Author: Jenny List

3312 Articles

Images As Excel FIles Are Gloriously Nasty

March 1, 2018 by 58 Comments

Almost every person of a technical persuasion who has worked in an office will have some tale of wildly inappropriate use of office technology for a task that could have been accomplished far more simply with an appropriate tool. There are jokes about people photocopying a blank sheet of paper when they need a few sheets themselves, but some of the real stories are very bit as surreal.

[Bjonnh]’s patience for such things was exceeded when he received a screenshot embedded in a Microsoft Word file. His response is both pointless and elegant, a Python script that takes a JPEG image and encodes it into an Excel file. It’s simply an array of cells whose background colours represent the pixels, and he warns us that the output files may take a while to load. We just had to subject it to a test, but are sorry to report that LibreOffice doesn’t seem to want to play ball.

So yes, this is a small departure from our usual fare of hardware, and it serves no use other than to be a fantastically awful misuse of office technology. If you’ve ever been emailed a PowerPoint invitation to the office party though, then maybe you’ll have cracked a smile.

If pushing your corporate spreadsheet to the limit is your thing, perhaps you’d also like to see it running a 3D engine.

Bye Bye, Maplin

March 1, 2018 by 97 Comments

Well, that was quick. Four days ago we mentioned that the British electronics retail chain Maplin was being offered for sale, and today it has been announced that no buyer has been found and the company is going into administration.

We dealt with all the nostalgia for what was roughly a British equivalent to Radio Shack in our previous post. Perhaps now it’s time to look beyond the jumpers-for-goalposts reminiscences about spaceships on the catalogues for a moment, and consider what this means for us in 2018.

It’s fairly obvious that a retail model for selling either electronic tat or components is no longer viable in an age of online ordering and availability of almost anything at knock-down prices for anyone prepared to wait for a packet from China. This applies on both sides of the Atlantic, but for British retailers, the killer combination of very high rents and local business taxes makes it particularly difficult. Maplin were extremely convenient when you needed a part immediately, but the universal reaction from Hackaday readers was that they were overpriced. It’s the same story that has cleared away numerous chains in other sectors, and the toxic view that retail property is still the goldmine it might have been in decades past is largely responsible.

Despite all that, there must still be some demand for electronic components at a retail level even if the economics no longer support a showroom model. Perhaps a trade counter operation might have better luck, it will be interesting to see whether suppliers such as RS Components or CPC expand their networks to try to capture that business. Whatever happens, we’ll keep you posted.

Microgamer Is A Micro:Bit Handheld Console

February 27, 2018 by 25 Comments

The BBC micro:bit single board ARM computer aimed at education does not feature as often as many of its competitors  in these pages. It’s not the cheapest of boards, and interfacing to it in all but the most basic of ways calls for a slightly esoteric edge connector. We’re then very pleased to see that edge connector turned from a liability into a feature by [Fabien Chouteau] with his handheld console, he uses micro:bits preprogrammed with different games in the manner of game cartridges in commercial consoles.

The micro:bit sits in its edge connector on the underside of a handheld PCB above a pair of AAA batteries, while on the other side are an OLED display and the usual set of pushbuttons. It’s a particularly simple board as the micro:bit contains all the circuitry required to support its peripherals.

He’s coded the games using the Arduino IDE with a modified version of the Arduboy2 library that allows him to easily port Arduboy games written for Arduino hardware. It’s a work in progress as there are a few more features to incorporate, but the idea of using micro:bits as cartridges is rather special. There is a video of the console in action, which we’ve placed below the break.

Continue reading “Microgamer Is A Micro:Bit Handheld Console” →

Chopper And Chopper-Stabilised Amplifiers, What Are They All About Then?

February 27, 2018 by 21 Comments

One of my first jobs as a freshly minted graduate engineer involved the maintenance of a set of analogue chart recorders. They were museum pieces by the early 1990s: a motorized roll of graph paper across which a pen would traverse in proportion to the voltage on the input terminals. Inside was a simple servo, with a differential amplifier comparing the feedback via a potentiometer from the mechanism with the amplified input.

The recorders dated from the early 1960s, and internally their electronics were from the germanium transistor era: many Mullard OC-series devices, black-painted glass tubes with a red dot, and, unexpectedly, a large electromagnet connected to the 50 Hz AC supply with a reed switch through its middle, something completely new to an overconfident youngster who thought she knew everything.

