Streaming Video From An ESP32

The ESP32, while first thought to be little more than a way of adding wireless capabilities to other microcontrollers, has quickly replaced many of them with its ability to be programmed as its own platform rather than simply an accessory. This also paved the way for accessories of its own, such as various sensors and even a camera. This guide goes over taking the input from the camera and streaming it out over the network to multiple browsers.

On the server side of things, the ESP32 and its attached camera are set up with MQTT, a lightweight communications protocol which uses a publish/subscribe model to send information. The ESP32 is configured to publish its images only, but not subscribe to any other nodes. On the client side, the browser runs a JavaScript program which is able to gather these images and stitch them together into a video.

This can be quite a bit of data to send out over the ESP32’s compact hardware, so there are some tips and tricks for getting more out of these little devices, including using an external antenna for better Wi-Fi signal, or omitting it entirely in favor of Ethernet. As far as getting a lot out of a tiny microcontroller, though, leveraging MQTT really helps the ESP32 go a long way. These chips have come along way since they were first introduced; they’re powerful enough to act as 8-bit gaming consoles too.

Thanks to [Surfskidude] for the tip!

Electro-Optical Control Of Lasers With A Licorice Twist

You’ve got to hand it to [Les Wright]; he really knows how to dig into optical arcana and present topics in an interesting way. Case in point: an electro-optical control cell that’s powered by ouzo.

OK, the bit about the Greek aperitif may be stretching things a bit, but the Kerr Cell that [Les] builds in the video below does depend on anethole, the essential component of aniseed extract, which lends its aromatic flavor to everything from licorice to Galliano and ouzo. As [Les] explains, the Kerr effect uses a high-voltage field to rapidly switch light passing through a medium on and off. The most common medium in Kerr cells is nitrobenzene, a “distressingly powerful organic solvent” with such fun side effects as toxicity, flammability, and carcinogenicity.

Luckily, [Les] found a suitable substitute in the form of anethole — a purified sample, not just an ouzo nip. The solution went into a plain glass cuvette equipped with a pair of aluminum electrodes, which got connected to one of the high-voltage supplies we’ve seen him build before for his nitrogen laser. A pair of polarizing filters go on either end of the cuvette, and are adjusted to blank out the light passing through it. Applying 45 kilovolts across the cell instantly turns the light back on. Watch it in action in the video below.

There’s a lot of room left for experimentation on this one, including purification of the anethole for potentially better results. We’d also be curious if plain ouzo would show some degree of Kerr effect. For science, of course.

Continue reading “Electro-Optical Control Of Lasers With A Licorice Twist”

Clean Up Your Resin-Printing Rinse With Dialysis

There’s a lot to like about resin 3D printing. The detail, the smooth surface finish, the mechanical simplicity of the printer itself compared to an FDM printer. But there are downsides, too, not least of which is the toxic waste that resin printing generates. What’s one to do with all that resin-tainted alcohol left over from curing prints?

How about sending it through this homebrew filtering apparatus to make it ready for reuse? [Involute] likens this process to dialysis, and while we see the similarities, what’s going on here is a lot simpler than the process used to filter wastes from the blood in patients with failing kidneys — there are no semipermeable membranes used here. Not that the idea suffers from its simplicity, mind you; it just removes unpolymerized resin from the isopropyl alcohol rinse using the same photopolymerization process used during printing. Continue reading “Clean Up Your Resin-Printing Rinse With Dialysis”

Raspi-Powered Typewriter Is A Real MUSE

Thanks to parenting and life in general, [Brendan] had fallen out of the habit of writing and wasn’t happy about it. If you write anything ever, you already know there are endless distractions when it comes to doing so on a computer. Sure, there always typewriters, but it’s difficult to do anything with the fruits of a typewriter other than scan it in or make copies, and it’s basically un-editable except by hand.

Instead of just sitting down and writing, [Brendan] did what any of us would do — took the time to create an elegant solution. The Most Unusual Sentence Extractor, or MUSE, is a Raspberry Pi-based typewriter with the best of both worlds. It’s essentially a word processor, but it can save to the cloud.

[Brendan] found beautiful inspiration in the Olympia Traveller de Luxe typewriter, a delightfully boxy affair made in the 1960s and 70s with lovely keys. Starting with a board, [Brendan] set about re-creating the lines of the Traveller de Luxe in Tinkercad.

Since it doesn’t really need a platen, this was the perfect place to mount a screen using black PVC. At first, [Brendan] was going to use an e-ink screen, but a mishap led to a better solution — an LCD touchscreen that makes document navigation a breeze.

