Amazing 3D-Scanner Teardown And Rebuild

February 6, 2017 by 14 Comments

0_10ea1b_776cdc71_origPour 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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Custom Sensor Head Turns 3D Printer Into Capacitive Scanner

January 13, 2017 by 25 Comments

The best thing about owning a 3D printer or CNC router may not just be what you can additively or subtractively create with it. With a little imagination you can turn your machine into a 3D scanner, and using capacitive sensors to image items turns out to be an interesting project.

[Nelson]’s scanner idea came from fiddling with some capacitive sensors at work, and with a high-resolution capacitance-to-digital sensor chip in hand, he set about building a scan head for his printer. In differential mode, the FDC2212 sensor chip uses an external LC tank circuit with two plain sensor plates set close to each other. The sensor plates form an air-dielectric variable capacitor, and the presence of an object can be detected with high sensitivity. [Nelson]’s custom sensor board and controller ride on a 3D-printed bracket and scan over the target on the printer bed. Initial results were fuzzy, but after compensating for room temperature variations and doing a little filtering on the raw data, the scans were… still pretty fuzzy. But there’s an image there, and it’s something to work with.

Need a slightly more approachable project to get your feet wet with capacitive sensors? Maybe you should use your phone’s touchscreen as a 2D-capacitive scanner.

[via r/electronics]

Hackaday Prize Entry: An Open Source Retina Scanner

August 10, 2016 by 16 Comments

An ophthalmoscope is a device used to examine the back of the eye. This is useful for diagnosing everything from glaucoma, diabetic retinopathy, to detecting brain tumors. As you would expect from anything related to medicine, these devices cost a lot, making them inaccessible for most of the world’s population. This project for the Hackaday Prize is for an ophthalmoscope that can be built for under $400.

An ophthalmoscope is a relatively simple device, that really only requires a clinician to wear a head-mounted lamp and hold a condensing lens in front of the patient’s eye. Light is reflected off the retina and into the clinician’s view. Of course, the simplest ophthalmoscope requires a bit of training to get right, and there’s’ no chance of being able to take a picture of a patient’s retina to share with other clinicians.

The Open Indirect Ophthalmoscope gets around these problems by using a digital camera in the form of a Raspberry Pi camera module. This camera, with the help of a 3 W LED, is able to image the back of the eye, snap a picture, and send that image anywhere in the world. It’s a simple device that can be constructed from a few mirrors, a cheap lens, and a few 3D-printed parts, but is still very valuable for the detection of ophthalmological disorders.

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Keytar Made Out Of A Scanner To Make Even The 80s Jealous

August 4, 2016 by 11 Comments

Do any of you stay awake at night agonizing over how the keytar could get even cooler? The 80s are over, so we know none of us do. Yet here we are, [James Cochrane] has gone out and turned a HP ScanJet Keytar for no apparent reason other than he thought it’d be cool. Don’t bring the 80’s back [James], the world is still recovering from the last time.

Kidding aside (except for the part of not bringing the 80s back), the keytar build is simple, but pretty cool. [James] took an Arduino, a MIDI interface, and a stepper motor driver and integrated it into some of the scanner’s original features. The travel that used to run the optics back and forth now produce the sound; the case of the scanner provides the resonance. He uses a sensor to detect when he’s at the end of the scanner’s travel and it instantly reverses to avoid collision.

A off-the-shelf MIDI keyboard acts as the input for the instrument. As you can hear in the video after the break; it’s not the worst sounding instrument in this age of digital music. As a bonus, he has an additional tutorial on making any stepper motor a MIDI device at the end of the video.

If you don’t have an HP ScanJet lying around, but you are up to your ears in surplus Commodore 64s, we’ve got another build you should check out.

The Most Useless Book Scanner

August 1, 2016 by 9 Comments

How do artificial intelligences get so intelligent? The same way we do, they get a library card and head on over to read up on their favorite topics. Or at least that’s the joke that [Jakob Werner] is playing with in his automaton art piece, “A Machine Learning” (Google translated here).

