Solder Two Boards At Once With This Dual Reflow Plate

November 10, 2023 by Dan Maloney 4 Comments

Homebrew reflow projects generally follow a pretty simple formula: find a thrift shop toaster oven or hot plate, add a microcontroller and a means to turn the heating element on and off, and close the loop with a thermistor. Add a little code and you’re melting solder paste. Sometimes, though, a ground-up design works better, like this scalable reflow plate with all the bells and whistles.

Now, we don’t mean to hate on the many great reflow projects we’ve seen, of course. But [Michael Benn]’s build is pretty slick. The business end uses 400-watt positive temperature coefficient (PTC) heating elements from Amazon controlled by solid-state relays, although we have to note that we couldn’t find the equivalent parts on the Amazon US site, so that might be a problem. [Michael] also included mechanical temperature cutoffs for each plate, an essential safety feature in case of thermal runaway. The plates are mounted at the top of a 3D-printed case, which also has an angled enclosure for a two-color OLED display and a rotary encoder.

The software runs on an ESP32 and supports multiple temperature profiles for different solder pastes. The software also supports different profiles on the two plates, and even allows for physical expansion to a maximum of four heating plates, or even just a single plate if that’s what you need. The video below shows it going through its paces along with the final results. There’s also a video showing the internals if that’s more your style

We appreciate the fit and finish here, as well as the attention to safety. Can’t find those heating elements for your build? You might have to lose your appetite for waffles.

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Hands On With Boondock Echo

November 10, 2023 by Dan Maloney 23 Comments

Perhaps no words fill me with more dread than, “I hear there’s something going around.” In my experience, you hear this when some nasty bug has worked its way into the community and people start getting whatever it is. I’m always on my guard when I hear about something like this, especially when it’s something really unpleasant like norovirus. Forewarned is forearmed, after all.

Since I work from home and rarely get out, one of the principal ways I keep apprised of what’s going on with public health in my community is by listening to my scanner radio. I have the local fire rescue frequencies programmed in, and if “there’s something going around,” I usually find out about it there first; after a half-dozen or so calls for people complaining of nausea and vomiting, you get the idea it’s best to hunker down for a while.

I manage to stay reasonably well-informed in this way, but it’s not like I can listen to my scanner every minute of the day. That’s why I was really excited when my friend Mark Hughes started a project he called Boondock Echo, which aims to change the two-way radio communications user experience by enabling internet-backed recording and playback. It sounded like the perfect system for me — something that would let my scanner work for me, instead of the other way around. And so when Mark asked me to participate in the beta test, I jumped at the chance.

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Cheap Power Supplies With Fake Chips Might Not Be That Bad

November 10, 2023 by Dan Maloney 33 Comments

We all know the old maxim: if it’s too good to be true, it’s probably made with fake components. OK, maybe that’s not exactly how it goes, but in our world gone a little crazy, there’s good reason to be skeptical of pretty much everything you buy. And when you pay the equivalent of less than a buck for a DC-DC converter, you get what you pay for.

Or do you? It’s not so clear after watching [Denki Otaku]’s video on a bargain bag of buck converters he got from Amazon — ¥1,290 for a lot of ten, or $0.85 a piece. The thing that got [Denki]’s Spidey senses tingling is the chip around which these boards were built: the LM2596. These aren’t especially cheap chips; Mouser lists them for about $5.00 each in a reel of 500.

Initial testing showed the converters, which are rated at 3 to 42 VDC in and 1.25 to 35 VDC out, actually seem to do a decent job. At least with output voltage, which stays at the set point over a wide range of input voltages. The ripple voltage, though, is an astonishing 400 mV — almost 10% of the desired 5.0 V output. What’s more, the ripple frequency is 18 kHz, which is far below the 150 kHz oscillator that’s supposed to be in the LM2596. Other modules from the batch tested at 53 kHz ripple, so better, but still not good. There were more telltales of chip fakery, such as dodgy-looking lettering on the package, incorrect lead forming, and finger-scorching heat under the rated 3 A maximum load. Counterfeit? Almost definitely. Useless? Surprisingly, probably not. Depending on your application, these might do the job just fine, especially if you slap a bigger cap on the output to smooth that ripple and keep the draw low. And keep your fingers away, of course.

Worried that your chips are counterfeits? Here’s a field guide for fake chip spotters. And what do you do if you get something fake? A refund might just be possible.

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Does Getting Into Your Garage Really Need To Be Difficult?

November 9, 2023 by Dan Maloney 78 Comments

Probably the last thing anyone wants when coming home from a long day at work or a trip is to be hassled at the last possible moment — gaining entrance to your house. But for some home automation enthusiasts, that’s just what happened when they suddenly learned that their own garage doors had betrayed them.

The story basically boils down to this: Chamberlain, a US company that commands 60% of the garage door market, recently decided to prevent “unauthorized usage” of their MyQ ecosystem through third-party apps. Once Chamberlain rolled out the change, users of Home Assistant and other unauthorized apps found themselves unable to open or close their doors with the apps they were accustomed to.

