Livestreaming Backpack Takes Streaming On-The-Go

August 19, 2022 by Bryan Cockfield 17 Comments

Anyone who’s anyone on the internet these days occasionally streams content online. Whether that’s the occasional livestream on YouTube or an every day video game session on Twitch, it’s definitely a trend that’s here to stay. If you want to take your streaming session on the go, though, you’ll need some specialized hardware like [Melissa] built into this livestreaming backpack.

[Melissa] isn’t actually much of a streamer but built this project just to see if it could be done. The backpack hosts a GoPro camera with a USB interface, mounted on one of the straps of the pack with some 3D printed parts, allowing it to act as a webcam. It is plugged into a Raspberry Pi which is set up inside the backpack, and includes a large heat sink to prevent it from overheating in its low-ventilation environment. There’s also a 4G modem included along with a USB battery pack to keep everything powered up.

The build doesn’t stop at compiling hardware inside a backpack, though. [Melissa] goes into detail on the project’s page about how to get all of the hardware to talk amongst themselves and where the livestream is setup as well. If you’d like a more permanently-located streaming setup with less expensive hardware, we have seen plenty of builds like this which will get the job done as well.

Replace An AA Battery With Paper

August 8, 2022 by Bryan Cockfield 54 Comments

Paper is an ubiquitous part of society; so much so that the incredible engineering behind it often goes unnoticed. That isn’t the case for [Robert], though, who has a deep appreciation for the material and all its many uses far beyond recording information. In this particular video, he recreates a method found by researchers to turn a piece of paper into a battery with equivalent performance to a AA-sized alkaline battery. (Video, embedded below the break.)

The process involves the creation of a few different types of ink, each of which can be made with relatively common materials such as shellac, ethanol, polyethylene glycol, and graphite. Each of these materials are mixed in different proportions to create the inks. Once the cathode ink and anode ink are made, a third ink is needed called a current collector ink which functions essentially as a wire. The paper is dipped into a salt solution and then allowed to dry, given a partial waterproof coating, and when it is needed it can be activated by wetting it which allows the ion flow of the battery to happen.

The chemistry of this battery makes a lot of sense once you see it in action, and the battery production method also has a perk of having a long shelf life as long as the batteries stay dry. They also don’t damage the environment as much as non-rechargable alkaline cells do, at least unless you want to go to some extreme measures to reuse them.

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Probing CAN Bus For EV Battery Info

July 27, 2022 by Bryan Cockfield 8 Comments

The widespread adoption of the CAN bus (and OBD-II) in automobiles was largely a way of standardizing the maintenance of increasingly complicated engines and their needs to meet modern emissions standards. While that might sound a little dry on the surface, the existence and standardization of this communications bus in essentially all passenger vehicles for three decades has led to some interesting side effects, like it’s usage in this project to display some extra information about an electric car’s battery.

There’s not a ton of information about it, but it’s a great proof-of-concept of some of the things CAN opens up in vehicles. The build is based on a Citroën C-Zero (which is essentially just a re-badged Mitsubishi i-MiEV) and uses the information on the CAN bus to display specific information about the state of charge of the battery that isn’t otherwise shown on the car’s displays. It also includes a build of a new secondary display specifically for this purpose, and the build is sleek enough that it looks like a standard part of the car.

While there are certainly other (perhaps simpler) ways of interfacing with a CAN bus, this one uses off-the-shelf electronics like Arduino-compatible microcontrollers, is permanently installed, and has a custom case that we really like. If you’re just starting to sniff around your own vehicle’s CAN bus, there are some excellent tools available to check out.

Thanks to [James] for the tip!

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Adding A Battery To Extend Speaker Life

July 23, 2022 by Bryan Cockfield 14 Comments

Perhaps the weakest point in modern electronics when it comes to user servicability is the lifecycle of the batteries included from the manufacturer. Without easily replaceable batteries, many consumer goods end up in the landfill when they’re otherwise working perfectly. If you’d like to get more out of your devices than the manufacturer intends, you might have to go to great lengths like [Théo] did with his JBL speaker.

