Mini-Banners for Small Occasions

Do you often find yourself needing to make small signs? Perhaps you’re trying to put a notice on the office fridge, but you’re just not in the mood for the usual Comic Sans-on-A4 staple today. A banner of some sort would do the trick, but… a small one, right? [Mike Ingle] has the answer – making mini-banners on old receipt printers.

[Mike] was a fan of Paint Shop in the 1980s, which among other things, enabled the printing of long banners on the popular dot matrix printers of the era. Realising that receipt printers have a similar ability to print on a long continuous strip of paper, he decided to see if it was possible to create small banners using the hardware.

The hack is simple – ImageMagick is used to generate a one-bit black & white bitmap that is then processed with some custom C code to generate something the printer can understand. It’s then a simple matter of hacking up the original RS-232 cable to fit a DB-9 (aka DE-9) connector, and spitting out the instructions over serial.

The mini-banners are cool, and we could imagine having some fun with such a project, using it to print out tweets or putting it into service as a stock ticker. It’s a great example of cleanly interfacing with existing hardware to create something outside of the original design intentions. Such printers are fertile ground for hacks – like this printer that can spit out the US Constitution in 6 seconds flat.

Poetry in Motion with a Sand-Dispensing Dot Matrix Printer

Hackaday gets results! Reader [John] saw our recent Fail of the Week post about a “sand matrix printer” and decided to share his own version, a sand-dispensing dot matrix printer he built last year.

Granted, [John]’s version is almost the exact opposite of [Vjie Miller]’s failed build, which sought to make depressions in the sand to print characters. [John]’s Sandscript takes a hopper full of dry, clean sand and dispenses small piles from six small servo-controlled nozzles. The hopper is mounted on a wheeled frame, and an optical encoder on one wheel senses forward motion to determine when to open each nozzle. As [John] slowly walks behind and to the side of the cart, a line of verse is slowly drizzled out onto the pavement. See it in action in the video below.

More performance art piece than anything else, we can see how this would be really engaging, with people following along like kids after the [Pied Piper], waiting to find out what the full message is. There’s probably a statement in there about the impermanence of art and the fleeting nature of existence, but we just think it’s a really cool build.

We’ve featured other sand writers before, like this high-resolution draw bot that also dispenses sandy verses, or this literal beach-combing art bot. Guess there’s just something about sand that inspires artists and hackers alike.

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Fail Of The Week: Arduino Sand Matrix Printer

NYC beaches are where tropical beaches addicted to meth go to die. So says [Vije Miller] in his write-up for his Arduino sand matrix printer. It’s a clever idea, five servo-operated cardboard plungers that indent a pattern of dots in the sand as the device is pulled forward, resulting in something not unlike a dot matrix printer that can write messages in the sand.

He’s submitted it to us as a Fail Of The Week, because it doesn’t do a very good job of writing in the sand, and it’s burned out a servo. But we feel this isn’t entirely fair, because whether or not it has delivered the goods it’s still an excellent build. Cardboard isn’t a material we see much of here at Hackaday, but in this case he’s mastered it in a complex mechanism that while it may have proved a little too flexible for the job in hand is nevertheless a rather impressive piece of work.

You can see a brief video below the break showing it in action. He tells us his motivation has waned on this project, and expresses the hope that others will take up the baton and produce a more viable machine.

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Peripherals Behind The Iron Curtain

The article Home Computers Behind the Iron Curtain sparked a lot of interest, which made me very happy. Therefore, I decided to introduce more computer curiosities from the Iron Curtain period, especially from the former Czechoslovakia (CSSR).

As I mentioned in the previous article, the lack of spare parts, literature and technology in Czechoslovakia forced geeks to solve it themselves: by improvisation and what we would today call “hacking.”  Hobbyist projects of one person or a small party was eventually taken over by a state-owned enterprise, which then began to manufacture and deliver to stores with some minor modifications. These projects most often involved a variety of peripherals that could only be found in the Czechoslovakia with great difficulty.

Much like the production of components, the production of peripherals was also distributed throughout the eastern block so that each country was specializing in certain types of peripherals. For example, East Germany produced matrix printers, and Bulgaria made floppy disks drives. This meant industrial enterprises had to wait for vital computer parts, because the production in another country was not sufficient to cover even the local requirements, let alone the home user.

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Homemade LED helmet

LEDHelmet

We’ve all seen Daft Punk helmet builds, but [George’s] project is a homemade LED helmet that takes no shortcuts and packs the visor full of hundreds of individual lights. He started with a prototype that uses a PIC 18F4580 microcontroller connected to a MAX7221 LED driver, which gave him control over some dot matrix displays to test the wiring and sample script. He then used this prototype setup to develop a scrolling text function.

With testing complete, [George] wired hundreds of LEDs into 8×8 block sections, using a cardboard jig to keep everything straight. He could have stopped there, but [George] took the build further, adding an LCD display and a 7-segment clock module to the inside of the helmet, in view of the wearer. The clock displays the helmet’s current beats per minute rate, while the LCD shows the content being displayed (pattern, text / Pacman, stripes). It’s possible to see out between the bottom of the display and the chin of the helmet. If you need better visibility we’d recommend a bike helmet matrix that isn’t as dense.

You can watch a video of the helmet running different patterns below. (Warning: music). When you’re done with that, why not LED all the things: from Infinity Mirrors to LED Sneakers.

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Dot matrix printer spits out any tweet mentioning @KWF

Earlier this month, [Kenneth] picked up an old dot matrix printer at the Silicon Valley Flea Market and subsequently found two cases of tractor feed printer paper. It’s a marriage made in heaven for a dot matrix twitter printer.

[Kenneth] used a BeagleBone – a tiny single board computer running Linux – to connect to the Internet and fetch any new tweets mentioning KWF every minute or so. The BeagleBone spits out these tweets over the USB port which is connected to the ancient printer by means of a cheap adapter cable.

Interestingly, [Kenneth] wrote the code for this project as a shell script. A lot of effort went into scrubbing the input of any escape characters, but he still implores his admirers to not attempt to break his project.

In case you’re wondering, at couple Twitter accounts announced this post’s headline to the Twitterverse when this story was published. This should have immediately sent [Kenneth]’s printer into motion, recording that harsh mistress that is sending a build log of a Twitter connected device into Hackaday.

After the break you can see [Kenneth]’s demo. Be sure to share this post on Twitter!

Reverse engineering a plasma dot matrix display

A while back, [DragonMinded] picked up a bunch of old arcade and pinball parts from a guy on Craigslist. These parts sat around for a while until a really neat plasma dot matrix display was found in the corner of a box in his garage. Doing the only reasonable thing, [DragonMinded] figured out how to interface this ancient display with a microcontroller.

After extensive Internet research on his display, [DragonMinded] could only find a one page datasheet for his APD-128G064A-1 display. Luckily, this datasheet had voltage requirements, and since the display only had six input pins he could probe the circuit to see what goes where.

After generating a crude schematic, [DragonMinded] prototyped a driver circuit with an Arduino. When the function of each pin was discovered, the Arduino libraries were discarded and replaced with raw register access.

It was a fair amount of work, but [DragonMinded] eventually got to the point where he could draw anything he wanted on the screen. Next on the to-do list is turning it into a terminal or Twitter machine, as with all good display hacks.