Hackaday Links: November 17, 2019

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

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

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”

These Maple Pod Inspired Drones Silently Carry Payloads

Researchers from the Singapore University of Technology and Design (SUTD) recently released a video showing their nature-inspired drone that is capable of breaking out into five separate smaller drones. The drones each have auto-rotating wings that slow their rate of descent, similar to seed pods from a maple tree. Due to their design, the drones are only made to be used for a one-way trip, with the five components each carrying a separate payload. The drones are designed to detach within a specified distance from their destination, allow the collective body to safely spiral downwards towards land.

In their paper published on the same subject, the researchers discuss how they optimized the balsa wood wings with servos, a LiPo battery, and a receiver attached to a 3D-printed body. Four are equipped with just these components, while the fifth also holds a 3-axis magnetometer, a Teensy 3.5 board, a GPS module, and a Pixracer controller.

They experimented with several motion capture setups and free-flight drop tests to verify their simulations on the models for the drones. Apart from simply detaching, they are also designed to cater to different mission profiles based on the environment they are dropped in.

We’ll admit that the implementation and design of the drones does seem fairly dystopian, especially when you wonder what could possibly be the payloads these drones are designed to carry. But in terms of nature-inspired robotics, the maple seed pod idea is pretty interesting.

Continue reading “These Maple Pod Inspired Drones Silently Carry Payloads”

A Drone Sprouts Wings

While there are some fixed-wing drones in the hobby world, most of us around here think of the quadcopter when this word is mentioned. There have been some fixed-wings around, and lots of multi-rotors, but not much of a mix of the two. [Paweł] wanted to see what would happen if he mixed these two together, and created a quadcopter drone with retractable wings, essentially just to see what would happen.

This isn’t something that can convert from fixed-wing flight to helicopter-style hovering like a V22 Osprey or Harrier, either. The lift and thrust is entirely generated by the rotors, and the “wings” are essentially deployable air brakes that allow the drone to slow down quickly without consuming as much energy under propeller power alone. The air brake wings are designed to automatically deploy as a function of throttle position, too, so there’s a lot that could be built on this idea in the future, in theory.

[Paweł] notes that this design is somewhat controversial, and although few of us are in the drone racing community we can imagine how a functional change like this might impact in an arena such as that. He also only saw marginal performance increases and isn’t planning on perusing this idea much further. If you’re interested in a drone with “true” wings, though, check out this one which gets fired out of a grenade launcher.

Continue reading “A Drone Sprouts Wings”

The Final Days Of The Fire Lookouts

For more than a century, the United States Forest Service has employed men and women to monitor vast swaths of wilderness from isolated lookout towers. Armed with little more than a pair of binoculars and a map, these lookouts served as an early warning system for combating wildfires. Eventually the towers would be equipped with radios, and later still a cellular or satellite connection to the Internet, but beyond that the job of fire lookout has changed little since the 1900s.

Like the lighthouse keepers of old, there’s a certain romance surrounding the fire lookouts. Sitting alone in their tower, the majority of their time is spent looking at a horizon they’ve memorized over years or even decades, carefully watching for the slightest whiff of smoke. The isolation has been a prison for some, and a paradise for others. Author Jack Kerouac spent the summer of 1956 in a lookout tower on Desolation Peak in Washington state, an experience which he wrote about in several works including Desolation Angels.

But slowly, in a change completely imperceptible to the public, the era of the fire lookouts has been drawing to a close. As technology improves, the idea of perching a human on top of a tall tower for months on end seems increasingly archaic. Many are staunchly opposed to the idea of automation replacing human workers, but in the case of the fire lookouts, it’s difficult to argue against it. Computer vision offers an unwavering eye that can detect even the smallest column of smoke amongst acres of woodland, while drones equipped with GPS can pinpoint its location and make on-site assessments without risk to human life.

At one point, the United States Forest Service operated more than 5,000 permanent fire lookout towers, but today that number has dwindled into the hundreds. As this niche job fades even farther into obscurity, let’s take a look at the fire lookout’s most famous tool, and the modern technology poised to replace it.

Continue reading “The Final Days Of The Fire Lookouts”

Military Gliders Are Making A Comeback, This Time In Unmanned Form

Sun Tzu said, “The line between disorder and order lies in logistics.” This is as true in the modern world as it was 2500 years ago, and logistics have helped win and lose many wars and battles over the centuries. To this end, Logistical Gliders Inc. is developing one-time use, unmanned delivery gliders, for the US Military.

Reminiscent of the military gliders used in WW2, the gliders are designed to be dropped from a variety of aircraft, glide for up to 70 miles and deliver supplies to troops in the field. Specifically intended to be cheap enough to be abandoned after use, the gliders are constructed from plywood, a few aluminum parts for reinforcement and injection molded wing panels. There are two versions of the glider, both with huge payloads. The LG-1K, with a payload capacity of 700 lbs/320 kg and the larger LG-2K, with a payload capacity of 1,600 lbs/725 kg. Wings are folded parallel to the fuselage during transport and then open after release with the help of gas springs. The glider can either do a belly landing in an open area or deploy a parachute from the tail at low altitude to land on the crushable nose.

Gliders like these could be used to deliver supplies after natural disasters, or to remote locations where road travel is difficult or impossible while reducing the flight time required for conventional aircraft. Powered UAVs could even be used to carry/tow a glider to the required release point and then return much lighter and smaller, reducing the required fuel or batteries.

Drones are already used to deliver medical supplies in Rwanda and Ghana, and it’s possible to build your own autonomous unmanned glider. Check out the video after the break to see the big boys in action. Continue reading “Military Gliders Are Making A Comeback, This Time In Unmanned Form”