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.

Wireless Charger Gives A Glimpse Into Industrial Design Process

Almost every product on the market has been through the hands of an industrial designer at some point in its development. From the phone in your pocket to the car in your driveway or the vacuum in your closet, the way things look and work is the result of a careful design process. Taking a look inside that process, like with this wireless phone charger concept, is fascinating and can yield really valuable design insights.

We’ve featured lots of [Eric Strebel]’s work before, mainly for the great fabrication tips and tricks he offers, like how to get a fine painted finish or the many uses of Bondo. But this time around, he walks us through a condensed version of his design process for a wireless phone charger and stand. His client had specific requirements, like being able to have the phone held up in landscape or portrait mode, so he started with pen and paper and sketched some ideas. A swiveling cylinder seemed to fit the bill, and after a quick mockup in PVC pipe, he started work on a full-size prototype in urethane foam. There are some great fabrication tips in the video below, mainly centered on dealing with not owning a lathe.

The thing for us with all of [Eric]’s videos, but especially this one, is seeing the design process laid out, from beginning to (almost) the end. He sure makes industrial design look like a cool gig, one that would appeal to the Jacks- and Jills-of-all-trades who hang out around here.

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Wireless Charging… Have A Heart

wireless heart charger

[Gal Naim] recently finished off an awesome Valentine’s day present for special someone. It’s a wireless charging heart for your phone!

He already had the Qi wireless charger but wasn’t much of a fan as it “looks so boring”. So he took it apart to salvage the charging circuit for his new project. As luck would have it, the Qi is very simple on the inside — all he had to do was lengthen the power wires to the coil. He then designed his heart in SolidWorks — Don’t forget to check out our 3D Printering tutorials on this — and printed it out in a nice candy apple red. To maximize the charging current he’s left the inductive loop on the outside so it can be as close to the phone as possible — he spray painted it red and it actually looks pretty cool!

The next step was adding the wireless charging capability to the phone, we’ve covered how to add this to any phone before, but for [Gal] it was as simple as cutting down the Qi Receiver card to fit in the phone.

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