We haven’t seen [Les Wright] in a while, and with the release of his new video, we know why — he’s been busy growing crystals.

Now, that might seem confusing to anyone who has done the classic “Crystal Garden” trick with table salt and laundry bluing, or tried to get a bit of rock candy out of a supersaturated sugar solution. Sure, growing crystals takes time, but it’s not exactly hard work. But [Les] isn’t in the market for any old crystals. Rather, he needs super-sized, optically clear crystals of potassium dihydrogen phosphate, or KDP, which are useful as frequency doublers for lasers. [Les] has detailed his need for KDP crystals before and even grown some nice ones, but he wanted to step up his game and grow some real whoppers.

And boy, did he ever. Fair warning; the video below is long and has a lot of detail on crystal-growing theory, but it’s well worth it for anyone taking the plunge. [Les] ended up building an automated crystal lab, housing it in an old server enclosure for temperature and dust control. The crystals are grown on a custom-built armature that slowly rotates in a supersaturated solution of KDP which is carefully transitioned through a specific temperature profile under Arduino control. As a bonus, he programmed the rig to take photographs of the growing crystals at intervals; the resulting time-lapse sequences are as gorgeous as the crystals, one of which grew to 40 grams in only a week.

We’re keen to see how [Les] puts these crystals to work, and to learn exactly what a “Pockels Cell” is and why you’d want one. In the meantime, if you’re interested in how the crystals that make the whole world work are made, check out our deep dive into silicon.

youtube.com/embed/uSSoSIcXWa0?…

Thanks to [Joseph Hopfield] for the tip.

hackaday.com/2024/12/12/automa…

Google’s Chromecast was first released in 2013, with a more sophisticated follow-up in 2015, which saw itself joined by the Chromecast Audio dongle. The device went through an additional two hardware generations before the entire line of products was discontinued earlier this year in favor of Google TV.
Marvell’s Armada 88DE3006 dual-core Cortex-A7 powers the second-generation Chromecast. (Credit: Brian Dipert, EDN)
In addition to collecting each generation of Chromecast, [Brian Dipert] over at EDN looked back on this second-generation dongle from 2015 while also digging into the guts of a well-used example that got picked up used.

While not having any of the fascinating legacy features of the 2nd-generation Ultra in his collection that came with the Stadia gaming controller, it defines basically everything that Chromecast dongles were about: a simple dongle with a HDMI & USB connector that you plugged into a display that you wanted to show streaming content on. The teardown is mostly similar to the 2015-era teardown by iFixit, who incidentally decided not to assign any repairability score, for obvious reasons.

Most interesting about this second-generation Chromecast is that the hardware supported Bluetooth, but that this wasn’t enabled until a few years later, presumably to fix the wonky new device setup procedure that would be replaced with a new procedure via the Google Home app.

While Google’s attention has moved on to newer devices, the Chromecast isn’t dead — the dongles in the wild still work, and the protocol is supported by Google TV and many ‘smart’ appliances including TVs and multimedia receivers.

hackaday.com/2024/12/12/a-look…

As a British taxpayer it’s reassuring to know that over in Cheltenham there’s a big round building full of people dedicated to keeping us safe. GCHQ is the nation’s electronic spying centre, and just to show what a bunch of good eggs they are they release a puzzler every year to titillate the nation’s geeks. 2024’s edition is out if you fancy trying it, so break out your proverbial thinking caps.

The puzzle comes in several stages each of which reveals a British landmark, and we’re told there’s a further set of puzzles hidden in the design of the card itself. We know that Hackaday readers possess fine minds, so you’ll all be raring to have a go.

Sadly GCHQ would for perfectly understandable reasons never let Hackaday in for a tour, but we’ve encountered some of their past work. First the Colossus replica codebreaking computer at Bletchley Park was the progenitor of the organisation, and then a few years ago when they had an exhibition from their archive in the London Science Museum.

hackaday.com/2024/12/12/britis…

It’s perhaps not fair, but even if you have the best idea for a compelling video, few things will make people switch off than poor lighting. Good light and plenty of it is the order of the day when it comes to video production, and luckily there are many affordable options out there. Affordable, that is, right up to the point where you need batteries for remote shoots, in which case you’d better be ready to open the purse strings.

When [Dane Kouttron] ran into the battery problem with his video lighting setup, he fought back with these cheap and clever cordless tool battery pack adapters. His lights were designed to use Sony NP-F mount batteries, which are pretty common in the photography trade but unforgivably expensive, at least for Sony-branded packs. Having access to 20 volt DeWalt battery packs, he combined an off-the-shelf battery adapter with a 3D printed mount that slips right onto the light. Luckily, the lights have a built-in DC-DC converter that accepts up to 40 volts, so connecting the battery through a protection diode was a pretty simple exercise. The battery pack just slots right in and keeps the lights running for portable shoots.

