What Can You Do With Discarded Fish Aggregation Devices

Often we bring you projects at the end of their trajectory so that you can marvel at a job well done, but sometimes we point you instead to the start of the story. Such is the case with [Brett Smith]’s investigation of discarded fish aggregation buoys, referred to as FADs. These 700-plus dollar devices are deployed in the ocean in the thousands by commercial fishing fleets, and most are not recovered. He’s looking at them from the point of view of re-using their technology in the marine conservation business.

His progress has been documented in a series of short YouTube videos, starting with an introduction that we’ve placed below the break. So far he’s gone on to a complete teardown, and then a detailed look at the PCB. Inside they have a solar charger for a bank of NiCd cells, an echo sounder, a GPS receiver, and an Iridium satellite modem allowing the device to phone home. There’s certainly plenty in there to experiment with, including a few slightly exotic parts, so keep an eye on his channel as we’re sure to see more.

These devices have never made it to Hackaday before, but we have seen an echo sounder on a surfboard.

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Swarm Vs. Iridium: Which Satellite IoT Service Is Right For You?

In a world where it seems like everyone’s face is glued to a device screen, the idea that wireless service might be anything other than universal seems just plain silly. But it’s not, as witnessed by vast gaps in cell carrier coverage maps, not to mention the 70% of the planet covered by oceans. The lack of universal coverage can be a real pain for IoT applications, which is a gap that satellite-based IoT services aim to fill.

But which service is right for your application? To help answer that question, [Mike Krumpus] has performed the valuable work of comparing the services offered by Swarm and Iridium in a real-world IoT shootout. On the face of it, the match-up seems a little lopsided — Iridium has been around forever and has a constellation of big satellites and an extensive ground-based infrastructure. But as our own [Al Williams] discovered when he tested out Swarm, there’s something to be said for having a lot of 1/4U Cubesats up there.

[Mike] picked up the gauntlet and did head-to-head tests of the two services under real-world conditions. Using the same Swarm development kit that [Al] used for his test, alongside an Iridium dev board of his own design, [Mike] did basic tests on uplink and downlink times for a short message on each service. We couldn’t find specs on the test message length, but Swarm’s FAQ indicates that packets are limited to 192 bytes, so we assume they’re both in that ballpark. Iridium was the clear winner on uplink and downlink times, which makes sense because Swarm’s constellation is much smaller at this point and leaves large gaps in coverage. But when you consider costs, Swarm wins the day; what would cost over $1,500 with Iridium would set you back a mere $60 with Swarm.

The bottom line, as always, depends on your application and budget, but [Mike]’s work makes it easier to do that analysis.

Drone Buoy Drifts Along The Gulf Stream For Citizen Science

It may be named after the most famous volleyball in history, but “Wilson” isn’t just a great conversationalist. [Hayden Brophy] built the free-drifting satellite buoy to see if useful science can be done with off-the-shelf hardware and on a shoestring budget. And from the look of the data so far, Wilson is doing pretty well.

Wilson belongs to a class of autonomous vessels known as drifters, designed to float along passively in the currents of the world’s ocean. The hull of [Hayden]’s drifter is a small Pelican watertight case, which contains all the electronics: Arduino Pro Trinket, GPS receiver, a satellite modem, and a charger for the LiPo battery. The lid of the case is dominated by a 9 W solar panel, plus the needed antennas for GPS and the Iridium uplink and a couple of sensors, like a hygrometer and a thermometer. To keep Wilson bobbing along with his solar panel up, there’s a keel mounted to the bottom of the case, weighted with chains and rocks, and containing a temperature sensor for the water.

Wilson is programmed to wake up every 12 hours and uplink position and environmental data as he drifts along. The drifter was launched into the heart of the Gulf Stream on August 8, about 15 nautical miles off Marathon Key in Florida, by [Captain Jim] and the very happy crew of the “Raw Deal”. As of this writing, the tracking data shows that Wilson is just off the coast of Miami, 113 nautical miles from launch, and drifting along at a stately pace of 2.5 knots. Where the buoy ends up is anyone’s guess, but we’ve seen similar buoys make it all the way across the Atlantic, so here’s hoping that hurricane season is kind to Wilson.

We think this is great, and congratulations to [Hayden] for organizing a useful and interesting project.

