Open Source Underwater Distributed Sensor Network

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.

Underwater distributed sensor network descent and ascentThe 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.

MoAgriS: A Modular Agriculture System

Hackaday.io user [Prof. Fartsparkle] aims to impress us again with MoAgriS, a stripped-down rig for bringing crops indoors and providing them with all they need.

This project is an evolution of their submission to last year’s Hackaday Prize, MoRaLiS — a modular lighting system on rails — integrating modules for light, water, airflow, fertilizer and their appropriate sensors. With an emphasis on low-cost, a trio of metal bars serve as the structure, power and data transmission medium with SAM D11 chips shepherding each plant.

Reinforced, angled PCBs extend rails horizontally allowing the modules to be mounted at separate heights. Light module? Up top. Water sensor? Low on the rails above the pot’s rim. You get the idea. 3D printed clamps attach the rails to the plant’s pot with a touch of paint to keep it from sticking out like a sore thumb among the leaves.

Airflow modules replicate wind currents — the lack of which results in thin, fragile stems — and light modules include a soft white LED to accompany and mitigate the full-spectrum LEDs’ pink neon-like glow. To manage watering the plants, [Prof. Fartsparkle] initially wanted to use one pump to distribute water to every plant, but found some smaller pumps at a low enough price-point to make one per plant viable — and simpler to integrate as a module as well!

If you prefer your gardening to take place outdoors, consider a robot assistant to tackle your weeding.

Battery-Powered Watering Timer Converted to Solar on the Cheap

Watering the garden or the lawn is one of those springtime chores that is way more appealing early in the season than later. As the growing season grinds along, a chore that seemed life-giving and satisfying becomes, well, just another chore, and plants often suffer for it.

Automating the watering task can be as simple as buying a little electronic timer valve that turns on the flow at the appointed times. [A1ronzo] converted his water hose timer to solar power. Most such timers are very similar, with a solenoid-operated pilot valve in line with the water supply and an electronic timer of some sort. The whole thing is quite capable of running on a pair of AA batteries, but rather than wasting money on new batteries several times a season, he slipped a LiPo pack and a charge controller into the battery case slot and connected a small solar panel to the top of the controller.

The LiPo is a nominal 3.7-volt pack, so he did a little testing to make sure the timer would be OK with the higher voltage. The solar panel sits on top of the case, and the whole thing should last for years. And bonus points for never having to replace a timer that you put away at the end of the season with batteries still in it, only to have them leak. Ask us how we know.

Like the best of hacks, this one is quick, easy and cheap — $15 in parts, aside from the timer. There are more complicated irrigation solutions, of course, one of which even won the Hackaday Prize once upon a time. But this one has us ordering parts to build our own right now.

The Metabolizer Turns Trash into Treasure

The amount of stuff we humans throw away is too damn high, and a bunch of it harms the ecosystem. But what are you gonna do? [Sam Smith] thinks we can do better than shoving most of it in a landfill and waiting for it to break down. That’s why he’s building The Metabolizer. It’s a series of systems designed to turn household trash (including plastic!) into useful things like fuel, building materials, and 3D prints.

The idea is to mimic the metabolism of a living organism and design something that can break down garbage into both useful stuff and fuel for itself. [Sam] is confident that since humans figured out how to make plastic, we can figure out a system to metabolize it. His proof-of-concept plan is to break down waste into combustible, gaseous fuel and use that fuel to power a small engine. The engine will power an open-source plastic shredder and turn a generator that powers an open-source plastic pellet printer like the SeeMeCNC Part Daddy.

Shredding plastic for use as a biomass requires condensing out the tar and hydrocarbons. This process leaves carbon monoxide and hydrogen syngas, which is perfect for running a Briggs & Stratton from Craigslist that’s been modified to run on gaseous fuel. Condensation is a nasty process that we don’t advise trying unless you know what you’re doing. Be careful, [Sam], because we’re excited to watch this one progress. You can watch it chew up some plastic after the break.

If [Sam] ever runs out of garbage to feed The Metabolizer, maybe he could build a fleet of trash-collecting robots.

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Broken Screen Becomes Polarizing Art Lamp

Got a broken laptop screen sitting around? If you haven’t already pilfered the LEDs and used the polarizing sheets for screen privacy filters, why not turn it into a unique table lamp? See if you can use more parts of the screen than [alexmaree-ross] did.

This is a simple idea with great-looking results, but the process is a bit fiddly. After all the layers are separated and the LEDs extracted, there’s still the matter of figuring out how they’re wired up. [alexmaree] tested them in pairs to see how they’re grouped together and ultimately powered them with a transformer from an old printer. To build the case, [alexmaree] carefully scored and snapped the pieces from the plastic layer and carefully glued pieces of the polarizing layer on top to give it that underwater infinity mirror look. The finishing touch comes from edging the shade with thin metal from the bezel.

The case could be in any shape you want, but we think the prism is quite appropriate considering the polarizing effects. And it looks really cool when you walk around it, which you can do vicariously after the break.

If the screen still works but laptop doesn’t, why not drive it with an FPGA?

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Thermoelectric Fan Harvests Wood Stove Heat Junkyard Style

Anyone who heats with a wood stove knows that the experience is completely different from typical central heating. It’s not for everyone, though, and it’s certainly not without its trade-offs. One of the chief complaints is getting heat away from the stove and into other areas of the house, and many owners turn on an electric fan to circulate the heated air.

That’s hardly in the green nature of wood heating, though, and fans can be noisy. So something like this heat-powered stove-top fan can come in handy. Such fans, which use Peltier devices to power a small electric motor, are readily available commercially. [bongodrummer] thought that sounded like no fun, though, and created his own mostly from junk. The Peltier module was salvaged from an old travel fridge and mounted to a heat sink from a computer to harvest heat from the stove. The other side of the Peltier needs to have a heat sink to keep it cooler than the hot side, and [bongodrummer] chose an unconventional bit of salvage for the job — the cylinder of a chainsaw engine. The spark plug hole sprouts the mount for the fan motor, and the cooling fins help keep the Peltier cool. And to prevent overheating of the device, he added a surprise — a car cooling system thermostat to physically lift the device off the stove when it gets too hot. Genius!

The video below shows the build, which was not trivial. But we think the end results are worth it, and it reminds us a little of the woodstove generator we featured a while back.

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Neural Network Names Nightshades

Neural networks are a core area of the artificial intelligence field. They can be trained on abstract data sets and be put to all manner of useful duties, like driving cars while ignoring road hazards or identifying cats in images. Recently, a biologist approached AI researcher [Janelle Shane] with a problem – could she help him name some tomatoes?

It’s a problem with a simple cause – like most people, [Darren] enjoys experimenting with tomato genetics, and thus requires a steady supply of names to designate the various varities produced in this work. It can be taxing on the feeble human brain, so a silicon-based solution is ideal.

[Janelle] decided to use the char-rnn library built by [Andrej Karpathy] to do the heavy lifting. After training it on a list of over 11,000 existing tomato varieties, the neural network was then asked to strike out on its own.

The results are truly fantastic – whether you’re partial to a Speckled Garfech or you prefer the smooth flavor of the Golden Pow, there’s a tomato to suit your tastes. When the network was retrained with additional content in the form of names of metal bands, the results get even better – it’s only a matter of time before Angels of Saucing reach a supermarket shelf near you.

On the surface, it’s a fun project with whimsical output, but fundamentally it highlights how much can be accomplished these days by standing on the shoulders of giants, so to speak. Now, if you need some assistance growing your tomatoes, the machines can help there, too.