A Close Look At USB Power

May 22, 2021 by Tom Nardi 29 Comments

It’s not a stretch to say that most devices these days have settled on USB as their power source of choice. While we imagine you’ll still be running into the occasional wall wart and barrel jack for the foreseeable future, at least we’re getting closer to a unified charging and power delivery technology. But are all USB chargers and cables created equal?

The answer, of course, is no. But the anecdotal information we all have about dud USB gear is just that, which is why [Igor Brkić] wanted to take a more scientific approach. Inspired by the lighting bolt icon the Raspberry Pi will flash on screen when the voltage drops too low, he set out to make a proper examination of various USB chargers and cables to see which ones aren’t carrying their weight.

In the first half of his investigation, [Igor] tests four fairly typical USB chargers with his TENMA 72-13200 electronic load. Two of them were name brand, and the other just cheap clones. He was surprised to find that all of the power supplies not only met their rated specifications, but in most cases, over-performed by a fair amount. For example the Lenovo branded charger that was rated for only 1 A was still putting out a solid 5 V at 1.7 A. Of course there’s no telling what would happen if you ran them that high for hours or days at a time, but it does speak to their short-term burst capability at least.

He then moved onto the USB cables, were things started to fall apart. The three generic cables saw significant voltage drops even at currents as low as 0.1 A, though the name brand cable with 20 AWG power wires did fare a bit better. But by .5 A they were all significantly below 5 V, and at 1 A, forget about it. Pulling anything more than that through these cables is a non-starter, and in general, you’ll need to put at least 5.2 V in if you want to actually run a USB device on the other side.

Admittedly this might not be groundbreaking research, but we appreciate [Igor] taking a scientific approach and tabulating all the information. If you’re still getting low voltage warnings on the Pi after swapping out your cheapo cables, then maybe the problem is actually elsewhere.

Simple Probe Sniffs Out EMI

May 21, 2021 by Tom Nardi 19 Comments

Unable to account for the strange glitches he was seeing on his DIY CNC router, [Daniël Van Den Berg] wondered if his electronics might be suffering from some form of electromagnetic interference (EMI). So he did what any good hacker would do, and rummaged through the parts bin to build an impromptu EMI detector.

[Daniël] is quick to point out that he’s not an electrical engineer, and makes no guarantees about the accuracy of his tossed together gadget. But it does seem to work well enough in his testing that he’s able to identify particularly “noisy” electronic components, so it’s probably worth putting one together just to hear what your hardware is pumping into the environment.

The hardware here is very simple, [Daniël] just attached a coil of solid copper wire to one of the analog pins on an Arduino Nano with a resistor, and hung a speaker off of one of the digital pins. From there, it just took a few lines of code to read the voltage in the coil and convert that into a tone for the speaker. The basic idea is that a strong alternating magnetic field will set up voltage fluctuations in the coil large enough for the Arduino’s ADC to read.

If you’re looking for a bit more insight into what kind of interference your electronic creations might be putting out, [Alex Whittimore] gave a fantastic presentation during the 2020 Hackaday Remoticon about performing RF debugging using a cheap RTL-SDR dongle.

Perfecting A 3D Printed Camera Motion Control Rig

May 21, 2021 by Tom Nardi 10 Comments

If you’ve ever watched one of those high production value YouTube videos and wondered how they’re able to get those smooth shots where the camera seems to be spinning around an object, you were probably looking at the product of an motorized camera motion system. There’s no question these rigs can produce visually striking shots, but their high cost usually keeps them out of the hands of us lowly hackers.

Unless of course you do like [Andy], and build your own. The latest version of this impressive rig features the ability to continuously rotate thanks to commercial 12-wire slip rings, with optical endstops so the machine can still be homed at the beginning of a move. An onboard Raspberry Pi and Arduino Uno are responsible for controlling the stepper motors, the configuration of which ends up being reminiscent of a standard 3D printer.

The MQTT remote can hold a phone for live video.

The software [Andy] has come up with lets him synchronize the camera rig with a small rotating platform he built, which allows for even more complex shots as demonstrated in the video below. It also supports a very slick MQTT-enabled remote controller that he built as a previous project, which makes taking direct control over the camera and monitoring its status much easier.

Want to add a little polish to your own project videos? [Andy] has released all of the files and information you’d need to build your own version of his motion control rig, though we wouldn’t blame you for feeling a bit intimidated by this one. It might not be the most elaborate camera motion control system we’ve seen, but it’s certainly up there. If you just want an overhead video and don’t need those fancy tracking shots, perhaps a modified VESA arm would fit the bill.

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With A Big Enough Laser, The World Is Your Sensor

May 21, 2021 by Tom Nardi 31 Comments

It’s difficult to tell with our dull human senses, but everything around us is vibrating. Sure it takes more energy to get big objects like bridges and houses humming compared to a telephone pole or mailbox, but make no mistake, they’ve all got a little buzz going on. With their new automated laser, the team behind VibroSight++ believes they can exploit this fact to make city-scale sensing far cheaper and easier than ever before.

The key to the system is a turret mounted Class 3B infrared laser and photodetector that can systematically scan for and identity reflective surfaces within visual range. Now you might think that such a setup wouldn’t get much of a signal from the urban landscape, but as it so happens, the average city block is packed with retroreflectors. From street signs to road studs and license plates, the team estimates dense urban areas have approximately 7,000 reflectors per square kilometer. On top of those existing data points, additional reflectors could easily be added to particularly interesting devices that city planners might want to monitor.

