OWON Oscilloscope Teardown

January 15, 2020 by Al Williams 27 Comments

We sympathize with [learnelectronic’s] statement: “I’m ashamed. I may have bought another oscilloscope.” We get it and we enjoyed watching him tear down the OWON SDS1102. (Video, embedded below.) As you might guess, this is a 100 MHz, two-channel scope, and very similar to many other Chinese scopes you can get inexpensively.

The last ten minutes are so of the video below shows him removing the case. There’s only three little boards inside. One is clearly a power supply. The other two don’t have much on them. There’s a tiny RF shield over one part of the board, so you assume that’s the input section.

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Fail Of The Week: Thermostat Almost Causes A House Fire

January 8, 2020 by Dan Maloney 63 Comments

Fair warning: any homeowners who have thermostats similar to the one that nearly burned down [Kerry Wong]’s house might be in store for a sleepless night or two, at least until they inspect and perhaps replace any units that are even remotely as sketchy as what he found when he did the postmortem analysis in the brief video below.

The story begins back in the 1980s, when the Southern New England area where [Kerry] lives enjoyed a housing boom. Contractors rushed to turn rural farmland into subdivisions, and new suburbs crawled across the landscape. Corners were inevitably cut during construction, and one common place to save money was the home’s heating system. Rather than engage an HVAC subcontractor to install a complicated heating system, many builders opted instead to have the electricians install electric baseboards. They were already on the job anyway, and at the time, both copper and electricity were cheap.

Fast forward 40 years or so, and [Kerry] finds himself living in one such house. The other night, upon catching the acrid scent of burning insulation, he followed his nose to the source: a wall-mounted thermostat for his electric baseboard. His teardown revealed burned insulation, bare conductors, and scorched plastic on the not-so-old unit; bearing a 2008 date code, the thermostat must have replaced one of the originals. [Kerry] poked at the nearly combusted unit and found the root cause: the spot welds holding the wires to the thermostat terminal had become loose, increasing the resistance of the connection. As [Kerry] points out, even a tenth of an ohm increase in resistance in a 15 amp circuit would dissipate 20 watts of heat, and from the toasty look of the thermostat it had been a lot more than that.

The corner-cutting of the 1980s was nothing new, of course – remember the aluminum wiring debacle? Electrical fires are no joke, and we’re glad [Kerry] was quick to locate the problem and prevent it from spreading.

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Peek Inside These Same-But-Different Power Supplies

December 28, 2019 by Donald Papp 5 Comments

When [Kerry Wong] found an Amrel PPS 35-2 Programmable Power Supply from the late 90s on eBay, he recognized it as the single-channel version of another unit he owned, the dual-channel Amrel PPS-2322. Naturally, he purchased it and did a compare and contrast of the two models.

From the outside, they look fairly different but weigh about the same. But the similarities on the inside make it quite clear that they share a common design. There are a few things that grab your eye and the 35-2 doesn’t seem quite as well thought out, with some components being soldered into awkward-looking places. Capacitors bristle like barnacles where they are soldered directly to a connector, and a blob of hot glue anchors two resistors that rise up out of the board like a couple of weeds.

The link above shows some high resolution side-by-side photos between the two models, and [Kerry] thoughtfully provides a link to the manual for the PPS series as well as a dump of the firmware (.zip) for the 35-2. A teardown video is embedded below.

Benchtop power supplies are important tools, but we’ve also seen how modern breadboard power supplies are remarkably full-featured.

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See How Wildly Different Air Conditioners Can Be (On The Inside)

December 15, 2019 by Donald Papp 16 Comments

Air conditioners are easy to take for granted. From refrigerators to climate control, most of us would miss them dearly if they disappeared. That’s part of what draws [Josh Levine]’s interest in air conditioners, and he has provided an interesting tour of several different units and how different they can be, despite all working in basically the same way.

That white PCB is crucial (for running the bluetooth speaker and LED flashlight, that is.)

One way that air conditioners try to stand out is by being quiet, and the bulk of noise comes from the fans and the compressor. One unit (the Haier Serenity) aimed to be the quietest unit possible, but while this effort had mixed results at best it is still interesting to see [Josh] give a tour of the different ways they tried to reduce noise (YouTube, embedded below). Noise-limiting elements include the unusual step of using separate motors for the indoor and outdoor fans, and even little counterweights to ensure they are perfectly balanced, just like wheel weights on automobile tires.

