Update: Igaging Origin Series use a Mitutoyo cable and output the Mitutoyo 52 bit datastream. The code and schematics below work with SPC Digimatic Calipers, Micrometers, Dial indicators, and Scales from both companies.

Discuss a variety of manufacturer's data formats and interfacing for all microcontrollers and SPC enabled measuring systems, like scales, micrometers, calipers, dial indicators, and more.


We had a project that required connection to a digital micrometer with a data output jack. The idea was to connect a microcontroller to the micrometer, to read the measurements and make decisions based on the readings. The micrometers that we used are made by Mitutoyo, and have a funky 52 character data stream in reverse bit order. The microcontroller we chose is the Arduino, and we used a 4D systems uVGA-II to take serial output from the Arduino and display it on a VGA monitor.

Order a prebuilt interface kit:

male shrouded header to fit mitutoyo cable
(2) 10k Ohm Resistors
6 pin male header (wires to Arduino)

Now includes an onboard Arduino Nano clone with usb cable. No seperate Arduino needed.

Major Components:

Mitutoyo 293-335 Coolant Proof LCD Micrometer, Friction Thimble, 0-1"/0-25.4mm Range, 0.001mm/0.00005" Graduation, +/-0.00005" Accuracy, SPC Output


Mitutoyo 05CZA662, Digimatic Cable, 40", With Data Switch for Coolant Proof Micrometers


Mitutoyo Absolute LCD Digimatic Indicator ID-C, Calculation Type, Inch, #4-48 UNF Thread, 0.375" Stem Diameter


Mitutoyo 500-171-30 Advanced Onsite Sensor Absolute Scale Digital Caliper, 0-6" Range


Mitutoyo 572-211-20, Horizontal Digimatic Scale Unit, 0 -6" X .0005"/0.01mm, With Output


Arduino Mega or compatible

Protoshield recommended

2 PN2222A transistors
four 10k Ohm resistors
2x5 shrouded header
one momentary pushbutton

Step 1: Mitutoyo Cable Schematic

This is a diagram showing how the Mitutoyo cable is wired. There is a red "data" button on the micrometer end of the cable that we were not using in this application, so we decided to use it as a "menu" button.
<p>Hello,</p><p>Great job. I want to get &quot;continuous&quot; readings from my iGaging IP-54 depth gauge. I have the SPC cable from iGaging. From my noob status it looks like your void section does the measurement, so I wonder if the void section is looped, how many samples per second could I expect to get from this? (using iGaging with Arduino Uno).</p><p>Thank you!</p><p>Bob</p>
The reading is continuous (void loop be definition is looped) and real time. I have not counted the samples per second, but it's faster than the eye can see.
<p>Hello, </p><p>Have you finish the code that would allow for multiple calipers to measured at once? Also do you know how to read if the caliper is either positive or negative?</p><p>Thank You</p>
Yes on both counts. I'll try to get the code posted shortly.
<p>Thank you for the reply, I am looking forward to seeing it. Awesome project by the way.</p>
<p>hello, great instructable.</p><p>Two questions please. </p><p>Are you intending at any point in to making this a 3 (or 4) axis reader? and any tips how I would identify (before I purchase) if a prospective calliper or micrometre would be compatible with this? </p><p>for $15 it's not worth me losing sweat and tears trying to build my own but I would need three axis on the same VGA output. OR serial/ i2c or some sort of output I could connect to a raspberry pi and make my own three axis display. I believe a lot of the cheap Chinese calipers etc use a different protocol but I'm not sure which ones are which...</p><p>Thanks again for the info...</p>
<p>Now that I have the Igaging SPC connectivity working, I have more time to build a VGA output 3 axis reader. Still need one?</p>
<p>Just finished the 2 interface board. Two such boards will give you up to 4 instrument measurements.</p>
If a 3-axis machine DRO for use with Chinese caliper (or even higher quality) scales is what you're after, then search TouchDRO. I've built set ups for a mill and a lathe, and it is a killer way to a DIY DRO.
I looked at TouchDRO, and it's not what I'm looking for. I want more control over what I can do with the signals I'm reading, for activating other equipment, inventory and process control. The Arduino gives me that. I can easily measure a dozen different devices, and save data to a mysql database, display on a vga monitor, and direct other processes to happen. I'm currently reading micrometers, calipers, and scales, and will be expanding the number and types of data formats I can read. I'm working on Igaging Origin series now.<br>
This particular project only works with the Mitutoyo calipers and micrometers. It would be easy to use three gauges,and read all three axis. I'm presently working on a companion piece that works with Igaging equipment. Poor man's DRO if you will.<br>
<p>Now trying to do the same project with an Igaging Origin SpeedMic. Igaging is not being helpful with the pinout or the data spec.</p>
<p>Shumatech has a write-up about the iGaging interface here - <a href="http://www.shumatech.com/web/21bit_protocol?page=0,0" rel="nofollow"> http://www.shumatech.com/web/21bit_protocol?page=...</a></p><p>I have a mitutoyo and am thinking I'll try your example to log data to a PC. I specifically want to automate height profiles as a function of length. This looks like a great way to do it cheaply. Thanks for sharing!</p>
<p>The interface for the Igaging Origin SPC series is not 21 bit, it's the same as the Mitutoyo 52 bit protocol. Igaging bought the SPC interface from a third party.</p>
<p>If you want to add software support for another brand of micrometer, these guys reverse engineered a cheap chinese device: http://robocombo.blogspot.com/2010/12/using-tis-launchpad-to-interface.html and published the specs for the 24bit data stream. I'm not 100% sure, but I suspect (from a quick eyeball with a scope) it may be compatible with the cheap micrometer sold at Harbor Freight, which I've seen priced anywhere between $8 and $16 depending on their convoluted sales and coupon promotions...</p>
<p>Hi !</p><p>Could you please send me a link here to buy the complete kit ?</p><p>Thank you ! </p>
<p>A link to the kit is listed above! It's $15 for the interface board, and comes assembled.</p>
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