Lock-In Thermography On A Cheap IR Camera

October 28, 2024 by Dan Maloney 16 Comments

Seeing the unseen is one of the great things about using an infrared (IR) camera, and even the cheap-ish ones that plug into a smartphone can dramatically improve your hardware debugging game. But even fancy and expensive IR cameras have their limits, and may miss subtle temperature changes that indicate a problem. Luckily, there’s a trick that improves the thermal resolution of even the lowliest IR camera, and all it takes is a little tweak to the device under test and some simple math.

According to [Dmytro], “lock-in thermography” is so simple that his exploration of the topic was just a side quest in a larger project that delved into the innards of a Xinfrared Xtherm II T2S+ camera. The idea is to periodically modulate the heat produced by the device under test, typically by ramping the power supply voltage up and down. IR images are taken in synch with the modulation, with each frame having a sine and cosine scaling factor applied to each pixel. The frames are averaged together over an integration period to create both in-phase and out-of-phase images, which can reveal thermal details that were previously unseen.

With some primary literature in hand, [Dmytro] cobbled together some simple code to automate the entire lock-in process. His first test subject was a de-capped AD9042 ADC, with power to the chip modulated by a MOSFET attached to a Raspberry Pi Pico. Integrating the images over just ten seconds provided remarkably detailed images of the die of the chip, far more detailed than the live view. He also pointed the camera at the Pico itself, programmed it to blink the LED slowly, and was clearly able to see heating in the LED and onboard DC-DC converter.

The potential of lock-in thermography for die-level debugging is pretty exciting, especially given how accessible it seems to be. The process reminds us a little of other “seeing the unseeable” techniques, like those neat acoustic cameras that make diagnosing machine vibrations easier, or even measuring blood pressure by watching the subtle change in color of someone’s skin as the capillaries fill.

An Arduino Triggers A Flash With Sound

October 15, 2024 by Jenny List 37 Comments

To capture an instant on film or sensor with a camera, you usually need a fast shutter. But alternately a flash can be triggered with the scene in the dark and the shutter wide open. It’s this latter technique which PetaPixel are looking at courtesy of the high-speed class at Rochester Institute of Technology. They’re using a cheap sound sensor module and an Arduino to catch instantaneous photographs, with students caught in the act of popping balloons.

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Barbie’s Video Has Never Looked So Good

October 8, 2024 by Jenny List 8 Comments

For those who missed it, there’s been something of a quiet revolution in the world of analogue video over the last year, due to the arrival of inexpensive “MiniDVR” devices. These little modules are a complete video recorder including battery, recording PAL or NTSC composite video and audio to SD card. They’ve become the box of choice for camcorder enthusiasts, but that’s not where the fun ends. [Max Vega] has taken a Barbie video camera toy from 2001 and added a MiniDVR to make it into a fully self-contained novelty camcorder. But this isn’t a simple case of duct-taping the DVR to the toy, instead it’s a comprehensive upgrade resulting in a device which could almost have been a real product.

The original toy had a small transmitter which could send over a short distance to a receiver that connected to a domestic VCR, so all that circuitry had to go. The camera itself is a small enough module in the fake lens assembly, with an easily identifiable output cable with the required composite signal. The video below the break steps through the proces of making the space for the MiniDVR module, and putting in extensions for all its buttons, and the SD card. Finally it has a new power supply module with an associated USB-C input, providing juice to both DVR and camera.

The result has what we can only describe as a pleasingly retro feel, in that it’s not of high quality and the colour is, well, Never The Same. But when a smartphone can record HD video that’s not the point, instead it’s there to be a retro toy, and in that it succeeds completely.

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An Open Source Mirrorless Camera You’d Want To Use

October 5, 2024 by Jenny List 18 Comments

Making a digital camera is a project that appears easy enough, but it’s one whose complexity increases depending on the level to which a designer is prepared to go. At the simplest a Raspberry Pi and camera module can be stuck in a 3D printed case, but in that case, the difficult work of getting the drivers and electronics sorted out has already been done for you.

At the other end of the scale there’s [Wenting Zhang]’s open source mirrorless digital camera project, in which the design and construction of a full-frame CCD digital camera has been taken back to first principles. To understand the scale of this task, this process employs large teams of engineers when a camera company does it, and while it’s taken a few years and the software isn’t perhaps as polished as your Sony or Canon, the fact it’s been done at all is extremely impressive.

