Working With BGAs: Design And Layout

June 20, 2022 by 27 Comments

The Ball Grid Array, or BGA package is no longer the exclusive preserve of large, complex chips on computer motherboards: today even simple microcontrollers are available with those little solder balls. Still, many hobbyists prefer to stay with QFP and QFN packages because they’re easier to solder. While that is a fair point, BGA packages can offer significant space savings, and are sometimes the only choice: with the ongoing chip shortage, some other package versions might simply be unavailable. Even soldering doesn’t have to be complicated: if you’re already comfortable with solder paste and reflow profiles, adding a BGA or two into the mix is pretty easy.

In this article we’ll show that working with BGA chips is not as difficult as it may seem. The focus will be on printed circuit board design: how to draw proper footprints, how to route lots of signals and what capabilities your PCB manufacturer should have. We’ll cover soldering and rework techniques in a future article, but first let’s take a look at why BGAs are used at all.

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Ubuntu 22.04 setup screen shown on the Google's Nest Hub display

Breaking Google Nest Hub’s Secure Boot

June 20, 2022 by 4 Comments

[frederic] tells a story about their team’s hack of a Google Nest Hub (2nd generation) — running Ubuntu on it, through bypassing Google’s boot image signature checks. As with many good hacks, it starts with FCC website pictures. Reverse-engineering a charger and USB daughterboard pin-out, they found a UART connection and broke it out with a custom adapter. With a debug console and insights into the process, they went on hacking, slicing through hardware and software until it was done with.

This story gives plenty of background and insight into both the code that was being investigated, and the way that attack targets were chosen. Through fuzzing, they found a buffer overflow in the bootloader code that could be triggered with help of a non-standard block size. USB flash drives tend to have these hard-coded, so they built a special firmware for a Pi Pico and shortly thereafter, achieved code execution. Then, they hooked into uboot functions and loaded Ubuntu, bypassing the boot image signature checks.

This is a wonderful documentation of a hacking journey, and an exciting read to boot (pun intended). The bug seems to have been patched for half a year now, so you probably can’t flash your Google Nest into Ubuntu anymore. However, you might be able to run an up-to-date Linux on your Amazon Echo.

We thank [Sven] for sharing this with us!

Automate The Freight: The Convenience Store That Comes To Your Door

June 20, 2022 by 45 Comments

For as popular as they became during the COVID-19 lockdowns, grocery delivery services like InstaCart rely on a basic assumption to work: that customers know exactly what they want when they order. Once that hurdle is overcome, the transaction is simple — the driver accepts the job, drives to the store to pick up the order, and takes it to the customer. It requires the use of a fair amount of technology to coordinate everything, but by and large it works, and customers are generally willing to pay for the convenience.

But what if you could cut out that step where the driver goes to pick up your order? What if instead of paying someone to pick and pack your order and bring it to your front step, you just ordered up the whole store instead? That’s the idea behind Robomart, which seeks to deploy a fleet of mobile stores for when the convenience store isn’t quite convenient enough.  And the way the company is choosing to roll out its service, not to mention the business model itself, may hold key lessons for other delivery automation platforms.

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Raspberry Pi Simulates The Real Analog TV Experience

June 20, 2022 by 18 Comments

If you’ve laid hands on a retro analog TV, have the restoration bug, and you plan to make the final project at least somewhat period-correct, you face a bit of a conundrum: what are you going to watch? Sure, you can serve up just about any content digitally these days, but some programs just don’t feel right on an old TV. And even if you do get suitably retro programming, streaming isn’t quite the same as the experience of tuning your way through the somewhat meager selections as we did back in the analog days.

But don’t worry — this Raspberry Pi TV simulator can make your streaming experience just like the analog TV experience of yore. It comes to us from [Rodrigo], who found a slightly abused 5″ black-and-white portable TV that was just right for the modification. The battery compartment underneath the set made the perfect place to mount a Pi, which takes care of streaming a variety of old movies and shorts. The position of the original tuning potentiometer is read by an Arduino, which tells the Pi which “channel” you’re currently tuned to.

