An image of a grey plastic carrying case, approximately the size of an A5 notebook. Inside are darker grey felt lined cubbies with a mirror, piece of glass, a viewfinder, and various small printed parts to assemble a camera lucida.

Camera Lucida – Drawing Better Like It’s 1807

May 23, 2024 by Navarre Bartz 14 Comments

As the debate rages on about the value of AI-generated art, [Chris Borge] printed his own version of another technology that’s been the subject of debate about what constitutes real art. Meet the camera lucida.

Developed in the early part of the nineteenth century by [William Hyde Wollaston], the camera lucida is a seemingly simple device. Using a prism or a mirror and piece of glass, it allows a person to see the world overlaid onto their drawing surface. This moves details like proportions and shading directly to the paper instead of requiring an intermediary step in the artist’s memory. Of course, nothing is a substitute for practice and skill. [Professor Pablo Garcia] relates a story in the video about how [Henry Fox Talbot] was unsatisfied with his drawings made using the device, and how this experience was instrumental in his later photographic experiments.

[Borge]’s own contribution to the camera lucida is a portable version that you can print yourself and assemble for about $20. Featuring a snazzy case that holds all the components nice and snug on laser cut felt, he wanted a version that could go in the field and not require a table. The case also acts as a stand for the camera to sit at an appropriate height so he can sketch landscapes in his lap while out and about.

Interested in more drawing-related hacks? How about this sand drawing bot or some Truly Terrible Dimensioned Drawings?

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Tiny Prisms Let You See What Lies Beneath A BGA Chip

May 1, 2024 by Dan Maloney 14 Comments

Compared to through-hole construction, inspecting SMD construction is a whole other game. Things you thought were small before are almost invisible now, and making sure solder got where it’s supposed to go can be a real chore. Add some ball grid array (BGA) chips into the mix, where the solder joints are not visible by design, and inspection is more a leap of faith than objective proof of results.

Unless, of course, you put the power of optics to work, as [Petteri Aimonen] does with this clever BGA inspection tool. It relies on a pair of tiny prisms to bounce light under one side of a BGA chip and back up the other. The prisms are made from thin sheets of acrylic; [Petteri] didn’t have any 1-mm acrylic sheet on hand, so he harvested material from a razor blade package. The edge of each piece was ground to a 45-degree angle and polished with successively finer grits until the surfaces were highly reflective. One prism was affixed to a small scrap of PCB with eleven SMD LEDs in a row, forming a light pipe that turns the light through 90 degrees. The light source is held along one edge of a BGA, shining light underneath to the other prism, bouncing light through the forest of solder balls and back toward the observer.

The results aren’t exactly crystal clear, which is understandable given the expedient nature of the materials and construction employed. But it’s certainly more than enough to see any gross problems lying below a BGA, like shorts or insufficiently melted solder. [Petteri] reports that flux can be a problem, too, as excess of the stuff can crystalize between pads under the BGA and obstruct the light. A little extra cleaning should help in such cases.

Haven’t tackled a BGA job yet? You might want to get up to speed on that.

New Take On The Camera Obscura Brings Paris Indoors

August 19, 2023 by Dan Maloney 13 Comments

We haven’t checked, but we’ll go out on a limb here and say this is the first project we’ve featured with a BOM that includes “an apartment in Paris with a breathtaking view of the Eiffel Tower.” We suppose there are other places in the world where a giant camera obscura like this would work too, but you’ve got to admit that the view is pretty spectacular.

Of course, a camera obscura is really just a dark room — that’s literally what it means in Latin — with a small aperture to admit light from the outside world. This projects an inverted image on the opposite wall, which must have looked absolutely magical to pre-technical people and honestly is still pretty stunning today. Either way, it’s a low-tech way of seeing the world in a different light. [Mathieu Stern] decided his camera obscura would turn the traditional design on its head. Literally — he wanted an upright image. Luckily, he found a supplier that makes special optics for camera obscura that do just that. It looks like the optic uses a Dove prism to invert the image, or in this case to turn it back into an upright image.

The real hack here was finding the perfect place with just the right view of the Eiffel Tower — not at all an easy task in a medieval city where streets go where they will and buildings tend to block the sightlines. [Mathieu] eventually managed to find just the right place. With a little aluminum foil to make the rented room really obscura and some strategically positioned sheets to improve the projection surface, he was able to project some beautiful images of the landmark and surrounding cityscape in a panorama on the apartment walls. The video below has some stills and time-lapse sequences that are pretty breathtaking.

