DSP Spreadsheet: IQ Diagrams

In previous installments of DSP Spreadsheet, we’ve looked at generating signals, mixing them, and filtering them. If you start trying to work with DSP, though, you’ll find a topic that always rears its head: IQ signals. It turns out, these aren’t as hard as they appear at first and, as usual, we’ll tackle them in a spreadsheet.

What does IQ stand for? The I stands for “in phase” and the Q stands for quadrature. By convention, the I signal is a cosine wave and the Q signal is a sine wave. Another way to say that is that the I and Q signals are 90 degrees out of phase. By manipulating the amplitude of I and Q, you can create complex modulation or, conversely, demodulate signals. We’ll see a spreadsheet that shows that completely next time.

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This Week In Security: Fuzzing Fixes, Foul Fonts, TPM Timing Attacks, And More!

An issue was discovered in libarchive through Google’s ClusterFuzz project. Libarchive is a compression and decompression library, widely used in utilities. The issue here is how the library recovers from a malformed archive. Hitting an invalid header causes the memory in use to be freed. The problem is that it’s possible for file processing to continue even after that working memory has been freed, leading to all kinds of problems. So far an actual exploit hasn’t been revealed, but it’s likely that one is possible. The problem was fixed back in May, but the issue was just announced to give time for that update to percolate down to users.

Of note is the fact that this issue was found through Google’s fuzzing efforts. Google runs the oss-fuzz project, which automatically ingests nightly builds from around 200 open source projects and runs ClusterFuzz against them. This process of throwing random data at programs and functions has revealed over 14,000 bugs.
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Best Buy’s IoT Goes Dark, Leaving Some “Smart” Products Dumbfounded

Bad news if you bought several Insignia-branded smart devices from Best Buy. The company has decided to shut down the back end systems that make them work — or at least work as a smart device. On the chopping block are smart outlets, switches, a security camera, and an upright freezer. If you bought, say, the freezer, it will still keep things cold. But the security camera will apparently be of no use at all now that the backend systems have gone dark. The company is offering an unspecified partial refund to users of the affected devices.

Best Buy announced this in September, and the shutdown date was last week on November 6th. Not all Insignia products are impacted, just the ones that rely on their app.

Anytime we talk about cloud-based technology, there are always a few people who say something like, “I’ll never rely on anything in the cloud!” Perhaps they have a point — certainly in this case they were right. There are really two things to consider: hardware devices that rely on the cloud, and data that resides in the cloud. In some cases, one product — like a camera — might have both.

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Ask Hackaday: Is Anyone Sad Phone VR Is Dead?

It’s official: smartphone-based VR is dead. The two big players in this space were Samsung Gear VR (powered by Oculus, which is owned by Facebook) and Google Daydream. Both have called it quits, with Google omitting support from their newer phones and Oculus confirming that the Gear VR has reached the end of its road. Things aren’t entirely shut down quite yet, but when it does it will sure leave a lot of empty headsets laying around. These things exist in the millions, but did anyone really use phone-based VR? Are any of you sad to see it go?

Google Cardboard, lowering cost and barrier to entry about as low as it could go.

In case you’re unfamiliar with phone-based VR, this is how it works: the user drops their smartphone into a headset, puts it on their head, and optionally uses a wireless controller to interact with things. The smartphone takes care of tracking motion and displaying 3D content while the headset itself takes care of the optics and holds everything in front of the user’s eyeballs. On the low end was Google Cardboard and on the higher end was Daydream and Gear VR. It works, and is both cheap and portable, so what happened?

In short, phone-based VR had constraints that limited just how far it could go when it came to delivering a VR experience, and these constraints kept it from being viable in the long run. Here are some of the reasons smartphone-based VR hit the end of the road: Continue reading “Ask Hackaday: Is Anyone Sad Phone VR Is Dead?”

Review: Ear Wax Cleaning Cameras As Cheap Microscopes, We Take A Closer Look

Those of us who trawl the world of cheap imported goods will most often stay in our own comfortable zones as we search for new items to amaze and entertain us. We’ll have listings of electronic goods or tools, and so perhaps miss out on the scores of other wonders that can be ours for only a few dollars and a week or two’s wait for postage.

Who knew sticky ears were such big business!
Who knew sticky ears were such big business!