Simulating a reading machine, a pair of eyeballs on stalks scan left-right and slowly work their way down the page as another arm swings around and flips to the next one. It’s all done with hand-crafted wooden gears, in contrast to the high-tech subject matter. It’s an art piece, and you can tell that [Jakob] has paid attention to how it looks. (The all-wooden rollers are sweet.) But it’s also a “useless machine” with a punch-line.

Is it a Turing test? How can we tell that the machine isn’t reading? What about “real” AIs? Are they learning or do they just seem to be? OK, Google’s DeepMind is made of silicon and electricity instead of wood, but does that actually change anything? It’s art, so you get license to think crazy thoughts like this.

We’ve covered a few, less conceptual, useless machines here. Here is one of our favorite. Don’t hesitate to peruse them all.

Six Years Of Work And Rationale In A DIY Book Scanner Documented

April 29, 2016 by 6 Comments

[Daniel Reetz] spent six years working as a Disney engineer during the day and on his book scanner, the archivist at night. Some time last year, [Daniel] decided enough is enough, got married, and retired from the book scanner business. There’s a bit more to it than that, but before leaving he decided to dump, not just the design, but the entire rationale behind the design into a twenty-two thousand word document.

One of his big theses in this document, is his perceived failure of the open hardware movement. The licenses aren’t adequate, as they are based on copyright law that only applies to software. This makes it impossible to enforce in practice, which is why he released the entire design as public domain. He also feels that open hardware shares design, but not rationale. In his mind this is useless when encouraging improvement, and we tend to agree. In the end rationale is the useful thing, or the source code, behind a design that truly matters. So, putting his money time where his mouth is, he wrote down the rationale behind his scanner.

The rationale contains a lot of interesting things. At a first glance the book scanner almost seems a simple design, not the culmination of so much work. Though, once we began to read through his document, we began to understand why he made the choices he did. There’s so much to getting a good scan without destroying the book. For example, one needs a light that doesn’t lose any color information. It doesn’t have to be perfect, as the software can correct the white balance. However, it can’t lean too far away from the natural spectrum, it can’t be too bright, and it can’t be uneven, and it can’t be prohibitively expensive. A lot of thought went into the tent light design.

[Daniel]’s book scanners are immensely popular, and are being used all over the world. He’s certainly made an impact, and the community that formed around his project continues to grow without him. He made some interesting points, and if anything wrote a really good build and design log for the rest of us to learn from.

Milk-Based 3D Scanner

April 16, 2016 by 32 Comments

3D scanners don’t have to be expensive or high-tech because all of the magic goes on in software. The hardware setup just needs to gather a bunch of cross-sections. In perhaps the lowest-tech of scanners that we’ve seen, [yenfre]’s GotMesh scanner uses milk.

Specifically, the apparatus is a pair of boxes, one with a hole drilled in it. You put the object in the top box and fill it with milk to cover the object. A camera takes pictures of the outline of the object in the milk as it drains out the hole, these get stitched together, and voilà.

There are limitations to this method. The object gets soaked in milk, so it won’t work for scanning sand-castles. (It’s optimally suited for chocolate-chip cookies, in our opinion.) If the camera is located directly above, the objects have to get wider as the milk drains out. You can do multiple takes with the object rotated at different angles or use multiple cameras to solve this problem. The edge-detection software will have issues with white objects in milk, so maybe you’ll want to scan that porcelain figurine in coffee, but you get the idea. More seriously, the rate of milk drain will slow down a bit as the amount of milk in the upper box decreases. This could also be handled in software.

In all, we’re not surprised that we don’t see commercial versions of this device, but we love the idea. It’s based on this experiment where they dip a guy in a tank of ink! If you just drank all your milk, but still have a line-laser lying around, maybe this build is more your speed. What’s your cheapest 3D scanner solution?