All posts by Rosie Hattersley

Bluebot Shoal Fish Robot

Post Syndicated from Rosie Hattersley original https://www.raspberrypi.org/blog/bluebot-shoal-fish-robot/

If you loved the film Finding Dory, you might just enjoy the original story of these underwater robots, fresh out of the latest issue of The MagPi Magazine.

It’s no coincidence that the shoal of robot fish in this Raspberry Pi Zero W project look more than a little like Dory from Pixar’s movie. As with the film character, the Bluebot robot fish are based on the blue tang or surgeonfish. Unlike Dory, however, these robot fish are designed to be anything but loners. They behave collectively, which is the focus of the Blueswarm research project that began in 2016 at Harvard University.

Linked cameras attached to Raspberry Pi Zero W monitor what surrounding fish are doing. The Bluebot robot then mimics their behaviour, such as moving its fins
The Blueswarm team designed a PCB and wrote custom Python code for their subterranean Raspberry Pi experiments

Florian Berlinger and his PhD research project colleagues Radhika Nagpal, Melvin Gauci, Jeff Dusek, and Paula Wulko set out to investigate the behaviour of a synchronised group of underwater robots and how groups of such robot fish are co‑ordinated by observing each other’s movements. In the wild, birds, fish, and some animals co-ordinate in this way when migrating, looking for food and as a means of detecting and collectively avoiding predators. Simulations of such swarm behaviour exist, but Blueswarm has the additional challenge of operating underwater. Raspberry Pi Zero W works well here because multiple Bluebot robots can be accessed remotely over a secure wireless connection, and Raspberry Pi Zero W is physically small and light enough to fit inside a palm-sized robot. 

Mimicking movements

The team designed the fish-inspired, 3D-printed robot body as well as the fin-like actuators and the on-board printed circuit board which connects to all the electronics and communicates with Raspberry Pi Zero W. Designing the robot fish took the team four years, from working out how each robot fish would move and adding sensing capabilities, to refining the design and implementing collective behaviours, coded using Python 3. 

The Blueswarm team designed a PCB and wrote custom Python code for their subterranean Raspberry Pi experiments
The Blueswarm team designed a PCB and wrote custom Python code for their subterranean Raspberry Pi experiments

They used as many off-the-shelf electronics as possible to keep the robots simple, but adapted existing software algorithms for the purposes of their investigations, “with several clever twists on existing algorithms to make them run fast on Raspberry Pi,” adds Florian. 

On-board cameras that offer “an amazing 360-degree field of view” are one of the project’s real triumphs. These cameras are connected to Raspberry Pi via a duplexer board (so two cameras can operate as one) the project team co-designed with Arducam. Each Raspberry Pi Zero W inside follows the camera images and instructs the fins to move accordingly. The team developed custom algorithms for synchronisation, flocking, milling, and search behaviours to simulate how real fish move individually and as a group. As a result, says Florian, “Blueswarm can be used to study inter-robot co-ordination in the laboratory and to learn more about collective intelligence in nature.” He suggests other robot-based projects could make use of a similar setup. 

Imitation of life

Each robot fish cost around $250 and took approximately six hours to make. To make your own, you’d need a 3D printer, Raspberry Pi Zero W, a soldering station – and a suitably large tank for your robot shoal! Although the team hasn’t made the code available, the Blueswarm project paper has recently been published in Science Robotics and by the IEEE Robots and Automation Society. Several biology researchers have also been using the Bluebot shoal as ‘fish surrogates’ in their studies of swimming and schooling.

It may look cute, but Bluebot has a serious purpose
It may look cute, but Bluebot has a serious purpose

The MagPi #107 out NOW!

MagPi 107 cover

You can grab the brand-new issue right now from the Raspberry Pi Press store, the Raspberry Pi Store, Cambridge, or via our app on Android or iOS. You can also pick it up from supermarkets and newsagents. There’s also a free PDF you can download.

The post Bluebot Shoal Fish Robot appeared first on Raspberry Pi.

