Can You Print With Highlighter Ink?

March 29, 2020 by Lewin Day 30 Comments

With huge swathes of people either out of work or working from home, many are now attempting all manner of exciting or silly projects in their downtime. [Emily Velasco] is no exception. She decided to explore the feasability of printing with highlighter ink.

The hack starts with a rather ancient inkjet printer, so old that it works with tractor feed paper. [Emily] set about gutting several highlighter pens and squeezed out the ink reservoirs into a ladle. The printer’s ink cartridge was then filled with the fluid, and a test print was fired off. Upon initial extraction, it appears blank. However, with the aid of a UV light, the printed pattern is revealed. It appears that the inkjet is printing a very faint image, such that the system almost works as an “invisible ink”.

It’s a fun little hack with an old printer, made easier as it lacks the DRM of newer models. It’d probably be quite achievable with a dot-matrix, too. If you’re similarly tinkering in the innards of your peripherals, be sure to let us know. Video after the break.

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Faking Your Way To USB-C Support On Laptops Without It

March 27, 2020 by Mike Szczys 42 Comments

Is there no end to the dongle problem? We thought the issue was with all of those non-USB-C devices that want to play nicely with the new Macbooks that only have USB-C ports. But what about all those USB-C devices that want to work with legacy equipment?

Now some would say just grab yourself a USB-C to USB-A cable and be done with it. But that defeats the purpose of USB-C which is One-Cable-To-Rule-Them-All^[1]. [Marcel Varallo] decided to keep his 2011 Macbook free of dongles and adapter cables by soldering a USB-C port onto a USB 2.0 footprint on the motherboard.

How is that even possible? The trick is to start with a USB-C to USB 3 adapter. This vintage of Macbook doesn’t have USB 3, but the spec for that protocol maintains backwards compatibility with USB 2. [Marcel] walks through the process of freeing the adapter from its case, slicing off the all-important C portion of it, and locating the proper signals to route to the existing USB port on his motherboard.

[1] Oh my what a statement! As we’ve seen with the Raspberry Pi USB-C debacle, there are actually several different types of USB-C cables which all look pretty much the same on the outside, apart from the cryptic icons molded into the cases of the connectors. But on the bright side, you can plug either end in either orientation so it has that going for it.

Custom Reddit Keyboard Only Needs One Hand

March 17, 2020 by Tom Nardi 12 Comments

Sometimes you might want to browse your favorite social media site while eating a sandwich, or throwing darts, or fending off an attacker with a sword. You know, normal things that might occupy only one of your hands. If you’ve ever found yourself in such a situation, then this custom Reddit keyboard could be for you.

Built by [jangxx], this little board is about as simple as it gets. Even if you aren’t looking for a way to browse /r/cooking while practicing your single-handed egg cracking technique, the same principles could be used to quickly throw together a macro keyboard for whatever your particular needs might be.

Inside the 3D printed enclosure is nothing more exotic than an Arduino Pro Micro and five Cherry MX Red switches. The switches have been wired directly to the GPIO pins on the Arduino, and a simple Sketch takes care of the rest. [jangxx] has written the code in such a way that you can easily define the mapping of USB HID keys to physical switches right at the top of the file, making it easy to reuse for your own purposes.

As simple as this project is, we really like the trouble that [jangxx] went through on the 3D printed key caps. The white up and down arrows allow you to navigate through the posts, and the center key selects the one you want to view. Since it’s for Reddit, naturally the red and blue buttons for rapid voting. When you want to go back to the list of posts, just hit the center button again.

Back in 2011 we saw a dedicated Reddit voting peripheral, but we think the addition of simple navigation keys makes this project a bit more compelling. Incidentally, if you can think of any other reason you might want a one-handed keyboard for browsing Reddit…we definitely don’t want to hear about it.

Dumpster Finds Combined Into 4K Desktop Monitor

March 6, 2020 by Tom Nardi 31 Comments

Dumpster diving is a time honored tradition in the hacking community. You can find all sorts of interesting hardware in the trash, and sometimes it’s even fully functional. But even the broken gadgets are worth taking back to your lair to strip for parts. If you’re as lucky as [Jamz], you might be able to mash a few devices together and turn them into something usable.

In this case, [Jamz] scored a LG 27UK650 monitor with a cracked display and a Dell OptiPlex 7440 “All-in-One” computer that was DOA. Separately these two pieces of gear were little more than a pile of spare parts waiting to be liberated. But if the control board could be salvaged from the monitor, and the working LCD pulled from the Dell…

After taking everything apart, [Jamz] made a frame for this new Frankenstein monitor using pieces of aluminum channel from the hardware store and 3D printed side panels. With the Dell LCD mounted in the skeletal frame, the control board from the LG monitor was bolted to the back and wired in. Finally the center section of the LG monitor’s back panel was cut out and mounted to the new hybrid display with a 3D printed frame.

