DIY Power Station Puts Ryobi Batteries To Work

February 20, 2020 by Tom Nardi 35 Comments

Anyone with a few cordless tools has probably amassed quite a collection of batteries for them. If you’re a professional contractor, having a fleet of batteries you can swap out during the day’s work is a necessity. But if you’re just doing the occasional DIY project, those batteries are probably going to sit unused more often than not.

Looking to find alternative uses for his growing collection of Ryobi batteries, [Chris Nafis] has come up with a portable power station design that lets him put all that stored energy to use. With support for multiple charging standards and even an integrated work light, this device would be perfect to have around for power outages or to take with you on a camping trip.

Ryobi standardized on an 18 V battery a while back, so [Chris] is using a 10 A DC-DC buck converter to step that down to a more generally useful 12 V. From there he’s got a standard “cigarette lighter” automotive power connector which offers compatibility with a wide range of mobile devices such as small inverters or mobile radios. There’s also dual 2.4 USB “A” ports and a Quick Charge 3.0 compatible USB-C port for charging your mobile gadgets.

As an aside, this project is an excellent example of how powerful 3D printing can be when building your own hardware. Trying to make an interface for a Ryobi battery, without sacrificing a tool as a donor anyway, would be maddeningly difficult with traditional at-home manufacturing methods. But with a pair of calipers and a bit of time in your CAD package of choice, it’s possible to design and build an exact match that works like the real thing.

Which incidentally should make adapting the design to other battery types relatively easy, though editing STLs does pose its own set of unique challenges. A future improvement to this project could be making the battery interface a separate piece that can be swapped out instead of having to reprint the entire thing.

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Transparent LCD Makes Everything Look Futuristic

February 17, 2020 by Al Williams 43 Comments

According to [Kelsey], transparent displays are guaranteed to make “everything feel like the future.” Unfortunately they’re hard to find, and the ones typically available are OLED and can’t make solid black colors. But as luck would have it, it’s possible to repurpose a common LCD to be sort of transparent.

A LCD uses nematic crystals that can polarize light, with the amount of polarization changing based on the electric field applied to the crystal. Light enters the front of the panel through a polarizing film, passes through the display, and then bounces off a reflective back coating. The display itself usually polarizes light in a way that matches the front polarizer. That means if you do nothing you get reflected light. However, if a part of the LCD gets an electric field, it will repolarize in such a way as to block the reflected light making the display look black in that area.

[Kelsey’s] trick is to peel off the reflector and replace it with polarizing film taken from another display. The new polarizer needs to be bigger than the display for one reason: you need to match the polarizing angle of the front film with the new back film. That means if the new film is exactly the right size, it won’t be able to rotate without leaving gaps. By starting with a larger piece, you’ll be able to rotate for maximum transparency before you stick it on.

We’ve seen some homemade transparent numeric displays. The transparent wood, though, has usually left something to be desired.

Xbox Controller Provides Intro To SWD Hacking

February 11, 2020 by Tom Nardi 12 Comments

It’s amazing to see how much technology is packed into even the “simple” devices that we take for granted in modern life. Case in point, the third party Xbox controller that [wrongbaud] recently decided to tear into. Not knowing what to expect when he cracked open its crimson red case, inside he found an ARM Cortex microcontroller and a perfect excuse to play around with Serial Wire Debug (SWD).

Though even figuring out that much took a bit of work. As is depressingly common, all the interesting components on the controller’s PCB were locked away behind a black epoxy blob. He had no idea what chip was powering the controller, much less that debugging protocols it might support. But after poking around the board with his multimeter, he eventually found a few test points sitting at 3.3 V which he thought was likely some kind of a programming header. After observing that pulling the line labelled “RES” low reset the controller, he was fairly sure he’d stumbled upon a functional JTAG or SWD connection.

As [wrongbaud] explains in his detailed blog post, SWD is something of a JTAG successor that’s commonly used by ARM hardware. Using just two wires (data and clock), SWD provides hardware debugging capabilities on pin constrained platforms. It allows you to step through instructions, read and write to memory, even dump the firmware and flash something new.

For the rest of the post, [wrongbaud] walks the reader through working with an SWD target. From compiling the latest version of OpenOCD and wiring an FTDI adapter to the port, all the way to navigating through the firmware and unlocking the chip so you can upload your own code.

To prove he’s completely conquered the microcontroller, he ends the post by modifying the USB descriptor strings in the firmware to change what it says when the controller is plugged into the computer. From here, it won’t take much more to get some controller macros like rapid fire implemented; a topic we imagine he’ll be covering in the future.

This post follows something of a familiar formula for [wrongbaud]. As part of his continuing adventures in hardware hacking, he finds relatively cheap consumer devices and demonstrates how they can be used as practical testbeds for reverse engineering. You might not be interested in changing the ROM that a Mortal Kombat miniature arcade cabinet plays, but learning about the tools and techniques used to do it is going to be valuable for anyone who wants to bend silicon to their will.

Lessons Learned From A CubeSat Postmortem

January 24, 2020 by Tom Nardi 35 Comments

On the 3rd of June 2019, a 1U CubeSat developed by students of the AGH University of Science and Technology in Kraków was released from the International Space Station. Within a few hours it was clear something was wrong, and by July 30th, the satellite was barely functional. A number of problems contributed to the gradual degradation of the KRAKsat spacecraft, which the team has thoroughly documented in a recently released paper.

We all know, at least in a general sense, that building and operating a spacecraft is an exceptionally difficult task on a technical level. But reading through the 20-pages of “KRAKsat Lessons Learned” gives you practical examples of just how many things can go wrong.

