Finding The Sun And Moon The New Old-Fashioned Way

The ability to build a robot to take care of a tedious task for you is power indeed. For a few centuries, the task of helping determine one’s location fell to the sextant. Now, you can offload that task to this auto-sextant, courtesy of [Raz85].

To be clear, this robo-sextant doesn’t give you your exact location, but it does find and display the bearing and altitude of the most luminous object around and display them on the LCD — so, the sun and moon. A pair of cheap servos handle the horizontal and vertical movement, an Arduino Uno acts as the brains and nervous system, and a photoresistor acts as the all-seeing eye. Clever use of some cardboard allow [Raz85] to keep the photoresistor isolated from most all light except what the sextant is currently pointed at. Servos have a limited field of movement, so you might need to adjust [Raz85]’s code accordingly if you’re rebuilding this one yourself.

After taking three minutes to make its rounds of the sky, the Uno records the servos’ positions when fixed on the sun or moon, translating that data into usable coordinates. Don’t forget the best part, it runs on batteries making it convenient for all your wave-faring excursions!

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Bye Bye Solaris, it seems.

For readers of A Certain Age, this may bring a tear to the eye. Reports have been circulating of the decision by Oracle to lay off a significant portion of the staff behind its Solaris operating system and SPARC processors, and that move spells the inevitable impending demise of those products. They bore the signature of Sun Microsystems, the late lamented workstation and software company swallowed up by the database giant in 2009.

So why might we here at Hackaday be reaching for our hankies over a proprietary UNIX flavour and a high-end microprocessor, neither of which are likely to be found on many of the benches of our readers in 2017? To answer that it’s more appropriate to journey back to the late 1980s or early 1990s, when the most powerful and expensive home computers money could buy were still connected to a domestic TV set as a monitor.

If you received a technical education at a university level during that period the chances are that you would have fairly soon found yourself sitting in a lab full of workstations, desktop computers unbelievably powerful by the standards of the day. With very high resolution graphics, X-windows GUIs over UNIX, and mice that weren’t just used for a novelty paint package, these machines bore some resemblance to what we take for granted today, but at a time when an expensive PC still came with DOS. There were several major players in the workstation market, but Sun were the ones that seemed to have the university market cracked.

You never forget your first love, and therefore there will be a lot of people who will never quite shake that association with a Sun workstation being a very fast desktop computer indeed. Their mantra at the time was “The network is the computer”, and it is the memory of a significant part of a year’s EE students trolling each other by playing sound samples remotely on each other’s SPARCStations on that network that is replaying in the mind of your scribe as this is being written.

A Raspberry Pi with a Raspbian desktop probably outperforms one of those 1980s SPARCStations in every possible way, but that is hardly the point and serves only to demonstrate technological progress. It feels as though something important died today, even if it may be a little difficult to remember what it was when sat in front of a multi-core x86 powerhouse with a fully open-source 64-bit POSIX-compliant operating system running upon it.

Unsurprisingly we’ve featured no hardware hacks with such high-end computing. If you’d like to investigate some Sun Microsystems hardware though, take a look at the Centre for Computing History’s collection.

Sun Ray Thin Client Becomes Raspberry Pi Workstation

One of the great predictions of desktop computing from the mid 1990s was that we would all move to so-called thin clients, stripped-out desktop computers containing only processor, display driver, and peripheral interfaces, that would call up their applications not from a local hard disk but from a remote server. It was one that was never fulfilled in quite the way its proponents envisaged, but a business thin client hardware market did emerge for the likes of Citrix sharing of Windows applications. In a sense we have reached the same point through cloud-based in-browser applications such as Google Apps or Office 365, though even with newer thin client hardware such as the Chromebook these are still largely used on more traditional machines.

Even though thin clients never took the world by storm, it is still not unusual to encounter the hardware once it has outlived its usefulness. A surplus Sun Ray 270 all-in-one thin client came [Evan Allen]’s way, and to make something useful from it he converted it into a Raspberry Pi workstation.

