Matrix Of Resistors Forms The Hot Hands Behind This Thermochromic Analog Clock

If you’re going to ditch work, you might as well go big. A 1,024-pixel thermochromic analog clock is probably on the high side of what most people would try, but apparently [Daniel Valuch] really didn’t want to go to work that day.

The idea here is simple: heat up a resistor by putting some current through it, lay a bit of thermochromic film over it, and you’ve got one pixel. The next part was not so simple: expanding that single pixel to a 32 by 32 matrix.

To make each pixel square-ish, [Daniel] chose to pair up the 220-ohm SMD resistors for a whopping 2,048 components. Adding to the complexity was the choice to drive them with a 1,024-bit shift register made from discrete 74LVC1G175 flip flops. With the Arduino Nano and all the other support components, that’s over 3,000 devices with the potential to draw 50 amps, were someone to be foolish or unlucky enough to turn on every pixel at once. Luckily, [Daniel] chose to emulate an analog clock here; that led to additional problems, like dealing with cool-down lag in the thermochromic film when animating the hands, which had to be dealt with in software.

We’ve seen other thermochromic displays before, including recently with this temperature and humidity display. This one may not be the highest resolution display out there, but it’s big and bold and slightly dangerous, and that makes it a win in our book.

Printable, Castable Feeders Simplify Pick-and-Place Component Management

It goes without saying that we love to see all the clever ways people have come up with to populate their printed circuit boards, especially the automated solutions. The idea of manually picking and placing nearly-microscopic components is reason enough to add a pick and place to the shop, but that usually leaves the problem of feeding components to the imagination of the user. And this mass-production-ready passive component feeder is a great example of that kind of imagination.

Almost every design we’ve seen for homebrew PnP component feeders have one of two things in common: they’re 3D-printed, or they’re somewhat complex. Not that those are bad things, but they do raise issues. Printing enough feeders for even a moderately large project would take forever, and the more motors and sensors a feeder has, the greater the chance of a breakdown. [dining-philosopher] solved both these problems with a simple design using only two parts, which can be resin cast. A lever arm is depressed by a plunger that’s attached to the LitePlacer tool, offset just enough so that the suction cup is lined up with the component location on the tape. A pawl in the lower arm moves forward when the tool leaves after picking up the part, engaging with the tape sprocket holes and advancing to the next component.

[dining-philosopher] didn’t attack the cover film peeling problem in his version, choosing to peel it off manually and use a weight to keep it taut and expose the next component. But in a nice example of collaboration, [Jed Smith] added an automatic film peeler to the original design. It complicates things a bit, but the peeler is powered by the advancing tape, so it’s probably worth it.

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A Ploopy Pick And Place

A fair number of hackers reach that awkward age in their careers – too old for manual pick and place, but too young for a full-fledged PnP machine. The obvious solution is to build your own PnP, which can be as simple as putting a suction cup on the Z-axis of an old 3D-printer. Feeding parts into the pick and place, though, can be a thorny problem.

Or not, if you think your way through it like [Phil Lam] did and build these semi-automated SMD tape feeders. Built for 8-mm plastic or paper tapes, the feeders are 3D-printed assemblies that fit into a rack that’s just inside the work envelope of a pick and place machine. Each feeder has a slot in the top for the tape, which is advanced by using the Z-axis of the PnP to depress a lever on the front of the case. A long tongue in the tape slot gradually peels back the tape’s cover to expose a part, which is then picked up by the PnP suction cup. Any machine should work; [Phil] uses his with a LitePlacer. We like the idea that parts stay protected until they’re needed; the satisfyingly clicky lever action is pretty cool too. See it briefly in action in the video below.

It looks like [Phil] built this in support of his popular Ploopy trackball, which is available both as a kit and fully assembled. We think the feeder design is great whether you’re using PnP or not, although here’s a simpler cassette design for purely manual SMD work.

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Supercon SMD Challenge Gets 3D Printed Probes: Build Your Own

This year was the second SMD challenge at Supercon, so it stands to reason we probably learned a few things from last year. If you aren’t familiar with the challenge, you are served some pretty conventional tools and have to solder a board with LEDs getting progressively smaller until you get to 0201 components. Those are challenging even with proper tools, but a surprising number of people have managed to build them even using the clunky, large irons we provide.