What I’d stumbled upon was a chopper amplifier, a slightly ungainly and long superseded solution to the problem of DC amplification from the days before ubiquitous integrated circuit op-amps. We have become so used to DC amplifiers that just work, that we have forgotten that there was a time when such devices were an impossibility. The close matching of properties between devices on the same wafer allowed integrated circuit op-amps to achieve stable DC amplification in a way that the best attempts at the same circuits with discrete transistors had failed, but before they happened some desperate measures were called for. Continue reading “Chopper And Chopper-Stabilised Amplifiers, What Are They All About Then?” →

Maplin For Sale

February 24, 2018 by 78 Comments

If you are an American Electronics Enthusiast of a Certain Age, you will have misty-eyed reminiscences of the days when every shopping mall had a Radio Shack store. If you are a Brit, the name that will bring similar reminiscences to those Radio Shack ones from your American friends is Maplin. They may be less important to our community than they once would have been so this is a story from the financial pages; it has been announced that the Maplin chain is for sale.

Maplin started life as a small mail-order company supplying electronic parts, grew to become a large mail order company selling electronic parts, and them proceeded to a nationwide chain of stores occupying a similar niche to the one Radio Shack fitted into prior to their demise. They still sell electronic components, multimeters, and tools, but the bulk of their floor space is devoted to the more techy and hobbyist end of mass-market consumer electronics. As the competition from online retailers has intensified  it is reported that the sale may be an attempt to avoid the company going into administration.

It’s fair to say that in our community they have something of a reputation of late for being not the cheapest source of parts, somewhere you go because you need something in a hurry rather than for a bargain. A friend of Hackaday remarked flippantly that the asking price for the company would be eleventy zillion pounds, which may provide some clues as to why custom hasn’t been so brisk. But for a period in the late 1970s through to the 1980s they were the only place for many of us to find  parts, and their iconic catalogues with spaceships on their covers could be bought from the nationwide WH Smith newsagent chain alongside home computers such as the ZX Spectrum. It’s sad to say this, but if they did find themselves on the rocks we’d be sorry to see the name disappear, but we probably wouldn’t miss them in 2018.

One of the things Maplin were known for back in the day were their range of kits. We’ve shown you at least one in the past, this I/O port for a Sinclair ZX81.

Footnote: Does anyone still have any of the early Maplin catalogues with the spaceships on the cover? Ours perished decades ago, but we’d love to borrow one for a Retrotechtacular piece.

Maplin store images: Betty Longbottom [CC BY-SA 2.0], and Futurilla [CC BY-SA 2.0].

You’ve Never Seen A Flipping Eyeball Like This One!

February 24, 2018 by 20 Comments

Inspired by some impressive work on textile flip-bit displays, and with creative steampunk outfits to create for Christmas, [Richard Sewell] had the idea for a flippable magnetic eye in the manner of a flip-dot display. These devices are bistable mechanical displays in which a magnet is suspended above a coil of wire, and “flipped” in orientation under the influence of a magnetic field from the coil.

In [Richard]’s case the eyeball was provided by a magnetic bead with a suitable paint job, and the coil was a hand-wound affair with some extremely neat lacing to keep it all in place. The coil requires about 200 mA to ensure the eye flips, and the job of driving it is performed by a Digispark ATTiny85 board with an LM293 dual H-bridge driver upon which the two bridges are wired in parallel. The whole is mounted in the centre of a charity shop brooch that has been heat-treated to give a suitable aesthetic.

You can see the eyeball in all its glory in the two videos below the break, and should you be curious you can also read our write-up of the original pieces from [Irene Posch] that inspired it.

Continue reading “You’ve Never Seen A Flipping Eyeball Like This One!” →

A Robot For Everything: Now Even Zippers

February 23, 2018 by 30 Comments

Sometimes we see projects that are so clever while being remarkably simple, that we can’t help thinking: Why didn’t I think of that! Take [Haresh Karnan]’s zipper robot, for example. It’s a well-designed 3D-printed shell with two geared motors for traction, that can both undo and do up zippers. Behind that seemingly simple design probably lies a huge iterative design process to arrive at a shape perfect for the job, but the end result is so elegant that even [Haresh]’s write-up and Hackaday.io page for the project are short and to the point. Download the STL file, snap in the motors, apply to a zipper, and away you go. He suggests rubber bands as a traction aid, but that’s pretty much it.

The results can be seen in the video below the break. While we might be tempted to make jokes about the terminally lazy using this device to save unnecessary labour after a toilet break, we can see that it might have a real application. If you have any friends with restricted dexterity you will understand how having an automated helper with such a fiddly task as a zipper could be an extremely useful accessibility aid.

While we’re on the subject of zippers, if you missed it a few weeks ago here’s our in-depth look at their story.

Continue reading “A Robot For Everything: Now Even Zippers” →