Street Photography, With RADAR!

January 20, 2024 by Jenny List 8 Comments

As the art of film photography has gained once more in popularity, some of the accessories from a previous age have been reinvented, as is the case with [tdsepsilon]’s radar rangefinder. Photographers who specialized in up-close-and-personal street photography in the mid-20th century faced the problem of how to focus their cameras. The first single-lens reflex cameras (SLRs) were rare and expensive beasts, so for most this meant a mechanical rangefinder either clipped to the accessory shoe, or if you were lucky, built into the camera.

The modern equivalent uses an inexpensive 24 GHz radar module coupled to an ESP32 board with an OLED display, and fits in a rather neat 3D printed enclosure that sits again in the accessory shoe. It has a 3 meter range perfect for the street photographer, and the distance can easily be read out and dialed in on the lens barrel.

Whenever the revival of film photography is discussed, it’s inevitable that someone will ask why, and point to the futility of using silver halides in a digital age. It’s projects like this one which answer that question, with second-hand SLRs being cheap and plentiful you might ask why use a manual rangefinder over one of them, but the answer lies in the fun of using one to get the perfect shot. Try it, you’ll enjoy it!

Some of us have been known to dabble in film photography, too.

Thanks [Joyce] for the tip.

A Non-Destructive Digital Back For A Classic Leica

May 12, 2023 by Jenny List 16 Comments

As digital photography has become so good, perhaps just too good, at capturing near-perfect pictures, some photographers have ventured back into the world of film. There they have found the imperfections requiring technical skill to cope with that they desire, but they’ve also come face-to-face with the very high cost and sometimes sketchy availability of film stocks. From this has come the so-called post-digital movement which marries analog cameras and lenses with digital sensors, and of this a particularly nice example comes from [Michael Suguitan]. He’s taken a classic Leica M2 rangefinder camera, and built a new back for it containing a Raspberry Pi Zero and sensor.

Perhaps the best thing about this conversion, and something which should propagate forward into other builds, is the way it does not hack or modify the original camera beyond the replacement of the already-removable back. A vintage Leica is a pricey item, so it would be a foolhardy hacker who would proceed to gut it for a digital conversion. Instead he’s mounted everything that makes a digital camera, the sensor, Pi Zero, and screen board, behind the camera body. The Pi shutter trigger comes from the Leica’s flash terminal, meaning that there’s plenty of time for it to take a photo while the shutter is open.

He’s admirably preserved the usage and properties of the Leica, and his photographs as can be seen in the video below the break bear testament to what is possible with the camera. He still has to work with the tiny sensor size though, meaning that all photographs are at a much higher zoom level than on the original. We would love to see a camera conversion like this one that incorporates appropriate lenses to bring the picture to focus on this small sensor.

We won’t own a Leica any time soon, but we like this conversion. It’s by far the most sympathetic, but it’s not the first rangefinder conversion we’ve seen.

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Ultrasonic Sonar Detects Hidden Objects

April 2, 2021 by Bryan Cockfield 14 Comments

While early scientists and inventors famously underestimated the value of radar, through the lens of history we can see how useful it became. Even though radar uses electromagnetic waves to detect objects, the same principle has been used with other propagating waves, most often sound waves. While a well-known use of this is sonar, ultrasonic sensors can also be put to use to make a radar-like system.

This ultrasonic radar project is from [mircemk] who uses a small ultrasonic distance sensor attached to a rotating platform. A motor rotates it around a 180-degree field-of-view and an Arduino takes and records measurements during its trip. It interfaces with an application running on a computer which shows the data in real-time and maps out the location of all of the objects around the sensor. With some upgrades to the code, [mircemk] is also able to extrapolate objects hidden behind other objects as well.

While the ultrasonic sensor used in this project has a range of about a meter, there’s no reason that this principle couldn’t be used for other range-finding devices to extend its working distance. The project is similar to others we’ve seen occasionally before, but the upgrade to the software to allow it to “see” around solid objects is an equally solid upgrade.

Measuring The Time Is A Breeze With This Air Flow Clock

June 25, 2020 by Dan Maloney 15 Comments

If you’ve ever had surgery, and you’re over a certain age, chances are good you’re familiar with the dreaded incentive spirometer. It’s a little plastic device with one or more columns, each of which has a plastic ball in it. The idea is to blow into the thing to float the balls, to ensure that your lungs stay in good shape and reduce the chance of pneumonia. This unique air-powered clock reminds us a little of that device, without all the pain.

