Author: Jenny List

3292 Articles

Fail Of The Week: Never Assume All Crystals Are Born Equal

May 5, 2018 by 23 Comments

You should be used to our posting the hacks that didn’t quite go according to plan under our Fail Of The Week heading, things that should have worked, but due to unexpected factors, didn’t. They are the fault, if that’s not too strong a term, of the person making whatever the project is, and we feature them not in a spirit of mockery but one of commiseration and enlightenment.

This FOTW is a little different, because it reveals itself to have nothing to do with its originator. [Grogster] was using the widely-available HC-12 serial wireless modules, or clones or even possibly fakes thereof, and found that the modules would not talk to each other. Closer inspection found that the modules with the lack of intercommunication came from different batches, and possibly different manufacturers. Their circuits and components appeared identical, so what could possibly be up?

The problem was traced to the two batches of modules having different frequencies, one being 37 kHz ahead of the other. This was in turn traced to the crystal on board the off-frequency module, the 30 MHz component providing the frequency reference for the Si4463 radio chip was significantly out of spec. The manufacturer had used a cheap source of the component, resulting in modules which would talk to each other but not to the rest of the world’s HC-12s.

If there is a lesson to be extracted from this, it is to be reminded that even when cheap components or modules look as they should, and indeed even when they appear to work as they should, there can still be unexpected ways in which they can let you down. It has given us an interesting opportunity to learn about the HC-12, with its onboard STM8 CPU and one of the always-fascinating Silicon Labs radio chips. If you want to know more about the HC-12 module, we linked to a more in-depth look at it a couple of years ago.

Thanks [Manuka] for the tip.

Biasing That Transistor: The Common Emitter Amplifier

May 4, 2018 by 84 Comments

If you open up the perennial favourite electronics textbook The Art Of Electronics and turn to the section on transistors, you will see a little cartoon. A transistor is shown as a room in which “transistor man” stands watching a dial showing the base current, while adjusting a potentiometer that limits the collector current. If you apply a little more base current, he pushes up the collector a bit. If you wind back the base current, he drops it back. It’s a simple but effective way of explaining the basic operation of a transistor, but it stops short of some of the nuances of how a transistor works.

Of course the base-emitter junction is a diode and it is not a simple potentiometer that sits between collector and emitter. The “better” description of these aspects of the device fills the heads of first-year electronic engineering students until they never want to hear about an h-paramater or the Ebers-Moll model of transistor function again in their entire lives. Fortunately it is possible to work with transistors without such an in-depth understanding of their operation, but before selecting the components surrounding a device it is still necessary to go a little way beyond transistor man.

Continue reading “Biasing That Transistor: The Common Emitter Amplifier” →

More Details On That First Home-Made Lithographically Produced IC

May 3, 2018 by 19 Comments

A few days ago we brought you news of [Sam Zeloof]’s amazing achievement, of creating the first home-made lithographically produced integrated circuit. It was a modest enough design in a simple pair of differential amplifiers and all we had to go on was a Twitter announcement, but it promised a more complete write-up to follow. We’re pleased to note that the write-up has arrived, and we can have a look at some of the details of just how he managed to produce an IC in his garage. He’s even given it a part number, the Zeloof Z1.

For ease of manufacture he’s opted for a PMOS process, and he is using four masks which he lists as the active/doped area, gate oxide, contact window, and top metal. He takes us through 66 different processes that he performs over the twelve hours of a full production run, with comprehensive descriptions that make for a fascinating run-down of semiconductor manufacture for those of us who will never build a chip of our own but are still interested to learn how it is done. The chip’s oblong dimensions are dictated by the constraints of an off-the-shelf Kyocera ceramic chip carrier, though without a wire bonding machine he’s unable to do any more than test it with probes.

You can read our reporting of his first announcement, but don’t go away thinking that will be all. We’re certain [Sam] will be back with more devices, and can’t wait to see the Z2.

Auction Finds Combined For A Unique Desoldering Station

April 29, 2018 by No comments

If you are in the market for a high-quality soldering iron, a rewarding pursuit can be attending dispersal auctions. It is not unusual to see boxes of irons, as anything remotely iron-like is bundled up together by the auctioneer into a lot with little consideration for what combination has been gathered. [Stynus] found himself in this position, the proud owner of a Weller DSX80 desoldering iron from an auction, but without its accompanying solder station required for it to work. Fortunately, he had another Weller solder station, not suitable for the DSX80 as it stood, but which provided a perfect platform for a home-made Weller DSX set-up.