Just occasionally though something will burst out of another of those zones and unexpectedly catch our eye, and we are sent down an entirely new avenue in the global online supermarket.

Thus it was that when a few weeks ago I was looking for an inspection camera I had a listing appear from the world of personal grooming products. It seems that aural hygiene is a big market, and among the many other products devoted to it is an entire category of ear wax removal tools equipped with cameras. These can get you up close and personal with your ear canal, presumably so you can have a satisfying scoop at any accumulated bodily goop. I have a ton of electronics-related uses for a cheap USB close-up camera so I bought one of these so I could — if you’ll excuse the expression — get a closer look.

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Hackaday Links: November 10, 2019

In the leafy suburbs of northern Virginia, a place ruled by homeowner’s associations with tremendous power to dictate everything from the color of one’s front door to the length of grass in the lawn, something as heinous as garage doors suddenly failing to open on command is sure to cause a kerfuffle. We’ve seen this sort of thing before, where errant RF emissions cause unintentional interference, and such stories aren’t terribly interesting because the FCC usually steps in and clears things up. But this story is a little spicier given the source of the interference: Warrenton Training Center, a classified US government communications station located adjacent to the afflicted neighborhood. WTC is known to be a CIA signals intelligence station, home to spooks doing spooky stuff, including running high-power numbers stations. The interference isn’t caused by anything as cloak-and-dagger as that, though; rather, it comes from new land-mobile radios that the Department of Defense is deploying. The new radios use the 380-400 MHz band, which is allocated to the Federal Government and unlicensed Part 15 devices, like garage door remotes. But Part 15 rules, which are clearly printed on every device covered by them, state that the devices have to accept unwanted interference, even when it causes a malfunction. So the HOA members who are up in arms and demanding that the government buy them new garage door openers are likely to be disappointed.

Speaking of spooks, if you’re tired of the prying electronic eyes of facial recognition cameras spoiling your illusion of anonymity, have we got a solution for you. The Opt-Out Cap is the low-tech way to instantly change your face for a better one, or at least one that’s tied to someone else. In a move which is sure not to arouse suspicion in public, doffing the baseball cap deploys a three-piece curtain of semi-opaque fabric, upon which is printed the visage of someone who totally doesn’t look creepy or sketchy in any way. Complete instructions are provided if you want to make one before your next trip to the ATM.

It’s always a great day when a new Ken Shirriff post pops up in our feed, and his latest post is no exception. In it, Ken goes into great detail about the history of the 80×24 (or 25) line standard for displays. While that may sound a bit dry, it’s anything but. After dispelling some of the myths and questionable theories of the format’s origin – sorry, it’s not just because punch cards had 80 columns – he discusses the transition from teletypes to CRTs, focusing on the very cool IBM 2260 Display Station. This interesting beast used an acoustic delay line made of 50′ (15 m) of nickel wire. It stored data as a train of sound pulses traveling down the wire, which worked well and was far cheaper than core memory, even if it was susceptible to vibrations from people walking by it and needed a two-hour warm-up period before use. It’s a fascinating bit of retrocomputing history.

A quick mention of a contest we just heard about that might be right up your alley: the Tech To Protect coding challenge is going on now. Focused on applications for public safety and first responders, the online coding challenge addresses ten different areas, such as mapping LTE network coverage to aid first responders or using augmented reality while extricating car crash victims. It’s interesting stuff, but if you’re interested you’ll have to hurry – the deadline is November 15.

And finally, Supercon starts this week! It’s going to be a blast, and the excitement to hack all the badges and see all the talks is building rapidly. We know not everyone can go, and if you’re going to miss it, we feel for you. Don’t forget that you can still participate vicariously through our livestream. We’ll also be tweet-storming and running a continuous chat on Hackaday.io to keep everyone looped in.

Hackaday Podcast 043: Ploopy, Castlevania Cube-Scroller, Projection Map Your Face, And Smoosh Those 3D Prints

Before you even ask, it’s an open source trackball and you’re gonna like it. Hackaday Editors Mike Szczys and Elliot Williams get down to brass tacks on this week’s hacks. From laying down fatter 3D printer extrusion and tricking your stick welder, to recursive Nintendos and cubic Castlevania, this week’s episode is packed with hacks you ought not miss.

Take a look at the links below if you want to follow along, and as always tell us what you think about this episode in the comments!

Direct download (61 MB)

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