Build Your Own RGB Fill Light For Photography

April 19, 2024 by Lewin Day 9 Comments

Photography is all about light, and capturing it for posterity. As any experienced photographer will tell you, getting the right lighting is key to getting a good shot. To help in that regard, you might like to have a fill light. If you follow [tobychui]’s example, you can build your own!

The build relies on addressable WS2812B LEDs as the core of the design. While they’re not necessarily the fanciest LEDs for balanced light output, they are RGB LEDs, so they can put out a ton of different colors for different stylistic effects. The LEDs are under the command of a Wemos D1, which provides a WiFI connection for wireless control of the light.

[tobychui] did a nice job of building a PCB for the project, including heatsinking to keep the array of 49 LEDs nice and cool. The whole assembly is all put together inside a 3D printed housing to keep it neat and tidy. Control is either via onboard buttons or over the WiFi connection.

Files are on GitHub if you’re seeking inspiration or want to duplicate the build for yourself. We’ve seen some other similar builds before, too. Meanwhile, if you’re cooking up your own rad photography hacks, don’t hesitate to let us know!

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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The F Number On A Lens Means Something? Who Knew!

March 18, 2024 by Jenny List 58 Comments

The Raspberry Pi has provided experimenters with many channels of enquiry, and for me perhaps the furthest into uncharted waters it has led me has come through its camera interface. At a superficial level I can plug in one of the ready-made modules with a built-in tiny lens, but as I experiment with the naked sensors of the HD module and a deconstructed Chinese miniature sensor it’s taken me further into camera design than I’d expected.

I’m using them with extra lenses to make full-frame captures of vintage film cameras, in the first instance 8 mm movie cameras but as I experiment more, even 35 mm still cameras. As I’m now channeling the light-gathering ability of a relatively huge area of 1970s glass into a tiny sensor designed for a miniature lens, I’m discovering that maybe too much light is not a good thing. At this point instead of winging it I found it was maybe a good idea to learn a bit about lenses, and that’s how I started to understand what those F-numbers mean.

More Than The Ring You Twiddle To Get The Exposure Right

lose-up of the end of a lens, showing the F-number range — The F-number range of a 1990s Sigma consumer-grade zoom lens.

I’m not a photographer, instead I’m an engineer who likes tinkering with cameras and who takes photographs as part of her work but using the camera as a tool. Thus the f-stop ring has always been for me simply the thing you twiddle when you want to bring the exposure into range, and which has an effect on depth of field.

The numbers were always just numbers, until suddenly I had to understand them for my projects to work. So the first number I had to learn about was the F-number of the lens itself. It’s usually printed on the front next to the focal length and expressed as a ratio of the diameter of the light entrance to the lens focal length. Looking around my bench I see numbers ranging from 1:1 for a Canon 8mm camera to 1:2.8 for a 1950s Braun Paxette 35 mm camera, but it seems that around 1:1.2 is where most 8 mm cameras sit and 1:2 is around where I’m seeing 35 mm kit lenses. The F-stop ring controls an adjustable aperture, and the numbers correspond to that ratio. So that 1:2 kit lens is only 1:2 at the F2 setting, and becomes 1:16 at the F16 setting.

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Stereo Photography With Smartphones Made Better With Syncing

February 21, 2024 by Maya Posch 16 Comments

Stereo photography has been around for almost as long as photography itself, and it remains a popular way to capture a scene in its 3D glory. Yet despite the fact that pretty much everyone carries one or more cameras with them every day in the form of a smartphone, carrying a stereo photography-capable system with you remains tricky. As [Pascal Martiné] explains in a How-To article, although you can take two smartphones with you, syncing up both cameras to get a stereo image isn’t so straightforward, even though this is essential if you want to prevent jarring shifts between the left and right image.

Custom made twin shutter. (Credit: Pascal Martiné)

Fortunately, having two of the exact same smartphone with the exact same camera modules is not an absolute requirement, as apps like i3DStereoid offer auto-adjustments. But activating the camera trigger on each phone is essential. The usual assortment of wireless remote triggers don’t work well here, and the twin-pairing in i3DStereoid had too much delay for dynamic scenes. This left the wired remote trigger option, but with a dearth of existing stereo trigger options [Pascal] was forced to make his own for two iPhones out of Apple Lightning cables and wired earbud volume controls.

