Experimental Drone Flies Like A Bird

November 25, 2024 by Danie Conradie 11 Comments

Most RC planes follow a simple control scheme: elevators for pitch, rudder for yaw, and ailerons for roll. This one-to-one mapping keeps things straightforward, and fewer actuators means less weight. But nature has other ideas. Birds achieve flight control through complex, coordinated movements where different body parts can affect multiple degrees of freedom simultaneously. Now, researchers at EPFL have brought this biological approach to robotics with the LisEagle, a drone featuring morphing wings and tail that demonstrate remarkable stability.

All the control surfaces and actuators — All the actuators!

The LisEagle packs seven different actuation methods alongside its nose-mounted motor. Three of these control the bird-like wingtips and spreading tail, while the remaining actuators handle more conventional controls: independently twisting wing bases (similar to ailerons) and a tail assembly that combines elevator and rudder functions in its vertical stabilizer.

Testing took place in controlled indoor conditions, with the maintaining position in front of an open wind tunnel. Optical position tracking provided closed-loop feedback and power was provided via a tether to minimize weight. A PID flight controller orchestrated all seven actuators in concert, achieving impressive stability even when faced with induced turbulence or being poked with a stick. In a demonstration of redundancy, the researchers deliberately disabled the twisting wing mechanisms, and the aircraft maintained control using just its wingtips and tail.

The team went further, employing Bayesian optimization to find the most efficient actuator combinations. This revealed potential energy savings of up to 11%, with optimal configurations varying based on airspeed as lift requirements changed.

While research into the flight mechanisms of bees, bats and birds might not immediately translate to practical applications, it deepens our understanding of flight control principles. Don’t be surprised if morphing wings become a more common sight in future aircraft designs.

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Customizable Bird Clock Sings The Hours By

May 16, 2024 by Bryan Cockfield 7 Comments

For those looking to build their own clocks, one of the easiest ways to get started is with a pre-built module that uses a simple quartz oscillator and drives a set of hands. This generally doesn’t allow for much design of the clock besides the face, and since [core weaver] was building a clock that plays bird songs, a much more hackable clock driver was needed to interface with the rest of the electronics needed to build this project.

The clock hands for this build are driven by a double stepper motor which controls an hour and minute hand coaxially but independently. Originally an H-bridge circuit was designed for driving each of the hands but they draw so little current in this configuration that they could be driven by the microcontroller directly. A DS3231 clock is used for timekeeping connected to an ATMega128a which controls everything else. At the start of each hour the clock plays a corresponding bird song by communicating with an mp3 module, and a remote control can also be used to play the songs on demand.

Bird clocks are not an uncommon thing to find off the shelf, but this one adds a number of customizations that let it fly above those offerings, including customizing the sounds that play on the hour and adding remote control capabilities, a lithium battery charging circuit, and a number of other creature comforts. If you’re looking for even more unique bird clock designs this binary bird clock might fit the bill.

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That Drone Up In The Sky? It Might Be Built Out Of A Dead Bird

April 19, 2023 by Dan Maloney 40 Comments

In a lot of ways, it seems like we’re in the “plateau of productivity” part of the hype cycle when it comes to drones. UAVs have pretty much been reduced to practice and have become mostly an off-the-shelf purchase these days, with a dwindling number of experimenters pushing the envelope with custom builds, like building drones out of dead birds.

These ornithopomorphic UAVs come to us from the New Mexico Insitute of Mining and Technology, where [Mostafa Hassanalian] runs the Autonomous Flight and Aquatic Systems lab. While looking into biomimetics, [Dr. Hassanalian] hit upon the idea of using taxidermy birds as an airframe for drones. He and his team essentially reverse-engineered the birds to figure out how much payload they’d be able to handle, and added back the necessary components to make them fly again.

From the brief video in the tweet embedded below, it’s clear that they’ve come up with a huge variety of feathered drones. Some are clearly intended for testing the aerodynamics of taxidermy wings in makeshift wind tunnels, while others are designed to actually fly. Propulsion seems to run the gamut from bird-shaped RC airplanes with a propeller mounted in the beak to true ornithopters. Some of the drones clearly have a conventional fuselage with feathers added, which makes sense for testing various subsystems, like wings and tails.

It’s easy to mock something like this, and the jokes practically write themselves. But when you think about it, the argument for a flying bird-shaped robot is pretty easy to make from an animal behavior standpoint. If you want to study how birds up close while they’re flying, what better way than to send in a robot that looks similar to the other members of the flock? And besides, evolution figured out avian flight about 150 million years ago, so studying how birds do it is probably going to teach us something.

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Hackaday Prize 2022: Hedge Watcher Aims To Save Precious Bird Life

October 13, 2022 by Lewin Day 12 Comments

Hedges aren’t just a pretty garden decoration. They’re also a major habitat for many species of insects, birds, and other wildlife. In some areas, a lot of hedge trimming goes during the time that local birds are raising their fledglings, which causes harm at a crucial time. Thus, [Johann Elias Stoetzer] and fellow students were inspired to create Hedge Watcher.