Those of us with custom smart home setups can relate to how frustrating it is when something disturbs the systems you’ve spent a lot of time tweaking and optimizing. It’s especially upsetting for users who both Chamberlain hardware specifically because it was supported by Home Assistant, only to have the company decide to drop support. This feels like false advertising, but we strongly suspect that buried in the EULA users must have agreed to at some point is a clause that essentially says, “We can do anything we want and tough noogies to you.” And if you read through the article linked above, you’ll get an idea why Chamberlain did this — they probably didn’t like the idea that users were avoiding their ad-spangled MyQ app for third-party interfaces, depriving them of ad revenue and the opportunity for up-selling.

We feel the frustration of these users, but rather than curse the darkness, perhaps this will light a candle of righteous rage that leads to a clever workaround. The Home Assistant blog article mentions a dongle called ratgdo, which should allow any door with plain old dry contacts to work via MQTT or ESPHome. It’s extra work that users shouldn’t have to put in, but maybe getting one over on The Man would be worth the effort.

Thanks to [KC] for the tip; please keep us posted on your workaround.

Mining And Refining: Graphite

November 9, 2023 by Dan Maloney 26 Comments

In my teenage years I worked for a couple of summers at a small amusement park as a ride operator. Looking back on it, the whole experience was a lot of fun, although with the minimum wage at $3.37 an hour and being subjected to the fickle New England weather that ranged from freezing rains to heat stroke-inducing tropical swelter, it didn’t seem like it at the time.

One of my assignments, and the one I remember most fondly, was running the bumper cars. Like everything else in the park, the ride was old and worn out, and maintenance was a daily chore. To keep the sheet steel floor of the track from rusting, every morning we had to brush on a coat of graphite “paint”. It was an impossibly messy job — get the least bit of the greasy silver-black goop on your hands, and it was there for the day. And for the first few runs of the day, before the stuff worked into the floor, the excited guests were as likely as not to get their shoes loaded up with the stuff, and since everyone invariably stepped on the seat of the car before sitting on it… well, let’s just say it was easy to spot who just rode the bumper cars from behind, especially with white shorts on.

The properties that made graphite great for bumper cars — slippery, electrically conductive, tenacious, and cheap — are properties that make it a fit with innumerable industrial processes. The stuff turns up everywhere, and it’s becoming increasingly important as the decarbonization of transportation picks up pace. Graphite is amazingly useful stuff and fairly common, but not all that easy to extract and purify. So let’s take a look at what it takes to mine and refine graphite.

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Forever Writing On Monofilament Fishing Line

November 8, 2023 by Dan Maloney 50 Comments

Collectively, we have a long-term memory problem. Paper turns to mulch, dyes in optical disks degrade, iron oxides don’t last forever, and flash memories will eventually fade away. So what do you do when you want to write something down and make sure it’s around a couple of thousand years from now? Easy — just use something that even Mother Nature herself has trouble breaking down: plastic.

Specifically, fluoropolymer fishing line, which is what [Nikolay Valentinovich Repnitskiy] uses as a medium in his “Carbon Record” project. There’s not a lot of information in the repository, but the basic idea is to encode characters by nicking the fishing line along its length. The encoder is simple enough; a spool of fresh line is fed into a machine where a solenoid drives a sharpened bolt against the filament. This leaves a series of nicks that encode the ones and zeros of 255 ASCII characters. It looks like [Nikolay] went through a couple of prototypes before settling on the solenoid; an earlier version used a brushed motor to drive the encoder, but the short, rapid movements proved too much for the motor to handle. We’ve included a video below that shows the device encoding some text; sounds a little like Morse to us.

There seems to be a lot more going on with this device than the repo lets on; we’d love to know what the big heat sink on top is doing, for instance. Hopefully we’ll get more details, including how [Nikolay] intends to decode the dents. Or perhaps that’s an exercise best left to whoever finds these messages a few millennia hence.

3D Printing Improves Passive Pixel Water Gauge

November 8, 2023 by Dan Maloney 9 Comments

Here at Hackaday, we feature all kinds of projects, and we love them all the same. But some projects are a little easier to love than others, especially those that get the job done in as simple a way as possible, with nothing extra to get in the way. This completely electronics-free water gauge is a great example of doing exactly as much as needs to get done, and not a bit more.

If this project looks a bit familiar, it’s because we featured [Johan]’s previous version of “Pixel Pole” a few years back. Then as now, the goal of the build is to provide a highly visible level gauge for a large water tank that’s part of an irrigation system. The basic idea was to provide a way of switching a pump on when the tank needed filling, and off when full. [Johan] accomplished this with a magnetic float inside the tank and reed switches at the proper levels outside the tank, and then placed a series of magnetic flip dots along the path of the float to provide a visual gauge of the water level. The whole thing was pretty clever and worked well enough.

But the old metal flip dots were getting corroded, so improvements were in order. The new flip dots are 3D printed, high-visibility green on one side and black on the other. The only metal parts are the neodymium magnet pressed into a slot in the disc and a sewing pin for the axle. The housing for each flip dot is also printed, with each module snapping to the next so you can create displays of arbitrary height. The video below shows printing, assembly, and the display in action.

[Johan]’s improvements are pretty significant, especially in assembly; spot-welding was a pretty cool method to use in the first version, but printing and snapping parts together scales a lot better. And this version seems like it’ll be much happier out in the elements too. Continue reading “3D Printing Improves Passive Pixel Water Gauge” →