Custom Hat Gives Vintage Mitutoyo Calipers A New Lease On Life

August 2, 2024 by Dan Maloney 16 Comments

Metrology fans are usually at least a little bit in love with Mitutoyo, and rightfully so. The Japanese company has been making precision measuring instruments for the better part of 100 years, and users appreciate their precision almost as much as the silky smooth feel of their tools. If you can afford it, a Mitutoyo caliper is quite an addition to your toolbox.

As good as they are, though, they’re not perfect, which is what led to this clever Mitutoyo digital caliper hack by [turbanedengineer]. The calipers in question, a digital set from the early 1980s, happen to have a unique history with a tangential Hackaday angle — they belonged to [Dhaval], mechanical engineer and avid motorcyclist who happens to be the late elder brother of our own [Anool Mahidharia].

The tool, in need of a little TLC, made its way to [turbanedengineer] who first restored the broken battery contacts. Once powered up again, it became apparent that while the caliper’s native metric measurements were spot on, the internal conversion to inches was considerably off. This led [turbanedengineer] to the data port on the tool, which is intended to send serial data to an external computer for logging measurements. After a little experimentation to nail down the data format, he prototyped a tiny circuit using an ATtiny85 and an OLED display that reads the caliper data, converts metric to inches, and displays both measurements on the screen. The prototype led to a more permanent version, which cleverly sits over the original display and taps into the data port without any free wires. The video below shows the very slick results.

Our hearts go out to [Anool] and his family for their loss, and we tip our hats to [turbanedengineer] for his thoughtful and respectful hack of a storied tool. We know that anthropomorphizing tools makes no rational sense, but we think it’s safe to say that a tool like this has a soul, and it’s probably happy to be back in the game.

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Digitally Reading A Micrometer’s Output

July 17, 2024 by Lewin Day 11 Comments

If you’re instrumenting your machine tools, or if you’re just curious, you might want to get granular access to the output of a digital micrometer or the like. [Tommy] set his mind to figuring out the communications protocol of the ClockWise Tools dial indicator for this very purpose. And he succeeded!

Work began by finding the clock and signal lines for the gauge. With those identified, and the signals up on an AD2 logic analyzer, it was determined that once every 40 milliseconds, the device sent a data burst of six nibbles separated by 1.58 milliseconds apiece. The device communicates the absolute position of the gauge, and the data can be readily decoded with the aid of an op-amp to help boost up the 1.5-volt logic to a more reasonable level for a modern commodity microcontroller like the Arduino Nano. From there, the information can be trucked over serial to a PC, or you can do just about anything else with it besides.

We’ve seen similar hacks performed on calipers before, too, making automated measurements a breeze. If you’re working on something that needs precise measurements down to the, well… micrometer… this project might be just the thing you’re looking for.

About Right

May 18, 2024 by Elliot Williams 2 Comments

I really enjoyed reading Anne Ogborn’s piece on making simple DIY measurement devices for physical quantities like force, power, and torque. It is full of food for thought, if you’re building something small with motors and need to figure out how to spec them out.

Aside from a few good examples, what I really took home from this piece is how easy it can be to take approximate measurements. Take the push stick, which is a spring-loaded plunger in a transparent barrel. You use it to measure force by, well, squeezing the spring and reading off how far it deflects. That’s obvious, but the real trick is in calibration by pushing it into a weighing scale and marking divisions on the barrel. That quickly and easily turns “it’s pressing this hard” into an actual numerical force measurement.

The accuracy and precision of the push stick are limited by the quality of your scale and the fineness of the pen tip that you use to mark the barrel. But when you’re just looking to choose among two servo motors, this kind of seat-of-the-pants measure is more than enough to buy the right part. Almost any actual measurement is better than a wild-ass guess, so don’t hold yourself to outrageous standards or think that improvised quantitative measurement devices aren’t going to get the job done.

Al Williams quoted a teacher of his as saying that the soul of metrology is “taking something you know and using it to find something you don’t know”, and that sums up this piece nicely. But it’s also almost a hacker manifesto: “take something you can do and use it to do something that you can’t (yet)”.

Got any good measurement hacks you’d like to share?

Flexures Keep This Printed Displacement Sensor In Line

May 18, 2024 by Dan Maloney 4 Comments

When the job at hand is measuring something with micron-range precision, thoughts generally turn to a tool with a Mitutoyo or Starrett nameplate. But with a clever design and a little electronics know-how, it turns out you can 3D print a displacement sensor for measuring in the micron range for only about $10.

