Accurate Dispensing Of Toilet Paper Will Get Us Through The Crisis

As we enter our second week of official COVID-19-related lockdown where this is being written, it’s evident that there are some resources we will have to conserve to help get us through all this. Instead of just using all of something because we can nip out to the store and buy more, we have to look at what we’ve got and treat it as though it will have to get us through the next three months. It’s not always certain that on our infrequent trips to the supermarket they’ll have stocks of what we want.

This is the very last of the toilet paper in my local supermarket, on the 8th of March.
This is the very last of the toilet paper in my local supermarket, on the 8th of March.

A particular shortage has been of toilet paper. The news was full of footage showing people fighting for the last twelve-pack, and since early last month there has been none to be had for love nor money. To conserve stocks and save us from the desperate measures of having to cut the Daily Mail into squares and hang them on the wall, a technical solution is required. To this end I’ve created a computerised toilet roll dispenser which carefully controls the quantity of the precious sanitary product, in the hope of curbing its consumption to see us through the crisis.

In the midst of a full lockdown it’s difficult to secure immediate delivery of our usual maker essentials, so rather than send off for the controller boards I might have liked it has been necessary to make do with what I had. In the end I selected an older single board computer I had in a box under my bench. The Sinclair ZX81 has a single-core Z80 processor running at 3.25 MHz, dual-channel memory, a Ferranti GPU, and plenty of expansion possibilities from its black plastic case. I chose it because I could repurpose its thermal printer peripheral as a toilet paper printer, and because it has an easily wiped and hygienic membrane keyboard rather than a conventional one that could harbour germs.

Hardware wise I found I was fairly easily able to adapt a standard roll of Cushelle to the ZX printer, and was soon dispensing sheets with the following BASIC code.

10 REM TOILET PAPER PRINTER
20 FOR T=0 TO 44
30 LPRINT ""
40 NEXT T
50 LPRINT "---------- TEAR HERE -----------"

For now it’s working on the bench, but it will soon be mounted with a small portable TV as a monitor on the wall next to the toilet. Dispensing toilet paper will be as simple as typing RUN and hitting the ZX’s NEW LINE key, before watching as a sheet of toilet paper emerges magically from the printer. It’s the little hacks like this one that will be so useful in getting us through the crisis. After all, this Sinclair always has a square to spare.

Gold Cables Really Do Work The Best

As a writer, I have long harboured a dream that one day an editor will buy me a top-of-the-range audio analyser, and I can set up an audio test lab and write pieces debunking the spurious claims made by audiophiles, HiFi journalists, and the high-end audio industry about the quality of their products. Does that amp really lend an incisive sibilance to the broader soundstage, and can we back that up with some measurable figures rather than purple prose?

An Audio Playground You Didn’t Know You Had

An Audio Precision APx525 audio analyser.
An Audio Precision APx525 audio analyser. Bradp723 (CC-BY-SA 3.0)

Sadly Hackaday is not an audio magazine, and if Mike bought me an Audio Precision he’d have to satisfy all the other writers’ test equipment desires too, and who knows where that would end! So there will be no Hackaday audio lab — for now. But that doesn’t mean I can’t play around with audio analysis.

Last month we carried a write-up of a Supercon talk from Kate Temkin and Michael Ossmann, in which they reminded us that we have a cracking general purpose DSP playground right under our noses; GNU Radio isn’t just for radio. Once I’d seen the talk my audio analysis horizons were opened up considerably. Maybe that audio analyser wouldn’t be mine, but I could do some of the same job with GNU Radio.

It’s important to stress at this point that anything I can do on my bench will not remotely approach the quality of a professional audio analyser. But even if I can’t measure infinitesimal differences between very high-end audio circuitry, I can still measure enough to tell a good audio product from a bad one.

Continue reading “Gold Cables Really Do Work The Best”

Hackaday Podcast Ep13: Naked Components, Shocking Power Supplies, Eye-Popping Clock, And Hackaday Prize

Editors Mike Szczys and Elliot Williams geek out about all things hackerdom. Did you catch all of our April Fools nods this week? Get the inside scoop on those, and also the inside scoop on parts that have been cut in half for our viewing pleasure. And don’t miss Mike’s interview with a chip broker in the Shenzhen Electronics markets.

We rap about the newly announced Hackaday Prize, a word clock to end all other word clocks, the delights of transformerless power supplies, and tricks of non-contact voltage testers. You’ll even find an ode to the App Note, as well as a time when electronics came in wooden cases. And who doesn’t love a Raspberry Pi that grinds for you on Nintendo Switch games?

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (60.1 MB)

Places to follow Hackaday podcasts:

Continue reading “Hackaday Podcast Ep13: Naked Components, Shocking Power Supplies, Eye-Popping Clock, And Hackaday Prize”

Now Toto’s Africa Is Stuck In Our Heads

April Fool’s Day is bad. April Fool’s Day is a terrible, horrible, no good, very bad day. For one day a year, we’re inundated with pieces that can, accurately and without any sense of irony, be called fake news. YouTube is worse. But you know what’s worse than April Fool’s Day? A hundred children playing plastic recorders. But it’s April Fool’s Day, and things must get worse. Here’s a vacuum cleaner playing Africa by Toto.

