Automate Your Pin Header Chopping Chores Away

July 29, 2023 by Dan Maloney 7 Comments

In most cases, cutting pin headers is a pretty simple job to tackle with a pair of cutters or even your bare fingers. But if you’re doing a lot of it, like for kitting up lots of projects for customers, then you might want to look at something like this automatic pin header cutter.

Even if you don’t need to follow [Mr. Innovative]’s lead on this, it’s worth taking a look at the video below, which has a couple of cool ideas that are probably applicable to other automation projects, especially those where lots of small parts are handled. Processing begins with a hopper that holds a stack of header strips over what we’d call a “reverse guillotine,” consisting of a spring-loaded plunger riding on a cam. A header strip is pushed out of the hopper to expose the specified number of terminals, the cam rotates and raises the plunger, and the correct length header is snapped off.

For our money, the neatest part of this build is the feed mechanism for the hopper. Rather than anything complicated like a rack-and-pinion, [Mr. Innovative] opted for a pusher made from a stiff yet flexible strip of plastic, which is forced along the bottom of the hopper by a pair of stepper-driven drive rollers. The plastic pusher is stored rolled up in a spiral fixture so it doesn’t take up much room.

Overall, it’s a simple and largely effective design. [Mr. Innovative] does express a little dissatisfaction with some aspects of the build, though; it looks like the stack of header strips needs a little weight on top of it to keep them feeding properly, and we notice a couple of iterations of the cutting mechanism in the video. The cut headers do seem to either fly off into the stratosphere or stay attached to each other, which could lead to jamming problems.

But still, it’s a solid design and reminds us of some other projects by [Mr. Innovative], like this SMD tape slicer or a CNC gear cutter.

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Kerfmeter Measures Laser Cutter Kerf Allowances On The Fly

May 3, 2023 by Dan Maloney 21 Comments

Nothing beats a laser cutter and a sheet of Baltic birch plywood or MDF when it comes to making quick, attractive enclosures. Burning out all the pieces and fitting them together with finger joints is super satisfying — right up until you realize that you didn’t quite get the kerf allowance right, and your pieces don’t fit together very nicely. If only there was a way to automate kerf measurement.

There is, in the form of Kerfmeter. It comes to us by way of the lab of [Patrick Baudisch] at the University of Potsdam, where they’ve come up with a clever way to measure the kerf of a laser cutter right during the cutting session. With the Kerfmeter mounted directly to the laser cutter head, a small test artifact based on an Archimedean spiral is cut into a corner of the workpiece. Pins on a small motor engage with the object and turn it until it jams in its hole; the wider the kerf, the greater the angle. Once the kerf is calculated, the rest of the design can be dilated by the proper amount to achieve a perfect fit. The video below shows it better than words can explain it.

What we like about this is its simplicity — all it involves is a motor and a microcontroller, plus a little software. It seems much faster than using a traditional kerf gauge, not to mention more precise. And while it does use up a little bit of material, the test pattern is really pretty small, all things considered. Seems like a reasonable trade-off to us. Still, if you want to figure out your kerfs the old-fashioned way, we’ve got you covered.

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Flip-Segment Digital Clock Is A Miniature Mechanical Marvel

October 9, 2022 by Dan Maloney 35 Comments

Clocks are such mundane objects that it’s sometimes hard for them to grab your attention. They’re there when you need them, but they don’t exactly invite you to watch them work. Unless, of course, you build something like this mechanical flip-segment clock with a captivating exposed mechanism

“Eptaora” is the name of this clock, according to its inventor [ekaggrat singh kalsi]. The goal here was to make a mechanical flip-segment display as small as possible, which meant starting with the smallest possible printable screw hole and scaling the design up from there. Each segment is controlled by a multi-lobed cam which bears on a spring-loaded cam follower. When the cam rotates against the follower, a segment is flipped up from the horizontal rest position to the vertical display position. A carryover mechanism connects two adjacent displays so that each pair of digits can be powered by a single stepper, and the finished clock is quite small — a little bit larger than the palm of a hand. The operation seems quite smooth, too, which is always a bonus with clocks such as these. Check out the mesmerizing mechanism in the video below.

We’d have sworn we covered a similar clock before — indeed [ekaggrat] says the inspiration for this clock came from one with a similar mechanism — but we couldn’t find it in the back catalog. Oh sure, there are flip-up digital clocks and all manner of mechanical seven-segment displays, but this one seems to be quite unique, and very pleasing.

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Hand-Cranked Doodler Made Using A 3D Printer

September 16, 2022 by Lewin Day 20 Comments

3D printers are great at creating complex geometry out of plastic, and that geometry can often pull off some impressive tricks. [DaveMakesStuff] found a way to generate geometry that draws 2D shapes with a pen and some fancy cams, and it’s really fun to watch.

The build is relatively simple. It consists of a frame which holds a 3D-printed cam turned by a hand crank. That cam controls the movement of a pen in two dimensions, letting it draw all manner of shapes. Videos on Reddit demonstrate it drawing squares, figure eights, and stars, while on YouTube, it writes the phrase “CAM I AM.”

