Laser Sound Visualizations Are Not Hard To Make

You might think that visualizing music with lasers would be a complicated and difficult affair. In fact, it’s remarkably simple if you want it to be, and [byte_thrasher] shows us just how easy it can be.

At heart, what you’re trying to do is make a laser trace out waveforms of the music you’re listening to, right? So you just need a way to move the laser’s beam along with the sound waves from whatever you’re listening to. You might be thinking about putting a laser on the head of a servo-operated platform fed movement instructions from a digital music file, but you’d be way over-complicating things. You already have something that moves with the music you play — a speaker!

[byte_thrasher’s] concept is simple. Get a Bluetooth speaker, and stick it in a bowl. Cover the bowl with a flexible membrane, like plastic wrap. Stick a small piece of mirror on the plastic. When you play music with the speaker, the mirror will vibrate and move in turn. All you then have to do is aim a safe laser in a safe direction such that it bounces off the mirror and projects on to a surface. Then, the laser will dance with your tunes, and it’ll probably look pretty cool!

We’ve seen some beautiful laser visual effects before, too. Just be careful and keep your power levels safe and your beams pointing where they should be.

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AI Face Anonymizer Masks Human Identity In Images

We’re all pretty familiar with AI’s ability to create realistic-looking images of people that don’t exist, but here’s an unusual implementation of using that technology for a different purpose: masking people’s identity without altering the substance of the image itself. The result is the photo’s content and “purpose” (for lack of a better term) of the image remains unchanged, while at the same time becoming impossible to identify the actual person in it. This invites some interesting privacy-related applications.

Originals on left, anonymized versions on the right. The substance of the images has not changed.

The paper for Face Anonymization Made Simple has all the details, but the method boils down to using diffusion models to take an input image, automatically pick out identity-related features, and alter them in a way that looks more or less natural. For this purpose, identity-related features essentially means key parts of a human face. Other elements of the photo (background, expression, pose, clothing) are left unchanged. As a concept it’s been explored before, but researchers show that this versatile method is both simpler and better-performing than others.

Diffusion models are the essence of AI image generators like Stable Diffusion. The fact that they can be run locally on personal hardware has opened the doors to all kinds of interesting experimentation, like this haunted mirror and other interactive experiments. Forget tweaking dull sliders like “brightness” and “contrast” for an image. How about altering the level of “moss”, “fire”, or “cookie” instead?

A light grey box about the size of a brick with exposed screws held in a person's hand. There are two illuminated push buttons on the bottom left of the top panel. One is illuminated blue while the other is green. A small square screen sits next to a bank of nine different sections with an LED indicator and text of "HW, BAT, HBEAT, ECG, LOD +, LOD -, PPG, Pump, Valve."

Open Cardiography Signal Measuring Device

Much of the world’s medical equipment is made by a handful of monopolistic megacorps, but [Milos Rasic] built an open cardiography signal measuring device for his master’s thesis.

Using a Pi Pico W for the brains, [Rasic]’s device can record, store and analyze the data from an arm cuff, stethoscope, electrocardiograph (ECG), and pulse oximeter. This data can be used for monitoring blood pressure in patients and he has results from some of his experiments to determine the optimal algorithm for the task on the GitHub if you really want to get into the nitty gritty details.

Inside the brick-sized enclosure is the custom PCB, an 18650 Li-ion cell, and a pneumatic assembly for the arm cuff. Medical sensors attach via GX12 connectors on the back, a USB type B connector is used for data, and a USB C connector provides power for the device. The brightly colored labels will no doubt come in handy in a clinical setting where you really want to be sure you’ve got everything plugged in correctly.

Want more open medical equipment? How about an open ECG or this less accurate, but more portable, credit card ECG? We’d be remiss not to mention the huge amount of work on ventilators during the worst days of the COVID-19 pandemic as well.

