Author: Jenny List

3212 Articles

A Mouse Becomes A Camera

January 29, 2024 by 24 Comments

If your pointing device is a mouse, turn it over. The chances are you’ll see a red LED light if you’re not seriously old-school and your mouse has a ball, this light serves as the illumination for a very simple camera sensor. The mouse electronics do their thing by looking for movement in the resulting image, but it should be possible to pull out the data and repurpose the sensor as a digital camera. [Doctor Volt] has a new video showing just that with the innards of a Logitech peripheral.

The mouse contains a microcontroller and the camera part, which fortunately has an SPI interface. The correct register to query the sensor information was deduced, and as if my magic, an image appeared. An M12 lens provided focus with a handy 3D printed mount, and the board went back into the mouse case as a housing. The pictures have something of the Game Boy camera about them, being low-res and monochrome, but it’s still a neat hack.

If you’d like to give it a go you can find the code in a GitHub repository. You might find it worth finding a gaming mouse though, for the much higher resolution sensor.

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A Vintage Monitor Lives Again With A New Heart

January 29, 2024 by 25 Comments

Aside from keeping decades-old consumer-grade computing hardware working, a major problem for many retrocomputing enthusiasts lies in doing the same for vintage monitors. Whether your screen is a domestic TV or a dedicated monitor, the heat and voltage stress of driving a CRT made these devices significantly less reliable than many of their modern-day counterparts. [Adrian’s Digital Basement] has a worn-out and broken Commodore 1701 monitor, which he’s brought back to life with a modern circuit board and a CRT transplant.

Following on from a previous project, he’s using a replacement board sold as a repair option for CRT TVs on AliExpress. The Commodore monitor has its board on a metal chassis which takes the replacement with a bit of modification. He doesn’t say where the new CRT came from, but we’re guessing it was a late model TV as CRTs made over the last few decades are more interchangeable than might be expected. There’s a moment of mild dodginess as he makes a voltage doubler to run the 220 V board from 120 V with a pair of large electrolytic capacitors hot glued in place, but otherwise it’s a success.

At the end of it all after some testing and set-up he has a Commodore monitor with a new heart and multi-standard support. Is it really a Commodore monitor though, or should it have been repaired? It’s a difficult one to answer, but we’d suggest that CRT monitor repair is less easy today than it used to be because many of the parts are now difficult to find. If it saves at least some of the original from the dumpster it’s better than doing nothing. We wonder how long these upgrades will remain possible as even with Chinese plants making these boards and a handful of CRT TVs still appearing on AliBaba it’s clear that CRTs are at the very end of their life.

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Flux, From Scratch

January 29, 2024 by 53 Comments

Soldering flux is (or at least, should be) one of the ubiquitous features of any electronics bench. It serves the purpose of excluding oxygen from a solder joint as it solidifies, and in most cases its base is derived from pine rosin. Most of us just buy flux, but [pileofstuff] is having a go at making his own.

He starts with a block of rosin and a couple of different solvents. Isopropanol we’re happy with, but perhaps using methanol for something to be vaporized within breathing distance isn’t something we’d do. At about 25% rosin to solvent ratio the result is a yellow liquid flux, which he tests against some commercial fluxes. The result is a reasonable liquid flux, something which perhaps shouldn’t be too much of a surprise, and is a handy piece of information to store away should we ever be MacGuyver-like stuck in a pine forest with a need to save the day with electronics.

It would be interesting to try the same technique but with a solvent selected to soften the rosin for a paste flux, and perhaps any chemists among our readership could enlighten us about just what rosin is beside the heavy fractions left after extracting the volatiles from pine resin.

In the past we’ve taken a close look at how solder really works.

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Bringing An IBM Butterfly Laptop Back From The Dead

January 28, 2024 by 8 Comments

Among all the laptops produced over the last few decades, there is one which rises above the rest and which has retained an appeal long after its meager computing resources became obsolete. It’s the IBM 701c, the famous “Butterfly” laptop, whose fold-out keyboard still gives it star  quality, and [John Graham-Cumming] has documented the restoration of one from the tattered remains of two scrap examples.

The two laptops in question were someone else’s never-started project, and were in a sorry state. The flexible cables were in poor condition, and the 1990s Ni-MH batteries had leaked and damaged both circuits and case. We were unaware that NiMH leakage could damage plastic, but the parts of these machines were significantly damaged.

