Vintage Pro Audio Hack Chat Gets In The Groove

Despite the fact that we’ve been doing them for years now, it’s still hard to predict how a Hack Chat will go. There’s no question it will be an hour of interesting discussion of course, that much is a given. But the dynamics of the conversation can range from a rigid Q&A, which isn’t exactly unexpected when you’ve only got a limited amount of time with a subject matter expert, to a freewheeling hangout with a group of people who all happen to be interested in the same thing.

This week’s Vintage Pro Audio Hack Chat with Frank Olson definitely took the latter approach. The allotted hour flew by in a blink, with so many anecdotes and ideas flying back and forth that at times it was tricky to follow. But no worries, with the Chat transcript to pore over, we can make sure none of that accrued first-hand knowledge goes to waste.

So what did we learn during this Chat? Well, it probably won’t come as much of a surprise to find that those who have an opinion on audio gear tend to have a strong opinion on it. Folks were painting with some fairly broad brushes, with particular manufacturers and even whole fields of technology receiving a bit of good-natured ribbing. If your favorite brand or piece of gear gets a specific shout-out, try not to take it too personally — at the end of the day, most in the Chat seemed to agree that sound is so subjective that the right choice is more often than not whatever sounds best to you at the moment.

Which leads directly into Frank’s work with custom microphones. As a musician he knew the sound he was looking for better than anyone, so rather than spend the money on big-name gear, he prefers to build it himself. But the real hook here is their unique construction, with pieces that reimagine design concepts from mid-century commercial equipment using unexpected materials such as thin pieces of walnut cut with a vinyl cutter. Frank explains that the structure of the microphone isn’t as critical these days thanks to the availability of powerful neodymium magnets, which gives the builder more freedom in terms of materials and tools. He says the goal is to inspire others to try building gear from what’s available to them rather than assuming it won’t work because it’s unconventional.

We appreciate Frank, and everyone else, stopping by this week for such a lively and friendly discussion. Let’s be honest, a Chat specifically for folks who want to discuss concepts as personal and nebulous as how they perceive the warmth of sound could have gotten a little heated. But the fact that everyone was able to express their opinions or ask for advice constructively is a real credit to the community.


The Hack Chat is a weekly online chat session hosted by leading experts from all corners of the hardware hacking universe. It’s a great way for hackers connect in a fun and informal way, but if you can’t make it live, these overview posts as well as the transcripts posted to Hackaday.io make sure you don’t miss out.

Hackaday Podcast 170: Poop Shooting Laser, Positron Is A 3D Printer On Its Head, DIY Pulsar Capture, GPS’s Achilles Heel

Join Hackaday Editor-in-Chief Elliot Williams and Managing Editor Tom Nardi for a recap of all the best tips, hacks, and stories of the past week. We start things off with an update on Hackaday’s current slate of contests, followed by an exploration of the cutting edge in 3D printing and printables. Next up we’ll look at two achievements in detection, as commercial off-the-shelf hardware is pushed into service by unusually dedicated hackers to identify both dog poop and deep space pulsars (but not at the same time). We’ll also talk about fancy Samsung cables, homebrew soundcards, the surprising vulnerability of GPS, and the development of ratholes in your cat food.

Direct Download link

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

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PSP Turned Robot Remote With Custom Software

There’s no question that Sony’s PlayStation Portable (PSP) was an impressive piece of hardware when it was released in 2004, but for all its technical wizardry, it wasn’t able to shake Nintendo’s vice-like grip on the handheld market. Perhaps that explains why we still see so many nostalgia-fueled hacks for Nintendo’s Game Boy and Dual Screen (DS) systems, while PSP hacks tend to be few and far between.

But looking at projects like this one that turn the PSP into a capable robot controller (video, embedded below) we can’t help but wonder if the community has been missing out. Thanks to an open source software development kit for the system, [iketsj] was able to write a WiFi controller program that can be run on any PSP with a homebrew-compatible firmware.

The other side of the equation is a simple robot powered by an ESP8266. To take control of the bot, the user connects their handheld to the WiFi network being offered by the MCU and fires up the controller application from the main menu. It’s all very slick, and the fact that you don’t need to make any modifications to the PSP’s hardware is a huge plus. From the video after the break we get the impression that the remote software is pretty simplistic in its current form, but we imagine the only really limitations are how good you are at writing C code for what by today’s standards would be considered a fairly resource constrained system. We’d love to see that widescreen display lit up and showing live first-person video from the bot’s perspective.

Many of the PSP hack’s we’ve seen over the years have been about repurposing the hardware, or in some cases, replacing the system’s internals with something raspberry flavored. Those projects have certainly been interesting in their own ways, but we really like the idea of being able to push a largely stock system into a new role just by writing some custom code for it.

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Fighting Back Against Dodgy Dyson Batteries

If you’ve ever worked with multi-cell rechargeable battery packs, you know that the individual cells will eventually become imbalanced. To keep the pack working optimally, each cell needs to be analyzed and charged individually — which is why RC style battery packs have a dedicated balance connector. So if you know it, and we know it, why doesn’t Dyson know it?

It’s that question which inspired [tinfever] to start work on the FU-Dyson-BMS project. As you might have surmised from the name, [tinfever] believes that Dyson has intentionally engineered their V6 and V7 batteries to fail by not using the cell balancing function of the onboard ISL94208 battery management IC. What’s worse, once the cells get as little as 300 mV out of balance, the controller considers the entire pack to be shot and will no longer allow it to be charged.

These missing resistors deserve justice.

