lot of stuff in the pipeline for the Android DRO project for the 2014, including a new version of the TouchDRO application, new MSP430 Launchpad controller firmware and better documentation among other things. Now that I’m back from the holiday vacation, I’m ready to start tackling my “to-do” list.

New DRO for my Sieg X3 Mill Finished

In the last post I started covering the installation of the glass scales on my Grizzly G0463 (AKA Sieg X3) mill. You might recall that I got the scales loosely mounted on the mill but didn’t have a controller to use them with. I didn’t want to tie-up the unit I’ve been using for testing, so before going any further I had to build a new one. This weekend I got some free time to finally build the controller and [mostly] button thing up.

Adding DRO to my Grizzly G0463 (Sieg X3 Mill)

Several people asked me to post pictures of my DRO setup. Today I started installing a new DRO unit on my Grizzly G0463 (A.K.A. Grizzly Small Mill/Drill or Sieg X3) mill and decided to take advantage of this opportunity to take some pictures and post the progress.

I’ve been itching to get a set of glass DRO scales for a while but the cost has kept me off. Last July I randomly emailed a seller on eBay and asked if they would happen to have a returned or blemished unit they’d sell to me for experimenting. Surprisingly the guy replied that he is discontinuing the Easson scales and has two units [8” and 16”] that he’d sell at a steep discount. Additionally, he had one with a broken reading head that he’d throw in if I wanted it for parts. He wanted $200 for all three of the scales, including shipping. Needless to say, I jumped at the opportunity. When the scales came, I took the broken unit apart to see what’s inside and right off the bat found the problem. The Vcc line was broken and the exposed wire was shorting to the case. Five minutes later I had three working scales: one 8” long, and two 16”.

 

Selecting Scales for a DRO

When building a DRO the selection of scales is the most critical decision. Touch DRO Android application can work with a number of different scale types, ranging from inexpensive calipers to 1 micron glass scales. In addition to the cost considerations there are technical parameters that you should take into account. In the previous post I explained which parameters really matter in a DRO setup. Now let’s take a look at some of the commonly available scales and see how they stack up.

Selecting Scales for a DRO - Six Parameters that Matter

Things were easy when iGaging "Remote DRO" were the only scales Android DRO supported. Now that it can work with most of the common scales things are becoming a bit more confusing, judging from the number of emails I've been getting lately. With other things being equal, the choice of scales will have the biggest impact on you DRO's performance. There is a number of options, ranging from cheap Chinese calipers to glass scales and other quadrature encoders. Although I can't definitively answer the question "which scales should I use for my DRO setup", in this post I'll try to explain which parameters matter most in a DRO application.

Android DRO Mini FAQ #2

As the interest in the Android DRO project grows, so does the number of questions I get each day. Some of those questions keep coming up regularly, and since it’s been almost a year since I posted the “Android Digital Readout Micro FAQ”, it’s time to post another one. This post will not cover every question you might have, but hopefully it will address most of the common ones.

Mixed Scale Controller Firmware Posted

Recently I've been working on a new version of a DRO controller that will be able to read a combination of different scales. Although the project is taking much more time than I anticipated, I’m making steady [but slow] progress. Last week I had some free time, so I was finally able to button-up some stability issues with the common “Chinese” scales. Unfortunately I still haven’t finished a truly universal version, so you won’t be able to mix glass and capacitive linear scales (yet). Never the less I posted two versions of the firmware: one that read up to four scales and one that reads the common capacitive linear scales. Links to both versions are posted on the DRO Project Downloads Page.

Finishing the Voltage Shifter for Mixed Scale DRO

A few weeks ago I posted the build instructions for an adapter board that can be used for interfacing various digital scales to the MSP430 Launchpad DRO controller. Following those instructions you will end up with a base adapter board that still needs to be configured for your particular setup. This includes providing each scale with an appropriate power supply voltage, hooking them up to the corresponding “virtual ground”, and connecting the adapter to the MSP430 Launchpad. In this post I will use the DRO unit I built for my own mill as an example of a mixed-scale setup.