During the first challenge, we did find one problem though. The LEDs are all marked for polarity. However, since we don’t provide super high power magnification, it was often difficult to determine the polarity, especially on the smaller parts. Last year, [xBeau] produced some quick LED testers to help overcome this problem. This year we refined them a bit.

As you can see, the 2018 model was a very clever use of what was on hand. A CR2032 holder powered the probes and the probes themselves were two resistors. If you can get the LED to light with the probes you know which lead is the anode and which is the cathode. A little red ink makes it even more obvious. Continue reading “Supercon SMD Challenge Gets 3D Printed Probes: Build Your Own”

Creating Easy Glass Circuit Boards At Home

This tip for creating glass substrate circuit boards at home might hew a bit closer to arts and crafts than the traditional Hackaday post, but the final results of the method demonstrated by [Heliox] in her recent video are simply too gorgeous to ignore. The video is in French, but between YouTube’s attempted automatic translation and the formidable mental powers of our beloved readers, we don’t think it will be too hard for you to follow along after the break.

The short version is that [Heliox] loads her Silhouette Cameo, a computer-controlled cutting machine generally used for paper and vinyl, with a thin sheet of copper adhered to a backing sheet to give it some mechanical strength. With the cutting pressure of the Cameo dialed back, the circuit is cut out of the copper but not the sheet underneath, and the excess can be carefully peeled away.

Using transfer paper, [Heliox] then lifts the copper traces off the sheet and sticks them down to a cut piece of glass. Once it’s been smoothed out and pushed down, she pulls the transfer paper off and the copper is left behind.

From there, it’s just a matter of soldering on the SMD components. To make it a little safer to handle she wet sands the edges of the glass to round them off, but it’s still glass, so we wouldn’t recommend this construction for anything heavy duty. While it might not be the ideal choice for your next build, it certainly does looks fantastic when mounted in a stand and blinking away like [Heliox] shows off at the end.

Ironically, when compared to some of the other methods of making professional looking PCBs at home that we’ve seen over the years, this one might actually be one of the easiest. Who knew?

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A Newbie Takes The SMD Challenge At Supercon

First-time visitors to Disneyworld often naively think they’re going to “do” the park in three days: one day for the Magic Kingdom, one day for Epcot, and one day for everything else. It’s easy to spot such people, collapsed on a bench or dragging exhausted kids around while trying to make their way to the next must-see attraction. Supercon is something like that — a Disney-esque theme park for hackers that will exhaust you if you don’t have a plan, and if you don’t set reasonable expectations. Which is why I was glad that I set only one real goal for my first Supercon: take the SMD Soldering Challenge.

Now, while I’m pretty handy with a soldering iron, I was under no illusion that I would be at all competitive. All my soldering experience has been with through-hole components, and while I also used to doing some production soldering on fine-pitch connectors, the whole surface-mount thing is new to me. I entered mainly because I wanted to see what was possible coming in raw. At best I’d learn what my limits are, and at worst I’d fail spectacularly and provide grist for a “Fail of the Supercon” post. It’s a win either way.

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How To Design A BGA Breakout Module

Surface mount devices can take some adjusting to for hackers primarily used to working with through-hole components. Despite this, the lure of the hottest new parts has enticed even the most reticent to learn to work with the technology. Of course, time rolls on and BGA parts bring further difficulties. [Nate] from SparkFun worked on the development of the RedBoard Artemis, and broke down the challenges involved.

The RedBoard Artemis is an Arduino-compatible devboard built around the Ambiq Apollo3 chip. In addition to packing Bluetooth and 1 MB of Flash, it’s also capable of running TensorFlow models and using tiny amounts of power. The chip comes in an 81-Ball Grid Array at 0.5mm pitch, which meant SparkFun’s usual PCB fabrication methods weren’t going to cut it.

An initial run of prototype boards was run using 4 layers, blind and buried vias, and other fancy tricks to break out all the necessary signals. While this worked well, it was expensive and inefficient. The only part of the board that needed such fabrication was around the chip itself; the rest of the board could be produced with cheaper 2-layer methods. To improve this for mass production, instead, an SMD module was created to house the Apollo3, which could then be dropped into new designs on cheaper boards as necessary.

[Nate] does a great job of explaining the engineering involved, as well as sharing useful tips for others going down a similar path. So far, this is just part 1, with future posts promising to cover the RF shield design and FCC certification process. [Nate] has always been keen to share his wisdom, and we can’t wait to see what comes next!