Friday Hack Chat: Energy Harvesting

Think about an Internet-connected device that never needs charging, never plugs into an outlet, and will never run out of power. With just a small solar cell, an Internet of Thing module can run for decades. This is the promise of energy harvesting, and it opens the doors to a lot of interesting questions.

Joining us for this week’s Hack Chat will be [John Tillema], CTO and co-founder of TWTG. They’re working on removing batteries completely from the IoT equation. They have a small device that operates on just 200 lux — the same amount of light that can be found on a desktop. That’s a device that can connect to the Internet without batteries, wall warts, or the black magic wizardry of RF harvesting. How do you design a device that will run for a century? Are caps even rated for that? Are you really going to download firmware updates several decades down the line?

For this week’s Hack Chat, we’ll be discussing what energy harvesting actually is, what TWTG’s ‘light energy’ technology is all about, and the capabilities of this technology. Going further, we’ll be discussing how to design a circuit for low-power usage, how to select components that will last for decades, and how to measure and test the entire system so it lives up to the promise of being always on, forever, without needing a new battery.

This is a community Hack Chat, so of course we’ll be taking questions from the community. If you have a question, add it to the discussion sheet

join-hack-chatOur Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This Hack Chat will be going down noon, Pacific time on Friday, October 20th. Is it always five o’clock somewhere? Yes, so here’s a time zone converter!

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

Hackaday Prize Entry: Modular, Rapid Deployment Power Station

After a disaster hits, one obvious concern is getting everyone’s power restored. Even if the power plants are operational after something like a hurricane or earthquake, often the power lines that deliver that energy are destroyed. While the power company works to rebuild their infrastructure, [David Ngheim]’s mobile, rapid deployment power station can help get people back on their feet quickly. As a bonus, it uses renewable energy sources for power generation.

The modular power station was already tested at Burning Man, providing power to around 100 people. Using sets of 250 Watt panels, wind turbines, and scalable battery banks, the units all snap together like Lego and can fit inside a standard container truck or even the back of a pickup for smaller sizes. The whole thing is plug-and-play and outputs AC thanks to inverters that also ship with the units.

With all of the natural disasters we’ve seen lately, from Texas to Puerto Rico to California, this entry into the Hackaday Prize will surely gain some traction as many areas struggle to rebuild their homes and communities. With this tool under a government’s belt, restoration of power at least can be greatly simplified and hastened.

A Solar Freakin’ Walkway

Looking to add a little pizzazz to your back garden? Are those strings of lights hung in the trees looking a little dated? Why not try lighting your garden path with DIY solar-powered pavers?

If [jfarro]’s project looks like a miniature version of the much-touted solar freakin’ roadways concept, rest assured that there are huge differences. For one, these lighted pavers actually work — trust me on this; I live not far from the demo site for the Solar Roadways and the degree to which it underwhelms cannot be overstated. Granted, a garden path is a lot simpler to engineer than a road, but many of the challenges remain.

Using recycled glass blocks that are usually reserved for walls and windows, [jfarro] figured out how to attach Neopixel rings to the underside and waterproof them with a silicone conformal coating. The 12 lighted pavers he built draw considerable current, so a 45-watt solar array with charge controller and battery were installed to power the pavers. An Arduino and a motion sensor control the light show when someone approaches; more complicated programs are planned.

Hats off the [jfarro] for taking on a project like this. We don’t often see builds where electrical engineering meets civil engineering, and even on a small scale, dealing with dirt, stone, and water presents quite a few challenges. Here’s hoping his project lasts longer than the Solar Roadways project did.

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An Environmentally Conscious, Solar-Powered Throwie

The basic throwie is a a type of street art/graffiti/vandalism — depending on where you stand — consisting of a coin cell, an led, and a magnet taped together. Seeking to be a slightly more eco-friendly troublemaker, [Alaric Loftus] has kindly put together an Instructable on how to build a solar-powered throwie!

In order to be the best maker of mischief possible, [Alaric Loftus] tried a number of different products to find one that was hackable,  supplied the right voltage, had the right form factor, and cheap enough to literally throw away. Turns out, garden path lights hit that sweet spot. Once [Alaric Loftus] has drilled a hole in the light and opened it up, de-soldering the stock LED, attaching some leads to the contacts and sticking it into the freshly-drilled hole is simply done. Hot-gluing a strong magnet on the bottom completes the throwie.