Another notable air conditioner is the Zero Breeze, a portable unit that was the product of a Kickstarter campaign. Features included (either bizarrely or predictably, you be the judge) a bluetooth speaker and an LED flashlight. [Josh] more than half suspected the product would never actually ship, but was pleasantly surprised. Not only did it deliver, it turned out to be a pretty nice design with only a couple of mildly head scratching moments (YouTube, also embedded below).

There are a few more to check out in the roundup on [Josh]’s web site, which he also compares and contrasts with his own DIY unit which we featured in the past.

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Teardown: 168-in-1 Retro Handheld Game

December 9, 2019 by Tom Nardi 33 Comments

The holidays are upon us, and that can mean many furrowed brows trying to figure out what token gift they can give out this year as stocking-stuffers. Something that’s a bit more interesting than a coupon book or a lotto scratcher, but also affordable enough that you can buy a few of them without having to take part in that other great holiday tradition: unnecessary credit debit.

Includes the NES classic *Super Militarized Police Bros 3*

Which is how I came to possess, at least temporarily, one of these cheap handheld multi-games that are all over Amazon and eBay. The one I ordered carries the brand name Weikin, but there are dozens of identical systems available, all being sold at around the same $20 USD price point. With the outward appearance of a squat Game Boy, these systems promise to provide precisely 168 games for your mobile enjoyment, and many even include a composite video out cable and external controller for the less ambulatory classic game aficionado.

At a glance, the average Hackaday reader will probably see right through this ploy. Invariably, these devices will be using some “NES on a Chip” solution to emulate a handful of legitimate classics mixed in with enough lazy ROM hacked versions of games you almost remember to hit that oddly specific number of 168 titles. It’s nearly a foregone conclusion that at the heart of this little bundle of faux-retro gaming lies a black epoxy blob, the bane of hardware tinkerers everywhere.

Of course, there’s only one way to find out. Let’s crack open one of these budget handhelds to see what cost reduction secrets are inside. Have the designers secured their place on the Nice List? Or have we been sold the proverbial lump of coal?

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A Magnetron Tear Down

December 5, 2019 by Al Williams 28 Comments

Microwave ovens are everywhere, and at the heart of them is a magnetron — a device that creates microwaves. [DiodeGoneWild] tore one apart to show us what was inside and how it works. If you decide to do this yourself, be careful. The magnetron may have insulators made of beryllium oxide and inhaling dust from the insulator even one time can cause an incurable lung condition.

Luckily, you can’t get a lung problem from watching a video. In addition to just seeing the guts of the magnetron, there are also explanations about how everything works with some quick sketches to illustrate the points.

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PixMob LED Wristband Teardown (Plus IR Emitters And How To Spot Them)

November 26, 2019 by Donald Papp 11 Comments

PixMob units are wearable LED devices intended for crowds of attendees at events like concerts. These devices allow synchronized LED effects throughout the crowd. [yeokm1] did a teardown of one obtained from a preview for the 2019 Singapore National Day Parade (NDP), and in the process learned about the devices and their infrastructure.

Suspected IR emitter for the PixMob units, mounted on a lighting tower (marked here in white).

PixMob hardware has been known to change over time. This version has two RGB LEDs (an earlier version had only one), an unmarked EEPROM, an unmarked microcontroller (suspected to be the Abov MC81F4104), and an IR receiver module. Two CR1632 coin cells in series power the device. [yeokm1] has made the schematic and other source files available on the teardown’s GitHub repository for anyone interested in a closer look.

One interesting thing that [yeokm1] discovered during the event was the apparent source of the infrared emitter controlling the devices. Knowing what to look for and reasoning that such an emitter would be mounted with a good view of the crowd, [yeokm1] suspected that the IR transmitter was mounted on a lighting tower. Viewing the tower through a smartphone’s camera revealed a purplish glow not visible to the naked eye, which is exactly the way one would expect an IR emitter to look.

Sadly, there wasn’t any opportunity to record or otherwise analyze the IR signals for later analysis but it’s possible that the IR protocol might be made public at some point. After all, running custom code on an earlier PixMob board was made possible in part by asking the right people for help.