We’ve seen other camera obscura before, including this mobile version which may have made things easier for [Mathieu], at the price of giving up a lot of the charm.

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Hackaday Links: June 4, 2023

June 4, 2023 by Dan Maloney 9 Comments

A report released this week suggests that 50 flights into its five-flight schedule, the Mars helicopter might be starting to show its age. The report details a protracted communications outage Ingenuity’s flight controllers struggled with for six sols after flight 49 back in April. At first attributed to a “communications shadow” caused by the helicopter’s robotic buddy, Perseverance, moving behind a rocky outcrop and denying line of sight, things got a little dicey once the rover repositioned and there was still no joy. Since the helicopter has now graduated from “technology demonstration” to a full-fledged member of the team tasked with scouting locations for the rover while respecting the no-fly zone around it, it was essential to get it flying again. Several attempts to upload a flight plan failed with nothing but an acknowledgment signal from the helicopter, but a final attempt got the program uploaded and flight 50 was a complete if belated success. So that’s good, but the worrying news is that since Sol 685, the helicopter has been switching in and out of nighttime survival mode. What that portends is unclear, but no matter how amazing the engineering is, there’s only so much that can be asked on Ingenuity before something finally gives.

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Holograms Display Time With ESP32

May 5, 2023 by Bryan Cockfield 30 Comments

Holograms and holographic imagery are typically viewed within the frame of science fiction, with perhaps the most iconic examples being Princess Leia’s message to Obi-Wan in Star Wars, or the holodecks from Star Trek. In reality, holograms have been around for a surprising amount of time, with early holographic images being produced in the late 1940s. There are plenty of uses outside of imagery for modern holographic systems as well, and it’s a common enough technology that it’s possible to construct one using an ESP32 as well.

In this build, [Fiberpunk] demonstrates the construction and operation of a holographic clock. The image is three-dimensional and somewhat transparent and is driven by an ESP32 microcontroller. The display is based around a beamsplitter prism which, when viewed from the front, is almost completely invisible to the viewer. The ESP32 is housed in a casing beneath this prism, and [Fiberpunk] has two firmware versions available for the device. The first is the clock which displays an image as well as the time, and the second is more of a demonstration which can show more in-depth 3D videos using gcode models and also has motion sensing controls.

For anyone interested in holography, a platform like this is might make an excellent entry point to explore, and with the source for this build available becomes even easier. It’s almost certainly less expensive than these 3D printers that can turn out custom holographic images, and has the added benefit of being customizable and programmable as well.

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Reflecting On A Queueing Prism Leads To Unexpected Results

May 7, 2022 by Matthew Carlson 6 Comments

Computers are difficult enough to reason about when there’s just a single thread doing one task. There are dozens of cores in today’s modern processor world, and your program might try to take advantage of using more than just one. Things happening concurrently makes the number of states and interactions explode in to a mess we as humans are likely going to have trouble understanding. So, like [Hillel], you might turn to the computer to try and model those interactions.

The model in question is a task queue. Things are added to the pile, and “workers” grab one from the pile and process it. There are two metrics used to measure the effectiveness of a task queue: throughput and latency. Throughput is the number of things you can do per second (like this maximum throughput 3d printer), while latency is the amount of time it takes to finish one thing. Continue reading “Reflecting On A Queueing Prism Leads To Unexpected Results” →

Light projected through prisms on to laser-cut letters submerged in water.

YOU Are A Projection Of Your Influences

November 18, 2021 by Kristina Panos 5 Comments

Who are you? No, who are you really? You’re an amalgamation of influences from your family, your friends, the media, and the parasocial relationships you have with fictional characters. It’s okay; we all are. It can’t be helped that there’s a lot of it about.

[Kim Pimmel]’s YOU examines this question of identity in the form of projected typography. YOU are solidly laser-cut at birth, but then come the influences — the water of everyday life that surrounds you, the lights that mask your dread or lay you bare, and the prisms of circumstance that twist the light into brilliant patterns that burn memories into your brain.

In this case, the light comes from a hacked camping headlamp that was past its prime. [Kim] laser-cut the letters from acrylic and submerged them in water, which can be manipulated to enhance the effect and mimic the turmoil of life. For added effect, [Kim] held prisms in the light’s path to refract it and cause the patterns to dance. Be sure to check it out after the break, and don’t forget to turn on the sound so you can hear [Kim]’s original composition.

Want to see more trippy typography? Check out this vector art that started as Perlin noise.

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