This was a Bluetooth device produced by JBL nearly a decade ago, and while the original device boasted several hours of battery life, after so many years of service, it was lucky to get a half hour before the battery died. To replace it, [Théo] removed the original battery and extended the case to be able to hold a larger cell phone battery. He also decided to use the original battery management circuit from the speaker with the new battery after verifying the voltage and chemistry were close enough to the original.

Since the phone battery is a proprietary Samsung device, [Théo] also decided to build a version that uses standard 18650 cells instead, although he prefers the slimmer design with the phone battery for his use case. Straightforward as this build may be, it does go a long way to demonstrate the principle that if you can’t fix your devices, you don’t really own them.

The State Of Play In Solid State Batteries

April 27, 2022 by Lewin Day 141 Comments

Electric vehicles are slowly but surely snatching market share from their combustion-engined forbearers. However, range and charging speed remain major sticking points for customers, and are a prime selling point for any modern EV. Battery technology is front and center when it comes to improving these numbers.

Solid-state batteries could mark a step-change in performance in these areas, and the race to get them to market is starting to heat up. Let’s take a look at the current state of play.

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Desktop Performance In A Custom Mac Laptop

March 24, 2022 by Bryan Cockfield 17 Comments

Most of us either own or have used a laptop at some point. For traveling, as a student, or even for browsing Hackaday on the couch in front of the TV, they are pretty much indispensable. They do tend to have a sharp performance reduction compared to a desktop though thanks to the thermal and battery limitations of a portable form factor. [Scott Yu-Jan] wanted to solve that in his own life by building a custom Mac laptop with none of these downsides.

Noticing that a modern iPad Mini has exactly the same width of his Mac Mini, [Scott] set about combining the two devices into a single unit that he could assemble when traveling. A 3D printed case with a traditional laptop clamshell design takes care of physically combining these two devices, and a USB-C cable between the two takes care of combining them in software thanks to Apple’s Duet program. While this has better performance than a Macbook Pro it might actually have some perks, since Apple continues to refuse to make a laptop with a touchscreen.

There are some downsides, of course. The price is higher than a comparable Macbook Pro for the iPad and Mac together, plus it doesn’t include a keyboard or mouse. It also has no battery, so it needs to be plugged in. In the follow-up video linked below, though, [Scott] notes that for him this still made sense as he uses the Mac and iPad individually already, and only works remotely at places that have power outlets readily available. For the average person, though, we might recommend something different if you really need an esoteric laptop-like machine.

Thanks to [Varun] for originally sending in this tip!

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Careful Cuts Lets Logger Last A Year On A Coin Cell

March 14, 2022 by Bryan Cockfield 21 Comments

Coin cells are great for backup power for things like real-time clocks, or even for powering incredibly small mechanical devices like watches. But for something like a data logger, running on a standard microcontroller, most people would reach for a lithium cell of some sort. Not so with this build, though, which squeezes every joule of energy from a coin cell in order to run a data logger for a full year.

Most of the design and engineering required to improve the efficiency of the data logger involve standard practices for low-power devices such as shutting off unnecessary components and putting the device to sleep when not actively running, but this build goes far beyond that. The Vcc pin on the RTC was clipped which disables some of its internal logic but still keeps its basic functionality intact.

All of the voltage regulators were removed or disabled in favor of custom circuitry that doesn’t waste as much energy. The status and power LEDs were removed where possible, and the entire data logger is equipped with custom energy-efficient code as well.

If you’re starting a low-power project, even one that isn’t a datalogger, it’s worth checking out this build to see just how far you can go if you’re willing to hack at a PCB with cutting tools and a soldering iron. As to why this data logger needed such a low power requirement, it turns out it’s part of a kit being used in classrooms and using a coin cell brought the price of the entire unit down tremendously. Even if you have lithium cells on hand, though, it’s still worthwhile to check out the low power modes of your microcontroller.

Thanks to [Adrian] for the tip!