Adjustable Lights Help Peer Inside Chips With IR

April 9, 2024 by Dan Maloney 3 Comments

If you’re used to working through a microscope, you’ve probably noticed that the angle of the light greatly affects how your workpiece looks. Most of us prefer the relatively flat lighting provided by a ring light, but variable angle side lighting can be useful too, especially when you’re peering inside ICs to make sure the silicon is what it’s supposed to be.

That’s what [Bunnie] is working on these days with his Project IRIS, short for “Infrared in situ,” a non-destructive method for looking inside chip packages. The technique relies on the fact that silicon is transparent to certain wavelengths of light, and that some modern IC packages expose the underside of the silicon die directly to the outside world. Initial tests indicated that the angle of the incident IR light was important to visualizing features on the metal interconnects layered onto the silicon, so [Bunnie] designed a two-axis light source for his microscope. The rig uses curved metal tracks to guide a pair of IR light sources through an arc centered on the focal point of the microscope stage. The angle of each light source relative to the stage can be controlled independently, while the whole thing can swivel around the optical axis of the microscope to control the radial angle of the lighting.

The mechanism [Bunnie] designed to accomplish all this is pretty complex. Zenith angle is controlled by a lead screw driving a connecting rod to the lights on their guide tracks, while the azimuth of the lights is controlled by a separate motor and pulley driving a custom-built coaxial bearing. The whole optical assembly is mounted on a Jubilee motion platform for XYZ control. The brief videos below show the lights being put through their paces, along with how changing the angle of the light affects the view inside a chip.

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Four images in as many panes. Top left is a fuchsia bottle with a QR code that only shows up on the smartphone screen held above it. Top right image is A person holding a smartphone over a red wristband. The phone displays a QR code on its screen that it sees but is invisible in the visible wavelengths. Bottom left is a closeup of the red wristband in visible light and the bottom right image is the wristband in IR showing the three QR codes embedded in the object.

Fluorescent Filament Makes Object Identification Easier

August 17, 2023 by Navarre Bartz 14 Comments

QR codes are a handy way to embed information, but they aren’t exactly pretty. New work from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) have a new way to produce high contrast QR codes that are invisible. [PDF]

If this sounds familiar, you may remember CSAILs previous project embedding QR codes into 3D prints via IR-transparent filament. This followup to that research increases the detection of the objects by using an IR-fluorescent filament. Another benefit of this new approach is that while the InfraredTags could be any color you wanted as long as it was black, BrightMarkers can be embedded in objects of any color since the important IR component is embedded in traditional filament instead of the other way around.

One of the more interesting applications is privacy-preserving object detection since the computer vision system only “sees” the fluorescent objects. The example given is marking a box of valuables in a home to be detected by interior cameras without recording the movements of the home’s occupants, but the possibilities certainly don’t end there, especially given the other stated application of tactile interfaces for VR or AR systems.

We’re interested to see if the researchers can figure out how to tune the filament to fluoresce in more colors to increase the information density of the codes. Now, go forth and 3D print a snake with snake in a QR code inside!

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Feeling The Heat: Railway Defect Detection

March 28, 2023 by Dan Maloney 29 Comments

On the technology spectrum, railroads would certainly seem to skew toward the brutally simplistic side of things. A couple of strips of steel, some wooden ties and gravel ballast to keep everything in place, some rolling stock with flanged wheels on fixed axles, and you’ve got the basics that have been moving freight and passengers since at least the 18th century.

But that basic simplicity belies the true complexity of a railway, where even just keep keeping the trains on the track can be a daunting task. The forces that a fully loaded train can exert on not only the tracks but on itself are hard to get your head around, and the potential for disaster is often only a failed component away. This became painfully evident with the recent Norfolk Southern derailment in East Palestine, Ohio, which resulted in a hazardous materials incident the likes of which no community is ready to deal with.

Given the forces involved, keeping trains on the straight and narrow is no mean feat, and railway designers have come up with a web of sensors and systems to help them with the task of keeping an eye on what’s going on with the rolling stock of a train. Let’s take a look at some of the interesting engineering behind these wayside defect detectors.

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Adversarial IR Hoodie Lets You Own The Night In Anonymity

March 6, 2023 by Dan Maloney 75 Comments

If you’re in the market for something to obfuscate your nefarious nocturnal activities, rejoice — this adversarial infrared hoodie may be just what you’re looking for.

Not that we condone illegal activities, of course, and neither does artist [Mac Pierce], who created “The Camera-Shy Hoodie.” His purpose seems to be exploring the nature of the surveillance state, or rather to perplex it in the name of anonymity. The idea is simple — equip a standard hoodie with a ring of super-bright IR LEDs, and control them with an RP2040.

We’ve seen blinding hoodies before, but here the LEDs strobe on and off in one of three different patterns, all of which are timed to confound the autoexposure mechanism in just about any surveillance camera by not giving it time to adjust to the rapidly and drastically changing light level. The result is near-total obfuscation of the wearer’s facial features, at least when the camera is in night-vision mode. Check out the results in the video below.

There are some nice touches to [Mac]’s approach, like aluminum PCBs for the LEDs and the use of soldered-on fabric snaps to attach them to the inside of the hoodie, making them easy to remove for laundering. With the LEDs peeking through holes in the fabric, the hoodie looks pretty run-of-the-mill — until, of course, night falls and the USB battery bank in the hoodie’s pocket powers up the light show.