Like a spirometer, [Nir Tasher]’s clock has three calibrated tubes, each big enough to hold a foam ball loosely. At the bottom of each tube is a blower whose motor is under PWM control. A laser rangefinder sits below each ball and measures its height; the measurement is used by a PID loop to control the speed of each fan and thus the height of each ball. The video below shows that the balls are actually pretty steady, making the clock easy to read. It doesn’t, however, reveal what the clock sounds like; we’re going to go out on a limb here and guess that it’s pretty noisy. Still, we think it’s a fantastic way to keep time, and unique in the extreme.

[Nir]’s Air Flow clock is an early entry in the 2020 Hackaday Prize, the greatest hardware design contest on Earth. Everyone should enter something, or at least check out the cool things people are coming up with. It’s still early in the process, but there are so many neat projects already. What are you waiting for?

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LIDAR System Isn’t Just A Rangefinder Anymore

March 24, 2020 by Bryan Cockfield 15 Comments

For any project there’s typically a trade-off between quality and cost,as higher quality parts, more features, or any number of aspects of a project can drive its price up. It seems as though [iliasam] has managed to avoid this paradigm entirely with his project. His new LIDAR system knocks it out of the park on accuracy, sampling, and quality, and somehow manages to only cost around $114 in parts.

A LIDAR system works by sending out many pulses of light in different directions, measuring the reflections of that light as it returns. LIDAR systems therefore improve with higher frequency pulses and faster control electronics for both the laser output and the receiving data. This system manages to be accurate to within a few centimeters and works up to 25 meters all while operating at 15 scans per second. The key was a high-powered laser module which can output up to 75 watts for extremely short times. More details can be found at this page (Google Translate from Russian).

Another bonus from this project is that [iliasam] has made everything available from his GitHub page including hardware specifications, so as long as you have a 3D printer this won’t take long to produce either. There’s even detailed breakdowns of how the laser driving circuitry works, and how there are safety features built in to keep anyone’s vision from accidentally getting damaged. Needless to say, this isn’t just a laser rangefinder module but if you want to see how you can repurpose those, [iliasam] can show you that as well.

Hackaday Prize Entry: Rangefinder + Camera = SmartZoom

May 23, 2017 by Donald Papp 17 Comments

The interesting thing about submissions for The Hackaday Prize is seeing unusual projects and concepts that might not otherwise pop up. [ken conrad] has a curious but thoughtfully designed idea for Raspberry Pi-based SmartZoom Imaging that uses a Pi Zero and camera plus some laser emitters to create a device with a very specific capability: a camera that constantly and dynamically resizes the image make the subject appear consistently framed and sized, regardless of its distance from the lens. The idea brings together two separate functions: rangefinding and automated zooming and re-sampling of the camera image.

The Raspberry Pi uses the camera board plus some forward-pointing laser dots as a rangefinder; as long as at least two laser dots are visible on the subject, the distance between the device and the subject can be calculated. The Pi then uses the knowledge of how near or far the subject is to present a final image whose zoom level has been adjusted to match (and offset) the range of the subject from the camera, in effect canceling out the way an object appears larger or smaller based on distance.

We’ve seen visible laser dots as the basis of rangefinding before, but never tied into a zoom function. Doubtlessly, [ken conrad] will update his project with some example applications, but in the meantime we’re left wondering: is there a concrete, practical use case for this unusual device? We have no idea, but we’d certainly have fun trying to find one.

Amazing 3D-Scanner Teardown And Rebuild

February 6, 2017 by Elliot Williams 14 Comments

Pour yourself a nice hot cup of tea, because [iliasam]’s latest work on a laser rangefinder (in Russian, translated here) is a long and interesting read. The shorter version is that he got his hands on a broken laser security scanner, nearly completely reverse-engineered it, got it working again, put it on a Roomba that was able to map out his apartment, and then re-designed it to become a tripod-mounted, full-room 3D scanner. Wow.

The scanner in question has a spinning mirror and a laser time-of-flight ranger, and is designed to shut down machinery when people enter a “no-go” region. As built, it returns ranges along a horizontal plane — it’s a 2D scanner. The conversion to a 3D scanner meant adding another axis, and to do this with sufficient precision required flipping the rig on its side, salvaging the fantastic bearings from a VHS machine, and driving it all with the surprisingly common A4988 stepper driver and an Arduino. A program on a PC reads in the data, and the stepper moves another 0.36 degrees. The results speak for themselves.

This isn’t [iliasam]’s first laser-rangefinder project, naturally. We’ve previously featured his homemade parallax-based ranger for use on a mobile robot, which is equally impressive. What amazes us most about these builds is the near-professional quality of the results pulled off on a shoestring budget.

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