Make Christmas Commercial Again with this Tiny TV Ornament

Readers of a certain age will remember a time when the Christmas season in the US officially kicked off after Thanksgiving. That was when advertisers began saturation bombing the communal mind with holiday-themed TV commercials night and day. Broadcast TV no longer holds sway like it did back then, and advertisers now start their onslaught in September, but you can put a little retro-commercialism back to Christmas with this 90s Christmas commercial-playing ornament for your tree.

The idea came to [SeanHodgins] after stumbling upon a collection of Christmas commercials from the 1990s on YouTube. With his content identified, he set …read more

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Cheap RC Truck Mod Is Slightly Risky Fun

The world of RC can be neatly split into two separate groups: models and toys. The RC models are generally big, complex, and as you’d imagine, more expensive. On the other hand, the RC toys are cheap and readily available. While not as powerful or capable as their more expensive siblings, they can often be a lot of fun; especially since the lower costs means a crash doesn’t put too big of a ding into to your wallet.

With his latest mod, [PoppaFixIt] has attempted to bridge the gap between toy and model by sticking a considerably overpowered battery into …read more

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The Science Behind Lithium Cell Characteristics and Safety

To describe the constraints on developing consumer battery technology as ‘challenging’ is an enormous understatement. The ideal rechargeable battery has conflicting properties – it has to store large amounts of energy, safely release or absorb large amounts of it on demand, and must be unable to release that energy upon failure. It also has to be cheap, nontoxic, lightweight, and scalable.

As a result, consumer battery technologies represent a compromise between competing goals. Modern rechargeable lithium batteries are no exception, although overall they are a marvel of engineering. Mobile technology would not be anywhere near as good as it is …read more

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A Battery-Tab Welder with Real Control Issues

Spot welding should easier than it looks. After all, it’s just a lot of current in a short time through a small space. But it’s the control that can make the difference between consistently high-quality welds and poor performance, or maybe even a fire.

Control is where [WeAreTheWatt]’s next-level battery tab spot welder shines. The fact that there’s not a microwave oven transformer to be seen is a benefit to anyone sheepish about the usual mains-powered spot welders we usually see, even those designed with safety in mind. [WeAreTheWatt] chose to power his spot welder from a high-capacity RC battery …read more

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LiPo Added to LEGO Power Functions Power Brick

LEGO’s Power Functions elements mostly consist of DC motors and the hardware to be driven by those motors like gears and wheels. They also include battery packs, usually a bunch of AA cells in a plastic box. One of the challenges of the system — for hackers, anyway — is interfacing with the product line’s plugs, which resemble 2×2 plates with power and ground connectors built in, designed to be impossible to connect in reverse. It’s difficult to make the physical shape of the plug, with the connectors right where they should be. This hurdle means you also pretty much …read more

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Ask Hackaday: Dude, Where’s My MOSFET?

Transistors versus MOSFETs: both have their obvious niches. FETs are great for relatively high power applications because they have such a low on-resistance, but transistors are often easier to drive from low voltage microcontrollers because all they require is a current. It’s uncanny, though, how often we find ourselves in the middle between these extremes. What we’d really love is a part that has the virtues of both.

The ask in today’s Ask Hackaday is for your favorite part that fills a particular gap: a MOSFET device that’s able to move a handful of amps of low-voltage current without losing …read more

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DIYing A Raspberry Pi Power Bank

Over the last decade or so, battery technology has improved massively. While those lithium cells have enabled thin, powerful smartphones and quadcopters, [patrick] thought it would be a good idea to do something a little simpler. He built a USB power bank with an 18650 cell. While it would be easier to simply buy a USB power bank, that’s not really the point, is it?

This project is the follow-up to one of [patrick]’s earlier projects, a battery backup for the Raspberry Pi. This earlier project used an 14500 cell and an MSP430 microcontroller to shut the Pi down gracefully …read more

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