19 Coils Make Charging Wireless

Wireless charging is conceptually simple. Two coils form an ad hoc transformer with the primary in the charger and the secondary in the charging device. However, if you’ve ever had a wireless charging device, you know that reality can be a bit more challenging since the device must be positioned just so on the charger. Xiaomi has a multi-coil charger that can charge multiple devices and is tolerant of their positioning on the charger. How does it work? [Charger Lab] tears one apart and finds 19 coils and a lot of heat management crammed into the device.

The first part of the post is a terse consumer review of the device, looking at its dimensions and features. But the second part is when the cover comes off. The graphite heat shield looks decidedly like an accidental spill of something, but we’re sure that’s just how it appears. The coils are packed in tight in three layers. We have to wonder about their mutual interactions, and we assume that only some of them are active at any given time. The teardown shows a lot of the components and even pulls datasheets on many components, but doesn’t really go into the theory of operation.

Still, this is an unusual device to see from the inside. It is impressive to see so much power and thermal management in such a tiny package. We wonder that we don’t see more wireless charging in do-it-yourself projects. We do see some, of course. Not to mention grafting a charging receiver to an existing cell phone.

Gaming Headset Gets Simple Wireless Charging

Despite the technology itself being widely available and relatively cheap, devices that offer wireless charging as a feature still aren’t as common as many would like. Sure it can’t deliver as much power as something like USB-C, but for low-draw devices that don’t necessarily need to be recharged in a hurry, the convenience is undeniable.

Sick of having to plug it in after each session, [Taylor Burley] decided to take matters into his own hands and add wireless charging capability to his Turtle Beach Recon 200 headset. But ultimately, there’s nothing about this project that couldn’t be adapted to your own particular headset of choice. Or any other device that charges via USB, for that matter.

To keep things simple, [Taylor] used an off-the-shelf wireless charging transmitter and receiver pair. The transmitter is housed in a 3D printed mount that the headset hangs from, and the receiver was simply glued to the top of the headset. The receiver is covered with a thin 3D printed plate, but a couple turns of electrical tape would work just as well if you didn’t want to design a whole new part.

Once everything was in place, he then ran a wire down the side of the headset and tapped into the five volt trace coming from the USB port. So now long as [Taylor] remembers to hang the headset up after he’s done playing, the battery will always be topped off the next time he reaches for it.

Considering how many projects we’ve seen that add wireless charging to consumer devices, it’s honestly kind of surprising that it’s still not a standard feature in 2021. Until manufacturers figure out what they want to do with the technology, it seems like hackers will just have to keep doing it themselves.

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Giant DIY Mouse Sets The Ball Free

Make the move to a split keyboard and the first thing you’ll notice is that you have all this real estate between the two halves. (Well, as long as you’re doing it right). This is the perfect place to keep your cat, your coffee cup, or in [Jacek]’s case, your fantastic DIY trackball mouse.

Don’t be fooled by the orange plastic base — all the electronics are rolled up inside that big sexy ball, which [Jacek] printed in two halves and glued together. Inside the ball there’s an Adafruit Feather nRF52840 Sense, which has an onboard accelerometer, gyroscope, and magnetometer. As you’ll see in the video after the break, the Feather takes readings from these and applies a sensor-fusing algorithm to determine the ball’s orientation in 3D space before sending its position to the computer. To send the click events, [Jacek] baked some mouse buttons into the keyboard’s firmware. Among the other Feather sensors is a PDM MEMS microphone, so detecting taps on the ball and translating them to clicks is not out of the question for a future version.

Here comes the really clever part: there are two reed switches inside the ball. One is used as a power switch, and the other is for setting the ‘up’ direction of the trackball. The ball charges wirelessly in a 3D printed base, which also has a small neodymium magnet for activating the reed switches. Check out the demo after the break, which shows [Jacek] putting the trackball through its paces on a mouse accuracy testing program.

If you prefer your DIY trackballs to be more standard looking, click on over to the Ploopy project.

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Custom Coil Lets Mouse Charge Without Wires

It’s 2021, shouldn’t all of our devices be able to pull the power they need from the ether? [Sasa Karanovic] certainly thinks so, which is why he recently took it upon himself to add wireless charging capabilities to his desktop computer peripherals. The Qi transmitter and receiver modules are relatively cheap and easy to come by, the trick is in getting them installed.

