The No-MCU Fan Controller

December 31, 2021 by Jenny List 33 Comments

The default for any control project here in 2019 was to reach for a microcontroller. Such are their low cost and ubiquity that they can be used to replicate what might once have needed some extra circuitry, with the minimum of parts. But here we are at the end of 2021, and of course microcontrollers are hard to come by in a semiconductor shortage. [Hesam Moshiri] has a project that takes us back to a simpler time, a temperature controlled fan the way they used to be made, without a microcontroller in sight.

Old hands will no doubt guess where this design is heading, there is an LM35 temperature sensor producing a voltage proportional to its temperature, and half of an LM358 which forms a comparator against a static voltage from a divider. The LM358’s output drives a MOSFET which in turn switches on or off the fan motor. This type of circuit used to be the daily fare of simple control electronics in the days when a microcontroller represented a significant expense, and it’s still a handy circuit to be reminded of.

Have you forgotten sensors such as the LM35 in a world of on-board sensors? Time to refresh your sensing memory.

Electric Wheelchair Dump Truck Hack Really Hauls

December 30, 2021 by Ryan Flowers 5 Comments

Have you ever looked at a derelict electric wheelchair and thought “I bet I could make something great with that!” Of course you have- this is Hackaday, after all! And so did [Made in Poland], who managed to get a hold of a broken down electric wheelchair and put the full utility of his well equipped metalworking shop to work. The results? Lets just say it hauls.

What we really enjoyed about the build was that there wasn’t much that couldn’t be done by an average garage hacker with a drill press, angle grinder, and a stick welder. While it’s definitely nicer to have a lathe and a high quality welding table, plasma cutter, and everything in between, nothing that [Made in Poland] did in the video is such high precision that it would require those extensive tools. There may be some parts that would be a lot more difficult, or lower precision, but still functional.

Another aspect of the build is of course the control circuitry and user interface. Keeping the skid steer and castor approach meant that each motor would need to be controllable independently. To achieve this, [Made in Poland] put together a purely electromechanical drive controlled with momentary rocker switches and automotive relays to form a simple H-Bridge for each motor.

Of course you just have to watch until the end, because it really proves that a man will do anything to get out of hauling wood around! Old electric wheelchairs can also make a great base for big robots, as it turns out.

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The Pinouts Book Is Here, And It’s Just What You Need

December 28, 2021 by Tom Nardi 42 Comments

Updates from the enigmatic [NODE] are unfortunately few and far between these days. In fact his latest post is only the second time we’ve heard from the hacker in 2021. But as we’ve come to expect from his white-on-sorta-black releases, it certainly doesn’t disappoint.

Just in time to ring in whatever holiday you may celebrate, [NODE] has unveiled The Pinouts Book. A project he’s been working on for some time now with colleague [Baptiste], the free PDF download contains over 300 pages of high-contrast hardware diagrams and their respective pinouts. It’s about as straightforward as you can get, beyond the dedication page in the beginning, there’s not a word of fluff in the entire document. This is a work of hacker minimalism at its best, and we’re all about it.

From audio/video connectors all the way to development boards and single-board computers, The Pinouts Book sticks to the same format of a diagram and accompanying chart, making it exceptionally easy to find what you’re looking for. If you need more information than this streamlined layout can provide, each entry includes a link to a dedicated page on the book’s companion website. This will redirect you to supplemental data such as the manufacturer’s website, the part’s full datasheet, etc.

According to [NODE], the original plan for the Creative Commons BY-SA licensed work was to release it as a physical book, but the project ballooned up to such a scale that they realized it would be much easier to navigate and use as a digital document. While we don’t disagree, a physical release would certainly look lovely on our bookshelf. In the meantime, those who want to support the effort financially can purchase shirts emblazoned with diagrams pulled straight from the book’s pages.

We’ve long believed that a large-format electronic paper device would be an ideal gadget for the hacker’s workbench, as it allows for browsing through schematics and datasheets with a minimum of eye strain. Now we can also add a copy of The Pinouts Book to the list of things we’d install on our hacker-friendly e-ink compendium.

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Ordering prototypes like they were fast food

Made To Spec: The Coming Age Of Prototyping As A Service

December 8, 2021 by Sonya Vasquez 38 Comments

In the last decade, the price for making a single PCB plummeted. And we’ve featured tons of hacks with boards hailing from places like OSH Park or Seeed Studio. But this phenomenon isn’t isolated, and all sorts of one-off prototyping services are becoming cheaper and looking to satiate both hobbyist and engineer alike.

Today, I want to blow the lid off a few places offering one-off mechanical prototyping services. I’ll take us through some history of how we got here, introduce a few new players, and finally highlight some important tradeoffs before you start ordering bespoke aluminum parts straight to your doorstep.

Now go get your ANSI Z87+ safety glasses, and let’s get started.

