Booting The Game Boy Advance Into Bluetooth

While it might not be quite as revered as its predecessor, the Game Boy Advance is arguably the peak of “classic” handheld gaming, before things got all 3D and dual screen on us. One of its best features is the so-called multiboot mode, which allows the GBA to download a program from its link port. Officially this feature was introduced so you could play multiplayer with your friends even if they didn’t have the game cartridge, but naturally it didn’t take long for hackers to realize you can use it to run arbitrary code on an unmodified system.

[Shyri Villar] has put this capability to excellent use with a plug-in board that allows a stock GBA to be used as a general purpose Bluetooth HID controller. Now you can emulate GBA games on your computer while using the real thing as your input device. Or if that’s a bit too redundant for you, then any 2D game you think could benefit from the classic Game Boy control layout.

An ATmega328P on the board initiates the multiboot sequence when the system powers up, and feeds it the GBA program that’s stored on a W25Q32 chip. Once the code is running on the GBA, it communicates with a common HC-05 Bluetooth module through the same link port. To perform this handoff, [Shyri] uses a HCF4066 switch IC to literally change the pin assignments in the connector from the SPI used to upload the ROM to the UART lines of the Bluetooth module.

With everything powered from the 3.3 V provided by the GBA’s link port, and some software niceties like the ability to store Bluetooth pairing information for subsequent device connections, this is actually a very practical gadget. The fact that you can do this on a completely stock GBA is very compelling, especially considering some of the previous Bluetooth Game Boy modifications we’ve seen. Granted the market might be somewhat limited, but with a custom PCB and a 3D printed enclosure, we could see this potentially being a popular accessory for the classic handheld. It’s not like it can be any more niche than using the GBA as a remote display for your multimeter.

Wireless Mouse Power-Up: Logitech MX Master Gets USB-C And Big Battery

When the internal rechargeable battery in his wireless mouse died, [cmot17] decided it was the perfect excuse for making a couple of modifications. The Logitech MX Master isn’t exactly a budget mouse to begin with, but that doesn’t mean there’s no room for improvement. With the addition of a larger battery and USB-C charging port, a very nice mouse just got even better.

As it turns out, there’s plenty of empty space inside the Logitech MX Master, which made it easy to add a larger battery. The original 500 mAh pack was replaced with a new 950 mAh one, which is often sold under the model number 603443. Realistically, if you wanted to go even bigger it looks like any three wire 3.7 V Li-Po pack would probably work in this application, but nearly doubling the capacity is already a pretty serious bump.

Adding the USB-C connector ended up being quite a bit trickier. [cmot17] ordered a breakout board from Adafruit that was just a little too large to fit inside the mouse. In the end, not only did some of the case need to get cut away internally, but the breakout PCB itself got a considerable trimming. Once it was shoehorned in there, a healthy dose of hot glue was used to make sure nothing shifts around.

Since [cmot17] didn’t change the mouse’s original electronics, the newly upgraded Logitech MX Master won’t actually benefit from the faster charging offered by USB-C. If anything, it’s actually going to charge slower thanks to the beefier battery. But considering how infrequently it will need to be charged with the upgraded capacity (Logitech advertised 40 days with the original 500 mAh battery), we don’t think it will be a problem.

Over the years, we’ve seen plenty of stuff crammed into the lowly mouse. Everything from a full computer, to malicious firmware code has been grafted onto that most ubiquitous of computer peripherals. So in the grand scheme of things, this is perhaps one of the most practical mouse modifications to ever grace these pages.

Up Your Game With A Battle Tested Input Device

If you’re looking to add some realism to your flight setup without converting the guest bedroom into a full-scale cockpit simulator, you might be interested in the compromise [MelkorsGreatestHits] came up with. He bolted a genuine military keypad to his PC joystick and instantly added 100% more Top Gun to his desktop.

The Rockwell Collins manufactured keypad came from eBay, and appears to have been used in aircraft such as the EA-6B Prowler and Lockheed C-130 Hercules for data input. Each key on the pad is wired to the 37 pin connector on the rear, which [MelkorsGreatestHits] eventually mapped out after some painstaking work with a breakout board.

Once the matrix was figured out, he made up a cable that would go from the connector to a Teensy 2.0 microcontroller. The Teensy reads the keypad status and converts button presses over to standard USB HID that can be picked up in any game.

The joystick side of the build is a VKB Gunfighter, which is already a pretty nice piece of kit on its own. No modifications were necessary to the joystick itself, other than the fact that it’s now mounted to the top of a black project enclosure. It still connects directly to the computer via its original USB cable, as the keypad has its own separate connection. As luck would have it, the joystick is almost a perfect fit in the opening on the keypad, which presumably would have been for a small screen when installed in the aircraft.

Finding cockpit components from military aircraft on eBay is not as hard as you may think; something to keep in mind if you ever decide to tackle that custom flight simulator build.

Overengineering The Humble USB Power Bank

Back in the flip phone days, you could get through the whole weekend before you had to even think about plugging the thing in. But as the processing power of our mobile devices increased, so to did their energy consumption. Today you’re lucky if your phone doesn’t die before you make it home at the end of the day. To avoid the horrors of having to live without their mobile devices, many people have resorted to lugging around small “power banks” to keep their phones topped off.

That said, the “Ultimate 18650 Power Bank” created by [Kennedy Liu] is on a whole new level. Only true Road Warriors need apply for this particular piece of kit. Inside the 3D printed enclosure is…well, pretty much everything. It’s got an internal inverter to power your AC devices, a Qi wireless charging coil, an adjustable DC output, displays for all relevant voltages, and naturally plenty of USB ports to charge your gadgets. Oh, and some RGB LEDs tossed in for good measure.