It all started with a steadily decreasing battery voltage. The voltage was dropping slowly enough that the team knew the solar panels were doing something, but unfortunately the KRAKsat didn’t have a way of reporting their output. This made it difficult to diagnose the energy deficit, but the team believes the issue may have been that the tumbling of the spacecraft meant the panels weren’t exposed to the amount of direct sunlight they had anticipated.

This slow energy drain continued until the voltage dropped to the point that the power supply shut down, and that’s were things really started going south. Once the satellite shut down the batteries were able to start charging back up, which normally would have been a good thing. But unfortunately the KRAKsat had no mechanism to remain powered down once the voltage climbed back above the shutoff threshold. This caused the satellite to enter into and loop where it would reboot itself as many as 150 times per orbit (approximately 90 minutes).

The paper then goes into a laundry list of other problems that contributed to KRAKsat’s failure. For example, the satellite had redundant radios onboard, but the software on them wasn’t identical. When they needed to switch over to the secondary radio, they found that a glitch in its software meant it was unable to access some portions of the onboard flash storage. The team also identified the lack of a filesystem on the flash storage as another stumbling block; having to pull things out using a pointer and the specific memory address was a cumbersome and time consuming task made all the more difficult by the spacecraft’s deteriorating condition.

Of course, building a satellite that was able to operate for a couple weeks is still an impressive achievement for a student team. As we’ve seen recently, even the pros can run into some serious technical issues once the spacecraft leaves the lab and is operating on its own.

[Thanks to ppkt for the tip.]

Open Laptop Soon To Be Open For Business

January 21, 2020 by Kerry Scharfglass 74 Comments

How better to work on Open Source projects than to use a Libre computing device? But that’s a hard goal to accomplish. If you’re using a desktop computer, Libre software is easily achievable, though keeping your entire software stack free of closed source binary blobs might require a little extra work. But if you want a laptop, your options are few indeed. Lucky for us, there may be another device in the mix soon, because [Lukas Hartmann] has just about finalized the MNT Reform.

Since we started eagerly watching the Reform a couple years ago the hardware world has kept turning, and the Reform has improved accordingly. The i.MX6 series CPU is looking a little peaky now that it’s approaching end of life, and the device has switched to a considerably more capable – but no less free – i.MX8M paired with 4 GB of DDR4 on a SODIMM-shaped System-On-Module. This particular SOM is notable because the manufacturer freely provides the module schematics, making it easy to upgrade or replace in the future. The screen has been bumped up to a 12.5″ 1080p panel and steps have been taken to make sure it can be driven without blobs in the graphics pipeline.

If you’re worried that the chassis of the laptop may have been left to wither while the goodies inside got all the attention, there’s no reason for concern. Both have seen substantial improvement. The keyboard now uses the Kailh Choc ultra low profile mechanical switches for great feel in a small package, while the body itself is milled out of aluminum in five pieces. It’s printable as well, if you want to go that route. All in all, the Reform represents a heroic amount of work and we’re extremely impressed with how far the design has come.

Of course if any of the above piqued your interest full electrical, mechanical and software sources (spread across a few repos) are available for your perusal; follow the links in the blog post for pointers to follow. We’re thrilled to see how production ready the Reform is looking and can’t wait to hear user reports as they make their way into to the wild!

Via [Brad Linder] at Liliputing.

Who Invented The Mouse? Are You Sure?

January 17, 2020 by Al Williams 40 Comments

If you ask most people who invented the mouse, they won’t know. Those that do know, will say that Doug Englebart did. In 1964 he had a box with two wheels that worked like a modern mouse as part of his work at Stanford Research Institute. There is a famous demo video from 1968 of him showing off what looks a lot like an old Mcintosh computer. Turns out, two other people may have an earlier claim to a mouse — or, at least, a trackball. So why did you never hear about those?

The UK Mouse

Ralph Benjamin worked for Britain’s Royal Navy, developing radar tracking systems for warships. Right after World War II, Ralph was working on the Comprehensive Display System — a way for ships to monitor attacking aircraft on a grid. They used a “ball tracker.” Unlike Engelbart’s mouse, it used a metallic ball riding on rubber-coated wheels. This is more like a modern non-optical mouse, although the ball tracker had you slide your hand across the ball instead of the other way around. Sort of a trackball arrangement.

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A Behind The Scenes Look At Small Scale Production

January 16, 2020 by Tom Nardi 12 Comments

Back in 2013, [Karl Lautman] successfully got his kinetic sculpture Primer funded on Kickstarter. As the name implies, you press the big red button on the front of the device, and the mechanical counter at the top will click over to a new prime number for your viewing pleasure. Not exactly a practical gadget, but it does look pretty slick.

These days you can still by your very own Primer from [Karl], but he tells us that the sales aren’t exactly putting food on the table. At this point, he considers it more of a self-financing hobby. To illustrate just what goes into the creation of one of these beauties, he’s put together a time-lapse video of how one gets built from start to finish, which you can see after the break.

Even if you’re not interested in adding a mathematics appliance to your home, we think you’ll agree that the video is a fascinating look at the effort that goes into manufacturing a product that’s only slightly north of a one-off creation.

The biggest takeaway is that you really need to be a jack of all trades to pull something like this off. From milling and polishing the metal components to hand-placing the SMD parts and reflowing the board, [Karl] demonstrates the sort of multi-disciplinary mastery you need to have when there’s only one person on the assembly line.

Small scale manufacturing isn’t cheap, and is rarely easy. But stories like this one prove it’s certainly possible if you’re willing to put in the effort.

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