Of course, if you don’t already have DeWalt batteries on hand, it might just be cheaper to buy the Sony batteries and be done with it. Then again, there are battery adapters for pretty much every cordless tool brand out there, so you should be able to adapt the design. We’ve also seen cross-brand battery adapters which might prove useful, too.

hackaday.com/2024/12/12/good-l…

As part of a phosphorescence detector, [lcamtuf] has been working with photodiodes. The components, like all diodes, have some capacitance at the junction, and this can limit performance. That’s why [lcamtuf] turned to bootstrapping to make that parasitic capacitance almost disappear.

The technique appears in several Analog Devices datasheets that presents a mystery. An op amp circuit that would normally limit changes to about 52 kHz has an unusually-placed JFET and claims to boost the bandwidth to 350 kHz.

The JFET turns out to be in a voltage-follower configuration. The photodiode sees approximately the same voltage on both terminals, so the internal capacitor can’t charge and, therefore, doesn’t impose any limits on rate of change.

Of course, a better way to think of it is that tiny changes cause an immediate response to counteract them, and so the capacitor’s charging and discharging are kept to a minimum.

It really isn’t important that the capacitor is not charged, but rather that the capacitor doesn’t increase or decrease charge. This leads to a second design, which imposes a DC bias voltage on the diode but prevents any signal from causing the capacitor to change from its precharged value.

Photodiodes seem exotic, but honestly, all semiconductor diodes are photodiodes if you let the light get to them. It seems that capacitors and op amps are always at loggerheads.

hackaday.com/2024/12/12/the-di…

agenparl.eu/2024/12/11/millepr…

(AGENPARL) – mer 11 dicembre 2024 MILLEPROROGHE, COLUCCI (M5S): SU AUTONOMIA E LEP GOVERNO PERSEVERA E VA CONTRO CONSULTA
ROMA, 11 dic. – “Nel testo bollinato del decreto Milleproroghe all’articolo 16 il governo trasferisce presso il dipartimento per gli Affari regionali e le Autonomie, quindi al ministro Calderoli, l’attività istruttoria per la determinazione dei livelli essenziali delle prestazioni (LEP) e dei relativi costi e fabbisogni standard, fino al 31 dicembre 2025. Quindi, il Governo persevera nell’errore di avocare a sè la determinazione dei Lep, calpestando il Parlamento e soprattutto la Corte Costituzionale che, nella recente sentenza sulla legge per l’Autonomia Differenziata, ha bocciato questa possibilità. Vorremmo anche capire cosa significa che l’attività istruttoria è trasferita “presso” e non “al” dipartimento, il Comitato per la determinazione dei LEP, presieduto dal prof. Cassese, è stato licenziato o semplicemente trasferito presso il Ministero? Sarebbe doveroso il suo scioglimento, a seguito della sentenza della Corte Costituzionale che ha bocciato la legge Calderoli e le collegate norme contenute nella legge di Bilancio 2023. In ogni caso questa contenuta nel dl Milleproroghe è un’operazione a dir poco spregiudicata, tenuto conto che la legge Calderoli è stata bocciata dalla Corte in tutti i suoi pilastri portanti, e lo è ancor di più se si considera che l’attività istruttoria si riferisce alla determinazione delle sole materie Lep e non anche, come pure ha stabilito la Corte, delle materie non Lep nelle parti in cui incidano su diritti sociali e civili. E’ proprio il caso di dire che non c’è peggior sordo di chi non vuol sentire. Al governo e alla maggioranza lo hanno ricordato tantissimi cittadini che hanno firmato per cancellare l’Autonomia, poi la Consulta con la sentenza che smantella la legge Calderoli. Se vogliono perseverare, prenderanno altre batoste e purtroppo a pagare saranno i cittadini che assistono a questo scempio istituzionale che può avere drammatiche ricadute sulla loro vita quotidiana”.
Lo afferma il capigruppo M5S nella commissioni Affari Costituzionali della Camera Alfonso Colucci.
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MILLEPROROGHE, COLUCCI (M5S): SU AUTONOMIA E LEP GOVERNO PERSEVERA E VA CONTRO CONSULTA

(AGENPARL) - Roma, 11 Dicembre 2024(AGENPARL) – mer 11 dicembre 2024 MILLEPROROGHE, COLUCCI (M5S): SU AUTONOMIA E LEP GOVERNO PERSEVERA E VA CONTRO CONSULTA ROMA, 11 dic.

^Agenparl