Granted, this won’t exactly help you avoid detection — the big ball of light around your head will be instantly seen by even the most casual observer. But at least it makes it easier to keep your face to yourself. And it won’t help much in daylight — for that, you might want something a little more like this passive adversarial ugly sweater.

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IR Remote tester in use, showing a remote control lighting up an LED and screenshots of the Arduino serial terminal

IR Remote Tester Helps You Crack The Code

November 8, 2022 by Dave Walker 15 Comments

Even though some devices now use WiFi and Bluetooth, so much of our home entertainment equipment still relies on its own proprietary infrared remote control. By and large (when you can find them) they work fine, but what happens when they stop working? First port of call is to change the batteries, of course, but once you’ve tried that what do you do next? [Hulk] has your back with this simple but effective IR Remote Tester / Decoder.

IR remote tester schematic showing arduino, receiver, LED and resistor — How to connect the TSOP4838 to an Arduino to read the transmitted codes

By using a cheap integrated IR receiver/decoder device (the venerable TSOP4838), most of the hard work is done for you! For a quick visual check that your remote is sending codes, it can easily drive a visible LED with just a resistor for a current-limit, and a capacitor to make the flickering easier to see.

For an encore, [Hulk] shows how to connect this up to an Arduino and how to use the “IRremote” library to see the actual data being transmitted when the buttons are pressed.

It’s not much of a leap to imagine what else you might be able to do with this information once you’ve received it – controlling your own projects, cloning the IR remote codes, automating remote control sequences etc..

It’s a great way to make the invisible visible and add some helpful debug information into the mix.

We recently covered a more complex IR cloner, and if you need to put together a truly universal remote control, then this project may be just what you need.

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DIY Night Vision, Where Four Is Better Than Two

June 26, 2022 by Donald Papp 23 Comments

Night vision projects are great, and the hardware available to hobbyists just gets better and better. [Just Call Me Koko] shows off just such a build using four low-light, IR-sensitive cameras, four displays, and four lenses in 3D printed enclosures mounted to a helmet. Why four? Well, mounting two cameras and displays per eye is the easiest way to yield a wider field of view, and for bonus points, it sure looks extra weird.

At its heart, each of the four segments is the same. A Foxeer Night Cat 3 camera is mounted at the front, its output is connected directly to a 2″ diagonal NTSC/PAL display, and at the rear is a DCX (double convex) lens 38 mm in diameter with a 50 mm focal length. Add a printed enclosure, and the result is a monocular night vision display. Do it three more times and arrange them around one’s eyeballs, and one can make a night vision system with a panoramic view that probably takes only a little getting used to.

How well does it work? [Just Call Me Koko] does some walking around and also tries some target practice while wearing them, and concludes that while they don’t have nearly the clarity of the real deal (the 320×240 resolution displays limit the details one can perceive), they do work fairly well for what they are. Also, the cost of parts is a small fraction of the cost of the real thing, making it a pretty enjoyable project in the end.

The kind of hardware available to hobbyists today is what makes this kind of night vision project accessible, but there’s always the good old high-voltage analog method.

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A Google Pixel 3a with a filter wheel attached to its camera

Hackaday Prize 2022: Multispectral Smartphone Camera Reveals Paintings’ Inner Secrets

June 23, 2022 by Robin Kearey 18 Comments

Multispectral imaging, or photography using wavelengths other than those in ordinary visible light, has various applications ranging from earth observation to forgery detection in art. For example, titanium white and lead white, two pigments used in different historical eras, look identical in visible light but have distinct signatures in the UV range. Similarly, IR imaging can reveal a painting’s inner layers if the pigments used are transparent to IR.

Equipment for such a niche use is naturally quite pricey, so [Sean Billups] decided to transform an older model smartphone into a handheld multispectral camera, which can help him analyze works of art without breaking the bank. It uses the smartphone’s camera together with a filter wheel attachment that enables it to capture different spectral ranges. [Sean] chose to use a Google Pixel 3a, mainly because it’s cheaply available, but also because it has a good image sensor and camera software. Modifying the camera to enable IR and UV imaging turned out to be a bit of a challenge, however.

Image sensors are naturally sensitive to IR and UV, so cameras typically include a filter to block anything but visible light. To remove this filter from the Pixel’s camera [Sean] had to heat the camera module to soften the adhesive, carefully remove the lens, then glue a piece of plastic to the filter and pull it out once the glue had set. Perfecting this process took a bit of trial and error, but once he managed to effect a clear separation between camera and filter it was simply a matter of reattaching the lens, assembling the phone and mounting the filter wheel on its back.

The 3D-printed filter wheel has slots for four different filters, which can enable a variety of IR, UV and polarized-light imaging modes. In the video embedded below [Sean] shows how the IR reflectography mode can help to reveal the underdrawing in an oil painting. The system is designed to be extendable, and [Sean] has already been looking at adding features like IR and UV LEDs, magnifying lenses and even additional sensors like spectrometers.

We’ve seen a handful of multispectral imaging projects before; this drone-mounted system was a contestant for the 2015 Hackaday Prize, while this project contains an excellent primer on UV imaging.

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