The UA723 As A Switch Mode Regulator

February 15, 2018 by Jenny List 37 Comments

If you are an electronic engineer or received an education in electronics that went beyond the very basics, there is a good chance that you will be familiar with the Fairchild μA723. This chip designed by the legendary Bob Widlar and released in 1967 is a kit-of-parts for building all sorts of voltage regulators. Aside from being a very useful device, it may owe some of its long life to appearing as a teaching example in Paul Horowitz and Winfield Hill’s seminal text, The Art Of Electronics. It’s a favourite chip of mine, and I have written about it extensively both on these pages and elsewhere.

The Fairchild switching regulator circuit. From the μA723 data sheet in their 1973 linear IC databook, page 194 onwards.

For all my experimenting with a μA723 over the decades there is one intriguing circuit on its data sheet that I have never had the opportunity to build. Figure 9 on the original Fairchild data sheet is a switching regulator, a buck converter using a pair of PNP transistors along with the diode and inductor you would expect. Its performance will almost certainly be eclipsed by a multitude of more recent dedicated converter chips, but it remains the one μA723 circuit I have never built. Clearly something must be done to rectify this situation.

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Printed Nexus 7 SIM Tray Is Good ‘Nuff

February 2, 2018 by Tom Nardi 9 Comments

When repairing something, there are in effect two schools of thought: you can craft a repair that seamlessly blends into the original hardware and doesn’t look like a repair, or you can slap that thing together and keep it moving. A lot of variables go into this decision making process, such as the complexity of the repair, the available materials, and of course whether or not you need to keep the fact you broke the thing from your significant other.

When the SIM holder on his Nexus 7 tablet broke recently, [Alex Whittemore] did the mental arithmetic and came to the conclusion that it wasn’t worth his time trying to figure out how to model an exact replacement. But he was able to print something that works well enough for his purposes, which is all that matters in the end. A perfect entry for our ongoing “Repairs You Can Print” contest.

Apparently the SIM holder in the 2013 Nexus 7 is notoriously poor, and of course since this is a known issue, online retailers are trying to get as much as $100 USD out of you for a tiny sliver of plastic. Sometimes it really seems like Google was determined to run the Nexus line into the ground before bailing on it.

Printing such a tiny part, especially with the little details like the channel for you to hook your fingernail into, requires a fairly well calibrated printer. If you can’t muster up a 0.1mm first layer you might as well sit this one out; and if you haven’t mastered the art of bridging, that little valley to help you get the SIM back out may end up overflowing into a river of tears.

For [Alex], the piece ended up working perfectly. It might look a little weird, but if you’ve got the tablet in a case you’ll never see it anyway. It’s also worth noting that this design may work on other devices with a similar SIM arrangement, or at the very least, might be a good starting point to work from if you’ve got to come up with your own.

Remember, there’s still plenty of time to enter your own printed fix into our “Repairs You Can Print” contest. The top 20 repairs will take home $100 in Tindie credit, and for the best repair done by a Student or Organization, there’s two Prusa i3 MK3 printers with the Quad Material upgrade kits on the line.

Firing Up 750 Raspberry Pis

January 24, 2018 by Al Williams 37 Comments

Creating Raspberry Pi clusters is a popular hacker activity. Bitscope has been commercializing these clusters for a bit now and last year they created a cluster of 750 Pis for Los Alamos National Labs. You might wonder what an institution know for supercomputers wants with a cluster of Raspberry Pis. Turns out it is tough to justify taking a real high-speed cluster down just to test software. Now developers can run small test programs with a large number of CPU cores without requiring time on the big iron.

On the face of it, this doesn’t sound too hard, but hooking up 750 of anything is going to have its challenges. You have to provide power and carry away heat. They all have to communicate, and you aren’t going to want to house the thing in a few hundred square feet which makes heat and power even more difficult.

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Hackaday Links: January 7, 2018

January 7, 2018 by Brian Benchoff 23 Comments

Whelp, Spectre and Meltdown are the tech news du jour right now, and everyone is wondering: what is the effect of this problem on real hardware in real server rooms? Epic Games patched their machines and found something shocking. The CPU utilization for one of their online services increased about 100%. We don’t know what this server is doing, or what this process is, but the Spectre and Meltdown patches will increase CPU load depending on the actual code running. This is bad for Epic — they now have to buy an entirely new server farm. This is doubly bad for Intel, and there is speculation of a class action suit floating around the darker corners of the Interwebs.

It is with a heavy heart that I must report the passing of John Young, the only person to have commanded four different classes of spacecraft (five if you include the lunar rover), including the first launch of the Space Shuttle. He was, simply, the most badass astronaut to ever live. Need proof of that? His heart rate during the launch of a Saturn V was seventy.

By the time this post is published, you’ll have less than twenty-four hours to submit your project to the Coin Cell Challenge. Get to it!

A short reminder that Shmoocon is a mere two weeks away. What is Shmoocon? A totally chill cyber/sec/hacker con at the Washington D.C. Hilton (yes, where Reagan was shot). We’ll be there, and we’re looking for some like-minded Hackaday peeps to chill out with. Want a meetup? Reply in the comments.

A few years ago, the ESP8266 appeared out of the blue in a few Chinese reseller’s web shops, and everything has been gravy since. Now there’s a new magic do-everything chip appearing on AliExpress and Taobao. It’s the RDA5981, a chip with an ARM Cortex M4 core, 32Mbit of Flash, 192k or user RAM, b/g/n WiFi, I2S, and enough peripherals to be useful. Given the support for a MIC, line in, MP3, WAV, WMA and AAC, it appears this is an all-in-one chip designed for Bluetooth speakers or some other audio application. You can find modules on Alibaba and a few breakout boards on Taobao.

