Decap ICs Without The Peril

May 19, 2019 by Jenny List 13 Comments

There can be few of us who haven’t gazed with fascination upon the work of IC decappers, whether they are showing us classic devices from the early years of mass semiconductor manufacture, or reverse-engineering the latest and greatest. But so often their work appears to require some hardcore scientific equipment or particularly dangerous chemicals. We’ve never thought we might be able to join the fun. [Generic Human] is out to change all that, by decapping chips using commonly available chemicals and easy to apply techniques. In particular, we discover through their work that rosin — the same rosin whose smell you will be familiar with from soldering flux — can be used to dissolve IC packaging.

Of course, ICs that dissolved easily in the face of soldering wouldn’t meet commercial success, so an experiment with flux meets little success. Pure rosin, however, appears to be an effective decapping agent. [Generic Human] shows us a motherboard voltage regulator boiled in the stuff. When the rosin is removed with acetone, there among the debris is the silicon die, reminding us just how tiny these things are. We’re sure you’ll all be anxious to try it for yourselves, now, so take a while to look at the video below showing their CCC Congress talk.

The master of chip decapping is of course [Ken Shirriff], whose work we’ve featured many times. Our editor [Mike Szczys] interviewed him last year, and it’s well worth a look.

Continue reading “Decap ICs Without The Peril” →

Fun With Negative Resistance II: Unobtanium Russian Tunnel Diodes

May 16, 2019 by Ted Yapo 24 Comments

In the first part of this series, we took a look at a “toy” negative-differential-resistance circuit made from two ordinary transistors. Although this circuit allows experimentation with negative-resistance devices without the need to source rare parts, its performance is severely limited. This is not the case for actual tunnel diodes, which exploit quantum tunneling effects to create a negative differential resistance characteristic. While these two-terminal devices once ruled the fastest electronic designs, their use has fallen off dramatically with the rise of other technologies. As a result, the average electronics hacker probably has never encountered one. That ends today.

Due to the efficiencies of the modern on-line marketplace, these rare beasts of the diode world are not completely unobtainable. Although new-production diodes are difficult for individuals to get their hands on, a wide range of surplus tunnel diodes can still be found on eBay for as little as $1 each in lots of ten. While you’d be better off with any number of modern technologies for new designs, exploring the properties of these odd devices can be an interesting learning experience.

For this installment, I dug deep into my collection of semiconductor exotica for some Russian 3И306M gallium arsenide tunnel diodes that I purchased a few years ago. Let’s have a look at what you can do with just a diode — if it’s the right kind, that is.

[Note: the images are all small in the article; click them to get a full-sized version]

Continue reading “Fun With Negative Resistance II: Unobtanium Russian Tunnel Diodes” →

A Datasheet Manifesto For The 21st Century

May 8, 2019 by Jenny List 25 Comments

Selecting electronic components can be a frustrating process, one of trawling through the websites of distributors such as DigiKey, Mouser, or RS, and then poring over manufacturer data sheets. These documents produced as detailed guides to the technical specifications of a device contain enough to give an engineer everything they need to incorporate it into their designs.

Unfortunately many datasheets fall short of the ideal, and have instead become marketing documents designed to “win the socket”. This is a problem that vexes Boldport’s [Saar Drimer], and he has written a personal manifesto outlining his vision to make the world of datasheets a better place.

It’s a common-sense designer’s wishlist, and it’s one we could completely get behind. Chief among his desires are web-readable datasheets as well as the ubiquitous PDFs, with full data in human and machine readable forms instead of tiny printed graphs and tables. He also makes a plea for better UX testing to combat the scourge of the inaccurate pad layout, to which we’d add providing footprints ready-made for all popular CAD packages. These and the rest of his manifesto would be a game-changer, and wouldn’t displace the existing paper or PDF sheet for those who still use them. Whether or not the manufacturers will take heed is anyone’s guess, but to have such an ideal laid out is a start.

If you’re not familiar with [Saar]’s work, you’re in for a treat. Boldport produce some of the most beautiful artistic PCBs, and we’ve featured them before more than once.

Thanks to our colleague [Ted Yapo] for the header image.

Component Shelf Life: How To Use All That Old Junk

April 23, 2019 by Ted Yapo 31 Comments

There are two types of Hackaday readers: those that have a huge stock of parts they’ve collected over the years (in other words, an enormous pile of junk) and those that will have one a couple of decades from now. It’s easy to end up with a lot of stuff, especially items that you’re likely to use in more than one design; the price breakpoints at quantities of 10 or 100 of something can be pretty tempting, and having a personal stock definitely speeds the hacking process now that local parts shops have gone the way of the dinosaur. This isn’t a perfect solution, though, because some components do have shelf-lives, and will degrade in some way or another over time.

If your stash includes older electronic components, you may find that they haven’t aged well, but sometimes this can be fixed. Let’s have a look at shelf life of common parts, how it can be extended, and what you can do if they need a bit of rejuvenation.

