THP Semifinalst: Laser Solder Paste

laser

A relative latecomer to The Hackaday Prize, [AltMarcxs] has nevertheless come up with a very interesting tool for fabrication, the likes of which no one has ever seen before. It’s a rotating laser soldering paste applicator, meant to be an add-on to a CNC machine. What does it do? RIght now it looks extremely cool while being an immense time sink for [AltMarcxs], but the potential is there for being much more than that, ranging from a pick and place machine that also dispenses solder paste, to the closest thing you’ll ever get to a carbon fiber printer.

[AltMarcxs]‘s build consists of two 3W laser diodes focused just beyond the tip of the syringe. The syringe dispenses solder paste, and rotating the diodes around, [Alt] is able to put a melted solder blob anywhere on a piece of perfboard. He put up a reasonably well focused video demonstrating this.

With a few homebrew pick and place machines making the semifinalist cut for The Hackaday Prize, it’s easy to see the utility of something like this: Putting a board in a machine, pressing a button, and waiting a bit for a completely populated and soldered board is a dream of the electronic hobbyist rivaled only by a cheap and easy way to make PCBs at home. [AltMarxcs]‘s machine could be one step on the way to this, but there are a few other ideas he’d like to explore first.

The build also has wire feeders that allow a bit of copper wire to be soldered to the newly formed metal blob. There are plans to replace this with a composite fiber, replace the paste in the syringe with a UV resin, cut the fiber and cure the resin with the laser, and build something much better than other carbon fiber 3D printers we’ve seen before.


SpaceWrencherThe project featured in this post is a semifinalist in The Hackaday Prize. 

A 3D(ollar) Scanner

scanner

Once you have a 3D printer, making copies of objects like a futuristic Xerox machine is the name of the game. There are, of course, 3D scanners available for hundreds of dollars, but [Joshua] wanted something a bit cheaper. He built his own 3D scanner for exactly $2.73 in parts, salvaging the rest from the parts bin at his local hackerspace.

[Josh]‘s scanner is pretty much just a lazy suzan (that’s where he spent the money), with a stepper motor drive. A beam of laser light shines on whatever object is placed on the lazy suzan, and a USB webcam feeds the data to a computer. The build is heavily influenced from this Instructables build, but [Josh] has a few tricks up his sleeve: this is the only laser/camera 3D scanner that can solve a point cloud with the camera in any vertical position. This potentially means algorithmic calibration, and having the copied and printed object come out the same size as the original. You can check out that code on the git.

Future improvements to [Josh]‘s 3D scanner include the ability to output point clouds and STLs, meaning anyone can go straight from scanning an object to slicing it for a 3D printer. That’s a lot of interesting software features for something that was basically pulled out of the trash.

A DIY Geomagnetic Observatory

Magnetometer observatory

[Dr. Fortin] teaches physics at a French High School, and to get his students interested in the natural world around them, he built a geomagnetic observatory, able to tell his students if they have a chance at seeing an aurora, or if a large truck just drove by.

We’ve seen this sort of device before, and the basic construction is extremely similar – a laser shines on a mirror attached to magnets. When a change occurs in the local magnetic field, the mirror rotates slightly and the laser beam is deflected. Older versions have used photoresistors, but [the doctor] is shining his laser on a piece of paper and logging everything with a webcam and a bit of OpenCV.

The design is a huge improvement over earlier DIY attempts at measuring the local magnetic field, if only because the baseline between the webcam and mirror are so long. When set up in his house, the magnetometer can detect cars parked in front of his building, but the data he’s collecting (French, but it’s just a bunch of graphs) is comparable to the official Russian magnetic field data.

THP Entry: A Repurposed Luminiferous Aether Detector

laserIn the late 1800s, no one knew what light was. Everyone knew it behaved like a wave some of the time, but all waves need to travel through some propagation medium. This propagation medium was called the luminiferous aether and an attempt to detect and quantify this aether led to one of the coolest experimental setups of all time: the Michelson-Morely experiment. It was a huge interferometer mounted on a gigantic slab of marble floating in a pool of mercury. By rotating the interferometer, Michelson and Morely expected to see a small phase shift in the interferometer, both confirming the existence of a luminiferous aether and giving them how fast the Earth moved through this medium.

Of course, there was no phase shift, throwing physics into chaos for a few years. When [Beaglebreath] first learned about the Michelson-Morely interferometer he was amazed by the experimental setup. He’s built a few interferometers over the years, but for The Hackaday Prize, he’s making something useful out of one of these luminiferous aether detectors: a functional laser rangefinder capable of measuring distances of up to 60 inches with an error of 0.000005 inches.