Once VibroSight++ has identified its targets, the next step is to bounce the laser off of them and detect the minute perturbations in the returned signal caused by vibrations in the reflector. In the video below you can see how this basic concept could be put to practical use in the field, from counting how many cars pass over a certain stretch of road to seeing how popular a specific mailbox is. There’s a whole world of information out there just waiting to be collected, all without having to install anything more exotic than the occasional piece of reflective tape.

If this technology seems oddly familiar, it’s probably because we covered the team’s earlier work that focused (no pun intended) on using reflected laser beams for home automation in 2018. Back then they were aiming a much smaller laser at blenders and refrigerators instead of license plates and street signs, but the concept is otherwise the same. While we’ll admit the technology does give off a distinctive Orwellian vibe, it’s hard not to be intrigued by the “Big Data” possibilities afforded by the team’s upgraded hardware and software.

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Shop Exhaust Fan Salvaged From Broken Microwave

May 20, 2021 by Tom Nardi 7 Comments

You don’t have to look hard to find a broken microwave. These ubiquitous kitchen appliances are so cheap that getting them repaired doesn’t make economical sense for most consumers, making them a common sight on trash day. But is it worth picking one of them up?

The [DuctTape Mechanic] certainly thinks so. In his latest video, he shows how the exhaust fan from a dead microwave can easily and cheaply be adapted to blow smoke and fumes out of your workshop. While it’s obviously not going to move as much air as some of the massive shop fans we’ve covered over the years, if you’re working in a small space like he is, it’s certainly enough to keep the nasty stuff moving in the right direction. Plus as an added bonus, it’s relatively quiet.

Now as you might expect the exact internal components of microwave ovens vary wildly, so there’s no guarantee your curbside score is going to have the same fan as this one. But the [DuctTape Mechanic] tries to give a relatively high-level overview of how to liberate the fan, interpret the circuit diagram on the label, and wire it up so you can plug it into the wall and control it with a simple switch. Similarly, how you actually mount the fan in your shop is probably going to be different, though we did particularly like how he attached his to the window using a pair of alligator clips cut from a frayed jumper cable.

Got a donor microwave but not in the market for a impromptu shop fan? No worries. We recently saw a dud microwave reborn as a professional looking UV curing chamber that would be the perfect partner for your resin 3D printer. Or perhaps you’d rather turn it into a desktop furnace capable of melting aluminum, copper, or bronze.

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Freenode Debacle Prompts Staff Exodus, New Network

May 20, 2021 by Tom Nardi 68 Comments

It’s no secret that Internet Relay Chat (IRC) has lost some of its appeal in recent years. These days there’s plenty of free chat platforms boasting slick web interfaces and smartphone push notifications, to say nothing of social networks like Facebook and Twitter. The ability to communicate with like minded individuals from all over the planet in real-time is now something we take for granted, so it’s little surprise that newer and flashier protocols and services have steadily eroded the IRC user base.

But there’s often a hidden cost to using these more modern communication protocols. A lack of operational transparency naturally leads to concerns over monitoring and censorship, which makes such services a poor match for the free and open source community. As such, many open projects have eschewed these newer and more popular services for IRC networks that were developed and maintained by the community itself. Among these, the best-known and most respected is Freenode. Originally started as a Linux support channel in 1995, Freenode grew to become the defacto communication and support tool for free and open source projects of all shapes and sizes, and by 2013 had officially become the largest and most active IRC network in the world.

Unfortunately, the incredible legacy of Freenode is now being jeopardized by what former staff members are describing as nothing short of a hostile takeover. Through a complex series of events which actually started several years ago, control of Freenode has been taken from the community and put into the hands of an enigmatic and wealthy entrepreneur who claims his ultimate goal is to revolutionize IRC and return it to the forefront of online communication. Here’s where it gets weird.

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Transparent Hard Drive Gives Peek At The Platters

May 19, 2021 by Tom Nardi 29 Comments

Solid-state drives (SSDs) are all the rage these days, and for good reason. But that doesn’t mean the era of the spinning disk is over, as traditional mechanical hard drives still offer a compelling value for mass storage applications where access times aren’t as critical. But the components inside these “slow” mechanical drives are still moving at incredible speeds, which [The Developer Guy] has nicely illustrated with his transparent hard drive.

Now unfortunately the technology to produce a fully transparent hard drive doesn’t exist, but laser cutting a new top plate out of acrylic is certainly within the means of the average hacker. The process is pretty straightforward: cut out a piece of clear plastic in the same shape and size as the drive’s original lid, put the appropriate mounting holes in it, and find some longer screws to accommodate the increased thickness.

Because this is just for a demonstration, [The Developer Guy] doesn’t need to worry too much about dust or debris getting on the platters; but we should note that performing this kind of modification on a drive you intend on actually using would be a bad idea unless you’ve got a cleanroom to work in.

In the videos below [The Developer Guy] records the drive while it’s in use, and at one point puts a microscope on top of the plastic to get a close-up view of the read/write head twitching back and forth. We particularly liked the time-lapse of the drive being formatted, as you can see the arm smoothly moving towards the center of the drive. Unfortunately the movement of the platters themselves is very difficult to perceive given their remarkably uniform surface, but make no mistake, they’re spinning at several thousand RPM.

Have an old mechanical drive of your own that you’re not sure what to do with? We’ve seen them turned into POV clocks, impromptu rotary encoders, and even surprisingly powerful blower fans.

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