Continue reading “Component Shelf Life: How To Use All That Old Junk” →

Characterising A Potentiometer With A Stepper Motor

April 21, 2019 by Jenny List 16 Comments

Potentiometers, or variable resistors, are a standard component that we take for granted. If it says “10k log” on a volume pot, than we fit and forget. But if like [Ben Holmes] you are modelling electronic music circuitry, some greater knowledge is required. To that end he’s created a rig for characterising a potentiometer to produce a look-up table of its values.

It’s a simple enough set-up in which a voltage controlled current source feeds the pot while an Arduino with a motor controller turns it through a stepper motor, and takes a voltage reading from its wiper via an analogue pin. Probably most readers could assemble it in a fairly short time. Where it becomes interesting though is in what it reveals about potentiometer construction.

Audio potentiometers are usually logarithmic. Which is to say that the rate of change of resistance is logarithmic over the length of the track, in an effort to mimic the logarithmic volume response of the human ear in for example a volume control. If you are taught about logarithmic pots the chances are you’re shown a nice smooth logarithmic curve, but as he finds out in the video below that isn’t the case. Instead they appear as a set of linear sections that approximate to a logarithmic curve, something that is probably easier to manufacture. It’s certainly useful to know that for [Ben]’s simulation work, but for the rest of us it’s a fascinating insight into potentiometer manufacture, and shows that we should never quite take everything for granted.

Continue reading “Characterising A Potentiometer With A Stepper Motor” →

A Bolt-On I2C Navigation Key For Your Next Project

April 11, 2019 by Tom Nardi 10 Comments

We often talk about the advantages of modular hardware here at Hackaday; the ability to just order a few parts online, hook them up with some jumper wires, and move onto the software side of things is a monumental time saver when it comes to prototyping. So anytime we see a new module that’s going to save us time and aggravation down the road, we get a bit excited.

Today we present the very slick I2CNavKey developed by [Saimon], a turn-key interface solution for your builds that can’t quite get away with a couple toggle switches. It not only gives you a four-way directional pad with center button, but a rotary “wheel” like on the old iPods. All of which you can access easily and with a minimum of wiring thanks to the wonders of I2C.

But even that might be selling the module short. This isn’t just a couple of buttons on a breakout board, the I2CNavKey is powered by its own PIC16F18345 microcontroller and features three configurable GPIOs with PWM support (perfect for an RGB LED) plus 256 bytes of onboard EEPROM storage.

[Saimon] has released the entire project as open source hardware for your hacking pleasure, but you can also get them as ready-to-use modules on Tindie for $18 USD [Editor’s Note: Because of a typo we originally we left the 1 out of the price]. Whether you’re a paying customer or not, you get access to the project’s absolutely phenomenal documentation, including a nearly 30 page manual that contains everything you’d ever want to know about the I2CNavKey and how to integrate it into your project. If all hardware was documented with this level of dedication, the world would be a much nicer place for folks like us.

If you recognize the name, or perhaps the affinity for neat I2C-connected input devices, it’s probably because you’ve seen his very similar I2C rotary encoder on these pages previously, which was a finalist in our Open Hardware Design Challenge during the 2018 Hackaday Prize.

See What’s Inside Night Vision, And How To Build Your Own

April 10, 2019 by Donald Papp 26 Comments

[Nick Chen] shared some fascinating and useful details about building a AN/PVS-14 monocular night vision device from parts. It’s not cheap, but the build would be a simple one for most Hackaday readers, at least the ones who are residents of the USA. Since the PVS-14 is export controlled under the International Traffic in Arms Regulations (ITAR), parts are not sold outside of the US. Still, [Nick]’s illustrated build instructions provide a good look at what’s inside these rugged devices.

The build consists of purchasing a PVS-14 parts kit (or “housing kit”) which includes nearly everything except the image intensifier module, which must be purchased separately. Once all the parts are in hand, [Nick] explains how to assemble the pieces into a working unit.

The view through a blemished (or “blem”) image intensifier. Cheaper, and perfectly serviceable as long as the center is clear.

Since the image intensifier is by far the most expensive component, there is an opportunity to save money by shopping for what [Nick] calls “blem” units. These units are functional, but have blemishes or dead spots within the field of view. The good news it that this makes them cheaper, and [Nick] points out that as long as the center region of the tube is clear, they are perfectly serviceable.

How much can one save by building from parts? [Nick] says buying a complete PVS-14 with a Gen 3 tube (sensitive to 450-950 nm) can cost between $2500 to $4000. It’s expensive equipment, no doubt, but deals can be found on the parts. Housing kits can be had for well under $1000, and [Nick] has purchased serviceable image intensifiers for between $500 and $1000. He says searching for “blem tubes” can help zero in on deals.

Knowing the right terms for searching is half the battle, and along with his build instructions (and a chunk of cash) a curious hacker would have all they need to make their own. Heck, build two because the PVS-14 is designed such that two units can be combined to make a binocular unit! Not ready to drop that kind of cash? Check out OpenScope, the open source digital night vision tool.