Author: Jenny List

3308 Articles

This Vintage Op-Amp Opens A Fascinating Window Into Semiconductor History

March 2, 2019 by 6 Comments

We have covered enough of the work of [Ken Shirriff] on these pages to know that when he publishes something, it will be a fascinating read and work of the highest quality. And so it is with his latest, a very unusual op-amp on which he performs his usual reverse engineering. Not only does it lead us directly to some of the seminal figures in the early years of the semiconductor industry, it turns out to have been a component manufactured to a NASA specification and of which there is an example on the Moon.

The metal can revealed a hybrid circuit when the lid was removed, one in which individual transistors were wired together with a single block containing a group of thin-film resistors. At the start of the 1960s the height of consumer electronics would have been your domestic TV which would have been an all-tube affair, so while it sounds archaic this would truly have been a space-age piece of technology. The designer is revealed as the legendary [Bob Pease], and the transistors take us back to the semiconductor physicist [Jean Hoerni], inventor of the planar transistor and one of the famous eight defectors from Shockley Semiconductor in the 1950s who kick-started the semiconductor boom.

The op-amp itself is a relatively simple design without the compensation capacitor you might expect in a modern device, but what makes it unusual for its time is the use of [Hoerni]’s planar JFETs at its input. [Ken]’s analysis is as usual extremely thorough, and the bit of Silicon Valley history it gives us is the icing on the cake.

If you have a thirst for ancient op-amps, you might like our look at the first commercially available fully-integrated design, the Fairchild μA702.

The FAA Mandates External Registration Markings For Drones

February 26, 2019 by 68 Comments

Drone fliers in the USA must soon display their registration markings on the exterior of their craft, rather than as was previously acceptable, in accessible interior compartments. This important but relatively minor regulation change has been announced by the FAA in response to concerns that malicious operators could booby-trap a craft to catch investigators as they opened it in search of a registration. The new ruling is effective from February 25th, though they are inviting public comment on it.

As airspace regulators and fliers across the world traverse the tricky process of establishing a safe and effective framework for multirotors and similar craft we’ve seen a variety of approaches to their regulation, and while sometimes they haven’t made complete sense and have even been struck down in the courts, the FAA’s reaction has been more carefully considered than that in some other jurisdictions. Rule changes such as this one will always have their detractors, but as an extension of a pre-existing set of regulations it is not an unreasonable one.

It seems inevitable that regulation of multirotor flight will be a continuing process, but solace can be taken at the lower end of the range. A common theme across the world seems to be a weight limit of 250 g for otherwise unrestricted and unregistered craft, and the prospects for development in this weight category in response to regulation are exciting. If a smaller craft can do everything our 2 kg machines used to do but without the burden of regulation, we’ll take that.

An ATtiny Metal Detector

February 26, 2019 by 18 Comments

A metal detector used to be an entirely analogue instrument, an oscillator whose frequency changed with the inductance of its sense coil when a piece of metal approached. [Łukasz Podkalicki] shows us a more sophisticated machine, but with judicious use of an ATtiny 13 it is not a complex one.

A pulsed induction metal detector induces a current spike in its search coil, and times the decay of the resulting oscillation. The coil is part of a resonant circuit with a capacitor, and any metal in its field will change its resonant frequency. In [Łukasz]’s design the ATtiny13 fires a pulse at his coil using a MOSFET, and the voltages at the coil are sensed by an analogue pin through an appropriate clamp circuit. His software does the timing, and sounds a buzzer upon metal detection. It’s a deliciously simple implementation, and while as he shows us in the video below the break its relatively small coil is more suited to detecting coins or wires behind the drywall than locating lost hoards, there is probably ample scope for further experimentation.

This isn’t the first project from [Łukasz] that has found its way into these pages, his history with the ATtiny13 goes back a few years.

Continue reading “An ATtiny Metal Detector” →

Hands-on: Hacker Hotel 2019 Badge Packs ESP32, E-Ink, And A Shared Heritage

February 26, 2019 by 6 Comments

When you go to a hacker conference, you always hope there’s going to be a hardware badge. This is an interactive piece of custom electronics that gets you in the door while also delighting and entertaining during the con (and hopefully far beyond it).

Hot off the presses then is the Hacker Hotel badge, from the comfortable weekend hacker camp of that name in a Netherlands hotel. As we have already noted, this badge comes from the same team that created the SHA2017 hacker camp’s offering, and shares that badge’s display, ESP32 processor, battery, and firmware. The evolution of that firmware into the badge.team platform is an exciting development in its own right, but in the context of this badge it lends a very familiar feel to the interface for those attendees who were also at the 2017 event.

