Arm Gives Gift To Startups: Zero Cost

May 4, 2020 by Al Williams 24 Comments

Who hasn’t dreamed of pulling together some gadget in their garage and turning it into a big business? Of course, most gadgets today have a CPU in them, and Arm CPUs power just about any kind of embedded device you can think of. If you just want to use a chip, that’s easy. You buy them from a licensee and you use their tools for development. But if you want to integrate ARM’s devices into your own chips, that’s a different story. You have to pay fees, buy tools, and pay licenses on each chip you produce. Until now. Arm’s flexible access for startups program will let you apply to get all of that free.

To qualify, you have to be an “early stage silicon startup with limited funding.” Normally, flexible access costs about $75,000 to $200,000 a year and that doesn’t cover your license fees and royalties. The plan offered to qualifying startups is the $75,000 package, but that still includes access to nearly all Arm products, technical support, a few introductory training credits, and development tools. After your first tape-out, though, it looks as though you’ll have to pony up.

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Take This Cylindrical Coupler Design For A Spin

May 4, 2020 by Tom Nardi 19 Comments

We’re not exactly sure what kind of shenanigans [Conrad Brindle] gets himself into, but apparently it often requires cylindrical couplings to attach 3D printed parts to each other. He found himself designing and redesigning this type of connector so often that he decided to just make a parametric version of it that could be scaled to whatever dimensions are necessary for that particular application.

In the video after the break, [Concrad] explains the concept behind the coupler and how he designed it. Put simply, the tabs inside of the coupler are designed to grab onto each other once the coupler is spun. When he demonstrates the action, you can see that both sides of the coupler are pulled together tightly with a satisfying little snap, but then can be easily removed just by rotating them back in the opposite direction.

The nature of desktop 3D printing means that the female side of the connection requires support when printing, and depending on your printer, that might mean a relatively rough mating surface. [Conrad] notes that you’ll need to experiment a bit to find how small your particular machine can print out the design before things get too gummed up.

We can see how this would be useful for some applications, but if you need a printed joint that can handle a decent amount of torque before giving up the ghost, you might want to look into (mis)using one half of a spider coupling.

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Hardware Hacker’s Marie Kondo: How Many LM386s Is Too Many?

May 2, 2020 by Elliot Williams 57 Comments

We’re running a contest on Making Tech at Home: building projects out of whatever you’ve got around the house. As a hacker who’s never had a lab outside of my apartment, house, or hackerspace, I had to laugh at the premise. Where the heck else would I hack?

The idea is that you’re constrained to whatever parts you’ve got on hand. But at the risk of sounding like Scrooge McDuck sitting on a mountain of toilet paper, I’ve got literally hundreds of potentiometers in my closet, a couple IMUs, more microcontrollers than you can shake a stick at, and 500 ml of etching solution waiting for me in the bathroom. Switches, motors, timing belts, nichrome wire…maybe I should put in an order for another kilogram of 3D printer filament. In short, unless it’s a specialty part or an eBay module, I’m basically set.

But apparently not everyone is so well endowed. I’ve heard rumors of people who purchase all of the parts for a particular project. That ain’t me. The guru of household minimalism asks us to weigh each object in our possession and ask “does it spark joy?”. And the answer, when I pull out the needed 3.3 V low-dropout regulator and get the project built now instead of three days from now, is “yes”.

And I’m not even a hoarder. (I keep telling myself.) The rule that keeps me on this side of sanity: I have a box for each type of part, and they are essentially fixed. When no more motors fit in the motor box, no more motors are ordered, no matter how sexy, until some project uses enough of them to free up space. It’s worked for the last 20 years, long before any of us had even heard of Marie Kondo.

So if you also sit atop a heap of VFD displays like Smaug under the Lonely Mountain, we want to see what you can do. If you do win, Digi-Key is sending you a $500 goodie box to replenish your stash. But even if you don’t win, you’ve freed up space in the “Robot Stuff” box. That’s like winning, and you deserve some new servos. Keep on hacking!

Building A New RF Remote From Scratch

April 30, 2020 by Tom Nardi 5 Comments

We’ve seen no shortage of projects that use the ESP8266 or ESP32 to add “smart” features to existing home appliances, often by pairing the microcontroller with a radio or IR transmitter. If your device has an existing remote, integrating it into a custom home automation system is often just a matter of getting a few cheap modular components and writing some simple code to glue it all together.

But what if the appliance you want to control doesn’t use a common frequency? That’s a question that [eigma] recently had to answer after finding the remote control for the bedroom ceiling fan was operating at a somewhat unusual 304 MHz. Something like the MAX1472 could probably have been tuned to this frequency, but the chip doesn’t seem to be available in a turn-key module as the popular 315 MHz transmitters are.

