DIY Shade Finder Tool Takes The Tedium Out Of Solar Surveys

January 8, 2012 by Mike Nathan 20 Comments

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[Steven Dufresne] does a lot of tinkering with solar-powered applications, a hobby which can be very time consuming if done right. One process he carries out whenever building a solar installation is creating a sun chart to determine how much (or little) sun the target area will get.

The process requires [Steven] to take elevation and Azimuth measurements of many different points, which often consumes about half an hour of his time. While taking measurements recently, he started thinking about how he could improve the process, and came up with a stellar solution that reduces the process down to a one-minute task.

In short, his shade finder tool uses a pulley, a pair of rollerblade wheels, and a pencil to accomplish a full shade survey in under a minute. The science behind the tool is best explained by [Steven], so be sure to check out his site for plenty of details and diagrams.

We have to say that we’re extremely impressed by his shade finder – hopefully his work can help others maximize the efficiency of their solar solutions.

Stick around after the jump to see a short video of the shade finder in action.

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Video Series Shows How To Build Your Own Solar-charged R/C Lawnmower

December 28, 2011 by Mike Nathan 18 Comments

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As winter is officially upon us, we’re pretty sure that the last thing most of you are thinking about is mowing your lawn. We would argue that it’s actually the ideal time to do so – that is, if you are interested in automating the process a bit.

[Robert Smith] has spent a lot of time thinking about his lawn, wanting a way to sit back and relax while doing his weekly trimming. He set off for the workshop to build an R/C electric lawnmower, and thoroughly documented the process in order to help you do the same.

On his web site, you will find a series of videos detailing every bit of the solar charged R/C lawnmower’s construction, taking you through the planning phases all the way to completion. [Robert] has provided just about anything you could possibly need including parts lists, schematics, code, and more.

If the short introductory video below has you interested, be sure to swing by his site for everything you need to build one of your own.

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Crunching The Numbers: Using Solar Cells Indoors

December 12, 2011 by Mike Szczys 27 Comments

[Mathieu] was interested in using more solar cells for his everday electronics. He looked around but couldn’t find much information about using pholovoltaic for small indoor devices. We remember hearing some of the same things from [Dave Jones] in one of his EEVblog installments from a few years ago which looked at solar calculators; the only indoor solar gadget we can think of.

The quest for knowledge was on and [Mathieu] decided to build this indoor solar cell test platform. It’s a stable piece of hardware that allows him to run reliable tests in many different conditions. It’s designed to compare two identical cells. One is charging the Lithium cell, the other is driving a load directly. A second battery powers the platform separately from the solar circuits so that it can be used as a data logger. He collects, dumps, and graphs info from his test runs, then discusses his findings. We won’t spoil it, but the results are not great. Mostly you need sunlight to get real results as it’s just so much more powerful than artificial lighting.

Lighted Fan Pull Saves You From Flailing Around In The Dark

December 9, 2011 by Mike Nathan 25 Comments

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Like many people, [yardleydobon] had a hard time locating his ceiling fan’s pull chain at night when his room is completely dark. Rather than continue to flail around blindly grasping for the chain, he decided to find a way to illuminate it instead.

He started off by disassembling a solar garden light, retaining the solar cell, photoresistor, and batteries. After paring down the electronics to the bare essentials, he mounted them inside a plastic battery storage case which he attached to the outside of the fan’s lamp. [yardleydobon] then ran a pair of wires from the electronics box down to end of the chain, where he added an LED and a translucent pull to diffuse the light.

He admits that it’s not the nicest looking modification around, but it does the job in a pinch. He has some ideas that he may put into play if he has the time to revise the design, and we bet that many of you do as well. If so, be sure to share them in the comments.

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Camping Light Retrofitted As A Solar Recharging Station

November 4, 2011 by Mike Szczys 8 Comments

With grand plans of tenting out for several days at a music festival [Josh] needed a way recharge his portable devices. In the past he’s lugged around a 12V battery with him, but this year he wanted to make things easier. He ended retrofitting a camping light to do the job with the help of the summer sun.

The first step of the project was to source some rechargeable batteries. He toyed with the idea of Li-Ion cells but ended up going with NiMH because the charging is more forgiving and he got them at a great price. Because of the lower operating voltage (1.2V versus Alkaline’s 1.5V) he needed to squeeze two more into the lamp housing. Here you can see that he just managed to get them to fit in the wire-run area down the middle of the case.

Next comes the recharging circuit. He based his design around an ATmega44, using a voltage divider and the ADC to detect when the batteries are topped off. During the day this is connected to an external solar panel and it’s ready to charge his phone when he gets back at night.

Solar Charger For Occupy Boston

October 13, 2011 by Brian Benchoff 58 Comments

As soon as the team at Revolt Labs heard Occupy Wall Street was coming to Boston, they decided to pick up their soldering irons in support of the throngs of protestors. They came up with a Solar charging USB box to keep those cell phones and digital cameras charged.

The case came direct from an Army surplus store. Originally, the box was used by the Dutch military to test the air for poison gas and signal when it was safe to remove a gas mask – hopefully not a portent of things to come.

On top of the box is five solar panels that output two watts each. A bit of breadboard holds a 7805 voltage regulator, a few caps and a diode. This regulated output goes to a USB hub and provides power for recharging.

For a cheap and easy project for our brothers without arms, we couldn’t think of a better project for the Occupy Boston tent city. Of course heating units will be needed at the Occupy protests this winter, but at least now the protesters have the means to power their communications equipment.

update: Once again, this has devolved into political argument and name calling. We, as hackaday, really couldn’t care less which party you are for or what your political beliefs are. We want to talk about the project, in this case a portable solar charger. We go to other sites to argue politics. Maybe you should try here.

Sustainability Hacks: Solar Panels Built From Old Windows And Factory Rejects

October 7, 2011 by Mike Nathan 37 Comments

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The crew over at The Tech Junkies recently took another look at solar power and thought that the pricing had come down enough for them to consider powering their entire shop via the sun. Cheaper or not, they still didn’t want to pay retail for solar panels, so they decided to build their own instead.

They scoured eBay for a bit and scored a nice batch of “production error” solar cells for about $0.25/watt, which is a great deal. After unpacking and sorting the cells, they began fitting them into a set of old window panels they had sitting around their shop. The cells were wired together using tabbing wire, and after a quick test to ensure everything was working correctly, the panel was permanently set using epoxy.

In its current state, they estimate that their panel can generate 35 watts of power, though they have a few design changes in mind to raise that number a bit. The total cost was roughly $375 for enough materials to build 9 panels, which is pretty reasonable.

Be sure to check out their blog for a quick overview of what it takes to build a solar panel if you’re thinking of putting together one of your own.