Hackaday Links: January 5, 2020

January 5, 2020 by Dan Maloney 30 Comments

It looks like the third decade of the 21st century is off to a bit of a weird start, at least in the middle of the United States. There, for the past several weeks, mysterious squads of multicopters have taken to the night sky for reasons unknown. Witnesses on the ground report seeing both solo aircraft and packs of them, mostly just hovering in the night sky. In mid-December when the nightly airshow started, the drones seemed to be moving in a grid-search pattern, but that seems to have changed since then. These are not racing drones, nor are they DJI Mavics; witnesses report them to be 6′ (2 meters) in diameter and capable of staying aloft for 90 minutes. These are serious professional machines, not kiddies on a lark. So far, none of the usual government entities have taken responsibility for the flights, so speculation is all anyone has as to their nature. We’d like to imagine someone from our community will get out there with radio direction finding gear to locate the operators and get some answers.

We all know that water and electricity don’t mix terribly well, but thanks to the seminal work of White, Pinkman et al (2009), we also know that magnets and hard drives are a bad combination. But that didn’t stop Luigo Rizzo from using a magnet to recover data from a hard drive. He reports that the SATA drive had been in continuous use for more than 11 years when it failed to recover after a power outage. The spindle would turn but the heads wouldn’t move, despite several rounds of percussive maintenance. Reasoning that the moving coil head mechanism might need a magnetic jump-start, he probed the hard drive case with a magnetic parts holder until the head started moving again. He was then able to recover the data and retire the drive. Seems like a great tip to file away for a bad day.

It seems like we’re getting closer to a Star Trek future every day. No, we probably won’t get warp drives or transporters anytime soon, and if we’re lucky velour tunics and Spandex unitards won’t be making a fashion statement either. But we may get something like Dr. McCoy’s medical scanner thanks to work out of MIT using lasers to conduct a non-contact medical ultrasound study. Ultrasound exams usually require a transducer to send sound waves into the body and pick up the echoes from different structures, with the sound coupled to the body through an impedance-matching gel. The non-contact method uses pulsed IR lasers to penetrate the skin and interact with blood vessels. The pulses rapidly heat and expand the blood vessels, effectively turning them into ultrasonic transducers. The sound waves bounce off of other structures and head back to the surface, where they cause vibrations that can be detected by a second laser that’s essentially a sophisticated motion sensor. There’s still plenty of work to do to refine the technique, but it’s an exciting development in medical imaging.

And finally, it may actually be that the future is less Star Trek more WALL-E in the unlikely event that Segway’s new S-Pod personal vehicle becomes popular. The two-wheel self-balancing personal mobility device is somewhat like a sitting Segway, except that instead of leaning to steer it, the operator uses a joystick. Said to be inspired by the decidedly not Tyrannosaurus rex-proof “Gyrosphere” from Jurassic World, the vehicle tops out at 24 miles per hour (39 km/h). We’re not sure what potential market for these things would need performance like that – it seems a bit fast for the getting around the supermarket and a bit slow for keeping up with city traffic. So it’s a little puzzling, although it’s clearly easier to fully automate than a stand-up Segway.

3D Pens Can Make Ugly Drone Parts That Almost Work

January 5, 2020 by Donald Papp 23 Comments

Small hobby aircraft and light plastic parts go hand in hand, and a 3D printing pen makes lightweight plastic things without the overhead of CAD work and running a 3D printer. So could a 3D pen create useful plastic bits for small quadcopters? [Michael Niggel] decided to find out by building his drone parts with a 3D pen loaded with ABS plastic. He mostly discovered that the created objects could politely be said to look like they were sketched by a toddler, but that’s not all he learned.

He found that in general creating an object was harder than the marketing materials implied. As soon as the filament exits the pen’s nozzle, the thin little molten line of plastic cools rapidly and does two things: it has a tendency to curl, and loses its desire to stick to things. [Michael] found the whole affair worked much less like ‘drawing in thin air’ and rather more like piping frosting, or caulking.

An almost functional micro quad frame. The arms aren’t rigid enough to hold the motors vertical when under power.

Nevertheless, [Michael] sought to discover whether a 3D pen could be used to make quick and dirty parts of any use. He created two antenna brackets and one micro quad frame. All three are chaotic messes, but one antenna bracket was perfectly serviceable. The 3D pen was indeed able to create a strangely-shaped part that would have been a nightmare to CAD up. The other antenna part worked, but didn’t do anything a zip tie wouldn’t have done better. The rapid cooling of the plastic from the 3D pen has an advantage: extrusions don’t “droop” like a glob of hot glue does before it hardens.

By now, [Michael] agreed that the best way to create a plastic part of any complexity whatsoever seemed to be to draw sections flat, build them up in layers, then use the pen to weld the pieces together and add bulk. The micro quad frame he made in this way doesn’t look any nicer than the other attempts, but it did hold the parts correctly. Sadly, it would not fly. Once the motors powered up, the arms would twist and the flight controller was unable to compensate for motors that wouldn’t stay straight. This could probably be overcome, but while the end result was dirty it certainly wasn’t quick. The 3D pen’s niche seems restricted to simple, unstressed parts that aren’t permitted to gaze up themselves in a mirror.