There were a few possible options, including using a software defined radio (SDR), but [eigma] didn’t want to spend a fortune on this project or wait months for parts to get shipped from overseas. The most straightforward solution was to design a custom transmitter tuned to the proper frequency using discrete components; something of a dark art to those of us who’ve been spoiled by the high availability of modular components.

What follows is an fascinating look at the design, testing, and troubleshooting of a truly scratch-built transmitter. You won’t find any ICs here, the carrier signal is generated with just a transistor, some carefully measured pieces of wire, and a handful of passive components. By modulating the signal with an ESP32, [eigma] successfully makes the oddball ceiling fan an honorary member of the Internet of Things.

The write-up that [eigma] has done is an absolutely invaluable resource if you ever find yourself in need of rolling a bespoke transmitter. It easily ranks among some of the most informative radio reverse engineering work we’ve covered, and you’d be wise to file this one away for future reference. That said, most of the newer hardware you’re going to run into will probably be utilizing a widely-supported frequency like 433 MHz.

Greatest Keycaps And Where To Find Them

April 28, 2020 by Kristina Panos 25 Comments

Look at your keyboard. Do the keycaps excite you? That’s what we thought. You pound on that thing day in and day out. Shouldn’t it at least be attractive? Or even happiness-inducing? You don’t necessarily have to replace every single keycap to spark joy. When it comes to artisan keycaps, the point is to have something that stands out.

How about an Escape key that looks like a tall stack of flapjacks or a tiny, intricate cream puff? From a practical standpoint, how about a spiky Escape key that makes you think twice about rage quitting?

If you’re into games or anime, chances are good that there are more than enough artisan keycaps out there to keep you cash-poor for a while. The same goes for scrumptious foodstuffs with Cherry MX-compatible stems.

In this day and age, you can get just about any type of keycap you want, especially those encapsulating pop culture phenomena and fads. Yes there’s a fidget spinner keycap, and it’s adorable.

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In-Depth Design Of A Flyback Converter

April 25, 2020 by Jenny List 13 Comments

It is tempting to think of analogue and digital domains as entirely distinct, never to touch each other except like a cold war Checkpoint Charlie, through the medium of an ADC or DAC. In reality there are plenty of analogue effects upon digital circuitry which designers must be aware of, but there is one field in which the analogue and the digital are intricately meshed. Switch mode power supplies use digital techniques to exploit the analogue properties of components such as inductors and capacitors, and can be astoundingly clever in the way they do this to extract the last fraction of a percent efficiency from their conversion. Thus their design can be something of a Dark Art, so it’s always interesting to have a good read explaining some of the intricacies. [James Wilson] has built a flyback step-up converter to power Nixie tubes, and his write-up follows the whole process in great depth.

This type of converter seems at first glance to be a simple step-up design with a transformer that has a primary and secondary, where in fact it relies on the collapse in magnetic field during the off period of its duty cycle to provide a spike in voltage and thus a step-up beyond that you’d expect from the transformer alone. The write-up takes us through all this starting from a theoretical perspective, and then goes further into the realm of component selection and the effects of component properties on the waveforms involved. If you have ever battled ringing in a switch mode power supply you may recognise some of this.

If this field interests you, then there is probably no better place to send you for a start than Jim Williams’ 1987 app note 25 for Linear Technology: “Switching Regulators for Poets“.

New Part Day: The MSC313E Is A Computer On A Chip

April 22, 2020 by Jenny List 46 Comments

As the onward march of technology delivers ever more powerful semiconductors, it can be instructive to keep an eye on the periphery of the system-on-chip market for niche-application devices which may have an application in our sphere. Just such a chip is the Mstar MSC313E, a SoC designed for use in IP cameras that packs an ARM Cortex A7 and 64 MB of memory, 16 MB of flash, Ethernet, USB, and all the other usual interfaces you’d expect from a microprocessor. It’s available in a QFN package which makes it tantalisingly within the reach of the hardware hacker community, so naturally there is significant interest in unlocking its secrets. A cheap and accessible part with enough power to run a stripped-out GNU/Linux operating system has to be worth a second look!

QFNs are not the easiest packages to hand solder, but if you also find yourself in that position there is at least the prospect of a ready to go development board. The BreadBee is a small PCB that packs in the chip with all its interfaces including Ethernet and USB brought out for experimentation. If you don’t fancy building one, you don’t even have to: it’s soon to be crowdfunded.

One might ask what the point is of Yet Another Linux Capable Microcontroller Platform, given the plethora of Raspberry-pi and competitor boards. The answer to that is simple enough and contains within it the essence of hardware hacking: because it is there. We might never see it again save for in a few outlying projects, or perhaps it might find a niche in our world and become popular, without this early work we’ll never know. While we’re at it, this isn’t the first such SoC that’s emerged; we’ve previously seen an action cam chip give us a hand-solderable Linux single board computer.

Thanks [anonymouse] for the tip.