Inside is a Kodak full-frame sensor behind the Sony E-mount lens, for which all the complex CCD timing and acquisition circuitry has been implemented. The brains of the show lie in a Xilinx Zynq ARM-and-FPGA in a stack of boards with a power board and the CCD board. The controls and battery are in a grip, and a large display is on the back of the unit.

We featured an earlier version of this project last year, and this version is a much better development with something like the ergonomics, control, and interface you would expect from a modern consumer camera. The screen update is still a little slow and there are doubtless many tweaks to come, but this really feels close to being a camera you’d want to try. There’s an assembly video which we’ve placed below the break, feast your eyes on it.

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Shoot Smooth Video From Your Phone With The Syringe Slider

September 29, 2024 by Donald Papp 5 Comments

We love the idea [Btoretsukuru] shared that uses a simple setup called the Syringe Slider to take smoothly-tracked video footage of small scenes like model trains in action. The post is in Japanese, but the video is very much “show, don’t tell” and it’s perfectly clear how it all works. The results look fantastic!

The device consists of a frame that forms a sort of enclosed track in which one’s mobile phone can slide horizontally. The phone butts up against the plunger of an ordinary syringe built into the frame. As the phone is pushed along, it depresses the plunger which puts up enough resistance to turn the phone’s slide into a slow, even, and smooth glide. Want to fine-tune the resistance and therefore the performance? Simply attach different diameter tips to the syringe.

The results speak for themselves, and it’s a fantastically clever bit of work. There are plenty of DIY slider designs (some of which get amazingly complex) but they are rarely small things that can be easily gotten up close and personal with small subjects like mini train terrain.

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Copper Bling Keeps Camera Chill

September 25, 2024 by Dan Maloney 4 Comments

Every action camera these days seems prone to overheating and sudden shutdowns after mere minutes of continuous operation. It can be a real pain, especially when the only heat problem a photographer might face back in the day was fogged film from storing a camera in a hot car. Then again, the things a digital camera can do while it’s not overheated are pretty amazing compared to analog cameras. Win some, lose some, right?

Maybe not. [Zachary Tong], having recently acquired an Insta360 digital camera, went to extremes to solve its overheating problem with this slick external heat sink project. The camera sports two image sensor assemblies back-to-back with fisheye lenses, allowing it to capture 360° images, but at the cost of rapidly overheating. [Zach]’s teardown revealed a pretty sophisticated thermal design that at least attempts to deal with the excess heat, including an aluminum heat spreader built into the case, which would be the target of the mod.

He attached a custom copper heatsink to a section of the heat spreader, which had been carefully milled flat to provide the best thermal contact. [Zach] used a fancy boron nitride heat transfer paste and attached the heat sink to the spreader with epoxy. A separate aluminum enclosure was bonded to the copper heat sink, giving [Zach] a place to mount his audio sync and timecode recorder and providing extra thermal mass.

Does it help? It sure seems to; where [Zach] was previously getting about twenty minutes before thermal shutdown with both cameras running, the heatsink-adorned rig was able to run about six times longer, with the battery giving out first. True, the heatsink takes away from the original sleek lines of the camera and might make it tough to use while snowboarding or surfing, but it’s still more portable than some external camera heatsinks we’ve seen. And besides, the copper is pretty gorgeous. Continue reading “Copper Bling Keeps Camera Chill” →

Inviting The Public To Take Stereo Photos For Science

September 20, 2024 by Al Williams 14 Comments

[Lynnadeng]’s team wanted to monitor the Los Angeles River over time and wanted citizen scientists — or anyone, for that matter — to help. They built a dual phone holder to allow random passersby to use their phones to take photos. A QR code lets them easily send the pictures to the team. The 3D printed holder is fixed in place and has a known gap that allows stereo reconstruction from pairs of photos.

Of course, people aren’t going to know what to do, so you need a sign with instructions along with the QR code. One advantage to this scheme is that it’s cheap. All the camera hardware is in the public’s phone. Of course, you still have to make the holder robust to the elements, but that’s not nearly as difficult as supplying power and weatherproofing cameras and radios.

The real interesting part is the software. At first, we were disappointed that the post had a dead link to GitHub, but it was easy enough to find the correct one. In some cases, people will use a single camera, so 3D reconstruction isn’t always possible.

We love citizen science around here. No matter where you live, there are many opportunities to contribute.