If you have a 3D pen, we’d like to remind you of this mini spool design whose parts are welded together with the pen itself. For bigger jobs, a high-temperature hot glue gun can be used to dispense PLA instead.

Ask Hackaday: Drone Swarms Replace Fireworks; Where Are The Hackers?

December 26, 2019 by Al Williams 27 Comments

Your mom always warned you that those fireworks could put an eye out. However, the hottest new thing in fireworks displays is not pyrotechnic at all. Instead, a swarm of coordinated drones take to the sky with different lighting effects. This makes some pretty amazing shows possible, granting full control of direction, color, and luminosity of each light source in a mid-air display. It also has the side benefit of being safer — could this be the beginning of the end for fireworks accident videos blazing their way across social media platforms?

For an idea of what’s possible with drone swarm displays, check out the amazing pictures found on this site (machine translation) that show off the 3D effects quite well. Note that although it appears the camera is moving during many of these, the swam itself could be rotated relative to a stationary viewer for a similar effect.

What I couldn’t find was much going on here in the hobby space. Granted, in the United States, restrictive drone laws might hamper your ability to do things like this. But it seems that in a purely technical terms this wouldn’t be super hard to do — at least for simple designs. Besides, there must be some way to do this in US airspace since drone performances have been at the Super Bowl, Los Angeles, New York, Miami, and Folsom, CA.

So if the regulations were sorted, what would it take to build a swarm of your own performing drones?

Continue reading “Ask Hackaday: Drone Swarms Replace Fireworks; Where Are The Hackers?” →

Autonomous Boat For Awesome Video Hyperlapses

December 21, 2019 by Danie Conradie 7 Comments

With the ever-increasing capabilities of smart phones, action cameras, and hand-held gimbals, the battle for the best shots is intensifying daily on platforms like YouTube and Instagram. Hyperlapse sequences are one of the popular weapons in the armoury, and [Daniel Riley] aka [rctestflight] realised that his autonomous boat could be an awesome hyperlapse platform.

This is the third version of his autonomous boat, with version 1 suffering from seaweed assaults and version 2 almost sleeping with the fishes. The new version is a flat bottomed craft was built almost completely from pink insulation foam, making it stable and unsinkable. It uses the same electronics and air boat propulsion as version 2, with addition of a GoPro mounted in smart phone gimbal to film the hyper lapses. It has a tendency to push the bow into the water at full throttle, due to the high mounted motors, but was corrected by adding a foam bulge beneath the bow, at the cost of some efficiency.

Getting the gimbal settings tuned to create hyperlapses without panning jumps turned out to be the most difficult part. On calm water the boat is stable enough to fool the IMU into believing that it’s is not turning, so the gimbal controller uses the motor encoders to keep position, which don’t allow it to absorb all the small heading corrections the boat is constantly making. Things improved after turning off the encoder integration, but it would still occasionally bump against the edges of the dead band inside which the gimbal does not turn with the boat. In the end [Daniel] settled for slowly panning the gimbal to the left, while plotting a path with carefully calculated left turns to keep the boat itself out of the shot. While not perfect, the sequences still beautifully captured the night time scenery of Lake Union, Seattle. Getting it to this level cost many hours of midnight testing, since [Daniel] was doing his best to avoid other boat traffic, and we believe it paid off.

We look forward to his next videos, including an update on his solar plane. Continue reading “Autonomous Boat For Awesome Video Hyperlapses” →

Hackaday Links: November 17, 2019

November 17, 2019 by Dan Maloney 8 Comments

Friday, November 15, 2019 – PASADENA. The 2019 Hackaday Superconference is getting into high gear as I write this. Sitting in the Supplyframe HQ outside the registration desk is endlessly entertaining, as attendees pour in and get their swag bags and badges. It’s like watching a parade of luminaries from the hardware hacking world, and everyone looks like they came ready to work. The workshops are starting, the SMD soldering challenge is underway, and every nook and cranny seems to have someone hunched over the amazing Hackaday Superconference badge, trying to turn it into something even more amazing. The talks start on Saturday, and if you’re not one of the lucky hundreds here this weekend, make sure you tune into the livestream so you don’t miss any of the action.

The day when the average person is able to shoot something out of the sky with a laser is apparently here. Pablo, who lives in Argentina, has beeing keeping tabs on the mass protests going on in neighboring Chile. Huge crowds have been gathering regularly over the last few weeks to protest inequality. The crowd gathered in the capital city of Santiago on Wednesday night took issue with the sudden appearance of a police UAV overhead. In an impressive feat of cooperation, they trained 40 to 50 green laser pointers on the offending drone. The videos showing the green beams lancing through the air are quite amazing, and even more amazing is the fact that the drone was apparently downed by the lasers. Whether it was blinding the operator through the FPV camera or if the accumulated heat of dozens of lasers caused some kind of damage to the drone is hard to say, and we’d guess that the drone was not treated too kindly by the protestors when it landed in the midsts, so there’s likely not much left of the craft to do a forensic analysis, which is a pity. We will note that the protestors also trained their lasers on a police helicopter, an act that’s extremely dangerous to the human pilots which we can’t condone.

