Hackaday Prize Entry: Profiling Underwater Light

July 28, 2016 by Brian Benchoff 5 Comments

The goal for the Citizen Science portion of the Hackaday Prize is to empower people to create their own devices to perform their own analyses For [Adam]’s project, he’s designing a device that measures the health of waterways simply by looking at the light availability through the water column. It’s called PULSE, the Profiling Underwater Light SEnsor, and is able to monitor changes that are caused by algal blooms, suspended sediments, or sewer runoff.

The design of PULSE is a small electronic depth charge that can be lowered into a water column from anything between a research vessel to a kayak. On the top of this sinkable tube is a sensor to measure photosynthetically active radiation (PAR). This sensor provides data on light irradiance through the water column and gives a great insight into the health of photosynthesis, marine plant life, and ultimately the health of any aquatic environment.

Measuring the light available for photosynthesis through a water column is great, but PULSE isn’t a one trick pony. On the bottom of the aquatic probe are three sensors designed to measure photosynthesis, dissolved organic matter, and turbidity. These sensors are really just a few LEDs and photodiodes, proving just how much science you can do with simple tools.

The goal of the Citizen Science portion of the Hackaday Prize is to put scientific discovery in the hands of everyone. PULSE is a great example of this: it’s a relatively simple device that can be thrown over the side of a boat, lowered to the bottom or a lake, and hoisted back up again. It’s inexpensive to build, but still provides great data. That’s remarkable, and an excellent example of what we’re looking for in the Hackaday Prize.

Underwater Jetpack Is Almost Practical

December 17, 2025 by Tyler August 4 Comments

The jet pack is one of those pre-war sci-fi dreams that the cold light of rational consideration reveals to be a terrible idea. Who wants to cook their legs with hot exhaust while careening out of control? Nobody. Yet it’s such an iconic idea, we can’t get away from it. What if there was a better environment, one where your jetpack dreams could come true? [CPSdrone] has found one: the world’s oceans, and have taken that revelation to build the world’s fastest underwater jetpack.

Underwater? Yeah, water drag is worse than air drag. But there are two big advantages: one, humans are fairly buoyant, so you don’t need fight gravity with rocket thrust, and two, the high density of water makes small, electric props a reasonable proposition. The electric ducted fans on this “jetpack” each produce about 110 pounds of thrust, or just over 490 N. The first advantage is helped further by the buoyancy provided by the air-filled “hull” of the jetpack. That’s necessary because while the motors might be rated for submersion, but the rest of the electronics aren’t.

Alas, wearing the device on the back is considerably less hydrodynamic than hanging on behind in the standard ‘water scooter’ configuration. While they’re able to go faster than a swimming human, the ESCs weren’t able to handle the motors full power so we can’t tell you if this device would allow [CPSdrone] to outrun a shark with those 220 lbf on tap, which was the design goal. Apparently they’re working on it.

From the testing done on-screen, it’s safe to say that they’d at least need to hang on behind to get their desired speed goals, and abandon their jet pack dreams just as we landlubbers were forced to do long ago. Well, some of us, anyway.

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Love Is A Burning Flame, And So Is This Underwater Burning Ring Of Fire

July 29, 2022 by Ryan Flowers 22 Comments

When Johnny Cash wrote “Ring of Fire”, he was talking about love. But when an unnamed follower of [TheBackyardScientist] took it literally and suggested making actual rings of fire — underwater — they rose to the challenge as you can see in the video below the break.

Of course there are several ingredients to underwater fire rings. First you need water, and a pool clearly does the job in this video. Second, you need flammable rings of gas. [TheBackyardScientist] decided to build a machine to create the gas rings, and it’s quite interesting to see them go through several iterations before settling on a voice coil based poppet valve design. We must say that it works absolutely swimmingly.

Lastly there needs to be fire. And for fire, you need something flammable, and something shocking. Forty thousands volts light up a spark plug, even underwater. The fuel is provided by what appears to be compressed air and acetylene but we’re not 100% sure. We are sure that it goes bang! quite sufficiently, as demonstrated by its aptitude for blowing things up.

We appreciated the engineering that went into the project but also the rapid iterations of ideas, the overcoming of serious obstacles and the actual science that went into the project. Even if it is just randomly making literal burning rings of fire.

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Epoxy Resin Night Light Is An Amazing Ocean-Themed Build

February 12, 2022 by Lewin Day 17 Comments

We’ve all seen those “river” tables where a lovely old piece of tree is filled with some blue resin to create a water-like aesthetic. This project from [smartyleowl] takes that basic idea, but pushes it further, and the result is a beautiful build that is as much a diorama as it is a simple lamp.

First up, an appropriate rough piece of unprepared wood is chosen to create a cliff for the underwater scene. Speckles of UV-reactive blue powder are scattered on to the wood and some little plastic coral and marine plants are stuck down as well. A mold is then constructed around the wood using acrylic. Small whale and diver figurines are dangled in place, and blue resin poured in to complete the underwater scene. Once the resin has hardened, it’s polished to a clear sheen and its edges are nicely beveled. It’s then placed on a illuminated base which lights the scene from below, giving it a somewhat ethereal underwater quality.

It’s not a complicated project by any means, but it’s a great example of the beautiful things one can create with the creative application of colored resin. Producing a lamp that looks this good obviously takes some skill, of course – getting a bubble-free resin pour and a nice shiny finish on the wood isn’t easy. However, there’s no reason you can’t start learning today! Video after the break.

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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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Gliding To Underwater Filming Success

February 5, 2017 by Jenny List 17 Comments

If you are a fan of nature documentaries you will no doubt have been wowed by their spectacular underwater sequences. So when you buy a GoPro or similar camera and put it in a waterproof case accessory, of course you take it with you when you go swimming. Amazing footage and international documentary stardom awaits!

Of course, your results are disappointing. The professionals have years of experience and acquired skill plus the best equipment money can buy, and you just have your hand, and a GoPro. The picture is all over the place, and if there is a subject it’s extremely difficult to follow.

[Steve Schmitt] has an answer to this problem, and it’s a refreshingly simple one. He’s built an underwater glider to which he attaches his camera and launches across the submerged vista he wishes to film. Attached to a long piece of line for retrieval, it is set to glide gently downwards at a rate set by the position of the camera on its boom.

Construction is extremely simple. The wing is a delta-shaped piece of corrugated plastic roofing sheet, while the fuselage is a piece of plastic pipe. A T-connector has the camera mount on it, and this can slide along the fuselage for pre-launch adjustments. It’s that simple, but of course sometimes the best builds are the simple ones. He’s put up a video which you can see below the break, showing remarkable footage of a test flight through a cold-water spring.

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Highlights From Robotic Shipwreck Exploration

July 13, 2016 by Donald Papp 9 Comments

DIY Research Vessel in use, while ROV is busy below. [Source: NYT]

OpenROV shared the results of their June 2016 underwater expedition to locate and robotically explore the wreck of the S.S. Tahoe, currently sitting at a depth of 150m in Lake Tahoe. Back in 1940 the ship was intentionally scuttled in shallow water, but unexpectedly slid to a much deeper depth. OpenROV used a modified version of their new Trident design to dive all the way down to the wreck and take a good look at things, streaming it over the internet in the process.

We previously covered the DIY research vessel that was designed and created as a floating base station for the ROV while it located and explored the wreck, and now the results are in! The video highlights of the expedition are below, as is a video tour of the ROV used and the modifications required to enable it to operate at 150m.

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