Resurrecting A Cellphone With Blown USB Circuitry

[Script] is pretty lucky. One of the engineers who designed his cellphone included over-voltage protection in the circuit. Of course you probably wouldn’t know about this if there wasn’t a service schematic available. But a bit of searching around let him resurrect the fried USB segment of his Nokia N900.

Now [Script] has been experimenting with portable solar power like the system featured at 25C3 a few years back. Unfortunately he made an error which routed 12V into the USB connector’s 5V rail. After this unfortunate mistake the phone would not longer connect via USB, or charge the battery. Luickly the N900 is a favorite with the hacker community (you can see all kinds of N900 related projects here at Hackaday) and [Script] found his way to their N900 Schematic page. Digging into page four he found part F5300 which is labeled 2.0A. He removed the PCB and shielding, and tested the part with a multimeter to confirm it was blown. A quick wire bridge got the phone charging again, but [Script] plans to position a new fuse as soon as he can source the part.

Who says these devices aren’t user serviceable? If we could just get our hands on more service schematics perhaps our gear would last longer.

The Pirate Bay Aims For The Clouds…literally

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There is no shortage of government and entertainment-related agencies chomping at the bit to shut down the Pirate Bay for good. While the group has not suffered a permanent service ending raid like [Kim Dotcom] and the Megaupload crew, they are always thinking up novel ways to ensure that the site can endure whatever law enforcement throws at them.

In a recent blog post, representatives from the group unveiled plans to put their front line servers in the clouds, courtesy of custom-made autonomous drones called “Low Orbit Server Stations.” The project is in its infancy, but the general idea is to mount small computers like the Raspberry Pi on GPS-controlled drones kept aloft 24×7 (presumably) using solar energy. These drones would communicate with clients on the ground via radio transmitters which they state can provide a “100Mbps node up to 50km away”.

Calling the claims grandiose would be an understatement, but then again the Pirate Bay has proven to be a difficult organization to quash in any substantial way, so only time will tell.

[via The Daily What – Thanks, roboman2444]

Solar Charging A Buddha Machine

While having ambient music playing in the background can lead to a more relaxed state of mind, we can’t imagine the annoyance of having to replace the batteries constantly. Thankfully, [Phil] added solar charging to his Buddha Machine so he won’t have to worry about batteries anymore.

If you’re not familiar, the Buddha Machine is a small plastic box that loops nine tracks of ambient music inspired the Buddhist temples of south-east Asia. There’s not much to these little boxes; they’re just a plastic box with a speaker, on/off knob and an EEPROM loaded up with samples of music.

A year or so ago, the people behind the Buddha Machine posted a prototype of a solar-powered meditative noise box that was unfortunately never made. Thankfully, [Phil Stearns] stepped in posted a guide on how to convert a AA-powered Buddha Machine to solar power.

The modification is incredibly simple: after replacing the disposable AA batteries with NiMH rechargeable, two wires are swapped connecting the battery compartment with the main PCB and the box is sealed up again. Now, whenever one of [Phil]’s solar panels is connected to the power jack the batteries begin charging. [Phil] says he can get two days worth of runtime with a full 8-hour charge, so he shouldn’t need any batteries for his Buddha Machine anytime soon.

Reviewing The Numbers From One Month Of Solar Harvesting

[Mathieu] just finished analyzing the numbers from a month of solar energy harvesting. You may remember that he was curious to see what kind of energy can be collected from small solar cells used indoors. He built several copies of a test platform which collected data between December 16th and January 16th.

First of all, it’s not shocking to find out that rooms with no sunlight produced negligible energy during that time. When you think about it, if they had been gathering a statistically significant amount wouldn’t that mean the lighting used in those rooms was incredibly inefficient? In other words, there’s no way you need to be making that much light.

But he did find that proper positioning in rooms that catch sunlight during the day can result in usable energy for small loads. He established that a 0.5 Watt panel harvested just a bit more than half of what a 1 Watt panel did. But perhaps the most useful discovery was that it’s quite a bit more efficient to have a charging circuit store energy in a battery rather than directly powering a fixed load.

It will take us a few more viewings to really decide what we can take away from the experiment for our own projects. But we appreciate [Mathieu’s] quest for knowledge and his decision to put this information out there so that others can learn from it.

DIY Fresnel Reflector

Just like destroying an ant colony with a magnifying glass, there’s nothing like cooking hot dogs and roasting marshmallows with a nice parabolic reflector. Of course covering an old satellite dish with mylar or aluminum tape doesn’t take much skill, however cool it is. [Uwe] came up with a much more technical means of building a Fresnel reflector that will cook your hot dogs in seconds, but only on sunny days.

[Uwe] channeled a little bit of [Apollonius] when he realized that a flat cardboard ring with a section removed could be joined together into a conic section. The resulting section looks just like one concentric ring in a Fresnel reflector. [Uwe] wrote a small program in Visual Basic to calculate the necessary diameter and angle of his conic sections.

A bit of cardboard was cut out and pieced together with some very reflective aluminum tape. The resulting Fresnel reflector concentrates 117 times the normal solar radiation onto a small point. It’s more than enough to burn holes in construction paper, but we’ll be using a microwave for our lunch today.

DIY Shade Finder Tool Takes The Tedium Out Of Solar Surveys

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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.

Continue reading “DIY Shade Finder Tool Takes The Tedium Out Of Solar Surveys”

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

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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.

Continue reading “Video Series Shows How To Build Your Own Solar-charged R/C Lawnmower”