We absolutely love the look of this machine, which was obviously a labor of love. And yeah, it does the trick:[Brendan] is writing again. Though it maybe be inconvenient, we agree that it really is nice to have a dedicated workstation for certain things.

Looking for the complete opposite of this project? How about a Chat GPT-assisted daisywheel typewriter?

Spooky Noise Box Has Post-Halloween Potential

There’s more than one way to scare people on Halloween. Sure, there’s always the low-brow jump scare, but that will generally just annoy the person and possibly cause a heart attack. No, what you need is a sustained soundscape of hellish audio. And where does one find hellish audio? Well, you make your own with a spooky-sounds noise box.

And no, we’re not talking about a soundboard that goes ‘boo’ and ‘ooo-OOO-oooh’ and whatnot. This is a full-on DIY instrument that has potential beyond Halloween. Essentially, the wooden box takes input vibrations from various doodads, and these vibrations are picked up by a piezo disk or two glued to the underside of the lid. The piezos are wired up to a 3.5 mm jack, which runs out to the PC and [SvartalfarQc]’s favorite Digital Audio Workstation (DAW). From there, it’s just a matter of playing around with the sounds — looping them, running them through various instrument voices, adding effects, and so on.

We love the the things that [SvartalfarQc] came up with, including a wind-up walking heart thing, a retractable badge holder, and that noise box mainstay, a sproingy doorstop.

We all know piezos are awesome, but have you ever considered that they can be used to digitize old wax cylinder recordings?

Jenny’s Daily Drivers: Raspberry Pi Desktop

One of the more exciting prospects upon receiving one of the earliest Raspberry Pi boards back in 2012 was that it was a fully-functional desktop computer in the palm of your hand. In those far-off days, the Debian OS distro for the board wasn’t even yet called Raspbian, but it would run a full-on desktop on your TV and you could use it after a fashion to browse the web or do wordprocessing. It wasn’t in any way fast, but it was usable enough to be more than a novelty. I’ve said before on these pages that the Raspberry Pi folks’ key product is their OS rather than their computers. While they rarely have the fastest or highest spec hardware, you can depend on Raspberry Pi OS being updated and supported through the life of the board unlike many of their competitors. I can download their latest OS image and still run it on that 2012 board, which to me ranks as a very laudable achievement.

The OS They Don’t Really Tell You About

Screenshot of the first i386 Pi desktop
The background image may have changed since the first release back in 2016, but the UI hasn’t.

Raspberry Pi OS doesn’t run on any other ARM single board computers but their own, but it’s not quite accurate to say that it only runs on Raspberry Pi hardware. Since 2016 when it was launched as PIXEL, the folks in Cambridge have also maintained a PC version for 32-bit i386 computers, now called Raspberry Pi Desktop. It may be the Pi product they don’t talk about much, but  you can still find it on their downloads page.

Like the ARM version, it’s based on Debian and presents as close as possible to the environment you’d find on your Pi. I’m interested to see whether it still lives up to the claim of being usable on older hardware, so I’ve downloaded a copy and installed it on my trusty 2007 Dell Inspiron 640. It rocks a 1.6 GHz Core Duo with 4 GB of memory and a SATA SSD so it’s not the lowest spec hardware on the block, but by 2023’s standard it represents a giveaway-spec old laptop. Can I use it as a daily driver? Let’s find out! Continue reading “Jenny’s Daily Drivers: Raspberry Pi Desktop”

Hackaday Prize 2023: The Gearing Up Challenge Finalists

If there’s more to life than just a workshop full of tools, it’s probably a workshop full of tools that you’ve built yourself. At least that was the thinking behind the recently concluded “Gearing Up” challenge of the 2023 Hackaday Prize, which unsurprisingly generated quite a list of entries for our judges to review and whittle down to their top ten favorite tools, jigs, fixtures, and general labor-savers.

Having piqued the interest of our crack team of judges, these ten projects have not only earned a spot in the 2023 Hackaday Prize Finals, but they’ll also get a $500 cash prize to boot. But the heat is really on now; like all the finalists from the previous rounds, they’ve only got until October to get their projects as far along as they can before the final round. The grand prize is grand indeed — $50,000 in cash and a residency at the Supplyframe Design Lab in Pasadena!

We’re really getting down to the wire here, but it’s worth taking a little time out to look at some of the Gearing Up challenge winners, and what they came up with to make life in the shop a little easier. And don’t forget — the one who dies with the most tools wins!

Continue reading “Hackaday Prize 2023: The Gearing Up Challenge Finalists”