The Sun Ray 270 has a MIPS processor board integrated into a 17 inch monitor. [Evan] was fortunate enough to find a generic HDMI controller board for its LCD panel, so was able to dispense with the MIPS board entirely and couple the controller with an automatic HDMI switch. This allows him to use the device both as a Raspberry Pi and as a monitor.

This may not rank among the most epic hacks ever, but it has delivered [Evan] a useful computer and it’s reminding the rest of us that these thin clients can be repurposed. So if one lands on your bench, look at it with fresh eyes.

Of course, if you have a Pi in a thin client, you could always take it full circle and use it to run a thin client.

Two-Axis Solar Tracker

Solar panels are an amazing piece of engineering, but without exactly the right conditions they can be pretty fickle. One of the most important conditions is that the panel be pointed at the sun, and precise aiming of the panel can be done with a solar tracker. Solar trackers can improve the energy harvesting ability of a solar panel by a substantial margin, and now [Jay] has a two-axis tracker that is also portable.

The core of the project is a Raspberry Pi, chosen after [Jay] found that an Arduino didn’t have enough memory for all of the functionality that he wanted. The Pi and the motor control electronics were stuffed into a Pelican case for weatherproofing. The actual solar tracking is done entirely in software, only requiring a latitude and longitude in order to know where the sun is. This is much easier (and cheaper) than relying on GPS or an optical system for information about the location of the sun.

Be sure to check out the video below of the solar tracker in action. Even without the panel (or the sun, for that matter) the tracker is able to precisely locate the panel for maximum energy efficiency. And, if you’d like to get even MORE power from your solar panel, you should check out a maximum power point tracking system as well.

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Solar oven built to last

The problem with most solar ovens is that they’re flimsy builds that will stand up to only a handful of uses. But this one stands apart from that stereotype. It’s big, sturdy, and used a lot of math to efficiently gather the sun’s energy when cooking food.

This is the third version of the build and each has included many improvements. The obvious change here is a move from aluminum reflectors to actual mirror reflectors. These attach at a carefully calculated angle to get the most power from the rays they are redirecting. The orange mounting brackets for the mirrors also serve as a storage area for transport. The rectangular reflectors fit perfectly between them (stacked on top of the tempered glass that makes up the transparent side of the cooking chamber).

The body of the oven doesn’t track the sun and one of the future improvements mentions adding tilt functionality to the base. We’d suggest taking a look at some of the solar tracking setups used for PV arrays.

[Thanks John]

Sun-powered Stirling engine with automatic tracking

Check out this solar-powered Stirling engine (translated). The build is part of a high school class and they packed in some really nice features. The first is the parabolic mirror which focuses the sun’s rays on the chamber of the engine. The heat is what makes it go, and the video after the breaks shows it doing just that.

But the concept behind the mirror makes for an interesting challenge. The light energy is focused at a narrow point. When the sun moves in the sky that point will no longer be at an efficient position to power the engine. This issue is solved by a pair of stepper motors which can reposition the dish. It’s done automatically by an Arduino Uno which makes readings from four LDR (photoresistors) in that cardboard tube mounted at the top of the dish. If the light intensity is the same for all four, then the tube is pointed at the sun. If not, the motors are tweaked to get the best angle possible.

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Soda bottle skylights

Here’s a way to brighten up enclosed spaces in an environmentally friendly way. The power of the sun is harnessed using a bottle full of water. Quite simply they’re used 2-liter soda bottles. They’ve been filled with water along with two caps worth of bleach to keep microorganisms out. The cap is then covered with a film canister to protect it from the sun. They are installed through holes in the roof, and in full sun they put out the equivalent of a 50 watt incandescent light bulb.

Our first thought is keeping the weather out but that is addressed in the video after the break. With proper weather sealing they do not leak. We might not be installing them in the house just yet, but what a great addition to that dark shed that has no electricity and seems to gobble up yard implements. Perhaps we’ll finally be able to find all of those hand trowels that have gone missing.

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