Underwater Crawling Soft Robot Stays In Shape

April 23, 2020 by Moritz v. Sivers 9 Comments

When you think of robots that were modeled after animals, a brittle star is probably not the first species that comes to mind. Still, this is the animal that inspired [Zach J. Patterson] and his research colleagues from Carnegie Mellon University for their underwater crawling robot PATRICK.

PATRICK is a soft robot made from molded silicone. Each of his five limbs contains several shape memory alloy (SMA) springs which can be contracted through Joule heating thereby causing the limbs to bend. The robot’s control board is sending and receiving commands via Bluetooth Low Energy from a nearby computer. To control PATRICK’s motion the researchers constructed a closed-loop system where an offboard OpenCV based camera system is constantly tracking the robot. As shown in the video below with an average velocity of 1 cm/s, PATRICK’s movement is a bit sluggish but the system is supposedly very robust against uncertainties in the environment.

In the future [Zach J. Patterson et al.] would like to improve their design by giving the robot the ability to grasp objects. Ultimately, also the offboard camera should be replaced with onboard sensors so that PATRICK can navigate autonomously.

Soft robots like artificial jellyfish are especially useful underwater and sometimes almost cross the boundary to organic life.

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Lego Goes Underwater, With Model Submarines And Missiles

June 8, 2019 by Al Williams 7 Comments

It is fun to make a toy vehicle with Lego, but it is even more fun to make one that actually works. [PeterSripol] made two Lego submarines, and you can see them in the video below. There isn’t a lot of build information, but watching the subs fire missiles and then getting destroyed by depth charges is worth something.

One of the subs is larger and uses a rudder to steer. It was apparently harder to control than the other smaller sub which used two motors thrusting opposite one another to steer. Looks like fun.

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Wind turbine pumping air to an underwater scuba helmet

Breathing Underwater Using Wind Power

November 5, 2018 by Steven Dufresne 58 Comments

As hackers, our goal is to reuse something in a way in which it was not intended and [Rulof Maker] is a master at this. From his idyllic seaside location in Italy, he frequently comes up with brilliant underwater hacks made of, well, junk. This time he’s come up with a wind-powered pump to move air through a hose to a modified scuba mask.

The wind turbine’s blades look professional but you’ll be surprised to see that they’re simply cut from a PVC pipe. And they work great. The air compressor is taken from a car and the base of the wind turbine’s tower started life as a bed frame. As you’ll see in the video below, the whole setup is quite effective. It would have been nice to see him using his leg mounted, beer bottle propulsion system at the same time, but the air hose may not have been long enough to make good use of them.

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An Achievable Underwater Camera

August 18, 2018 by Jenny List 11 Comments

We are surrounded by sensors for all forms of environmental measurement, and a casual browse through an electronics catalogue can see an experimenter tooled up with the whole array for a relatively small outlay. When the environment in question is not the still air of your bench but the turbulence, sand, grit, and mud of a sea floor, that pile of sensors becomes rather useless. [Ellie T] has been addressing this problem as part of the study of hypoxia in marine life, and part of her solution is to create an underwater camera by encasing a Raspberry Pi Zero W and camera in a sturdy enclosure made from PVC pipe. She’s called the project LoBSTAS, which stands for Low-cost Benthic Sensing Trap-Attached System.

The housing is simple enough, the PVC has a transparent acrylic disk mounted in a pipe coupler at one end, with the seal being provided at the other by an expansion plug. A neopixel ring is mounted in the clear end, with the Pi camera mounted in its centre. Meanwhile the Pi itself occupies the body of the unit, with power coming from a USB battery bank. The camera isn’t the only sensor on this build though, and Atlas Scientific oxygen sensor completes the package and is mounted in a hole drilled in the expansion plug and sealed with silicone sealant.

Underwater cameras seem to have featured more in the earlier years of Hackaday’s existence, but that’s not to say matters underwater haven’t been on the agenda. The 2017 Hackaday Prize was carried off by the Open Source Underwater Glider.

Underwater VR Offers Zero Gravity On A Budget

August 12, 2018 by Tom Nardi 9 Comments

Someday Elon Musk might manage to pack enough of us lowly serfs into one of his super rockets that we can actually afford a ticket to space, but until then our options for experiencing weightlessness are pretty limited. Even if you’ll settle for a ride on one of the so-called “Vomit Comet” reduced-gravity planes, you’ll have to surrender a decent chunk of change, and as the name implies, potentially your lunch as well. Is there no recourse for the hacker that wants to get a taste of the astronaut experience without a NASA-sized budget?

