Capture Device Firmware Hack Unlocks All The Pixels

April 14, 2020 by 7 Comments

According to [Mike Walters], the Elgato Cam Link 4K is a great choice if you’re looking for a HDMI capture device that works under Linux. But the bad news is, it wouldn’t work with any of the video conferencing software he tried to use it with because they expect the video stream to be in a different pixel format. For most people, that would probably have been the end of the story. But you’re reading this on Hackaday, so obviously he didn’t give up without a fight.

Early on, [Mike] found there was a software workaround for this exact issue. The problem isn’t that the Elgato can’t generate the desired format, it’s that the video conferencing programs just don’t know how to ask it to switch modes. The software fix is to create a dummy Video4Linux device and use that to change the format in real-time using ffmpeg. It’s a clever trick if you’ve got a conference call coming up in a few minutes, but it does waste CPU resources and adds some unnecessary hoop jumping.

Putting the device into bootloader mode.

Inspired by the software fix, [Mike] wondered if there was a way he could simply force the Elgato to output video in the desire format by default. He found a firmware dump for the device online, and found where the pixel formats were referenced by searching for their names in ASCII with hexdump. Looking through the source for the Linux USB Video Class (UVC) driver, he was then able to determine what the full 16 byte sequence should be for each video mode was so he could zero out the unwanted ones. Then it was just a matter of flashing his modified firmware back to the hardware.

But there was a problem: with the modified firmware installed, the device stopped working. After investigating the obvious culprits, [Mike] broke out the oscilloscope and hooked it up to the Elgato’s flash chip. It turns out that due to a bug in the program he was using, the SPI erase commands weren’t getting sent during the flash. This lead to corrupted firmware which was keeping the Elgato from booting. After making a pull request with his fixes, the firmware flashed without incident and the capture device now does double-duty as a webcam when necessary.

We could certainly think of easier and quicker was to roll your own webcam, but we’re glad that [Mike] took the time to modify his Elgato Cam Link 4K and document it. It’s a fantastic example of practical firmware hacking, even if you’re not in the market for a new high-definition video conferencing rig.

Edge-Lit 7-Segments Clock The New Normal

April 14, 2020 by 6 Comments

People keep saying that time has lost all meaning now, but we’re still over here divvying up the days with hacks. Most of the hacks you see here are open source. But if you want something even more transparent to meter out the meaninglessness, we invite you to make one of these clearly awesome see-through clocks, which happens to be both.

A word of warning though — according to [GeekMomProjects], this is an incredibly fiddly build with tight tolerances everywhere that acrylic meets acrylic or an LED strip. We can see how it might be like forcing fragile puzzle pieces together. Since the whole thing is crystal clear acrylic, light is going to go everywhere.

[GeekMomProjects] cleverly blocked the escaping light by painstakingly applying non-conductive adhesive foil to the edges of all the smaller pieces. In spite of all that work, we think it would be worth it to have such a fantastic timepiece glowing away the hours somewhere in the house.

Electronically speaking, this beauty is pretty simple. The lights run off of an ItsyBitsy M4 Express, and the time is separately fetched with an ESP8266. [GeekMomProjects] had so much fun that she made one with seconds and one without. Check out their RGB dance routine after the break.

If you prefer your blinky 7-segment clocks a bit more utilitarian, here’s a clock made of shelves.

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Yeast Is A Hot Commodity; Brewing And Breadmaking During Lockdown

April 13, 2020 by 69 Comments

In the recent frenzy of stocking up with provisions as the populace prepare for their COVID-19 lockdown, there have been some widely-publicised examples of products that have become scarce commodities. Toilet paper, pasta, rice, tinned vegetables, and long-life milk are the ones that come to mind, but there’s another one that’s a little unexpected.

As everyone dusts off the breadmaker that’s lain unused for years since that time a loaf came out like a housebrick, or contemplates three months without beer and rediscovers their inner home brewer, it seems yeast can’t be had for love nor money. No matter, because the world is full of yeasts and thus social media is full of guides for capturing your own from dried fruit, or from the natural environment. A few days tending a pot of flour and water, taking away bacterial cultures and nurturing the one you want, and you can defy the shortage and have as much yeast as you need.

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Quarantine Clock Focuses On The Essential

April 12, 2020 by 21 Comments

In these dire times of self quarantining, social distancing, and life as know it coming to a halt, time itself can become rather blurry, and even word clocks may seem unnecessarily precise — especially if you happen to have a more peculiar circadian rhythm. And let’s face it, chances are your usual schedule has become somwehat irrelevant by now, so why bother yourself with dates or an exact time anyway? If you can relate to this, then [mwfisher3] has the perfect clock for you, displaying only the day of the week and a rough estimate of how far that day has progressed.