Landscape Motif Makes This E-Ink Weather Display Easy To Understand

True weather geeks will disagree, but there might be a better way to know how to dress for the day than divining what the weather will likely be from the current readings for temperature, pressure, humidity, and wind. Sure, the data will give you a good idea of where the weather is heading, but perhaps a quick visual summary such as the one offered by this pictorial landscape weather display is a better way to get out the door in the morning.

While many consumer weather stations incorporate some kind of graphical forecast for quick reference, [lds133] took a slightly different approach to forecasting. A cartoon landscape represents the day ahead, with various elements representing the coming weather scrolling across the display as time progresses. Trees are used to indicate wind direction and speed, with palm trees indicating south wind and pine trees winds from the north, and the taller the trees, the stronger the wind. The forest floor rises and falls with the expected temperature, the sun and moon appear at the proper time to indicate sunrise and sunset, and cloud icons are added when needed to show the degree of cloud cover. And because into each life a little rain must fall, animations show when you can expect rain or snow.

As for the electronics, if you think this would be a perfect application for an E-ink module, [lds133] agrees. The 296×128 pixel Waveshare display is the perfect aspect ratio for the job and provides nice, crisp icons. The display is updated every 15 minutes from the OpenWeather API by a Python program running on an ESP32 behind the scenes.

We’ve seen similar graphical forecast displays before, but we get it if that’s not your thing. Perhaps a more data-driven weather forecast will suit you better?

FLOSS Weekly Episode 809: Pi4J – Stable And Boring On The Raspberry Pi

This week, Jonathan Bennett and David Ruggles chat with Frank Delporte about Pi4J, the friendly Java libraries for the Raspberry Pi, that expose GPIO, SPI, I2C and other IO interfaces. Why would anyone want to use Java for the Pi? And what’s changed since the project started? Listen to find out!

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Making Sense Of Real-Time Operating Systems In 2024

The best part about real-time OS (RTOS) availability in 2024 is that we developers are positively spoiled for choice, but as a corollary this also makes it a complete pain to determine what the optimal choice for a project is. Beyond simply opting for a safe choice like FreeRTOS for an MCU project and figuring out any implications later during the development process, it can pay off massively to invest some time up-front matching the project requirements with the features offered by these various RTOSes. A few years ago I wrote a primer on the various levels of ‘real-time’ and whether you may even just want to forego an RTOS at all and use a simple Big Loop™ & interrupt-based design.

With such design parameters in mind, we can then look more clearly at the available RTOS options available today, which is the focus of this article. Obviously it won’t be an exhaustive comparison, and especially projects like FreeRTOS have seen themselves customized to various degrees by manufacturers like ST Microelectronics and Espressif, among others. This also brings to the forefront less pleasant considerations, such as expected support levels, as illustrated by e.g. Microsoft’s Azure RTOS (formerly ThreadX) recently getting moved to the Eclipse Foundation as the Eclipse ThreadX open source project. On one hand this could make it a solid open-source licensed RTOS, or it could have been open sourced because Microsoft has moved on to something else and cleared out its cupboard.

Thus without further ado, let’s have a look at RTOSes in 2024 and which ones are worth considering, in my opinion.

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A Vintage Radiator Core, From Scratch

There are sadly few 1914 Dennis fire engines still on the road, so when the one owned by Imperial College in London needs a spare part, it can not be ordered from the motor factors and must be made from scratch. Happily, [Andy Pugh] is an alumnus with the required metalworking skills, so in the video below we see him tackling the manufacture of flattened brass tubes for its radiator core.

Forming a round tube to a particular shape is done by pulling it through a die whose profile gradually changes from round to the desired shape. We see him make a couple of tries at this, finally succeeding with one carefully designed to have a constant circumference. The use of CNC machining is something that wouldn’t have been available in the Dennis works in the early 20th century, so we can marvel at the skills of the machinists back then who made the original. Here in 2024 he makes a drawing rig with a geared chain drive suitable for larger scale production.

The video is both a fascinating look at tube drawing and a mind-cleansing piece of workshop observation, and we have to say we enjoyed watching it. If [Andy]’s name sounds familiar to you, this might be because this isn’t the first go he’s had at manufacturing vehicle parts.

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