One had a working mainboard, the other a working modem card. One keyboard was in pretty bad shape, the other was complete. Of the pair there was a double super twisted nematic (DSTN) display and a more contemporary thin film transistor (TFT) panel. Be thankful if you have never had to use a DSTN laptop, as they were truly awful. From this pile of parts a working machine could be made, and with a new CMOS battery, that cable repair, and a repaint, he was ready. Or at least, as he says, ready for 1995.

This isn’t the first 701c restoration we’ve seen, and within reason, it’s even possible to give them a retro processor upgrade.

POTS At A Hacker Camp

January 25, 2024 by 1 Comment

For those of us off the Atlantic coast of Europe it’s a frigid winter as our isles are lashed by continuous storms. Summer seems a very long time ago, and the fun of the EMF 2022 hacker camp is an extremely distant memory. But the EMF team have been slowly releasing videos from the talks at that camp, the latest of which comes from [Matthew Harrold]. He was the force behind the public POTS phone network at the camp, providing anyone within range of one of his endpoints with the chance to have a wired phone line in their tent.

We’d love to imagine a mesh of overhead wires converging on a Strowger mechanical exchange somewhere on the field, but in a more practical move he used an array of redundant Cisco VOIP gear, and a multi-modem rack to provide dial-up services. Even then there were a few hurdles to overcome, but on the field it was definitely worth it as an array of unusual phone kit was brought along by the attendees. Our favourite is the Amstrad eMailer, an all-in-one phone and internet appliance from a couple of decades ago which perhaps due to its expensive pay as you go model, failed commercially. The video is below the break.

It’s a good time for this talk to come out, because it’s reminded us that the next EMF camp is on this summer. Time to dust off an old phone to bring along. Meanwhile, we’ve seen [Matthew] before, as he refurbished a sluggish dial mechanism.

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Another Chance To Revive Your Nabaztag

January 23, 2024 by 17 Comments

The early history of home internet appliances was replete with wonderful curios as a new industry sought to both find a function for itself and deliver something useful with whatever semiconductors were available nearly two decades ago. A favourite of ours is the Nabaztag, a French-designed information appliance in the form of a cute plastic rabbit whose ears would light up and move around as it delivered snippets of information.

The entity behind the Nabaztag folded and the servers went away years ago of course, but the original designer [Olivier Mével] never gave up on his creation. Back in 2019 he created an updated mainboard for the device packing a Raspberry Pi Zero W, which has been released in a series of crowdfunding campaigns. If you have a Nabaztag and haven’t yet upgraded, you can snag one now as the latest campaign has started.

We took a look at the Nabaztag back in 2020, at the time with out bricked original unit. Happily a year later we were able to snag one of the upgrades, so it’s now happily keeping us up to date with the time, weather, and other fun things. The upgrade motherboard is designed to slot into the same place as the original and mate with all its connectors, and even comes with that annoying triangle screwdriver. If you want to stand out against all the Alexa and Google Home owners, dig out your cute rabbit from the 2000s and give it this board!

640k Was Never Enough For Anyone: How DOS Broke Free

January 21, 2024 by 38 Comments

On modern desktop and laptop computers, there is rarely a need to think about memory. We all have many gigabytes of the stuff, and it’s just there. Our operating system does the heavy lifting of working out what goes where and what needs to be paged to disk, and we just get on with reading Hackaday, that noblest of computing pursuits. This was not always the case though, and for early PCs in particular the limitations of the 8086 processor gave the need for some significant gymnastics in search of an extra few kilobytes. [Julio Merion] has an interesting run-down of the DOS memory map, and how memory expansion happened on computers physically unable to see much of it.

The 8086 has a 20-bit address bus, giving it access to a maximum of 1 megabyte. When IBM made the PC they needed space for the BIOS, the display, and the various accessory ROMs intended to come with expansion cards. Thus they allocated a maximum 640k of the map for RAM, and many early machines shipped with much less than that. The quote from Bill Gates about 640k being enough for anyone is probably apocryphal, but it was pretty clear as the 1980s wore on that more would be needed. The post goes into how memory expansion worked, with a 64k page mapped to switchable RAM on a card, and touches on how DOS managed extended memory above 1 Mb on the later processors that supported it. We dimly remember there also being a device driver that would map the unused graphics memory as EMS when the graphics card was running in text mode, but such horrors are best left behind.

Of course, some of the tricks to boost RAM were nothing but snake oil.

8086 header: Thomas Nguyen, CC BY-SA 4.0