‘Epigone drone’ pays homage to NASA’s Mars Helicopter | The MagPi #107

Post Syndicated from Rosie Hattersley original https://www.raspberrypi.org/blog/epigone-drone-pays-homage-to-nasas-mars-helicopter-the-magpi-107/

Inspired by NASA’s attempt to launch a helicopter on Mars, one maker made an Earth-bound one of her own. And she tells Rosie Hattersley all about it in the latest issue of The MagPi Magazine, out now.

Epigone drone hero
To avoid being swiped by the drone’s rotors, the Raspberry Pi 4, which uses NASA’s especially written F Prime code for telemetry, had to be positioned very carefully

Like millions of us, in April Avra Saslow watched with bated breath as NASA’s Perseverance rover touched down on the surface of Mars. 

Like most of us, Avra knew all about the other ground-breaking feat being trialled alongside Perseverance: a helicopter launch called Ingenuity, that was to be the first flight on another planet – “a fairly lofty goal”, says Avra, since “the atmosphere on Mars is 60 times less dense than Earth’s.” 

With experience of Raspberry Pi-based creations, Avra was keen to emulate Ingenuity back here on earth.

Project maker holding their creation
Avra’s videographer colleague lent her the drone that enables Epigone to achieve lift-off

NASA chose to use open-source products and use commercially available parts for its helicopter build. It just so happened that Avra had recently begun working at SparkFun, a Colorado-based reseller that sells the very same Garmin LIDAR-Lite v3 laser altimeter that NASA’s helicopter is based on. “It’s a compact optical distance measurement sensor that gives the helicopter ‘eyes’ to see how far it hovers above ground,” Avra explains.

NASA posted the Ingenuity helicopter’s open-source autonomous space-flight software, written specifically for use with Raspberry Pi, on GitHub. Avra took all this as a sign she “just had to experiment with the same technology they sent to Mars.”

F Prime and shine

Her plan was to see whether she could get GPS and lidar working within NASA’s framework, “and then take the sensors up on a drone and see how it all performed in the air.” Helpfully, NASA’s GitHub post included a detailed F Prime tutorial based around Raspberry Pi. Avra says understanding and using F Prime (F´) was the hardest part of her Epigone drone project. “It’s a beast to take on from an electronics enthusiast standpoint,” she says. Even so, she emphatically encourages others to explore F´ and the opportunity  to make use of NASA’s code.

epigone drone front view
NASA recognises that Raspberry Pi offers a way to “dip your toe in embedded systems,” says Avra, and “encourages the idea that Linux can run on two planets in the solar system”

Raspberry Pi 4 brain

The Epigone Drone is built around Raspberry Pi 4 Model B; Garmin’s LIDAR-Lite v4, which connects to a Qwiic breakout board and has a laser rather than an LED; a battery pack; and a DJI Mini 2 drone borrowed from a videographer colleague. Having seen how small the drone was, Avra realised 3D-printing an enclosure case would make everything far too heavy. As it was, positioning the Epigone onto its host drone was challenging enough: the drone’s rotors passed worryingly close to the project’s Raspberry Pi, even when precisely positioned in the centre of the drone’s back. The drone has its own sensors to allow for controlled navigation, which meant Avra’s design had to diverge from NASA’s and have its lidar ‘eyes’ on its side rather than underneath.

Although her version piggybacks on an existing drone, Avra was amazed when her Epigone creation took flight:

“I honestly thought [it] would be too heavy to achieve lift, but what do ya know, it flew! It went up maybe 30 ft and we were able to check the sensors by moving it close and far from the SparkFun HQ [where she works].”

While the drone’s battery depleted in “a matter of minutes” due to its additional load, the Epigone worked well and could be deployed to map small areas of land such as elevation changes in a garden, Avra suggests.

The MagPi #107 out NOW!

MagPi 107 cover

You can grab the brand-new issue right now from the Raspberry Pi Press store, or via our app on Android or iOS. You can also pick it up from supermarkets and newsagents. There’s also a free PDF you can download.

The post ‘Epigone drone’ pays homage to NASA’s Mars Helicopter | The MagPi #107 appeared first on Raspberry Pi.