Composite video is fed from the Pi’s output right into the TV’s video input, and the image quality is just about what you’d expect. But for our money, the thing that really sells this is the use of a relay to switch the TV’s tuner back into the circuit for a short bit between channel changes. This gives a realistic burst of static and snow, just like we endured in the old days. Hats off to [Rodrigo] for capturing everything that was awful about TV back in the day — Mesa of Lost Women, indeed! — but still managing to make it look good.

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PS5 Goes On Slim-Fast

June 20, 2022 by 28 Comments

For the past few decades, most console makers have first come out with a large flagship model, and then a few years later, released a smaller, more compact slim edition. Not content to wait for it, [Matt] at DIY Perks made his own PS5 Slim, and the results are awe-inspiring.

Generally, slim editions are made by lowering the TDP of the chip under the hood. A lower power draw means less cooling is needed, a smaller power supply can be used, and a design that is overall easier to manage. Unfortunately, [Matt] had none of these benefits and instead had to contend with the full 180 W that the AMD CPU inside the PlayStation can draw.

Taking apart the console left him with the main board that was quite thick as it had heat pipes on both sides. His first thought was water cooling as it can rapidly move the heat needed, but even with right-angle fittings, it didn’t fit within the ambitious thickness goal he had set for himself of less than 2 cm (about 3/4″). To do that, [Matt] had to fabricate a copper water block from three sheets of copper. The first one connects to the motherboard via standoffs and has cut-outs for various connectors and parts. The middle layer has a channel through which water can flow, and the last layer seals it together.

With the three layers together, he soldered them in a toaster oven repurposed as a reflow oven. Cleverly, he used silicone grease to prevent solder from getting into areas he didn’t want, like the fins in the CPU block. Luckily, the grease dissolved in alcohol, and after flushing the chamber, he had a solid copper, water-tight, custom loop.  However, on his road to glory, [Matt] ran into a snag. He accidentally covered the intake vent on the radiator, and the PS5 overheated, killing it. With a fried mainboard and a project almost on the cusp of completion, he resorted to using the PS5 he had received for B-roll.

Last-minute motherboard swap aside, the final project is gorgeous. The polished exterior and sheer thinness of it are striking. [Matt] has already disguised his PS5 before and after this, we’re not quite sure where he could possibly take it next. But we’re excited to find out.

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This Arduino Pen Plotter Is Built For Speed

June 19, 2022 by 20 Comments

We see a lot of simple pen plotter projects around here, and while we appreciate them one and all, most of them are a little on the slow side. That’s OK — a glacial pace is sometimes all that’s needed, as long as it gets the job done. But there’s nothing wrong with putting the pedal to the metal, so to speak. And that’s exactly what this super-fast Arduino-based plotter is all about.

As the story goes, [IV Projects] felt the need for speed after building an earlier pen plotter project that worked, but failed to excite. With the additional goal of keeping the plotter easy to build with cheap parts, the design centers on a “grit roller drive” for the Y-axis — the one that actually moves the paper back and forth. And move it does, using Dremel tool sanding drums on a lightweight shaft to maximize acceleration. In fact, all the moving parts are kept as lightweight as possible, and the results really show — the three steppers really sing when this plotter is in action.

There are some really clever details in [IV Projects]’ design. We particularly like the way the pen lift mechanism works, and the surprise appearance of a clothespin spring as a belt tensioner was a real treat. Judging by the pile of rejected prototype parts, it took quite a bit of work to get this design right. If you’d like to build your own, STLs are available for the printed parts.

If you’re interested in what the other end of the speed scale looks like, check out this bare-minimum pen plotter.

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Your Own IBM Mainframe (or Vax, Or Cray…) The Easy Way

June 19, 2022 by 35 Comments

If you want the classic experience of working with an IBM mainframe or another classic computer like a DEC VAX, you have a few choices. You could spend a lot of money trying to find one, transport it, and refurbish it. But, of course, most of us will settle for an emulator. While there are great emulators out there, most of the time you aren’t interested in running just the bare machine — you want the operating systems, the compilers, and the other software that made these machines so interesting. Running your three lines of machine code isn’t as much fun as playing hunt the wumpus or compiling some Fortran IV code. Unfortunately, finding copies of all this old software can be daunting. But thanks to the efforts of [Rattydave], you can do it with no problems at all. The secret? Pre-built docker images that have everything you need in one place.

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