Admittedly, these were some pretty solid finds as far as trash goes. You won’t always be so lucky. But if you can keep an open mind, the curb is littered with possibilities. How about some impressive home lighting that started life as a cracked flat screen TV?

MIL-SPEC Keyboard Now Salutes USB

February 27, 2020 by Kristina Panos 6 Comments

When [easyjo] picked up this late ’80s Marconi mil-spec keyboard for cheap, he knew it wouldn’t be easy to convert it to USB — just that it would be worth it. Spoiler alert: those LEDs aren’t a mod, they’re native. They get their interesting shape from the key traces, which are in the four corners.

Despite having way-cool buttons such as WPNS HOLD, and the fact that Control is on the home row where it belongs, this keyboard does not look fun to type on at all for any length of time. Of course, the point of this keyboard is not comfort, but a reliable input device that keeps out dust, sweat, liquids, and the enemy.

This is probably why the controller is embedded into the underside of the key switch PCB instead of living on its own board. [easyjo] tried to analyze the signals from the existing 26-pin connector, but it didn’t work out.

So once he was able to decode the matrix, he removed the controller chip and wired the rows and columns directly to an Arduino Leonardo. Fortunately, the LEDs were just a matter of powering their columns from the front side of the board.

The availability of certain kinds of military surplus can make for really interesting modernization projects, like adding POTS to a field telephone.

Via r/duino

Little Printer Dispenses Short Stories

February 25, 2020 by Ted Yapo 11 Comments

We know how it happens. You buy a fancy new label printer, thinking this is the answer to your disorganized space, but soon entropy grabs the printer as well, and it becomes just another item in the pile. When you find such items later, though, they can spark ideas. The idea that struck [Eric Nichols] was to turn his diminutive thermal printer into a dedicated one for short stories.

Inspired by an article about a vending machine that dispenses stories selected by the reader’s time constraints, [Eric] took on the task of getting his Dymo LabelWriter 400 Turbo working in this new capacity. The first task was finding some continuous roll paper that would fit, because the official stock for this thing is all labels. He got lucky on the first try and a roll of 2 7/16″ receipt paper fit the bill perfectly.

The printer itself doesn’t have much brains; it prints bitmaps 672 bits wide, and as long as you care to make them. While the initial experiments succeeded in printing graphics, [Eric] needed a way to convert his stories to bitmapped text to send to the printer. The human-readable font file format known as BDF (glyph Bitmap Distribution Format) was a perfect fit, since a library to render it was readily available. On top of that, the open-source tool otf2bdf will convert a TrueType (TTF) font to BDF, completing his font-rendering chain.

[Eric] has these printers working with both Linux and windows, either one running on a PC where his software resides, and has it all well-documented on his site. With this in place, it’s simply a matter of coming up with the stories to print. We think it would be perfect for Hackaday dailies!

We’ve seen interesting hacks with disused printers before, like this ascii-art generating cartridge.

Stomp Switches Let You Skip Tracks Hands-Free

February 24, 2020 by Tom Nardi 11 Comments

You’ve (probably) got four limbs, so why are you only using half of them when you’re working on the computer? Just because your toes don’t have the dexterity to type (again, probably) doesn’t mean your feet should get to just sit there doing nothing all day. In a recent project, [MacCraiger] shows you just how easy it can be to put some functionality under foot by building a pair of media control stomp switches.

Crimp pin connectors grant +50 professionalism.

If the devices pictured above look a lot like guitar effects, that’s because they share a lot of parts. [MacCraiger] used the same sort of switch and aluminum case that you might see on a pedal board, as he figured they’d be better suited to a lifetime of being stepped on than something he 3D printed.

Up on the desk, and this time in a printed case, is the Arduino Leonardo that they connect to. The wiring for this project is very straightforward, with the switches connected directly to the GPIO pins. From there, the Arduino firmware emulates a USB Human Interface Device and fires off the appropriate media control keystrokes to skip to the next track or pause playback depending on which switch has been engaged.

This hardware isn’t exactly breaking any new ground here, but we did like how [MacCraiger] used standard 3.5 mm audio cable and the associated jacks to connect everything up. It’s obviously on-theme for what’s essentially a music project, but more importantly, gives the whole thing a very professional look. Definitely a tip to mentally file away for the future.

For the more accomplished toe-tapper, our very own [Kristina Panos] recently recently took us through the construction of her macro slinging footstool. Between these two examples of bespoke peripherals, you should have everything you need to create your own custom input devices. We suppose you could even make one that’s hand operated if you’re into that sort of thing.

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