Crappy Robots And Even Crappier Electronics Kits

Robots and DIY electronics kits have a long history together. There probably isn’t anyone under the age of forty that hasn’t had some experience with kit-based robots like wall-hugging mouse robots, a weird walking robot on stilts, or something else from the 1987 American Science and Surplus catalog. DIY robot kits are still big business, and walking through the sales booths of any big Maker Faire will show the same ideas reinvented again and again.

[demux] got his hands on what is possibly the worst DIY electronics kit in existence. It’s so incredibly bad that it ends up being extremely educational; pick up one of these ‘introduction to electronics’ kits, and you’ll end up learning advanced concepts like PCB rework, reverse engineering, and Mandarin.

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Let’s Blow Up an Explosive Lightning Arrestor

Lightning is some nasty stuff. Luckily, it doesn’t have a very long lifespan. [BigClive] decided to tear down an 11KV lighting arrestor used in power distribution systems. The fiberglass core has silicone rubber water-shedding disks that make the unit look sort of floppy, but inside is some serious hardware.

To protect the circuit, metal oxide varistors shunt high voltage from a lightning strike to ground as you’d expect. The interesting part is how the device deals with failure. It would be a disaster if the device shorted the 11KV power line to ground for any length of time due to a fault. To prevent that problem, a resistor heats up when struck by lightning and triggers an explosive charge that disconnects the ground wire and releases a flag to indicate the failure.

[BigClive] triggered the charge in the video below. So if you like to see things explode in a bucket of water, you’ll enjoy the video.

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Reverse Engineering the ARM ALU

[Dave] wanted to learn more about the ARM architecture, so he started with an image of the ARMV1 die. If you’ve had some experience looking at CPU die, you can make some pretty good guesses at what parts of the chip have certain functions. [Dave], however, went further. He reverse engineered the entire ALU–about 2,200 transistors worth.

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SRF01 Ultrasonic Sensor Teardown

The SRF01 is a popular ultrasonic sensor used primarily for range finding applications. [Jaanus] discovered that they had a few flaws, including not working after being dropped. The faulty ones began to pile up, so he decided sensor_01to tear one apart and put his engineering skills to use.

The SRF01 is unique in that it only uses a single transducer, unlike the SRF04, which uses two. Using only one transducer presents a problem when measuring very close distances. The transducer emits a pulse of sound and then must listen for the echo. The smaller the distance, the smaller the time interval between the pulse and when the echo returns. There is a fundamental limit to this time as the transducer has to recover from what is known as ringing. [Jaanus] discovered that the SRF01 solves the ringing problem with the use of a PIC24’s ADC and its 500 ksps (kilosamples per second) rate. This allows it to measure very close distances.

Be sure to check out the teardown for more details on how the SRF01 works.

Thorough Macbook Charger Teardown Reveals Some Complex Circuitry

Apple has a reputation in the tech world as being overpriced, and nowhere is that perception more common than in the Hackaday comments. The standard argument, of course, is that for a device with equivalent specs, Apple charges a lot more than its competitors. That argument is not without its flaws, especially when you consider factors other than simple specs like RAM and processor speed, and take into account materials used and build quality. But, as this teardown by [Ken Shirriff] shows, Apple’s attention to detail extends beyond simply machining Macbook bodies out of aluminum.

In his teardown, [Ken Shirriff] thoroughly investigates and describes all of the components and circuitry that go into the ubiquitous Macbook charger. Why does it cost $79? Other than the MagSafe connector, what makes it any better than the charger that came with your Toshiba Satellite in the ’90s? Isn’t it just a transformer to convert AC power to DC?

components1

[Ken Shirriff] answers all of this and more, and you may be surprised by what he found. As it turns out, the Macbook charger isn’t just a transformer in a plastic case with a fancy magnetic connector. There is a lot of high-quality circuitry involved to make the power output as clean and stable as possible, and to avoid potential damage to your Macbook that could be caused by dirty power or voltage spikes. Does it justify the costs, even with so many reported failures? That’s for you to decide, but there is no questioning that Apple put more thought into their chargers than simply converting AC to DC.

“Hello Barbie” Under the Knife

In February, Google and Mattel introduced their Hello Barbie Internet-connected toy. This Barbie has an internal microphone, a WiFi connection to Google’s voice recognition services, and a speaker to carry on a “conversation” with the targeted child.

Like the folks at Somerset Recon, we’d say that this is an Internet of Things (IoT) device that’s just begging for a teardown, and we’re totally looking forward to their next installment when they pore through the firmware.

BarbieTeardown2On the hardware front, Barbie looks exactly like what you’d expect on the inside. A Marvell 88MW300 WiFi SoC talks to a 24-bit (!) audio codec chip, and runs code from a 16Mbit flash ROM. There’s some battery management, and what totally looks like a JTAG port. There’s not much else, because all the brains are “in the cloud” as you kids say these days.

From day to day we alternate between the promise of IoT and being anti-IoT curmudgeons, so it should come as no surprise that we’re of two minds about Hello Barbie. First, there’s the creepy-factor of having your child’s every word overheard by a faceless corporation with “evil” in their mission statement (see what we did there?). Next, we’re not sure that it’s OK to record everything your child says to a toy and listen to it later, even if you are the parent. Hackaday’s [Sarah Petkus] summarized this neatly in this article.

But mostly, we’re curious about how well the thing actually works and what it will do with naughty words. And who will take on the task of reviving the Barbie Liberation Organization? Now we totally want to go out and buy one of these things.

Belkin WeMo Teardown

[Brian Dipert] over at EDN has a teardown of Belkin’s answer to the Internet of Things (IoT) craze: the WeMo. This little WiFi gadget plugs into an outlet and lets you turn a connected device on and off from a smart phone app or something like Amazon Echo.

As you might expect from a cheap piece of consumer hardware, there’s not a whole lot inside. The digital board contains a Ralink WiFi chip, an antenna etched on the PCB, and a handful of components, including an SDRAM and some flash memory.

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