In news that should shock literally nobody, Chris Petrich reports that there’s a pretty good chance the DS18B20 temperature sensor chips you have in your parts bin are counterfeits. Almost all of the 500 sensors he purchased from two dozen vendors on eBay tested as fakes. His Github readme has an extensive list that lumps the counterfeits into four categories of fake-ness, with issues ranging from inaccurate temperature offsets to sensors without EEPROM that don’t work with parasitic power. What’s worse, a lot of the fakes test almost-sorta like authentic chips, meaning that they may work in your design, but that you’re clearly not getting what you paid for. The short story to telling real chips from the fakes is that Maxim chips have laser-etched markings, while the imposters sport printed numbers. If you need the real deal, Chris suggests sticking with reputable suppliers with validated supply chains. Caveat emptor.

A few weeks back we posted a link to the NXP Homebrew RF Design Challenge, which tasked participants to build something cool with NXP’s new LDMOS RF power transistors. The three winners of the challenge were just announced, and we’re proud to see that Razvan’s wonderfully engineered broadband RF power amp, which we recently featured, won second place. First place went to Jim Veatch for another broadband amp that can be built for $80 using an off-the-shelf CPU heatsink for thermal management. Third prize was awarded to a team lead by Weston Braun, which came up with a switch-mode RF amp for the plasma cavity for micro-thrusters for CubeSats, adorably named the Pocket Rocket. We’ve featured similar thrusters recently, and we’ll be doing a Hack Chat on the topic in December. Congratulations to the winners for their excellent designs.

Tiny Drones Navigate Like Real Bugs

November 6, 2019 by Danie Conradie 14 Comments

When it comes to robotic navigation, the usual approach is to go as technically advanced and “smart” as possible. Yet the most successful lifeforms that we know of follow a completely different approach. With limited senses and cognitive abilities, the success of invertebrates like ants and honeybees lie in cooperation in large numbers. A joint team of researchers from TU Delft, University of Liverpool and Radboud University of Nijmegen, decided to try this approach and experimented with a simple navigation technique to allow a swarm of tiny flying robots to explore an unknown environment.

The drones used were of-the-shelf Crazyflie 2.0 micro quadcopters with add-on boards. Sensors consisted of it’s onboard IMU, simple range finding sensors on a Multi-ranger deck for obstacle detection, and a down pointing optical flow sensor, on a Flow deck, to keep track of the distance travelled. To navigate, the drones used a “swarm gradient bug algorithm” (SGBA). Each drone in has different preferred direction of travel from takeoff. When an obstacle encountered, it follows the contour of the obstacle, and then continues in the preferred direction once the path is clear. When the battery drops to 60%, it returns to a wireless homing beacon. While this technique might not be the most efficient, it has the major advantage of being “lightweight” enough to implement on a cheap microcontroller, an STM32F4 in this case. The full research article is available for free, and is a treasure trove of information.

The main application researchers have in mind is for search and rescue. A swarm of drones can explore an unstable or dangerous area, and identify key areas to focus rescue efforts on. This can drastically reduce wasted time and risk to rescue workers. It is always cool to see complex problems being solved with simple solution, and we are keen to see where things go. Check out the video after the break. Continue reading “Tiny Drones Navigate Like Real Bugs” →

Autonomous Air Boat Vs Lake Washington

November 6, 2019 by Danie Conradie 9 Comments

Autonomous vehicles make a regular appearance around here, as does [Daniel Riley] aka [rctestflight]. His fascination with building long-endurance autonomous vehicles continues, and this time he built an autonomous air boat.

This craft incorporates a lot of the lessons learnt from his autonomous boat that used a plastic food container. One of the biggest issues was the submerged propellers kept getting tangled in weeds. This led [Daniel] to move his props above water, sacrificing some efficiency for reliability, and turning it into an air boat. The boat itself is catamaran design with separate 3D printed hulls connected by carbon fibre tubes. As with the tupperware boat, autonomous control is done by the open source Ardupilot software.

During testing [Daniel] had another run in with his old arch-nemesis, seaweed. It turns out the sharp vertical bow is a nice edge for weeds to hook on to, create drag, and screw up the craft’s control. [Daniel]’s workaround involved moving the big batteries to the rear, causing the bows lift almost completely out of the water.

With a long endurance in mind right from the start of the project, [Daniel] put it to the test with a 13 km mission on Lake Washington very early one morning. For most of the mission the boat was completely on its own, with [Daniel] stopping at various points along the lake shore to check on its progress. Everything went smoothly until 10 km into the mission when the telemetry showed it slowing down and angling off course, after which is started going in circles. Lucky for Daniel he was offered a kayak by a lakeside resident, and he managed to recover the half sunken vessel. He suspects the cause of the failure was a slowly leaking hull. [Daniel] is already working on the next version, and were looking forward to seeing what he comes up with. Check out the video after the break. Continue reading “Autonomous Air Boat Vs Lake Washington” →