[Kennedy] packed a lot of hardware into this relatively small package, and in the video after the break, shows off exactly how everything is arranged inside of this power bank. A big part of getting the whole thing together is the 3D printed frame, which includes carefully designed insets for all of the key components. So if you want to build your own version, you’ll need to get the exact same hardware he used to make sure the puzzle fits together. Luckily, he’s provided links for all the relevant components for exactly that purpose.

Now, you might be wondering about the wisdom of packing all this electronic gear into a thermoplastic enclosure. But [Kennedy] has thought about that; in addition to tacking a heatsink onto pretty much everything, he’s added fans for active cooling and a fairly robust thermal overload protection scheme. By mounting thermally controlled switches to the heatsinks of the high-output components, the system can cut power to anything getting too hot before it has a chance to melt the plastic (or worse).

Most of the DIY power banks we’ve seen in the past have been little more than a simple collection of 18650 cells, so it’s interesting to see one with so much additional functionality packed in. Admittedly some elements of the construction are, to quote the great Dave Jones, “a bit how ya doin.” But with some refinements we think it would be a very handy device to have in your arsenal.

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A Customizable Open Source Mechanical Numpad

Mechanical keyboards with reduced key counts are all the rage these days, but while those streamlined input devices might look cool on your desk, there are times when the traditional number pad or navigation keys are quite handy. Rather than just going without, [Mattia Dal Ben] decided to put together his own mechanical auxiliary input device for when the main board just isn’t cutting it.

[Mattia] is calling his creation the YamPAD, which stands for Yet Another Mechanical numPAD. One of the major goals for the project is to produce a design that’s easy for others to replicate and customize. His PCB has a socket designed to fit an Arduino Pro Micro, which combined with the QMK firmware, offers a wide array of configuration options. All that’s left is to add in the Cherry MX switches and some 1N4148 diodes.

But if you want to take things a little further, [Mattia] has that covered as well. The PCB design has provisions for RGB LED back-lighting should you find yourself in need of crunching some numbers in the dark. There’s even a spot for a 0.91″ OLED display if you really want to take things to the next level.

As of right now, the YamPAD is just a bare PCB, but [Mattia] is planning to design a 3D printed enclosure for it soon. The sketches he’s done so far depict a printed case which we think bears more than a passing resemblance to a Wii Fit Balance Board, but of course being a fully open source project, you’ll be free to design your own case based on the PCB’s dimensions. It would be interesting to see what other kind of customization the community might come up with once the design is finalized.

If you like the idea of the YamPAD, you might also want to check out the kbord we covered back in 2017. If you want to see the full keyboard done in this DIY open hardware style, there are already some choice entries into the field.

Giving An Industrial Push Button USB, Elegantly

[Glen]’s project sounds perfectly straightforward: have a big industrial-style push button act as a one-key USB keyboard. He could have hacked something together in any number of ways, but instead he decided to create a truly elegant solution. His custom PCB mates to the factory parts perfectly, and the USB cable between the button and the computer even fits through the button enclosure’s lead hole.

It turns out that industrial push buttons have standardized components which can be assembled in an almost LEGO-like manner, with components mixed and matched to provide different switch actions, light indicators, and things of that nature. [Glen] decided to leverage this feature to make his custom PCB (the same design used in his one-key keyboard project) fit just like a factory component. With a 3D printed adapter, the PCB locks in just like any other component, and even lines up with the lead hole in the button’s enclosure for easy connecting of the USB cable.

What does [Glen] use the big button for? Currently he has two applications: one provides a simple, one-button screen lock on a Linux box running a virtual machine at his place of work. It first disengages the keyboard capture of the virtual machine, then engages the screen lock on the host. The other inserts a poop emoji into Microsoft documents. Code and PCB design files for [Glen]’s small keyboards are available on GitHub.

A Classy USB Knob For The Discerning Computerist

The keyboard and mouse are great, we’re big fans. But for some tasks, such as seeking around in audio and video files, a rotary encoder is a more intuitive way to get the job done. [VincentMakes] liked the idea of having a knob he could turn to adjust his system volume or move forward and backwards through a stream in VLC, but he also wanted to be able to repeatedly enter keyboard commands with it; something commercial offerings apparently weren’t able to do.

So he decided to build his own USB knob that not only looks fantastic, but offers the features he couldn’t find anywhere else. It’s another project which proves that DIY projects don’t have to look DIY. In fact, they can often give their commercial counterparts a run for their money. But this “Infinity USB Knob” isn’t just a pretty face, it allows the user to do some very interesting things such as quickly undo and redo changes to see how they compare.

As you might imagine, the electronics for this project aren’t terribly complex. The main components are the Adafruit Trinket M0 microcontroller and the EC11 rotary encoder itself. To provide nice visual feedback he added in a NeoPixel ring, but that’s not strictly necessary if you’re trying to rig this up yourself. Though we have to say the lighting effects are a big part of what makes this build look so good.

Though certainly not the only part. The aluminum enclosure, combined with the home theater style knob on the encoder, really give the finished product a professional look. We especially like his method of drilling out the top of the case and filling in the holes with epoxy to create easy and durable LED diffusers. Something to keep in mind for your next control panel build, perhaps.

[VincentMakes] has done an excellent job of documenting the hardware and software sides of this build on, and gives the reader enough information that replicating this project should be pretty straightforward for anyone who’s interested. While we’ve seen several rotary encoder peripherals for the computer in the past, we have to admit this is one of the most compelling yet from a visual and usability standpoint. If this build doesn’t make you consider adding a USB knob to your arsenal, nothing will.

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