According to [DaveMakesStuff], he figured out how to create the cams with “hours and hours of tedious CAD work.” We imagine there’s a way to do this with maths instead in parametric modelling software, and await such a build on the Hackaday tipsline. Those eager to recreate the build can explore the files on Thingiverse.

We’ve seen some great 3D-printed mechanisms before, too, like this zig-zag cam for a sewing machine. Video after the break.

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A Guide To Milling PCBs At Home

February 9, 2022 by Chris Lott 30 Comments

If you keep up with various retro vacuum tube projects, you probably have run across [UsagiElectric] aka [David]’s various PCBs that he makes on his own Bridgeport EZ-Track 3-axis milling machine — massively oversized for the job, as he puts it. In a recent video, [David] walks us through the steps of making a sample PCB, introducing the various tools and procedures of his workflow. He points out that these are the tools he uses, but the overall process should be similar no matter what tools you use.

Logisim to validate logic designs
TINA-TI, Texas Instrument’s version of the TINA SPICE simulator
DesignSpark PCB for schematic entry and PCB layout
FlatCAM, a computer-aided PCB manufacturing tool

For this video, [David] makes a half-adder circuit out of four vacuum tubes plus a seven-segment VFD tube to show the combined sum and carry outputs. Momentary switches are used to generate the two addends. Using this example, he proceeds to design, simulate, build and demonstrate a working circuit board. We like his use of the machined pin socket inserts for building a vacuum tube socket directly into the board.

Now this process isn’t for everyone. First of all, a Bridgeport mill is a pretty good sized, and heavy, tool. That said, these procedures should adapt well to other milling machines and engravers. We should point out that [David] is making boards mostly for vacuum tubes, where circuit trace width and spacing distances are generous. If you’re planning to make home PCBs for a 273-pin PGA chip, this isn’t the technique for you.

It seems that the bulk of [David]’s vacuum tube PCBs are single-sided, and reasonably so. They use wire links here and there to jump over traces. Adapting this process to double-sided PCBs is doable, but more complex. Are you milling double-sided boards in your lab? If so, let us know about it in the comments below.

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An array of 3D-printed parts for old sewing machines.

Printed Sewing Machine Parts Extend Singer’s Range

December 3, 2021 by Kristina Panos 6 Comments

[Grow Your Own Clothes] had finally found their ideal sewing machine for doing zig-zag stitches (/\/\/\) and converting to a treadle drive (mechanically foot-fed) — a Singer 411G. This is a well-respected workhorse of a machine, and if you see one in a secondhand store, you might want to grab it. The only problem is that its multi-step zig-zag stitch is a 4-stepper and not a 3-step, which is what [GYOC] prefers. Having heard it was possible to hack them into doing a 3-step, [GYOC] set out to learn Tinkercad and grow their own sewing machine parts.

A 3D-printed cam lets this machine do the zig-zag in three steps instead of four. — The new zig-zag top hat cam in place.

So once upon a time, sewing machines didn’t just do a bunch of things out of the box. They needed an array of plastic cams to do different stitches, kind of like trading out the element or disk in a typewriter to print in italics. While most machines still have exchangeable feet for different needs and special parts for sewing things like buttonholes, most domestics now have decorative stitches and their cams built in.

The 3-step zig-zag cam was just the beginning. [GYOC] decided to make a few more parts before their Tinkercad knowledge faded: a needle adapter with an improved design, some tension stud sprockets for a different machine, and a couple of buttonhole templates for making different sizes with a buttonholer. Although they aren’t giving away the files for free, all of these parts are available quite cheaply in their Shapeways store.

Got an old machine you don’t know what to do with? Try converting it to a computerized embroidery machine.

Thanks for the tip, [Raphael]!

A One-Servo Mechanical Seven-Segment Display

November 13, 2021 by Dan Maloney 21 Comments

The seven-segment display may be a bit prosaic after all these years, but that doesn’t mean there aren’t ways to spice it up. Coming up with a mechanical version of the typical photon-based display is a popular project, of which we’ve seen plenty of examples over the years. But this seven-segment display is quite a mechanical treat, and a unique way to flip through the digits.

With most mechanical displays, we’re used to seeing the state of each segment changed with some kind of actuator, like a solenoid or servo. [Shinsaku Hiura] decided on a sleeker design using a 3D-printed barrel carrying one cam for each segment. Each hinged segment is attached to an arm that acts as a follower, riding on its cam and flipping on or off in a set pattern. Which digit is displayed depends on the position of the barrel, which is controlled with a single servo and a pair of gears. It trades mechanical complexity for electrical simplicity and overall elegance, and as you can see from the video below, it’s pretty snappy.

We think the best part of this build is figuring out the shape of the cams. We wonder how they compare to the cam profiles in [Greg Zumwalt]’s mechanical display; it uses two separate discs with grooves, but the principle is pretty much the same.

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