Although the initial prototype more or less worked, [Pascal] found that each iPhone would often ‘decide’ to release the trigger at a slightly different time, requiring multiple attempts at the perfect shot. This led him down a rabbit hole of investigating different camera apps and configurations to make shutter delay as deterministic as possible. Much of this turned out to be due to auto exposure and auto focus, with enabling AE/AF lock drastically increasing the success rate, though this has to be done manually before each shot as an extra step.

With this one tweak, he found that most of the stereo photo pairs are now perfectly synced, while occasionally there is about a ~3 ms jitter, the cause of which he hasn’t tracked down yet, but which could be due to the camera app or iOS being busy with something else.

In the end, this iPhone-based stereo photography setup might not be as reliable or capable as some of the purpose-built rigs we’ve covered over the years, but it does get extra points for portability.

Watch The OpenScan DIY 3D Scanner In Action

February 19, 2024 by Donald Papp 20 Comments

[TeachingTech] has a video covering the OpenScan Mini that does a great job of showing the workflow, hardware, and processing method for turning small objects into high-quality 3D models. If you’re at all interested but unsure where or how to start, the video makes an excellent guide.

We’ve covered the OpenScan project in the past, and the project has progressed quite a bit since then. [TeachingTech] demonstrates scanning a number of small and intricate objects, including a key, to create 3D models with excellent dimensional accuracy.

[Thomas Megel]’s OpenScan project is a DIY project that, at its heart, is an automated camera rig that takes a series of highly-controlled photographs. Those photographs are then used in a process called photogrammetry to generate a 3D model from the source images. Since the quality of the source images is absolutely critical to getting good results, the OpenScan hardware platform plays a pivotal role.

Once one has good quality images, the photogrammetry process itself can be done in any number of ways. One can feed images from OpenScan into a program like Meshroom, or one may choose to use the optional cloud service that OpenScan offers (originally created as an internal tool, it is made available as a convenient processing option.)

It’s really nice to have a video showing how the whole workflow works, and highlighting the quality of the results as well as contrasting them with other 3D scanning methods. We’ve previously talked about 3D scanning and what it does (and doesn’t) do well, and the results from the OpenScan Mini are fantastic. It might be limited to small objects, but it does a wonderful job on them. See it all for yourself in the video below.

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All-Sky Camera Checks For Aurora

February 16, 2024 by Bryan Cockfield 4 Comments

The aurora borealis (and its southern equivalent, the aurora australis) is a fleeting and somewhat rare phenomenon that produces vivid curtains of color in the sky at extreme latitudes. It’s a common tourist activity to travel to areas where the aurora is more prevalent in order to catch a glimpse of it. The best opportunities are in the winter though, and since most people don’t want to spend hours outside on a cold night night in high latitudes, an all-sky camera like this one from [Frank] can help notify its users when an aurora is happening.

Because of the extreme temperatures involved, this is a little more involved than simply pointing a camera at the sky and hoping for the best. The enclosure and all electronics need to be able to withstand -50°C and operate at at least -30. For the enclosure, [Frank] is going with PVC tubing with a clear dome glued into a top fits to the end of the pipe, providing a water-resistant enclosure. A Raspberry Pi with a wide-angle lens camera sits on a 3D printed carriage so it can easily slide inside. The electronics use power-over-ethernet (PoE) rather than a battery due to the temperature extremes, which conveniently provides networking capabilities for viewing the images.

This is only part one of this build — in part two [Frank] is planning to build a system which can use this camera assembly to detect the aurora automatically and send out notifications when it sees it. Watching the night sky from the comfort of a warm house or sauna isn’t the only reason for putting an all-sky camera to use, either. They can also be used to observe meteors as they fall and then triangulate the position of the meteorites on the ground.

A Mouse Becomes A Camera

January 29, 2024 by Jenny List 24 Comments

If your pointing device is a mouse, turn it over. The chances are you’ll see a red LED light if you’re not seriously old-school and your mouse has a ball, this light serves as the illumination for a very simple camera sensor. The mouse electronics do their thing by looking for movement in the resulting image, but it should be possible to pull out the data and repurpose the sensor as a digital camera. [Doctor Volt] has a new video showing just that with the innards of a Logitech peripheral.

The mouse contains a microcontroller and the camera part, which fortunately has an SPI interface. The correct register to query the sensor information was deduced, and as if my magic, an image appeared. An M12 lens provided focus with a handy 3D printed mount, and the board went back into the mouse case as a housing. The pictures have something of the Game Boy camera about them, being low-res and monochrome, but it’s still a neat hack.

If you’d like to give it a go you can find the code in a GitHub repository. You might find it worth finding a gaming mouse though, for the much higher resolution sensor.

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