While the tool that [BubsBuilds] came up with isn’t as compact as a dial indicator and probably won’t win any industrial design awards, that doesn’t detract from its usefulness. And unlike a dial indicator — at least the analog type — this sensor outputs an easily digitized signal. That comes courtesy of a simple opto-interrupter sensor, which measures the position of a fine blade within its field of view. The blade is attached to a flexure that constrains its movement to a single plane; the other end of the flexure has a steel ball acting as a stylus. In use, any displacement of the stylus results in more or less light being received by the phototransistor in the opto-interrupter; the greater the deflection, the less light and the lower the current through the transistor. In addition to the sensor itself, [Bub] printed a calibration jig that allows precision gauge blocks or simple feeler gauges to be inserted in front of the stylus. The voltage across the emitter resistor for these known displacements is then used to create a calibration curve.

[Bub] says he’s getting 5-micron repeatability with careful calibration and multiple measurements of each gauge block, which seems pretty impressive to us. If you don’t need the digital output, this compliant mechanism dial indicator might be helpful too. Continue reading “Flexures Keep This Printed Displacement Sensor In Line” →

Hackaday Prize 2023: Over-the-Top Programmable Resistor Looks The Part And Performs

August 18, 2023 by Dan Maloney 18 Comments

Every once in a while we get wind of a project that we’re reluctant to write up for the simple reason that it looks too good to be true. Not that projects need to be messy to be authentic, mind you, but there are some that are just so finished and professional looking that it gives us a bit of pause. [Sebastian]’s programmable precision resistor is a shining example of such a project

While [Sebastian] describes this as “a glorified decade resistance box,” and technically that’s exactly right — at its heart it’s just a bunch of precision resistors being switched into networks to achieve a specific overall resistance — there’s a lot more going on here than just that. The project write-up, which has been rolling out slowly over the last month or so, has a lot of detail on different topologies that could have been used — [Sebastian] settled on a switched series network that only requires six relays per decade while also minimizing the contribution of relay contact resistance to the network. Speaking of which, there’s a detailed discussion on that subject, plus temperature compensation, power ratings, and how the various decades are linked together.

For as much that’s interesting about what’s under the hood, we’d be remiss to not spend a little time praising the exterior of this instrument. [Sebastian] appears to have spared no expense to make this look like a commercial product, from the rack-mount enclosure to the HP-esque front panel. The UI is all discrete pushbuttons and knobs with a long string of 16-segment LEDs — no fancy touch-screens here. The panel layout isn’t overly busy, and looks like it would be easy to use with some practice. We’d love to hear how the front and rear panel overlays were designed, too; maybe in a future project update.

This honestly looks like an instrument that you’d pay a princely sum to Keithley or H-P to own, at least back in the late 1990s or so. Kudos to [Sebastian] for the attention to detail here.

Hackaday Links: March 5, 2023

March 5, 2023 by Dan Maloney 40 Comments

Well, we guess it had to happen eventually — Ford is putting plans in place to make its vehicles capable of self-repossession. At least it seems so from a patent application that was published last week, which reads like something written by someone who fancies themselves an evil genius but is just really, really annoying. Like most patent applications, it covers a lot of ground; aside from the obvious capability of a self-driving car to drive itself back to the dealership, Ford lists a number of steps that its proposed system could take before or instead of driving the car away from someone who’s behind on payments.

Examples include selective disabling conveniences in the vehicle, like the HVAC or infotainment systems, or even locking the doors and effectively bricking the vehicle. Ford graciously makes allowance for using the repossessed vehicle in an emergency, and makes mention of using cameras in the vehicle and a “neural network” to verify that the locked-out user is indeed having, say, a medical emergency. What could possibly go wrong?

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New Metric Prefixes Get Bigger And Smaller

November 22, 2022 by Al Williams 72 Comments

It always fascinates us that every single thing that is made had to be designed by someone. Even something as simple as a bag and box that holds cereal. Someone had to work out the dimensions, the materials, the printing on it, and assign it a UPC code. Those people aren’t always engineers, but someone has to think it out no matter how mundane it is before it can be made. But what about the terms we use to express things? Someone has to work those out, too. In the case of metric prefixes like kilo, mega, and pico, it is apparently the General Conference on Weights and Measures that recently had its 27th session. As a result of that, we have four more metric prefixes to learn: ronna, quetta, ronto, and quecto.

Apparently, the new prefixes are to accommodate “big data” which is rapidly producing more data than there are atoms in the Universe. There were actually proposed earlier in a slightly different form but accepted at the conference. Apparently quecca is too close to a Portuguese swear word. So what do these actually mean? A QB (quettabyte) would be 10³⁰ bytes while an RB (ronnabyte) is only 10²⁷. So 1 QB would be 1,000,000 yottabytes (YB) the previous top of the scale.

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