This is the latest build from [James Bruton] or [Ecks Robots Dot Co Dot UK], who is the king of building just about anything with 3D printers. He’s got a BB8 and some of the cooler Star Wars droids, a Hulkbuster, and openDog. When it comes to confabulating robotics and 3D printers, [James] is the king. But this is April Fool’s Day, and if you’re a big YouTuber, you need to do something annoying. [James] is the king.

This build uses a Henry vacuum cleaner, a canister vacuum with a silk screened face, because why not, and you’re not truly living until you put googly eyes on your Roomba. Also, all vacuums in England are Hoovers, because reasons. In collaboration with [Mothcub], [James] adapted cheap children’s plastic recorders to a Henry vacuum cleaner with a few 3D printed parts, some servo-controlled valves, and a bit of plastic tubing. While using cheap kid’s recorders as the tone generator in what is effectively a pipe organ is interesting (the stickers over the holes are a great idea), this is something that should not be done ever. This idea should not be replicated. These recorders are not in tune and I don’t know how because they’re just one piece of plastic that came out of the same mold.

The servos, and therefore the entire pipe organ, are controlled via MIDI, which makes this the first DIY MIDI pipe organ we’ve seen. It’s a proof of concept, and a pretty good one. It also sounds terrible. This is proof that cheap plastic recorders don’t sound good. The video is below, and I highly suggest skipping the second half.

Continue reading “Now Toto’s Africa Is Stuck In Our Heads”

Bye Bye Vi: GNU/Linux Distros Drop Support

If you grew up with Unix systems like we did, you’ll be sorry to hear the news: vi, the noble text editor that has served us so well these 40 years, is going away — from many GNU/Linux systems, anyway. As of this writing, GNU/Linux Mint, Debian, Ubuntu, and OpenSUSE — four of the five most popular GNU/Linux distributions — have all announced that they will no longer ship the ‘vi’ editor as part of their base installs. For those of us who got our start in the punched-card era and still think of files as a collection of lines instead of a stream of bytes, this is a major blow. But, we can all take some comfort in the fact that, at least for now, the stripped-down version of vim synonymous with vi on these systems will continue to be available from package repositories.

The reasons for the move aren’t entirely clear to us, but from what we can see on the GNU/Linux mailing lists, the confusing modal interface and the fact that novice (and many seasoned) users can’t figure out how to save a file and exit the program seem to have influenced the decision. Also cited were support changes expected as GNU/Linux gains in popularity. As the user base expands to include less technically-savvy individuals, fewer people will be able to fix their constant boot issues, which is the primary use-case for vi. Replacing the self-help model will be a support infrastructure where users can take their machines to “GNU/Linux Geniuses” who will solve the problems for them.

Continue reading “Bye Bye Vi: GNU/Linux Distros Drop Support”

Regular Computer Reviews: The Commodore 64C

Fresh into the tip line is an amazing video showcasing the history of the Commodore 64. Unlike many historical retellings of the history of the Commodore 64, the history doesn’t start with the VIC-20, but instead the first Commodore machine to feature the VIC-II and SID chip, the Commodore Max.

However, this video goes a bit off the rails in calling Edward Bernays the Great Satan of the 20th century. Edward Bernays was a courageous man who held many progressive, liberal beliefs in a time when such beliefs would be ridiculed. Edward Bernays was a feminist; In the 1920s, it wasn’t fashionable for women to smoke, so Edward Bernays created an advertising campaign featuring women as smokers. Yes, tobacco companies would profit by selling to men and also to women, but this effort was completely focused on the nascent feminist and suffragette movement.

Additionally, Edward Bernays supported democracy. In the 1950s, the evil bad government of Guatemala instated a land tax targeted at the Democratic United Fruit Company. Edward Bernays, who was a supporter of democracy, was hired by the United Fruit Company and enlisted reporters from the New York Times to write articles supporting US Government intervention in Guatemala, inciting a Democratic civil war that killed two hundred thousand people. Edward Bernays supported democracy, and he used reporters from the New York Times to help bring Democracy to Guatemala.

Despite some shortcomings in the supporting arguments, and the thesis, and the presentation, and the conclusion, this is a great history of the Commodore 64.

One Pin To Rule Them All

When Maxim acquired Dallas Semiconductor, they took over the popular 1-Wire product line. These are sensors that get power and bidirectional data over the same pin. However, we never liked the name 1-Wire as you really need two wires: one for the power and data and, of course, a ground wire. A new startup company, Cyclopia, has announced their latest line of truly one pin CPUs, and we’re impressed. The low power system on chip devices multiplex data, power, clock, and ground on one wire.

A company spokesperson, [Star Lipfir], noted, “Our patent-pending technology uses two well-known effects. First, a FET gate doesn’t actually draw current but works on an electric charge. Second, capacitors store charge.”

Continue reading “One Pin To Rule Them All”