Restoring An HP LCZ Meter From The 1980s

We are fantastically lucky not only in the parts that are easily available to us at reasonable cost, but also for the affordable test equipment that we can have on our benches. It was not always this way though, and [NFM] treats us to an extensive teardown and upgrade of a piece of test equipment from the days when a hacker’s bench would have been well-appointed with just a multimeter and a 10MHz ‘scope.

The Hewlett Packard 4276A LCZ meter is, or perhaps was, the king of component testers. A 19″ rack unit that would comfortably fill a shelf, it has a host of functions and a brace of red LED displays. This particular meter had clearly seen better days, and required a look inside just to clean up connectors and replace aged batteries.

In the case is a backplane board with a series of edge connectors for a PSU, CPU, and analogue boards. Aged capacitors and those batteries were replaced, and those edge connectors cleaned up again. The CPU board appears to have a Z80 at its heart, and we’re sure we spotted a 1987 date code. There are plenty of nice high-quality touches, such as the individual 7-segment digits being socketed.

An after-market option for this equipment included a DC offset board, and incredibly HP publish its full schematic and a picture of its PCB in their manual. It was thus a simple process and quick PCB ordering to knock up a modern replica, with just a few component substitutions and single resistors replacing an HP specific encapsulated resistor pack.

As a treat we get a ringside seat for the set-up and alignment of the machine. The DC offset board gives the wrong voltage, which he traces to a voltage reference with a different tolerance to the original HP part. [NFM] makes some adjustments to resistor values, and is able to pull the voltage to the correct value. Finally we see the instrument put through its paces, and along the way have a demonstration of how capacitance of a ceramic capacitor can vary with voltage close to its working voltage. Even if you never have the need for an LCZ meter or never see an HP 4276A, this should be worth a watch. And if you now have an urge to find a bench full of similar treasures, take a look at our guide to old test equipment.

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A Vintage Sony Portable TV, Brought Up To Date

In the time before smartphones for on-the-go visual entertainment, there were portable TVs. You might think of a portable TV as a luggable device, but the really cool ones were pocket-sized. Perhaps if you are familiar with pocket TVs you’ll be thinking of a Citizen or a Casio with a matchbox-sized LCD, but before those devices reached the market there was an earlier generation that featured tiny CRTs. These were simply the coolest electronics that an ’80s kid could lust after, and [Nick Reynolds] is lucky enough to have one. It’s a Sony Watchman from some time in the first half of that decade, and because it’s useless in the age of digital broadcasts he’s upgraded it by installing a Raspberry Pi in its case.

The unlikely inspiration for the project came from the 1970s British sci-fi TV series Space 1999, in which portable CRT-based communicators were a prop. They were typical of the sci-fi vision of the future in shows of the period, one that got so much right but didn’t quite see the smartphone coming.

The Watchman features Sony’s angled CRT, and fitting a Pi Zero W into the limited space behind it called for some careful insulation of its parts with Kapton tape. He’s even included a Pi camera module with a contorted run of flexible cable, placing it beneath the screen where a tuning indicator once sat. He has no sound as yet, but is able to demonstrate a working videophone using Ekiga as a client. He has a few more Watchmen, and has plans for a suite of retro videophones, and a Pi 3 based model.

Surprisingly this isn’t the only Sony Watchman that’s had this kind of treatment, previously we’ve brought you one that hosted a Pong game.

Cambridge Mini Uncon: Robots, Light Boxes, PCB Watches, and Retro Computers

At Hackaday, we are nothing without our community. We meet up at conferences, shows, and camps, but one of our favourite way to congregate is with the Unconference format. It’s an event where you can stand up and give an eight-minute talk about what is important to you, and what you are working on.

Thank you to the Cambridge Makespace for hosting our most recent a Mini Unconference. Let’s take a look at the excellent talks and demos that highlighted the day!

Continue reading “Cambridge Mini Uncon: Robots, Light Boxes, PCB Watches, and Retro Computers”

In Praise Of The App Note

When I am at a loss for an explanation in the world of electronics, I reach for my well-thumbed Horowitz & Hill. When H&H fails me which is not that often, the chances are I’ll find myself looking in an application note from a semiconductor company who is in cut-throat competition with its rivals in a bid for my attention. These companies have an extensive sales and marketing effort, part of which comes in the dissemination of knowledge.

