SteamVR Controller Controlling Addressable LEDs

March 1, 2025 by 6 Comments

[Chris] had an idea. When playing VR games like BeatSaber, he realized that spectators without headsets weren’t very included in the action. He wanted to create some environmental lighting that would make everyone feel more a part of the action. He’s taken the first steps towards that goal, interfacing SteamVR controllers with addressable LEDs.

Armed with Python, OpenVR, and some help from ChatGPT, [Chris] got to work. He was soon able to create a mapping utility that let him create a virtual representation of where his WLED-controlled LED strips were installed in the real world. Once everything was mapped out, he was able to set things up so that pointing the controller to a given location would light the corresponding LED strips. Wave at the windows, the strips on that wall light up. Wave towards the other wall, the same thing happens.

Right now, the project is just a proof of concept. [Chris] has enabled basic interactivity with the controllers and lights, he just hasn’t fully built it out or gamified it yet. The big question is obvious, though—can you use this setup while actually playing a game?

“I just found the OpenVR function/object that allows it to act as an overlay, meaning it can function while other games are working,” [Chris] told me. “My longer term goals would be trying to interface more with a game directly such as BeatSaber, and the light in the room would correspond with the game environment.”

We can’t wait to see where this goes next. We fully expect flashy LED room setups to become the norm at VR cafes hosting BeatSaber competitions in future. We’ve featured plenty of other coverage of VR lately, too.

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Practice While You Work

March 1, 2025 by 20 Comments

This week, I had to do something I haven’t done in a long, long time: make myself a custom PCB the old-fashioned way, with laser toner and etchant. The reason? I bought a horrible K40 laser cutter, and the motion controller doesn’t seem to be able to do acceleration control, which means the machine rams full speed into and out of 90 degree corners, for instance. It sounds awful, and it dramatically limits how fast the laser cutter can run.

The plan, then, is to use a controller based on the wonderful FluidNC, but that meant making an adapter board for the flat-flex cable that connects to the X carriage, and the connector has 2 mm pin spacings instead of the usual 2.54 mm, and it just doesn’t fit into any prototyping boards that I have lying around. Besides, a custom PCB adapter board just looks neater.

I wasn’t confident that I could align and drill the dozen small holes for the flat-flex connector; they didn’t have much extra space around them for the copper pads. These holes had to be dead on, or risk ripping them up. And this is where I heard the voice of my old Jedi master.

When you have a tricky operation coming up that requires more precision than you’re immediately comfortable with, you can practice on the other parts of the project that don’t demand that much precision. Pretending that they do, and taking all the care that you can, gets you in shape to tackle the truly critical bits, and if you mess up a little on the easy stuff, it’s not a problem. I had more than a few pin-headers and other random holes to drill for practice anyway.

Now of course, you could always be giving all of your projects 100% all of the time, if time is never of the essence and effort is free. In the real world, you don’t always want to work at maximum precision. Good enough is often good enough.

But there’s also a time and a place for practicing precision, especially when you see a need for it up ahead. Drilling the big holes dead center got me back in the swing of things, and they needed to get drilled one way or the other. I find it useful to think about the job first, plan ahead where the tricky bits are going to be, and then treat the “easy” stuff along the way as practice for the more demanding operations. Hope you do too!

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A PCR machine with its side cover taken off exposing its guts, and the tray extended out

Making A PCR Machine Crypto Sign Its Results

March 1, 2025 by 20 Comments

Money, status, or even survival – there’s no shortage of incentives for faking results in the scientific community. What can we do to prevent it, or at least make it noticeable? One possible solution is cryptographic signing of measurement results.

Here’s a proof-of-concept from [Clement Heyd] and [Arbion Halili]. They took a ThermoFisher Scientific 7500 Fast PCR (Polymerase Chain Reaction) machine, isolated its daughter-software, and confined it into a pipeline that automatically signs each result with help of a HSM (Hardware Security Module).

A many machines do, this one has to be paired to a PC, running bespoke software. This one’s running Windows XP, at least! The software got shoved into a heavily isolated virtual machine running XP, protected by TEE (Trusted Execution Environment). The software’s output is now piped into a data diode virtual serial port out of the VM, immediately signed with the HSM, and signed data is accessible through a read-only interface. Want to verify the results’ authenticity? Check them against the system’s public key, and you’re golden – in theory.

This design is just a part of the puzzle, given a typical chain of custody for samples in medical research, but it’s a solid start – and it happens to help make the Windows XP setup more resilient, too.

Wondering what PCR testing is good for? Tons of things all over the medical field, for instance, we’ve talked about PCR in a fair bit of detail in this article about COVID-19 testing. We’ve also covered a number of hacker-built PCR and PCR-enabling machines, from deceivingly simple to reasonably complex!

Building A Nerf-like Rocket Launcher With Airburst Capability

March 1, 2025 by 25 Comments

Nerf blasters typically fire small foam darts or little foam balls. [Michael Pick] wanted to build something altogether more devastating. To that end, he created a rocket launcher with an advanced air burst capability, intended to take out enemies behind cover.