Birds can easily blend in with their surroundings, but thermal cameras are a great way to spot them.

The concept is simple – using thermal vision to spot birds inside a hedge when they may not otherwise be easily visible. Many species blend in with their surroundings in a visual manner, so thermal imaging is a great way to get around this. It can help to avoid destroying nests or otherwise harming birds when trimming back hedges. The idea was sourced from large-scale agricultural operations, which regularly use thermal cameras mounted on drones to look for wildlife before harvesting a field.

However, staring at a thermal camera readout every few seconds while trimming hedges isn’t exactly practical. Instead, the students created an augmented reality (AR) monocular to allow the user to trim hedges at the same time as keeping an eye on the thermal camera feed. Further work involved testing a binocular AR headset, as well as a VR headset. The AR setups proved most useful as they allowed for better situational awareness while working.

It’s a creative solution to protecting the local birdlife, and is to be applauded. There’s plenty of hubris around potential uses for augmented reality, but this is a great example of a real and practical one. And, if you’re keen to experiment with AR yourself, note that it doesn’t have to break the bank either!

picture of a brambling (a small bird), with "BirdNET-Pi" written above it

Neural Network Identifies Bird Calls, Even On Your Pi

June 25, 2022 by Arya Voronova 20 Comments

Recently, we’ve stumbled upon the extensive effort that is the BirdNET research platform. BirdNET uses a neural network to identify birds by the sounds they make, and is a joint project between the Cornell Lab of Ornithology and the Chemnitz University of Technology. What strikes us is – this project is impressively featureful and accessible for a variety of applications. No doubt, BirdNET is aiming to become a one-stop shop for identifying birds as they sing.

There’s plenty of ways BirdNET can help you. Starting with likely the most popular option among us, there are iOS and Android apps – giving the microphone-enabled “smart” devices in our pockets a feature even the most app-averse hackers can respect. However, the BirdNET team also talks about bringing sound recognition to our browsers, Raspberry Pi and other SBCs, and even microcontrollers. We can’t wait for someone to bring BirdNET to a RP2040! The code’s open-source, the models are freely available – there’s hardly a use case one couldn’t cover with these.

About that Raspberry Pi version! There’s a sister project called BirdNET-Pi – it’s an easy-to-install software package intended for the Raspberry Pi OS. Having equipped your Pi with a USB sound card, you can make it do 24/7 recording and analysis using a “lite” version of BirdNET. Then, you get a web interface you can log into and see bird sounds identified in real-time. Not just that – BirdNET-Pi also processes the sounds and creates spectrograms, keeps the sound in a database, and can even send you notifications.

The BirdNET-Pi project is open, too, of course. Not just that – the BirdNET-Pi team emphasizes everything being fully local, unless you choose otherwise, and perhaps decide to share it with others. Many do make their BirdNET-Pi instances public, and there’s a lovely interactive map that shows bird sounds all across the world!

BirdNET is, undoubtedly, a high-effort project – and a shining example of what a dedicated research team can do with a neural network and an admirable goal in mind. For many of us who feel joy when we hear birds outside, it’s endearing to know that we can plug a USB sound card into our Pi and learn more about them – even if we can’t spot them or recognize them by sight just yet. We’ve covered bird sound recognition on microcontrollers before – also using machine learning.

Magpies Help Each Other Escape Tracking Devices With This One Weird Trick

April 5, 2022 by Lewin Day 18 Comments

Scientists who work with animals love to track their movements. This can provide interesting insights on everything from mating behaviour, food sources, and even the way animals behave socially – or anti-socially, as the case may be.

This is normally achieved with the use of tracking devices, affixed to an animal so that it can be observed remotely while going about its normal business. However, Australian scientists have recently run into some issues in this area, as the very animals they try to track have been removing these very devices, revealing some thought-provoking behaviour in the process.

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Flapping Wings And The Science Of How Bees Can Fly

February 22, 2021 by Lewin Day 70 Comments

Jerry Seinfeld launched his career with Bee Movie, an insect-themed animated feature that took the world by storm in 2007. It posed the quandary – that supposedly, according to all known laws of aviation, bees should not be able to fly. Despite this, the bee flies anyway, because bees don’t care what humans think is impossible.

The quote isn’t easily attributed to anyone in particular, but is a cautionary tale about making the wrong assumptions in an engineering context. Yes, if you model a bee using the same maths as an airliner, of course you’ll find that it shouldn’t be able to fly. Its tiny wings can’t possibly generate enough lift to get its body off the ground. But that’s because the assumption is an erroneous one – because bees don’t fly in the same way planes do. Bees flap their wings. But that’s just the beginning. The truth is altogether more complex and interesting! Continue reading “Flapping Wings And The Science Of How Bees Can Fly” →