[Alaric Loftus] also advises that drilling the LED hole slightly smaller and sealing up any cracks with hot glue will strengthen its water resistance — because if it’s worth doing, it’s worth doing it right.

We’ve featured some really cooleven creepy — takes on the throwie concept, but please don’t contribute any further to e-waste buildup.

Innovating A Backyard Solar Battery System

Ever on the lookout for creative applications for tech, [Andres Leon] built a solar powered battery system to keep his Christmas lights shining. It worked, but — pushing for innovation — it is now capable of so much more.

The shorthand of this system is two, 100 amp-hour, deep-cycle AGM batteries charged by four, 100 W solar panels mounted on an adjustable angle wood frame. Once back at the drawing board, however, [Leon] wanted to be able track real-time statistics of power collected, stored and discharged, and the ability to control it remotely. So, he introduced a Raspberry Pi running Raspbian Jessie Lite that publishes all the collected data to Home Assistant to be accessed and enable control of the system from the convenience of his smartphone. A pair of Arduino Deuemilanoves reporting to the Pi control a solid state relay powering a 12 V, 800 W DC-to-AC inverter and monitor a linear current sensor — although the latter still needs some tinkering. A in-depth video tour of the system follows after the break!

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A Poor-Man’s Laser CNC Engraver

What do you get when you mix the disappointment that sometimes accompanies cheap Chinese electronics with the childhood fascination of torturing insects with a magnifying glass on a sunny day? You get a solar-powered CNC etcher, that’s what.

We all remember the days of focussing the sun on a hapless insect, or perhaps less sadistically on a green plastic army man or just a hunk of dry wood. The wonder that accompanied that intense white spot instantly charring the wood and releasing wisps of smoke stayed with you forever, as seemingly did the green spots in your vision. [drum303] remembered those days and used them to assuage his buyer’s remorse when the laser module on his brand new CNC engraver crapped out after the first 10 minutes. A cheap magnifying glass mounted to the laser holder and a sunny day, and he don’t need no stinkin’ lasers! The speed needs to be set to a super slow — 100mm per minute — and there’s the problem of tracking the sun, but the results are far finer than any of our childhood solar-artistic attempts ever were.

Do we have the makings of a possible performance art piece here? A large outdoor gantry with a big Fresnel lens that could etch a design onto a large piece of plywood would be a pretty boss beachside attraction. Of course, you’d need a simple solar tracker to keep things in focus.

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Autonomous Transatlantic Seafaring

[Andy Osusky]’s project submission for the Hackaday Prize is to build an autonomous sailboat to cross the Atlantic Ocean. [Andy]’s boat will conform to the Microtransat Challenge – a transatlantic race for autonomous boats. In order to stick to the rules of the challenge, [Andy]’s boat can only have a maximum length of 2.5 meters, and it has to hit the target point across the ocean within 25 kilometers.

The main framework of the boat is built from aluminum on top of a surfboard, with a heavy keel to keep it balanced. Because of the lightweight construction, the boat can’t sink and the heavy keel will return it upright if it flips over. The sail is made from ripstop nylon reinforced by nylon webbing and thick carbon fiber tubes, in order to resist the high ocean winds.

The electronics are separated into three parts. A securely sealed Pelican case contains the LiFePo4 batteries, the solar charge controller, and the Arduino-based navigation controller. The communications hardware is kept in polycarbonate cases for better reception. One case contains an Iridium satellite tracker, compass, and GPS, the other contains two Globalstar trackers. The Iridium module allows the boat to transmit data via the Iridium Short Burst Data service. This way, data such as GPS position, wind speed, and compass direction can be transmitted.

[Andy]’s boat was launched in September from Newfoundland headed towards Ireland. However, things quickly seemed to go awry. Storms and crashes caused errors and the solar chargers seemed not to be charging the batteries. The test ended up lasting about 24 days, during which the boat went almost 1000km.

[Andy] is redesigning the boat, changing to a rigid sail and enclosing the hardware inside the boat. In the meantime, the project is open source, so the hardware is described and software is available on GitHub. Be sure to check out the OpenTransat website, where you can see the data from the first sailing. Also, check out this article on autonomous kayaks, and this one about a swarm of autonomous boats.

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