The core of the system is an HP 5528A laser interferometer system. [Beaglebreath] has been collecting the individual components of this system off of eBay for several years now, and amazingly, he has all the parts. That’s dedication, right there. This laser interferometer system will be mounted to a simple camera slider, and with the interferometer measurements, humidity and temperature measurements, and some interesting code (running on one of these for hacker cred), [Beaglebreath] stands a good shot at measuring things very, very accurately.

The devil is in the details, and when you’re measuring things this precisely there are a lot of details. The original Michelson-Morely interferometer was affected by passing horse-drawn carriages and even distant lightning storms. While [Beaglebreath] isn’t using as long of a beam path as the OG interferometer, he’ll still have a lot of bugs to squash to bring this project to its full potential.


SpaceWrencherThe project featured in this post is an entry in The Hackaday Prize. Build something awesome and win a trip to space or hundreds of other prizes.

Pew Pew! An Arduino Based Laser Rangefinder

Arduino Laser Rangefinder
Lasers are some of the coolest devices around. We can use them to cut things, create laser light shows, and also as a rangefinder.[Ignas] wrote in to tell us about [Berryjam's] AMAZING write-up on creating an Arduino based laser rangefinder. This post is definitely worth reading.

Inspired by a Arduino based LIDAR system, [Berryjam] decided that he wanted to successfully use an affordable Open Source Laser RangeFinder (OSLRF-01) from LightWare. The article starts off by going over the basics of how to measure distance with a laser based system. You measure the time between an outgoing laser pulse and the reflected return pulse; this time directly relates to the distance of the object. Sounds simple? In practice, it is not as simple as it may seem. [Berryjam] has done a great job doing some real world testing of this device, with nice plots to top it all off. After fiddling with the threshold and some other aspects of the code, the resulting accuracy is quite good.

Recently, we have seen more projects utilizing lasers for range-finding, including LIDAR projects. It is very exciting to see such high-end sensors making their way into the maker/hacker realm. If you have a related laser project, be sure to let us know!

How To Laser Cut Mylar Solder Stencils

Solder Stencil

When you think about the difficulties of working with surface mount components, the first thing that often comes to mind is trying to solder those tiny little parts. Instead of soldering those parts by hand, you can actually apply solder paste to the pads and place all of the components on at once. You can then heat up the entire board so all of the parts are soldered simultaneously. It sounds so much easier! The only problem is you then need a solder stencil. You somehow have to get a thin sheet of material that has a perfectly sized hole where all of your solder pads are. It’s not exactly trivial to cut them out by hand.

[Juan] recently learned a new trick to make cutting solder stencils a less painful process. He uses a laser cutter to cut Mylar sheets into stencils. [Juan] appears to be using EagleCAD and Express PCB. Both tools are available for free to hobbyists. The first step in the process is to export the top and bottom cream layers from your CAD software.

The next step is to shrink the size of the solder pads just a little bit. This is to compensate for the inevitable melting that will be caused by the heat from the laser. Without this step, the pads will likely end up a little bit too big. If your CAD software exports the files as gerbers, [Juan] explains how to re-size the pads using ViewMate. If they are exported as DXF files, he explains how to scale them using AutoCAD. The re-sized file is then exported as a PDF.

[Juan's] trick is to actually cut two pieces of 7mil Mylar at the same time. The laser must be calibrated to cut all the way through the top sheet, but only part way into the bottom piece. The laser ends up slightly melting the edges of the little cut out squares. These then get stuck to the bottom Mylar sheet. When you are all done cutting, you can simply pull the sheets apart and end up with one perfect solder stencil and one scrap piece. [Juan] used a Full Spectrum 120W laser cutter at Dallas Makerspace. If you happen to have this same machine, he actually included all of the laser settings on his site.

Using Echoes of Light to Turn Walls into Mirrors

using a wall as a mirror

 

[Matthias] recently published a paper he worked on, in which he details how his group managed to reconstruct a hidden scene using a wall as a mirror in a reasonably priced manner. A modified time-of-flight camera (PMD CamBoard Nano) was used to precisely know when short bursts of light were coming back to its sensor. In the picture shown above the blue represents the camera’s field of view. The green box is the 1.5m*1.5m*2.0m scene of interest and we’re quite sure you already know that the source of illumination, a laser, is shown in red.

As you can guess, the main challenge in this experience was to figure out where the three-times reflected light hitting camera was coming from. As the laser needed to be synchronized with the camera’s exposure cycle it is very interesting to note that part of the challenge was to crack the latter open to sniff the correct signals. Illumination conditions have limited impact on their achieved tolerance of +-15cm.

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