The old station had a side-mounted valve and a 24V input, so he had to install a toroidal mains transformer and move the valve frontwards. Fortunately, this style of Weller station case was frequently available with just such a transformer installed, so there was plenty of space in the enclosure. A custom board was then created for a temperature controller centered upon a PIC microcontroller, and a new front panel was crafted to accommodate a Nokia 5110-style LCD display.

The resulting unit with its upper half repainted, is a pleasing and professional-looking project. Heated desoldering irons are an extremely useful tool that anyone should consider for their arsenal, but not all of them are as good as this Weller-based one. We recently reviewed a much cheaper example, with comedic results.

The Interesting Fate Of Kenya’s First Computers

April 28, 2018 by 20 Comments

If you are an enthusiast for 1950s computer hardware, you are probably out of luck when it comes to owning a machine of your own. Your best chance will be to join the staff of one of the various museums that preserve and operate these machines, at which you can indulge your passion to your heart’s content. But what if we told you that there is a 1950s computer available for pick-up at any time, to whoever is prepared to go and get it and has suitable transport? You’d be making plans straight away, wouldn’t you? The computer in question is real, but there’s a snag. It’s at the bottom of the Indian Ocean, just at the start of international waters off the coast of Kenya. The story of Kenya’s early computing and how the machine met its fate is the subject of a fascinating article from a year or two ago on owaahh.com that had us riveted from start to finish.

Like large state-owned enterprises worldwide, the Kenyan railway and power monopolies were among the first commercial customers for computing. In the final years of the British Empire, those were ordered from a company in London, International Computers & Tabulators, and it was their ICT1202 that served the railway company. The article goes into detail about the history of the company’s East African operation, the problems of running a tube-based computer in an African climate without air-conditioners, and the 1202’s demise and replacement. We’ll not spill the beans here on how the computer ended up on the seabed and how its replacement ended up being spirited away to China, for that you’ll have to read it all. It’s worth saying, the author also has a personal website in which he goes into much more detail about his experience with computers in the 1950s and ’60s.

Not had enough ancient computer tech? A couple of years ago we toured the primordial electronic computer, Colossus, and also took a look at the National Museum Of Computing that houses it.

An Open-Source Turbomolecular Pump Controller

April 28, 2018 by 18 Comments

It’s not every project write-up that opens with a sentence like “I had this TURBOVAC 50 turbomolecular pump laying around…”, but then again not every write-up comes from someone with a lab as stuffed full of goodies as that of [Niklas Fauth]. His pump had an expired controller board, so he’s created an open-source controller of his own centred upon an STM32. Intriguingly he mentions its potential use as “I want to do more stuff with sputtering and Ion implantation in the future“, as one does of course.

So given that probably not many Hackaday readers have a turbomolecular pump lying around but quite a few of you will find the subject interesting, what does this project do? Sadly it’s a little more mundane than the pump itself, since a turbomolecular pump is a highly specialised multi-stage turbine, this is a 3-phase motor controller with analogue speed feedback taken from the voltage across a couple of the motor phases. For this reason he makes the point that it’s a fork of his hoverboard motor controller software, the fruits of which we’ve shown you in the past. There isn’t a cut-out timer should the motor not reach full speed in a safe time, but he provides advice as to where to look in the code should that be necessary.

This is by no means the first turbomolecular pump to make it to these pages, in 2016 we brought you one taking inspiration from a Tesla turbine.

Today: Hackaday Is At UK Maker Faire Plus Afterparty

April 27, 2018 by No comments

As a finale to our month on the road through parts of the British Isles, we’ll be at UK Maker Faire this weekend, and we’ll also be hosting our final bring-a-hack at Maker Space Newcastle this evening, Saturday the 28th of April.

For the rest of the weekend’s UK Maker Faire, held at Newcastle’s Life Science Centre, you’ll find both Hackaday and Tindie at our booth number M118, and if you’re lucky you might even snag one of the [Brian Benchoff]-designed Tindie blinkie badge kits.

A few familiar faces from the Brits among our wider community will have their own booths, for example [Spencer] will be there with the RC2014 Z80-based retrocomputer, Rachel “Konichiwakitty” Wong will have her collection of wearables but no 3D-printed eyeballs, and Tindie seller extraordinaire [Partfusion], whose bone conduction skull radio we saw at EMF 2016 (Correction: the bone conduction radio was the work of fellow TOG stalwart [Jeffrey Roe]) and who also spoke at our Dublin Unconference.

There is still time to make your way to Geordieland to attend the event if you haven’t made plans already, and should you bring a conveniently portable hack with you then we’d love to see it. Especially if it’s a Hackaday Prize entry.