Unlike Nerf’s own rocket launchers, this build doesn’t just launch a bigger foam dart. Instead, it launches an advanced smart projectile that releases lots of smaller foam submunitions at a set distance after firing.

The rocket launcher itself is assembled out of off-the-shelf pipe and 3D printed components.  An Arduino Uno runs the show, hooked up to a Bluetooth module and a laser rangefinder. The rangefinder determines the distance to the target, and the Bluetooth module then communicates this to the rocket projectile itself so it knows when to release its foamy payload after launch. Releasing the submunitions is achieved with a small microservo in the projectile which opens a pair of doors in flight, scattering foam on anyone below. The rockets are actually fired via strong elastic bands, with an electronic servo-controlled firing mechanism.

We’ve featured some great Nerf builds over the years, like this rocket-blasting robot.

Continue reading “Building A Nerf-like Rocket Launcher With Airburst Capability” →

A balding man in a blue suit and tie sits behind rows of plants on tables. A bright yellow watering can is close to the camera and out of focus.

Phytoremediation To Clean The Environment And Mine Critical Materials

February 28, 2025 by 10 Comments

Nickel contamination can render soils infertile at levels that are currently impractical to treat. Researchers at UMass Amherst are looking at how plants can help these soils and source nickel for the growing EV market.

Phytoremediation is the use of plants that preferentially hyperaccumulate certain contaminants to clean the soil. When those contaminants are also critical materials, you get phytomining. Starting with Camelina sativa, the researchers are looking to enhance its preference for nickel accumulation with genes from the even more adept hyperaccumulator Odontarrhena to have a quick-growing plant that can be a nickel feedstock as well as produce seeds containing oil for biofuels.

Despite being able to be up to 3% Ni by weight, Odontarrhena was ruled out as a candidate itself due to its slow-growing nature and that it is invasive to the United States. The researchers are also looking into what soil amendments can best help this super Camelina sativa best achieve its goals. It’s no panacea for expected nickel demand, but they do project that phytomining could provide 20-30% of our nickel needs for 50 years, at which point the land could be turned back over to other uses.

Recycling things already in technical cycles will be important to a circular economy, but being able to remove contaminants from the environment’s biological cycles and place them into a safer technical cycle instead of just burying them will be a big benefit as well. If you want learn about a more notorious heavy metal, checkout our piece on the blessings and destruction wrought by lead.

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Building An Interferometer With LEGO

February 28, 2025 by 14 Comments

LEGO! It’s a fun toy that is popular around the world. What you may not realize is that it’s also made to incredibly high standards. As it turns out, the humble building blocks are good enough to build a interferometer if you’re so inclined to want one. [Kyra Cole] shows us how it’s done.

The build in question is a Michelson interferometer; [Kyra] was inspired to build it based on earlier work by the myphotonics project. She was able to assemble holders for mirrors and a laser, as well as a mount for a beamsplitter, and then put it all together on a LEGO baseboard. While some non-LEGO rubber bands were used in some areas, ultimately, adjustment was performed with LEGO Technic gears.

Not only was the LEGO interferometer able to generate a proper interference pattern, [Kyra] then went one step further. A Raspberry Pi was rigged up with a camera and some code to analyze the interference patterns automatically. [Kyra] notes that using genuine bricks was key to her success. Their high level of dimensional accuracy made it much easier to achieve her end goal. Sloppily-built knock-off bricks may have made the build much more frustrating to complete.

We don’t feature a ton of interferometer hacks around these parts. However, if you’re a big physics head, you might enjoy our 2021 article on the LIGO observatory. If you’re cooking up your own physics experiments at home, don’t hesitate to drop us a line!

Thanks to [Peter Quinn] for the tip!

A dark walnut table sits in the sun in what appears to be a field. Voids in the natural wood slab have been filled with shiny bronze, and a bundle of copper wire sits upon the edge of the table in a jaunty artistic fashion.

A Different Take On The River Table Does It In Bronze

February 28, 2025 by 6 Comments

River tables are something we’ve heard decried as a passé, but we’re still seeing some interesting variations on the technique. Take this example done with bronze instead of epoxy.

Starting with two beautiful slabs of walnut, [Burls Art] decided that instead of cutting them up to make guitars he would turn his attention to a river table to keep them more intact. Given the price of copper and difficulty in casting it, he decided to trim the live edges to make a more narrow “river” to work with for the project.

Since molten copper is quite toasty and wood likes to catch on fire, he wisely did a rough finish of the table before making silicone plugs of the voids instead of pouring metal directly. The silicone plugs were then used to make sand casting molds, and a series of casting trials moving from copper to bronze finally yielded usable pieces for the table. In case that all seems too simple, there were then several days of milling and sanding to get the bronze and walnut level and smooth with each other. The amount of attention to detail and plain old elbow grease in this project is impressive.

We’ve seen some other interesting mix-ups of the live edge and epoxy formula like a seascape night light or this river table with embedded neon. And if you’re looking to get into casting, why not start small in the microwave?

Continue reading “A Different Take On The River Table Does It In Bronze” →