Let The Solar Free

October 24, 2020 by Matthew Carlson 15 Comments

Anyone tackling solar power for the first time will quickly find there’s a truly dizzying amount of information to understand and digest. You might think you just need to buy some solar panels, wire them together, and just sort of plug them in. But there are a hundred and one different questions about how they’ll be connected, the voltage of the panels, and the hardware for driving a load. [Michel], [case06], and [Martin Jäger] have set out to create a simpler and easier to understand charge controller named LibreSolar.

A charge controller is fundamentally a simple idea. The goal is to charge a battery with solar panels, which means it’s essentially just a heavy-duty DC/DC buck converter. What makes this project different is that it is an open platform built for extensibility.

There are UEXT connectors included for adding extra peripherals, and with some tweaks to the STM32 firmware, it would be easy to handle small wind turbines (with some rectification to convert to DC, of course). LibreSolar seems to be designed with an eye towards creating a nano-scale localized networked grid. For example, they’ve developed a Raspberry Pi Zero module that uses WiFi to create a CAN bus allowing the boxes to communicate their maximum voltage to each other. This makes the system as plug-and-play as possible, as the bus doesn’t require a master controller to communicate.

With features such as MPPT (Maximum Power Point Tracking), 20 amp peak charging, a USB interface for updating, and several built-in protection mechanisms, it’s clearly a well thought through project. We look forward to seeing it deployed in the real world!

Skylight In Any Room

October 4, 2020 by Brian McEvoy 41 Comments

Despite a glut of introvert memes, humans need sunlight. If vitamin D isn’t your concern, the sun is a powerful heater, and it helps plants grow. Sadly for [mime], their house is not positioned well to capture all those yummy sunbeams. Luckily for us, their entry into the 2020 Hackaday Prize is their sun-tracking apparatus that redirects those powerful rays throughout the house. It uses a couple of mirrors to redirect the light around their shed and into the house. For those who work in a dim office, no amount of work is too great for a peek of natural sunlight.

Movie spoiler alert: We saw this trick in the 1985 movie Legend and it was enough to vanquish the Lord of Darkness.

This project started in 2014 and sat on hiatus for more than five years, but it is back and prime for improvements fueled by half-a-decade of experience. The parts that aren’t likely to change are the threaded struts that adjust the positioning mirror’s angle, the driving motors, and power circuitry. Their first plan was to build a solar-powered controller with an Arduino, DC motors, and sun telemetry data, but now they’re leaning toward stepper motors and a computer in the house with a long cable. They are a finalist this year, so we will keep our eyes peeled for further development.

Game Boy Plays Forever

September 11, 2020 by Bryan Cockfield 14 Comments

For those of us old enough to experience it first hand, the original Game Boy was pretty incredible, but did have one major downside: battery consumption. In the 90s rechargeable batteries weren’t common, which led to most of us playing our handhelds beside power outlets. Some modern takes on the classic Game Boy address these concerns with modern hardware, but this group from the Delft University of Technology and Northwestern has created a Game Boy clone that doesn’t need any batteries at all, even though it can play games indefinitely.

This build was a proof-of-concept for something called “intermittent computing” which allows a computer to remain in a state of processing limbo until it gets enough energy to perform the next computation. The Game Boy clone, fully compatible with the original Game Boy hardware, is equipped with many tiny solar panels which can harvest energy and is able to halt itself and store its state in nonvolatile memory if it detects that there isn’t enough energy available to continue. This means that Super Mario Land isn’t exactly playable, but other games that aren’t as action-packed can be enjoyed with very little impact in gameplay.

The researchers note that it’ll be a long time before their energy-aware platform becomes commonplace in devices and replaces batteries, but they do think that internet-connected devices that don’t need to be constantly running or powered up would be a good start. There are already some low-powered options available that can keep their displays active when everything else is off, so hopefully we will see even more energy-efficient options in the near future.

Thanks to [Sascho] for the tip!

Continue reading “Game Boy Plays Forever” →

Solar Satellite Glows At Night

August 30, 2020 by Kristina Panos 16 Comments

They say that imitation is the sincerest form of flattery. If we were going to imitate one of master circuit sculptor Mohite Bhoite’s creations, we’d probably pick the little blinky solar satellite as a jumping off point just like [richardsappia] did. It’s cute, it’s functional, and it involves solar power and supercapacitors. What more could you want?