According to my sources (the press releases that somehow slipped through the ‘CES’ filter on my email), the world’s fastest, smallest, biggest, least expensive, and newest drone is set to be unveiled at CES in Vegas this week.

2017: As The Hardware World Turns

December 27, 2017 by Brian Benchoff 28 Comments

The year is almost over, and now it’s time to look back on the last fifty-odd weeks. What happened in this year in hacking? 2017 will go down as the beginning of another AI renaissance, although we’re not going to call it that; this year was all about neural nets and machine learning and advancements resulting from the development of self-driving cars and very beefy GPUs. Not since the 80s have we seen more work in ‘AI’ fields. What will it amount to this time around the hype cycle? Find out in a few years.

Biohacking was big this year, and not just because people are installing RFID tags and magnets in their hands. CRISPR is allowing for Star Trek-style genome hacking, and this year saw in vivo experiments to enable and disable individual genes in rat models. Eventually, someone is going to get a Nobel for CRISPR.

We’re going to Mars, and soon — very soon — a SpaceX Falcon Heavy is going to either lob a Tesla Roadster into solar orbit or the Atlantic Ocean. We learned about the BFR that will take dozens of people to Mars in a single launch. Boeing and Lockheed think they can compete with the Elon Musk PR powerhouse. The Bigelow Aerospace inflatable module passed its in-flight test on the ISS, giving the space station a new storage closet. Even in space, amazing stuff is happening this year.

Is that it? Not by a long shot. This year has seen some of the coolest hacks we’ve ever seen, and some of the dumbest security breaches ever. Hackaday is doing awesome. What else did 2017 have? Read on to find out.

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Hackaday Links: December 17, 2017

December 17, 2017 by Brian Benchoff 4 Comments

Where do you go if you want crazy old electronic crap? If you’re thinking a ham swap meet is the best place, think again. [Fran] got the opportunity to clean out the storage closet for the physics department at the University of Pennsylvania. Oh, man is there some cool stuff here. This room was filled to the brim with old databooks and development boards, and a sample kit for the unobtanium Nimo tube.

The Gigatron is a Hackaday Prize entry to build a multi-Megahertz computer with a color display out of TTL logic. Now, all this work is finally paying off. [Marcel] has turned the Gigatron into a kit. Save for the memories, this computer is pretty much entirely 74-series logic implemented on a gigantic board. Someone is writing a chess program for it. It’s huge, awesome, and the kits should cost under $200.

What’s cooler than BattleBots, and also isn’t Junkyard Wars? BattleBots, but in drone form. Drone Clash was originally announced in March, but now they’re moving it up to February to coincide with the TUS Expo. What could be better than flaming piles of lithium?

The Atari Lynx went down in history as the first portable console with a color LCD. There was a problem with the Lynx; the display was absolutely terrible. [RetroManCave] found someone selling an LCD upgrade kit for the Lynx, and the results are extremely impressive. The colors aren’t washed out, and since the backlight isn’t a fluorescent light bulb (yes, really), this Lynx should get a bit more run time for each set of batteries.

Like dead tree carcasses? You need to butcher some dead tree carcasses. The best way to do this is on a proper workbench, and [Paul Sellers] is working on a video series on how to make a workbench. He’s up to episode 3, where the legs are mortised. This is all done with hand tools, and the videos are far more interesting than you would think.

If you need some very small, very blinky wearables, here’s an option. This build is literally three parts — an LED matrix, an ATtiny2313, and a coin cell battery. Seems like this could be an entry for the Coin Cell Challenge we have going on right now.

Hackaday Links: December 10, 2017

December 10, 2017 by Brian Benchoff 14 Comments

We have a contest going on right now challenging you to do the most with a coin cell. There are already quite a few interesting entries, and a few Hackaday writers are getting into the action by asking the question, ‘how do you open up a coin cell?’. The first thoughts were to open a lithium coin cell up while submerged in oil, but eBay came to the rescue with the cases for CR2025 cells. Of course that’s a thing.

Also falling into the, ‘of course that’s a thing’ category, there’s a project on Hackaday.io to execute arbitrary code on a calculator. A small group of calculator hackers have discovered an exploit on a line of Casio calculators running the obscure nX-U8/100 architecture. Right now, there’s not much to the project — just an LCD filled with bits of memory. However, this is a project we’re keenly watching, and we can’t wait to see what comes of it.

Hold onto your butts, because the ultimate multimeter is here. [Dave Jones] of the EEVBlog has released the 121GW Multimeter on Kickstarter. What’s cool about this meter? SD card logging, the ability to send data over Bluetooth, a 15V diode test voltage, a burden voltage display, and a whole bunch of hackable features. If you have a Fluke on your Christmas list, you would do well to check out the 121GW.

Also on Kickstarter, a new LattePanda board has been released. What’s a LattePanda? It’s a small single board computer built around a low-voltage Intel processor. This board features an Intel m3-7Y30 processor, comparable to the processor you’d get in a proper laptop that doesn’t have an i3, 8 gigs of DDR3, 64 gigs of eMMC, 802.11ac, BlueTooth 4.2, USB 3.0 with a Type C connector, HDMI, and a whole bunch of GPIOs. Yes, it runs Windows (but why would you?). If you need a somewhat beefy x86 system in a small form factor, there ‘ya go.

We’ve seen 3D printed remote-controlled airplanes, but never one this big. The guys at Flite Test printed a 1.6 meter Spitfire. It’s got flaps, it’s got retracts, and it’s friggin’ huge. The files for the print came from 3DLabPrint, and it flies beautifully, despite being a Spitfire. Want to see the video? Here ya go.