Razor blades may be sold to young men with images of jet fighters and a subtle suggestion that a clean-shaven guy gets his girl, but semiconductor brands are sold by piquing the engineer’s interest with information. To that end, companies become publishing houses in praise of their products. They produce not only data sheets that deal with individual device, but app notes documents which cover a wider topic and tell the story of why this manufacturer’s parts are naturally the best in the world.

These app notes frequently make for fascinating reading, and if you haven’t found them yet you should head for the documentation sections of semiconductor biz websites and seek some of them out.

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Let A Dinosaur Show You The Future

Our lives in the 21st century are in part governed by a series of systems which we rarely encounter directly but which can have a great impact upon our lives. The oil futures market, for example, for which [Igor Nikolic] has created a real-time visualisation in the form of a clock in which the “hand” is a plastic dinosaur (As ever, XKCD reminds us that oil contains homeopathic quantities of real dinosaur, but it makes a good talking point).

The clock is part of a series continuing from his previous grid balance lamp project which monitored supply and demand in the electricity grid, and takes a feed of oil futures pricing to an MQTT server which is then picked up by an ESP8266 in the clock. The dinosaur hand is attached to a stepper motor, the position of which is set according to the market movements. There are also three LEDs whose colours change according to price. The whole is mounted on a plaque made from the top of an oil drum, and placed for effect over a map of the Port of Rotterdam, one of Europe’s busiest trading hubs.

Monitoring of these invisible socio-technical systems is a fascinating subject, and in the past we have brought you news of the very real impact they can have on entire continents when international politics intrude.

Who Knew Cut Grass Would Be So Tricky To Move!

Like all publications, here at Hackaday we are besieged by corporate public relations people touting press releases. So-and-so inc. have a new product, isn’t it exciting! But we know you, our readers, we know you like hacks, and with the best will in the world, the vast majority of such things have nothing of the hack about them. Just occasionally though a corporate offering does contain a hack, and today we have a fascinating one from Charm Industrial, who are doing their best to make hydrogen from biomass. They were finding cut grass to be an extremely difficult material to handle, and their account of how they managed to feed it from a hopper into their machinery makes for interesting reading.

You might expect grass to flow from a conical hopper like an ungainly liquid, but in fact it readily clogs and forms bridges, blocking the outlet. Changing the design of the hopper made little difference, so they tried an auger. The auger simply compressed the blockage harder, resulting in the counter-intuitive strategy of running the auger in reverse. But even that didn’t work, leaving the area round the auger clear but the rest of the grass as a solid clump. Rotating plows were tried with multiple different profiles followed, but finally they settled upon a vibrating bin activator. It’s a crash course in materials handling, and though the Hackaday bench is likely to avoid having to handle cut grass except when emptying the lawnmower, it’s still worth a look.

We may have done very little with handling cut grass, but we’ve certainly taken a look at creating it.

Britain Rejoins The Space Race

Jubilant crowds at the gates of Downing Street. (Jenny List)
Jubilant crowds at the gates of Downing Street. (Jenny List)

In a completely unexpected move, the British Prime Minister Theresa May yesterday announced outside Number 10 Downing Street that the UK would resume its space launch programme, 47 years after its cancellation following the launch of the Prospero satellite. She outlined a bold plan with a target of placing the Doc Martens of a British astronaut on the Lunar surface as early as 2024. Funded by the £350m per week Brexit windfall, the move would she said place the country at the forefront of a new 21st century Space Race with the North Koreans.

An estimated 2 million jubilant supporters took to the streets of London at the news, bringing the capital to a halt as they paraded with colourful banners from Hyde Park to Trafalgar Square and down Whitehall past her Downing Street home. Meanwhile the value of shares in the popular British high street bakery firm Patisserie Gregoire jumped by 19% as it was revealed that their new vegan sausage roll had in fact been a secret trial of the British astronaut diet. Continue reading “Britain Rejoins The Space Race”