Update: Igaging Origin Series use a Mitutoyo cable and output the Mitutoyo 52 bit datastream. The code and schematics below work with both Calipers and Micrometers 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)

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


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, 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>A little tangentially, if you're looking at tech for CNC measurements or automatic bed levelling etc, http://www.optex-ramco.com/products/laser-measurement-sensors/cd22-laser-measurement-sensor.html is quite interesting technology. (Although is a whole different price range from a digital caliper)</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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Bio: Professionally, I'm an IT Engineer (Executive Level) and Electronics Tech. I'm a Amateur Radio Operator (KK4HFJ). I lived off grid, with Solar (PV ... More »
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