3D Printed Caliper Extensions Make Hole Measurement Easier

December 6, 2024 by Dan Maloney 21 Comments

If there’s anything more frustrating than mounting holes that don’t line up with the thing you’re mounting, we don’t know what it could be. You measure as carefully as possible, you drill the holes, and yet at least one hole ends up being just out of place. Sometimes you can fudge it, but other times you’ve got to start over again. It’s maddening.

Getting solid measurements of the distance between holes would help, which is where these neat snap-on attachments for digital calipers come in. [Chris Long] came up with the 3D printed tools to make this common shop task a little easier, and they look promising. The extensions have cone-shaped tips that align perfectly with the inside edge of the caliper jaws, which lines the jaws up with the center of each hole. You read the center-to-center distance directly off the caliper display, easy peasy.

Of course, there’s also the old machinist’s trick (last item) about zeroing out the calipers after reading the diameter of one of the holes and then measuring the outside-to-outside distance between the two holes. That works great when you’ve got plenty of clearance, but the shorter inside jaws might make measuring something like a populated PCB with this method tricky. For the price of a little filament and some print time, these might be just the tool to get you out of a bind.

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A set of brass safety glasses sit on a marred black workbench. The top and earpiece sections of the frames are in squarish brass plate and have ruler marks on them.

Combination Safety Glasses And Measurement Tool

November 8, 2024 by Navarre Bartz 19 Comments

While rulers and tape measures are ubiquitous, they always seem to disappear when you need them. We know you’d never forget your safety glasses (safety first!), so what if they were also a measuring tool?

Starting by snapping pieces from a folding yardstick, [Simone Giertz] and [Laura Kampf] worked out a rough prototype before letting [Giertz] complete the project in brass. Some initial issues with the weight of the frames were alleviated by switching to a lighter weight plate material and using thinner frames and weight-saving holes near the ear pieces.

Beauty is in the eye of the beholder, so we’ll let somebody else decide whether or not these will be the newest fashion craze. But it’s hard to argue with the timelessness of brass unless you have a copper allergy. We could definitely see a less expensive plastic version catching on in makerspaces for the PPE bin.

Want some other cool wearable gear? How about [Giertz]’s grocery bag hat, an evening gown with servo-driven flowers, or a shirt that reflects heat out the atmospheric window?

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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.

Rulers Of The Ancient World — Literally!

July 13, 2024 by Al Williams 29 Comments

If you were expecting a post about ancient kings and queens, you are probably at the wrong website. [Burn Heart] has a fascination with ancient measuring devices and set out to recreate period-correct rules, although using decidedly modern techniques.

The first example is a French rule for measuring the “pied du Roi” or king’s foot. Apparently, his royal highness had large feet as a the French variant is nearly 13 inches long. The next rulers hail from Egypt and measure cubits and spans. Turns out the pyramid builders left a lot of information about measurements and their understanding of math and tools like dividers.

Other rules from Rome, Japan, and the Indus Valley are also included. According to the post, one set of these rulers used locally sourced wood, but a second “limited” edition used wood that the originals might have. Most of the rulers were etched via CNC, although the French ruler was hand-etched.

The Romans, apparently, had smaller feet than French royalty, as their Pes or foot was about 11.65 inches. There are plenty of little tidbits in the post ranging from the origin of the word inch to why the black wood used for piano keys is called ebony.

We’ll stipulate this isn’t exactly a hack, although it is fine workmanship and part of hacker culture is obsessing over measuring things, so we thought it was fair game. These days, rulers are often electronic. Which makes it natural to put them on a PC board.

Is This The World’s Smallest Multichannel Voltmeter?

May 22, 2024 by Jenny List 8 Comments

The instrument which probably the greatest number of Hackaday readers own is likely to be the humble digital multimeter. They’re cheap and useful, but they’re single-channel, and difficult to incorporate into a breadboard project. If you’ve ever been vexed by these limitations then [Alun Morris] has just the project for you, in the world’s smallest auto-ranging multichannel voltmeter. It’s a meter on a tiny PCB with a little OLED display, and as its name suggests, it can keep an eye on several voltages for you.

At its heart is an ATtiny1614 microcontroller on a custom PCB, but for us the part we most like lies not in that but in the prototype version made on a piece of protoboard. There’s considerable soldering skill in bending surface mount components to your will on this material, and though these aren’t quite the smallest parts it’s still something that must have required some work under the magnifier.

All of the code and hardware details can be found in the GitHub repository, and for your viewing pleasure there’s a video showing it in action which we’ve placed below.

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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?

Ask Hackaday: Do You Calibrate Your Instruments?

May 9, 2024 by Jenny List 54 Comments

Like many of you, I have a bench full of electronic instruments. The newest is my Rigol oscilloscope, only a few years old, while the oldest is probably my RF signal generator that dates from some time in the early 1950s. Some of those instruments have been with me for decades, and have been crucial in the gestation of countless projects.

If I follow the manufacturer’s recommendations then just like that PAT tester I should have them calibrated frequently. This process involves sending them off to a specialised lab where their readings are compared to a standard and they are adjusted accordingly, and when they return I know I can trust their readings. It’s important if you work in an industry where everything must be verified, for example I’m certain the folks down the road at Airbus use meticulously calibrated instruments when making assemblies for their aircraft, because there is no room for error in a safety critical application at 20000 feet.

But on my bench? Not so much, nobody is likely to face danger if my frequency counter has drifted by a few Hz. Continue reading “Ask Hackaday: Do You Calibrate Your Instruments?” →