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SuperCapacitors Vs Batteries Again

December 1, 2021 by Dave Rowntree 41 Comments

Supercapacitors are definitely not the same as batteries, we all know that. They tend to have a very low operating voltage, and due to their operating principle of storing charge on parallel plates, their discharge curve is quite unfriendly for modern microcontroller devices. Energy storage efficiency per unit volume is also low compared with modern lithium polymer (LiPo) batteries so all in all they don’t look all that useful for many of our projects. However, as [Andreas Spiess’] latest video demonstrates, they do have some redeeming features that might make them useful for certain embedded applications.

The low operating voltage initially looks like an issue for devices operating at a typical 3.3V, and it’s tempting to simply wire a few in series and roll with it. But as [Andreas] explains in his typically clear manner, it would be necessary to have a complex power stage, operating in buck mode with capacitor voltage above the required level, and in boost mode when it heads below. Too complex – it’s much easier to simply stick with a low voltage bank of paralleled supercaps, and just operate always in boost mode. Even doing this, you’re not realistically going to get more than a handful of hours operating voltage with an always active device.

So why bother at all with supercaps, surely using a LiPo is so much easier and better? In many cases the answer is definitely a yes. But LiPo cells must not be charged in freezing temperatures (apart from certain special low temp products), else the cell can rapidly be destroyed due to lithium metal deposition at the anode. Also you need to be careful charging them, especially when they’re heavily discharged, as they are easily damaged without the proper treatment. LiPo cells operate based on chemical principles – lithium ions literally have to move around inside the structure, and eventually the battery will wear out.

Supercapacitors have the advantage of very long life (but sometimes, they do leak) much more aggressive charging and discharging behaviours and will operate down to very low temperatures. This makes them very useful when a large amount of power is available sporadically (for super fast charge cycles) or in places where temperatures stay persistently very low, such as up a mountain were solar will work, albeit slowly, but LiPo batteries will definitely not be suitable.

Other battery chemistries are available, such as Lithium Iron Phosphate which can tolerate the cold. Also you can always just insulate the battery with an integrated heater and preheat the battery to a safe charging temperature as well. So, just like everything with electronics, it’s important to choose the correct parts for your application, and it all starts with the power source. Supercapacitors might just hit an appropriate price/performance point for that special application you had in mind.

Supercapacitors aren’t really suitable for many applications, like powering an eBike or running your laptop, but hey, they did it anyway.

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Prusa XL Goes Big, But That’s Only Half The Story

November 29, 2021 by Tom Nardi 44 Comments

For a few years now it’s been an open secret that Prusa Research was working on a larger printer named, imaginatively enough, the Prusa XL. Positioned at the opposite end of their product spectrum from the wildly popular Prusa Mini, this upper-tier machine would be for serious hobbyists or small companies that need to print single-part objects that were too large for their flagship i3 MK3S+ printer. Unfortunately, the global COVID-19 pandemic made it difficult for the Czech company to focus on bringing a new product to market, to the point that some had begun to wonder if we’d ever see this mythical machine.

But now, finally, the wait is over. Or perhaps, it’s just beginning. That’s because while Prusa Research has officially announced their new XL model and opened preorders for the $1,999+ USD printer, it’s not expected to ship until at least the second quarter of 2022. That’s already a pretty substantial lead time, but given Prusa’s track record when it comes to product launches, we wouldn’t be surprised if early adopters don’t start seeing their machines until this time next year.

So what do you get for your money? Well, not an over-sized Prusa i3, that’s for sure. While many had speculated the XL would simply be a larger version of the company’s popular open source printer with a few modern niceties like a 32-bit control board sprinkled in, the reality is something else entirely. While the high purchase price and ponderous dimensions of the new machine might make it a tough sell for many in the hacker and maker communities, there’s little question that the technical improvements and innovations built into the Prusa XL provide a glimpse of the future for the desktop 3D printer market as a whole.

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Bug Clive goes into detail about electrical safety even at the most basic level of wearing gloves.

The Unofficial Guide To (Avoiding) Electrocution

November 26, 2021 by Ryan Flowers 38 Comments

If you’re reading this sentence, there’s a pretty good chance that you interact with electricity more than just as an end-user. You’re a hacker. You aren’t afraid of a few volts, and your projects may involve both DC and AC voltage. Depending on what you’re working on, you might even be dealing with several thousand volts. And it’s you who Big Clive made the video below the break for.

“Familiarity breeds contempt” as the old saying goes, and the more familiar we are with electronics, the more cavalier we may tend to get. If we allow ourselves to get too lax, we may be found working on live circuits, skimping on safety for the sake of convenience, or jokingly saying “safety third!” far too often as we tear into a hazardous situation without scoping it out first.

Who better to bring us down to earth than Big Clive. In this video, he explains how electricity has the potential to impede the beating of our hearts, the action of our lungs, and even break bones. You’ll find a candid discussion about what electric shock does to a person, how to avoid it, and how to help if someone near you suffers electric shock.

Of course, if safety isn’t your thing, then maybe you’re ready to Shake Hands With Danger.

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