Using a Raspberry Pi and a spare touch screen, [mwfisher3] had an easy game to begin with, so the clock itself is just Chrome running in Kiosk mode, displaying a local web site with the hours of the day mapped to an array of their textual representation. A few lines of JavaScript are then updating the web site content with the current day and “time”, and a Python script is handling the screen’s back light based on the readings from a Philips Hue motion sensor, using the phue library.

While this is definitely one of the simpler clock projects we’ve seen, this simplicity offers actually a great introduction to some easy JavaScript-based web displays on a Raspberry Pi without much fuzz and distraction. But if that’s not your thing, and you like things more mechanical, we’ve recently covered this day clock that follows the same idea, and then there’s also this light box for an artistic approach of getting a rough estimate of the time.

Bike Lock Secures Car

April 11, 2020 by 13 Comments

[Buttim] loses his car a lot, which might sound a little bit like the plot from an early-00s movie, but he assures us that it’s a common enough thing. In a big city, and after several days of not driving one’s car, it can be possible to at least forget where you parked. There are a lot of ways of solving this problem, but the solution almost fell right into his lap: repurposing a lock from a bike share bicycle. (The build is in three parts: Part 2 and Part 3.)

These locks are loaded with features, like GPS, a cellular modem, accelerometers, and in this case, an ARM processor. It took a huge amount of work for [Buttim] to get anything to work on the device, but after using a vulnerability to dump the firmware and load his own code on the device, spending an enormous amount of time trying to figure out where all the circuit traces went through layers of insulation intended to harden the lock from humidity, and building his own Python-based programmer for it, he has basically free reign over the device.

To that end, once he figured out how it all worked, he put it to use in his car. The device functions as a GPS tracker and reports its location over the cellular network so it can’t become lost again. As a bonus, he was able to use the accelerometers to alert him if his car was moving without him knowing, so it turned into a theft deterrent as well. Besides that, though, his ability to get into the device’s firmware reminded us of a recent attempt to get access to an ARM platform.

The Key To This City Opens A Real Lock

April 11, 2020 by 6 Comments

There are few more satisfying moments than the first time you pick a lock. No matter that it’s a dollar-store padlock that you opened with a pick from a $10 eBay kit, the magic of something that should be secure clicking open in the palm of your hand is hard to beat. Pin tumbler locks are surprisingly simple devices, and to demonstrate this [Farmcraft 101] has produced one at 10x scale to demonstrate their operation on the bench.

The video is a delightful exercise in wood-shop voyerism, as we see him construct the various parts of the lock using his lathe and other workshop tools. A key of the size usually reserved for Freedom Of The City is made, but this one really does slide into the keyway and operate those pins. At the back is a latch mechanism, and the result is a fully-functional model that anyone should be able to use to figure out how the lock works.

Thelock itself isn’t the whole story though, because given the date he’s used it as the basis for a cracking April Fool in which he sends up the [Lock Picking Lawyer] and proceeds to demonstrate the glaring insecurities in his creation. Both videos are there for your enjoyment, below the break. And if you can’t wait to have a go at a lock or two, don’t forget you can always make your own tools using paperclips.

[Ed note: streetcleaner bristles. Thank me later.]

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Planetary Gears Tell Time In This Ornamental Clock

April 10, 2020 by 8 Comments

A clock is perhaps one of the the most popular projects among makers. Most designs we see are purely electronic and do not bother with the often more complicated mechanical part. Instructables user [Looman_projects] though was not afraid of calculating gear ratios and tooth counts for his planetary gear clock.

As shown in the picture, a planetary gear, also known as epicyclic gear, consists of three parts: a central sun gear, planetary gears moving around the sun gear and an outer ring with inward-facing teeth holding it all together. The mechanism dates back to ancient Greece but is still being used in car transmissions and has become quite popular in 3D printing. In his instructable [Looman_projects] has some useful inlinks including an explanation video of how planetary gear sets work and a website helping you to calculate the tooth counts for specific gear ratios. It is also noteworthy that he tried to cut the gears from aluminum with a waterjet which unfortunately failed because the parts were too small. What makes the clock visually stand out is the beautiful ornamental see-through design of the dial plate and hands made from laser-cut wood. Despite the mechanical gearbox, it is not surprising that the driving mechanism is based on ubiquitous pieces of digital electronics including an Arduino Nano, DS3231 RTC module, and a stepper motor. To avoid a cabling mess [Looman_projects] designed a custom PCB that interconnects all the electronics and says he even got some spare PCBs left for people interested in rebuilding the clock.

Actually, this is not the first laser-cut planetary gear clock that we have seen. In case you are wondering about the advantages of planetary gearboxes, you might want to check out how a 3D printed version is lifting an anvil.

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