[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.
Continue reading “[Festo’s] Underwater Robot Uses Body-Length Fins”
If you’re like us, a body of water is a source of wonder and awe. The wonder comes from imagining what lies hidden below the surface, and the awe is from the fear of trying to find out and becoming one of those submerged objects on a permanent basis. So if you want to explore the depths in relative comfort and safety, a DIY remotely operated underwater vehicle might be the thing you need to build.
Most ROV builds these days seem to follow more or less similar designs, which is probably because they all share project goals similar to those of [dcolemans]: build something to take a look around under the water, make it easy to operate, and don’t spend a ton of money. To achieve that, he used 1/2″ PVC pipe and fittings to build the frame and painted it yellow for visibility. A dry tube for the electronics was fashioned from 4″ ABS pipe. The positive buoyancy provided by the dry tube is almost canceled out by the water flooding the frame through weep holes and the lead shot ballast stored in the landing skids. Propulsion is provided by bilge pump cartridges with 3D-printed ducted propellers. A nice touch is a separate topside control box with a screen for the ROV’s camera that talks to a regular RC controller, along with simplified controls and automatic station keeping. Check out the recent swimming pool test in the video below.
There’s a lot going on under the sea, and plenty of ways to explore it. You could deploy sensors shaped like clams, zap underwater lice with lasers, or even glide your way to a Hackaday Prize.
Continue reading “DIY Submersible Aims for Low Cost, Ease of Operation”
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.
It’s no shock that electric eels get a bad rap for being scary creatures. They are slithery fleshy water snakes who can call down lightning. Biologists and engineers at the University of California had something else in mind when they designed their electric eel. Instead of hunting fish, this one swims harmlessly alongside them.
Traditional remotely operated vehicles have relied on hard shells and spinning propellers. To marine life, this is noisy and unnatural. A silent swimmer doesn’t raise any eyebrows, not that fish have eyebrows. The most innovative feature is the artificial muscles, and although the details are scarce, they seem to use a medium on the inside to conduct a charge, and on the outside, the saltwater environment conducts an opposite charge which causes a contraction in the membrane between to the inside and outside. Some swimming action can be seen below the break, and maybe one of our astute readers can shed some light on this underwater adventurer’s bill of materials.
One of our favorite submarines is the 2017 Hackaday Prize winner, The Open Source Underwater Glider. For a more artistic twist on submersibles, the Curv II is one of the most elegant we have seen.
Continue reading “Gentle Electric Eel”
Logging data with an Arduino is old-hat for most Hackaday readers. However, [Patricia Beddows] and [Edward Mallon] had some pretty daunting requirements. Their sensors were going underground and underwater as part of an effort to study conditions underwater and in caves. They needed to be accessible, yet rugged. They didn’t want to use batteries that would be difficult to take on airplanes, but also wanted more than a year of run time. You can buy all that, of course, if you are willing to pay the price.
Instead, they used off-the-shelf Arduino boards connected together inside PVC housings. Three alkaline AA batteries are compact and give them more than a year of run time. They wrote a journal paper to help other scientists use the same techniques for the Sensors journal published by the Multidisciplinary Digital Publishing Institute.
Continue reading “Underwater Logging for Science”
At the Bay Area Maker Faire last weekend, Intel was showing off a couple of sexy newcomers in the Single Board Computer (SBC) market. It’s easy to get trapped into thinking that SBCs are all about simple boards with a double-digit price tag like the Raspberry Pi. How can you compete with a $35 computer that has a huge market share and a gigantic community? You compete by appealing to a crowd not satisfied with these entry-level SBCs, and for that Intel appears to be targeting a much higher-end audience that needs computer vision along with the speed and horsepower to do something meaningful with it.
I caught up with Intel’s “Maker Czar”, Jay Melican, at Maker Faire Bay Area last weekend. A year ago, it was a Nintendo Power Glove controlled quadcopter that caught my eye. This year I only had eyes for the two new computing modules on offer, the Joule and the Euclid. They both focus on connecting powerful processors to high-resolution cameras and using a full-blown Linux operating system for the image processing. But it feels like the Joule is meant more for your average hardware hacker, and the Euclid for software engineers who are pointing their skills at robots but don’t want to get bogged down in first-principles of hardware. Before you rage about this in the comments, let me explain.
Continue reading “Intel’s Vision for Single Board Computers is to Have Better Vision”
De-lousing is a trying agricultural process. It becomes a major problem in pens which contain the hundreds of thousands of salmon farmed by Norwegians — the world’s largest salmon exporter — an environment which allows the parasite to flourish. To tackle the problem, the Stingray, developed by [Stingray Marine Solutions], is an autonomous drone capable of destroying the lice with a laser in the order of tens of thousands per day.
Introduced in Norway back in 2014 — and some areas in Scotland in 2016 — the Stingray floats in the salmon pen, alert and waiting. If the lice-recognition software (never thought you’d hear that term, huh?) detects a parasite for more than two frames in the video feed, it immediately annihilates it with a 530 nanometre-wide, 100 millisecond laser pulse from up to two metres away. Don’t worry — the salmon’s scales are reflective enough to leave it unharmed, while the pest is fried to a crisp. In action, it’s reminiscent of a point-defense laser on a spaceship.
Continue reading “Submersible Robots Hunt Lice With Lasers”