SATtiny is a pummer, which is BEAM robotics speak for a bot that soaks up the sun all day and blinks (or ‘pumms’, we suppose) for as long as it can throughout the night on the juice it collected. This one uses four mini solar panels to charge up a 4 F supercapacitor.

At the controls is an ATtiny25V, which checks every eight seconds to see if the supercapacitor is charging or not as long as there is enough light. Once night has fallen, the two red LEDs will pumm like a pair of chums until the power runs out. Check out the brief demo after the break.

Would you rather have something more nightstand-friendly? Here’s a mini night light sculpture with a friendly glow. If you haven’t started your entry into our Circuit Sculpture Challenge, there’s still plenty of time — the contest runs until November 10th.

Continue reading “Solar Satellite Glows At Night” →

Four Years Later, Off-Grid Office Shed Still Rocks

August 21, 2020 by Donald Papp 25 Comments

About four years ago, [Russell Graves] created what was, to him, the ultimate work-from-home environment: an off-grid office shed. The shed might look a bit small, but it’s a considerably larger workspace than most people in an office are granted. Four years later, in the middle of a global pandemic, working from home has become much more common and [Russel] shares some thoughts on working from home and specifically reflects on how his off-grid, solar powered shed office (or “shoffice” as he likes to call it) has worked out. In short, after four years, it rocks hard and is everything he wanted and more.

Its well-insulated plywood walls let him mount monitor arms and just about anything else anywhere he wants, and the solar power system allows him to work all day (and into the night if he wants, which he doesn’t) except for a few spells in the winter where sunlight is just too scarce and a generator picks up the slack. Most importantly, it provides a solid work-life separation — something [Russell] is convinced is critical to basic wellness as a human being.

That’s not to say an off-grid solar shed is the perfect solution for everyone. Not everyone can work from home, but for those who can and who identify with at least some of the motivations [Russell] expressed when we covered how he originally created his office shed, he encourages giving it some serious thought.

The only thing he doesn’t categorically recommend is the off-grid, solar powered part. To be clear, [Russell] is perfectly happy with his setup and even delights in being off-grid, but admits that unless one has a particular interest in solar power, it makes more sense to simply plug a shed office into the grid like any other structure. Solar power might seem like a magic bullet, but four years of experience has taught him that it really does require a lot of work and maintenance. Determined to go solar? Maybe give the solar intensity sensor a look, and find out just how well your location is suited to solar before taking the plunge.

Building A Serious Solar Inverter Battery Pack

May 27, 2020 by Lewin Day 35 Comments

If you’re out in the wilderness, having plenty of electricity on hand is a blessing. Eschewing fossil fuels, [LithiumSolar] is, as their name suggests, a fan of other technologies – undertaking the construction of a 3.5kWh solar generator that’s rugged and ready for the outdoors.

The build starts with 18650 lithium-ion cells sourced from a recycler, packed inside obsolete modem battery packs. After harvesting 390 cells, the best 364 are chosen and assembled into plastic holders to create a 14S26P configuration. A spot welder is employed to weld the pack together, with XT60 connectors used as the main bus connectors, albeit in a very non-standard configuration. Balance leads are hooked up to a 14S battery management system, to keep things in check. The huge pack is then installed inside a stout Craftsman toolbox, along with a MPPT solar charger module, and a 1500W inverter for output.

The build video is a great resource for anyone interested in building custom 18650 packs or battery solar power systems. [LithiumSolar] does a great job of clearly explaining each step and the reasons for part selections along the way. Of course, in a neat dovetail to this project, we’ve even seen solar-powered spot welders before – which would be useful if you need to replicate this build out in the field somewhere. Video after the break.

Continue reading “Building A Serious Solar Inverter Battery Pack” →

Searching For Alien Life With The Sun As Gravitational Telescope

April 21, 2020 by Moritz v. Sivers 19 Comments

Astronomy is undoubtedly one of the most exciting subjects in physics. Especially the search for exoplanets has been a thriving field in the last decades. While the first exoplanet was only discovered in 1992, there are now 4,144 confirmed exoplanets (as of 2nd April 2020). Naturally, we Sci-Fi lovers are most interested in the 55 potentially habitable exoplanets. Unfortunately, taking an image of an Earth 2.0 with enough detail to identify potential features of life is impossible with conventional telescopes.

The solar gravitational lens mission, which has recently been selected for phase III funding by the NASA Innovative Advanced Concepts (NIAC) program, is aiming to change that by taking advantage of the Sun’s gravitational lensing effect. Continue reading “Searching For Alien Life With The Sun As Gravitational Telescope” →