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Hackaday Belgrade: Luka Mustafa On Exploiting IoT Niches

Ecology is a strange discipline. At its most basic, it’s the study of how living things interact with their environment. It doesn’t so much seek to explain how life works, but rather how lives work together. A guiding principle of ecology is that life finds a way to exploit niches, subregions within the larger world with a particular mix of resources and challenges. It’s actually all quite fascinating.

But what does ecology have to do with Luka Mustafa’s talk at the 2018 Hackaday Belgrade Conference? Everything, as it turns out, and not just because Luka and his colleagues put IoT tools on animals and in their environments to measure and monitor them. It’s also that Luka has found a fascinating niche of his own to exploit, one on the edge of technology and ecology. As CEO of Institute IRNAS, a non-profit technology development group in Slovenia, Luka has leveraged his MEng degree, background in ham radio, and interest in LoRaWAN and other wide-area radio networks to explore ecological niches in ways that would have been unthinkable even 10 years ago, let alone in the days when animal tracking was limited by bulky radio collars.

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Disaster Area Communications With Cloud Gateways

2017, in case you don’t remember, was a terrible year for the Caribbean and Gulf coast. Hurricane Maria tore Puerto Rico apart, Harvey flooded Houston, Irma destroyed the Florida Keys, and we still haven’t heard anything from Saint Martin. There is, obviously, a problem to be solved here, and that problem is communications. Amateur radio only gets you so far, but for their Hackaday Prize entry, [Inventive Prototypes] is building an emergency communication system that anyone can use. It only needs a clear view of the sky, and you can use it to send SMS messages. It’s the PR-Holonet, and it’s something that’s already desperately needed.

The basis for the PR-Holonet is built around an Iridium satellite modem. To date, satellite communication is the best way to get a message out to the world without any infrastructure. It’ll work in the middle of the Sahara, the depths of the Amazon, and conveniently anywhere that was just hit by a category five hurricane.

Along with the Iridium modem, [Inventive Prototypes] is using standard, off-the-shelf equipment to turn that connection to a satellite network into something any smartphone can use. That means pulling out a Raspberry Pi, of course. But building a project for areas that were recently ravaged by hurricanes is no easy task. The enclosure it the key here, and [Inventive Prototypes] is using some great water-resistant, dust-proof junction boxes, solar panels, and a whole bunch of batteries to keep everything humming along. It’s a great project and something that was desperately needed a year ago.

Mechanisms: The Reed Switch

Just about everywhere you go, there’s a reed switch nearby that’s quietly going about its work. Reed switches are so ubiquitous that you’re probably never more than a few feet away from one at any given time, especially at home or in the car. You might have them on your doors and windows as part of a burglar alarm system. They keep your washing machine from running when the lid is open, and they put your laptop to sleep when you close the lid. They know if the car has enough brake fluid and whether or not your seat belt is fastened.

Reed switches are interesting devices with a ton of domestic and industrial applications. We call them switches, but they’re also sensors. In fact, they only do the work of a switch while they can sense a magnetic field. They are capable of switching AC or DC at low and high voltages, but they don’t need electricity to work. Since they’re sealed in glass, they are impervious to dirt, dust, corrosion, temperature swings, and explosive environments. They’re cheap, they’re durable, and in low-current applications they can last for about a billion actuations.

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Fallen Radiosonde Reborn As Active L-band Antenna

If your hobby is chasing radiosondes across vast stretches of open country, and if you get good enough at it, you’ll eventually end up with a collection of the telemetry packages that once went up on weather balloons to record the conditions aloft. Once you’ve torn one or two down though, the novelty must wear off, which is where this radiosonde conversion to an active L-band antenna comes from.

As it happens, we recently discussed the details of radiosondes, so if you need a primer on these devices, check that out. But as Australian ham [Mark (VK5QI)] explains, radiosondes are a suite of weather instruments crammed into a lightweight package with a GPS receiver and a small transmitter. Lofted beneath a weather balloon into the stratosphere, a radiosonde transmits a wealth of data back to the ground before returning on a parachute after the balloon bursts. [Mark] had his eyes on the nice quadrifilar helical antenna used by the Vaisla R92 radiosonde’s GPS receiver, with the aim of repurposing them. He had a lot of components to remove while still retaining the low-noise amplifier (LNA), but in the end managed to get a working antenna with 40 dB gain in the L-band, and with the help of an RTL-SDR dongle he picked up solid signals from Iridium satellites.

Want to score your own radiosonde to play with? First, you have to know how to listen in so you can find them. Or, you know – there’s always eBay.

[via RTL-SDR.com]