The keyboard gets non-invasive Qi charging.

For the keyboard, [Sasa] took the path of least resistance. The receiver coil lives inside a little 3D printed box attached to the back, and power is routed through a hacked up right-angle USB cable. It’s a simple addition that doesn’t make any permanent changes to the keyboard; perfect for those who don’t want to risk toasting their gear.

But that wasn’t really an option for the mouse. Obviously the Qi hardware would have to go on the inside, but at a glance it was clear there wasn’t enough room to mount the stock coil. So [Sasa] pulled the original coil apart and rewound it around a small 3D printed jig. This resulting coil was perfectly sized to fit inside the flat area on the left side of the mouse with no apparent degradation in charging ability. Wiring the module up to an unpopulated pad on the PCB allowed him to easily inject the 5 V output into the device’s existing charging circuitry.

We’ve seen plenty of aftermarket Qi charging coils take up permanent residence in various gadgets, but rewinding the coil is a neat trick that we’ve only seen pulled off a couple times in the past. Something to file away mentally should you ever want to wirelessly power up one of your projects.

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Supercap Drink Coasters Are The Life Of The Party

You’ve probably seen multicolored flashing LEDs embedded into clear plastic cups or coasters before, they’re quite commonly used in fancy restaurants that also feature animatronic characters and a gift shop on the way out. But have you ever wondered about the logistics of maintaining such devices? When the anthropomorphic rodent shuts down for the night, you’re going to want to clean all those blinking doodads; but any opening to connect a charger or insert a battery is just a leak waiting to happen.

[Scott Clandinin] has come up with a solution to this problem that’s equal parts brilliant simplicity and unabashed overengineering. Using wireless charging and supercapacitors, he’s developing an LED coaster that can be hermetically sealed in clear resin.

With no plugs to connect or batteries to change, these coasters can be permanently encapsulated with no ill effects. Granted the supercapacitors will degrade with time and eventually won’t hold a charge for as long, but even the most conservative estimates would have these coasters still partying in a decade.

For his prototype version [Scott] has put together a simple charging base, but we imagine in a full deployment such devices could be charged with induction coils built into a bar or table. While the energy consumption could potentially be a showstopper, we’d love to see a future version that integrates a radio receiver. Then the coasters could double as pagers to let diners know their table is ready.

While this device is obviously much thicker than a traditional coaster, it looks fairly reasonable even at this early stage. We like the concentric design that puts the coil inside the PCB, and wonder if similar cutouts couldn’t be used to get the twin 15F supercapacitors and charging module hunkered down just a few millimeters more. The 2019 Hackaday Prize is all about evolving an idea into a design suitable for production, and those are the sort of incremental improvements that the judges will certainly be keeping an eye out for.

Curbing Internet Addiction In A Threatening Manner

Those who have children of their own might argue that the youth of today are getting far too much internet time. [Nick] decided to put an emergency stop to it and made this ingenious internet kill switch to threaten teenagers with. Rather unassuming on the outside, the big red button instantly kills all network traffic as soon as you push it down, doing its label justice. Reset the toggle button, and the connection is restored, simple as that.

In order to achieve this, [Nick] fit inside the enclosure a Raspberry Pi Zero W, along with a battery and a wireless charging circuit for portability and completely wireless operation. The button is wired into the Pi’s GPIO and triggers a command to the router via SSH over WiFi, where a script listening to the signal tells it to drop the network interfaces talking to the outside world. It’s simple, it’s clean, and you can carry it around with you as a warning for those who dare disobey you. We love it.

Another use for big red buttons we’ve seen in the past is an AC power timer, but you can do just about anything with them if you turn one into an USB device. Check this one in action after the break.

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Hackaday Podcast Ep15: Going Low Frequency, Robotic Machines, Disk Usage For Budgets, And Cellphones Versus Weather

Hackaday Editors Mike Szczys and Elliot Williams discuss the highlights of the great hacks from the past week. On this episode we discuss wireless charging from scratch, Etch-A-Sketch selfies, the robot arm you really should build yourself, bicycle tires and steel nuts for anti-slip footwear, and bending the piezo-electric effect to act as a VLF antenna. Plus we delve into articles you can’t miss about 5G and robot firefighting.

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!

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 (60 MB or so.)

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