Or at least, that’s what used to happen. With the replacement firmware [tinfever] has developed, the pack’s battery management system (BMS) will ignore imbalanced cells so you can continue to use the pack (albeit at a reduced capacity). Of course the ideal solution would have been to enable cell balancing on the ISL94208, but unfortunately Dyson didn’t include the necessary resistors on the PCB. Though it’s worth noting that earlier versions of the board did have unpopulated spots for them, lending some credence to the idea that their omission was intentional on Dyson’s part.

But not everyone is onboard with the conspiracy theory. Over on the EEVBlog forums, some users pointed out that a poorly implemented cell balancing routine can be more problematic than not having one at all. It’s possible that Dyson had some bad experiences with the technology in earlier packs, and decided to move away from it and try to compensate by using higher-quality cells. That said, at least one person in the thread was able to revive their own “dead” battery pack by installing this unofficial firmware, so whether intentional or not, it seems there’s little debate that usable batteries are indeed being prematurely marked as defective.

Proper cell balancing is key even in DIY projects, so we do have to agree that it seems more than a little unusual that Dyson would intentionally turn off this important feature in their packs. But the jury is still out on whether or not Sir James is trying to pull a fast one on his customers — as Hanlon’s Razor states, “never attribute to malice that which is adequately explained by stupidity”.

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An Illuminating Look At A Wolf 5151 Light Source

While originally designed to put light where the sun don’t shine for medical purposes, [Nava Whiteford] says the Wolf 5151 Xenon endoscopic light source also works well for microscopy and general optical experiments, especially since you can get them fairly cheap on the second hand market. His cost just $50 USD, which is a steal when you consider a replacement for its 300 watt Olympus-made bulb will run you about 200 bucks alone.

That said, [Nava] recently moved on to a more compact light source, and figured that was a good enough excuse to crack open the Wolf 5151 and see what makes it tick. In this particular post he’s just looking at the optical side of things, which is arguably the most interesting aspect of the device. Helpfully, the whole assembly is mounted to its own sled of sorts that can be pulled from the light source for a closer examination.

A Steampunk dimmer switch.

Beyond that expensive bulb we mentioned earlier, there’s a thick piece of what appears to be standard plate glass being used as an IR and UV filter. [Nava] suspects this component is responsible for keeping the rest of the optics from overheating, which is backed up by the fact that the metal plate its mounted to appears to feature a K-type thermocouple to keep an eye on its operating temperature. Forward of that is a unique aspheric lens that features a rough spot to presumably scatter the light at the center of the beam.

Our vote for the most fascinating component has to go to the Neutral Density (ND) filter, which is used to control the intensity of the light. In a more pedestrian light source you could just dim the bulb, but in this case, the Wolf 5151 uses a metal disk with an array of holes drilled into it. By rotating the disc with a DC motor, the lens can be variably occluded to reduce the amount of light that reaches the aperture, which connects to the fiber cable.

While it’s perhaps no surprise the build quality of this medical gear is considerably beyond the commercial gadgets most of us get to play with, it still doesn’t hold a candle (no pun intended) to the laser module pulled from a Tornado jet fighter.

Kindle, EPUB, And Amazon’s Love Of Reinventing Wheels

Last last month, a post from the relatively obscure Good e-Reader claimed that Amazon would finally allow the Kindle to read EPUB files. The story was picked up by all the major tech sites, and for a time, there was much rejoicing. After all, it was a feature that owners have been asking for since the Kindle was first released in 2007. But rather than supporting the open eBook format, Amazon had always insisted in coming up with their own proprietary formats to use on their readers. Accordingly, many users have turned to third party programs which can reliably convert their personal libraries over to whatever Amazon format their particular Kindle is most compatible with.

Native support for EPUB would make using the Kindle a lot less of a hassle for many folks, but alas, it was not to be. It wasn’t long before the original post was updated to clarify that Amazon had simply added support for EPUB to their Send to Kindle service. Granted this is still an improvement, as it represents a relatively low-effort way to get the open format files on your personal device; but in sending the files through the service they would be converted to Amazon’s KF8/AZW3 format, the result of which may not always be what you expected. At the same time the Send to Kindle documentation noted that support for AZW and MOBI files would be removed later on this year, as the older formats weren’t compatible with all the features of the latest Kindle models.

If you think this is a lot of unnecessary confusion just to get plain-text files to display on the world’s most popular ereader, you aren’t alone. Users shouldn’t have to wade through an alphabet soup of oddball file formats when there’s already an accepted industry standard in EPUB. But given that it’s the reality when using one of Amazon’s readers, this seems a good a time as any for a brief rundown of the different ebook formats, and a look at how we got into this mess in the first place.

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Round LCDs Put To Work In Rack Mount Gauge Cluster

Like many of you, we’re intrigued by the possibilities offered by the availability of affordable round LCD panels. But beyond the smartwatches they were designed for, it’s not always easy to come up with an appropriate application for such non-traditional displays. Digital “steam gauges” are one of the first ideas that come to mind, so it’s perhaps no surprise that’s the direction [Tom Dowad] took his project. But rather than just one or two gauges, he decided to go all out and put eight of them in a 1U rack mountable unit.

What do you need eight faux-analog gauges for? Beats us, but that’s not our department. Now [Tom] has a whole row of indicators that can be used to show whatever it is he likes to keep an eye on. The fact that the device is actually controlled via MIDI may provide us a clue that there’s a musical component at play (no pun intended), but then, it wouldn’t be the first time we’d seen MIDI used simply as a convenient and well supported way of synchronizing gadgets. Continue reading “Round LCDs Put To Work In Rack Mount Gauge Cluster”