Continue reading “Hands-on: Hacker Hotel 2019 Badge Packs ESP32, E-Ink, And A Shared Heritage” →

E-Ink Price Tags Fall Off Store Shelves Onto Your Workbench

February 25, 2019 by 38 Comments

There’s always a magic moment for our community in the lifecycle of any piece of technology: the point at which it first becomes available for pennies on the surplus market. Something which could previously be had only at a price is rendered down to mere pennies, and we are free to hack to our heart’s content.

Such a moment came for [Aaron Christophel] when he bought a quantity of used e-ink price tags (German, Google Translate link) that had formerly graced the shelves of a supermarket. A pile of readily hackable e-ink displays lay before him, so he set to work.

Cracking them open he found the display itself as well as a PCB with its own microcontroller, but he soon identified it as compatible with a WaveShare module for which he had data. Since its interface was thus identified as SPI he could desolder the unknown CPU and break out the pins for an Arduino or other board. The display itself turned out to be a custom model with a few quirks for price tags, it had a black border that could be enabled, and for some reason it appeared as a two-colour red-and-black model in which its black pixels responded as though they were the red channel. He has a quick overview video that we’ve placed below the break.

These displays have started appearing in our community, not least in electronic conference badges. This source of cheap components from the surplus market makes them ever more accessible, and we look forward to the projects that will come from them.

Continue reading “E-Ink Price Tags Fall Off Store Shelves Onto Your Workbench” →

Teach Computing The Old-School Way With A Digi-Comp II

February 25, 2019 by 8 Comments

Ubiquitous computing has delivered a world in which there seem to be few devices left that no longer contain a microprocessor of some sort. Thus should a student wish to learn about the inner workings of a computer they can easily do so from a multitude of devices. For an earlier generation though this was not such a straightforward process, in the 1950s or 1960s you could not simply buy a microcomputer and set to work. Instead a range of ingenious teaching aids providing the essentials of computing without a computer were created, and those students saw their first computational logic through the medium of paper, ball bearings, or flashlight bulbs.

The DigiComp II was just such a device, performing logic tasks through ball bearings rolling down trackways. Genuine machines are now particularly rare, so [Mike Gardi] created a modern 3D printed replica that delivers all the fun without the cost. It’s a complicated build with a multitude of parts and wire linkages, and there is an element of fine tuning of its springs required to achieve reliable operation. You’ll neither run a Beowulf cluster of DigiComp IIs nor will you mine any Bitcoin with one, but it’s definitely one of the more unusual computing devices you could have in your collection.

Of course, should you need a truly authentic period computing device, there is always the slide rule.

Via Hacker News.

DAT, The HD Video Tape Format We Never Knew We Had

February 24, 2019 by 48 Comments

When we consume our music online via streaming services it is easy to forget the days of recordings being contained on physical media, and to overlook the plethora of competing formats that vied for space in our hi-fi systems to play them. [Andrew Rossignol] has an eye for dated recording media formats as a chiptune enthusiast though, because not only has he found a DAT machine from the 1990s, he’s hacked it to record HD video rather than hi-fi audio.

If you’ve not encountered DAT before, it’s best to consider the format as the equivalent of a CD player but on a tape cassette. It had its roots in the 1980s, and stored an uncompressed 16-bit CD-quality stereo audio data stream on the tape using a helical-scan mechanism similar to that found in a video cassette recorder. It was extremely expensive due to the complexity of the equipment, the music industry hated it because they thought it would be used to make pirate copies of CDs. But despite those hurdles it established a niche for itself among well-heeled musicians and audiophiles. If any Hackaday readers have encountered a DAT cassette it is most likely to have not contained audio at all but computer data, it was common in the 1990s for servers to use DAT tapes for backup purposes.

[Andrew]’s hack involves using the SPDIF digital interface on his Sony DAT player to carry compressed video data. SPDIF is a mature and well-understood standard that he calculated has a bandwidth of 187.5 kB/s, plenty to carry HD video using the H.265 compression scheme. The SPDIF data is brought into the computer via a USB sound card, and from there his software could either stream or retrieve the video. The stream is encoded into frames following the RFC1662 format to ensure synchronization, and he demonstrates it in the video below with a full explanation.

Continue reading “DAT, The HD Video Tape Format We Never Knew We Had” →