Well, if you’re willing to get wet, [spiritplumber] might have the answer for you. Using a few 3D printed components he’s designed, it’s possible to use Google Cardboard compatible virtual reality software from the comfort of your own pool. With Cardboard providing the visuals and the water keeping you buoyant, the end result is something not entirely unlike weightlessly flying around virtual environments.

To construct his underwater VR headset, [spiritplumber] uses a number of off-the-shelf products. The main “Cardboard” headset itself is the common plastic style that you can probably find in the clearance section of whatever Big Box retailer is convenient for you, and the waterproof bag that holds the phone can be obtained cheaply online. You’ll also need a pair of swimmers goggles to keep water from rudely interrupting your wide-eyed wonderment. As for the custom printed parts, a frame keeps the waterproof bag from pressing against the screen while submerged, and a large spacer is required to get the phone at the appropriate distance from the operator’s eyes.

To put his creation to the test, [spiritplumber] loads up a VR rendition of NASA’s Neutral Buoyancy Laboratory, where astronauts experience a near-weightless environment underwater. All that’s left to complete the experience is a DIY scuba regulator so you can stay submerged. Though at that point we wouldn’t be surprised if a passerby confuses your DIY space simulator for an elaborate suicide attempt.

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[Festo]’s Underwater Robot Uses Body-Length Fins

June 21, 2018 by Steven Dufresne 17 Comments

[Festo] have come up with yet another amazing robot, a swimming one this time with an elegant propulsion mechanism. They call it the BionicFinWave. Two fins on either side almost a body-length long create a wave which pushes water backward, making the robot move forward. It’s modeled after such fish as the cuttlefish and the Nile perch.

What was their elegant solution for making the fins undulate? Nine lever arms are attached to each fin. Those lever arms are controlled by two crankshafts which extend from the front of the body to the rear, one for each side. A servo motor then turns each crankshaft. Since the crankshafts are independent, that means each fin operates independently. This allows for turning by having one fin move faster than the other. A third motor in the head flexes the body, causing the robot to swim up or down.

There’s also a pressure sensor and an ultrasonic sensor in the head for depth control and avoiding objects and walls. While these allow it to swim autonomously in its acrylic, tubular track, there is wireless communication for recording sensor data. Watch it in the video below as it effortlessly swims around its track.

[Festo] has created a lot of these marvels over the years. We’ve previously covered their bionic hopping kangaroo (we kid you not), their robot ants with circuitry printed on their exoskeleton, and perhaps the most realistic flapping robotic bird ever made.

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Open Source Underwater Distributed Sensor Network

May 23, 2018 by Steven Dufresne 32 Comments

One way to design an underwater monitoring device is to take inspiration from nature and emulate an underwater creature. [Michael Barton-Sweeney] is making devices in the shape of, and functioning somewhat like, clams for his open source underwater distributed sensor network.

The clams contain the electronics, sensors, and means of descending and ascending within their shells. A bunch of them are dropped overboard on the surface. Their shells open, allowing the gas within to escape and they sink. As they descend they sample the water. When they reach the bottom, gas fills a bladder and they ascend back to the surface with their data where they’re collected in a net.

Thus far he’s made a few clams using acrylic for the shells which he’s blown himself. He soldered the electronics together free-form and gave them a conformal coating of epoxy. He’s also used a thermistor as a stand-in for other sensors and is already working on a saturometer, used for measuring the total dissolved gas (TDG) in the water. Knowing the TDG is useful for understanding and mitigating supersaturation of water which can lead to fish kills.

He’s also given a lot of thought into the materials used since some clams may not make it back up and would have to degrade or be benign where they rest. For example, he’s been using a lithium battery for now but would like to use copper on one shell and zinc on another to make a salt water battery, if he can make it produce enough power. He’s also considering using 3D printing since PLA is biodegradable. However, straight PLA could be subject to fouling by underwater organisms and would require cleaning, which would be time-consuming. PLA becomes soft when heated in a dishwasher and so he’s been looking into a PLA and calcium carbonate filament instead.

Check out his hackaday.io page where he talks about all these and more issues and feel free to make any suggestions.