Giant Video Walls Powered By A Raspberry Pi

September 16, 2013 by 33 Comments

There’s no denying that giant video walls are awesome, but creating one usually means a fairly complex setup with either multiple computers or very expensive video cards. Now, with Pi Wall, you can make a video wall as large as your wallet will allow with only one Raspi per monitor, and a single master pi to control the whole shebang.

As long as you have a few displays with an HDMI input, it’s easy to turn them into a giant monitor. Just plug one Pi per monitor into a network switch, have a Pi (or other Linux box) transmit a video to all the video tiles, and sit back and enjoy the show.

Right now there is an installation guide for creating a Pi Wall, but there are a few limitations; this software only works with the video player provided with the Raspberry Pi, omxplayer. If you’re looking to create an enormous display for a flight simulator or what have you, you might need to do a bit of tinkering under the hood.

Wall-wart Retrofitted With A High-power LED Supply Circuit

February 13, 2013 by 10 Comments

high-power-LED-wall-wart-supply

This custom circuit board picks up some of the pieces from a wall wart to drive a high-power LED.  The basic concept is to keep the high-voltage components and swap out the low voltage ones for parts that will be able to drive the 10W load.

The PCB is custom designed, but you can see that it was shaped to match the wall wort’s original board. To the right is the original 500mA transformer. The low-voltage side uses an LM393 because of its dual-comparators. This provides feedback for both current and voltage and is a perfect compliment for the TOP242. We haven’t seen that part before, but [Mincior] says that it’s nice for this application as it has safety features that lock down the chip if power or temperature are above spec. Once the replacement is nestled inside of the plastic case it looks stock and makes sure that your custom LED fixtures will stand the test of time safely.

Making A Wall Power Adapter For A Digital Camera

November 3, 2011 by 21 Comments

Instructables user [txoof] was unhappy with the fact that Olympus didn’t manufacture a wall power adapter for the E-510 camera and decided to do something about it. The resulting new power adapter is described in this article. What it amounts to is a fake battery pack made out of plywood.

A 2.5mm DC power adapter is attached as seen in the picture above and the fake battery contacts are made with a thin brass or steel plate. According to the article, a steel soda can or bean tin works well for this.  Google sketchup with the slicer plugin is used to make slices of wood to be glued together in a “battery” shape.  Alternatively, something like this would be a good project for a 3D printer or CNC router.

Although there is nothing that revolutionary about this hack, it solves a problem that many people have with cameras or other electronics without a readily available wall power supply. This can be especially evident when trying to do time-lapse photography or other activities that need a long time span. For another hacked-together wooden camera project, check out this remote trigger built using plywood and air freshener components.

A fisheye lens picture over the Junma Solar Power station in the Mongolian desert. There is a large image of a horse made out of solar panels in the image. A sunset is visible in the upper right of the image, but most the picture is brown sand where there aren't dark blue solar panels.

China’s Great Solar Wall Is A Big Deal

August 18, 2025 by 61 Comments

Data centers and the electrification of devices that previously ran on fossil fuels is driving increased demand for electricity around the world. China is addressing this with a megaproject that is a new spin on their most famous piece of infrastructure.

At 250 miles long and 3 miles wide with a generating capacity of 100 GW, the Great Solar Wall will be able to provide enough energy to power Beijing, although the energy will more likely be used to power industrial operations also present in the Kubuqi Desert. NASA states, “The Kubuqi’s sunny weather, flat terrain, and proximity to industrial centers make it a desirable location for solar power generation.” As an added bonus, previous solar installations in China have shown that they can help combat further desertification by locking dunes in place and providing shade for plants to grow.

Engineers must be having fun with the project as they also designed the Guinness World Record holder for the largest image made of solar panels with the Junma Solar Power Station (it’s the horse in the image above). The Great Solar Wall is expected to be completed by 2030 with 5.4 GW already installed in 2024.

Want to try solar yourself on a slightly smaller scale? How about this solar thermal array inspired by the James Webb Telescope or building a solar-powered plane?

Three stages of the dam construction

How To Convert A Drain Into A Hydropower Facility

August 16, 2025 by 31 Comments

Over on his YouTube channel [Construction General] shows us how to convert a drain into a hydropower facility. This type of hydroelectric facility is known as a gravitation water vortex power plant. The central structure is a round basin which includes a central drain. The water feeds into the basin through a series of pipes which help to create the vortex which drives the water turbine before flowing out the drain.

To make the facility [Construction General] starts by laying some slabs as the foundation. One of the slabs has a hole to which the central drain pipe is attached. Bricks and mortar are then used to build the basin around the drain. A temporary central pipe is used for scaffolding along with some strings with hooks attached to hold the bricks and mortar in place for the basin. Integrated into the top half of the basin are fifteen inlet pipes which feed in water at an angle.

The next step is to build the dam wall. This is a bricks and mortar affair which includes the drain in the bottom of the wall and two spillways at the top. The spillways are for letting water flow out of the dam if it gets too full. Around the drainage in the dam wall a valve is installed. This valve is called the low-level outlet or the bottom outlet, and in this case it is a sluice, also known as a slide gate, which can be raised or lowered to control the rate of flow through the turbine.

Once the basin is complete and the low-level outlet is in place the scaffolding is removed. The basin is then painted, pink on the inside and white around the top. A turbine is constructed from various metal pieces and installed into the basin. The turbine is attached to a generator which is fixed atop the basin. The apparatus for operating the low-level outlet is installed and the dam is left to fill.

Hydropower is a topic we’ve covered here at Hackaday before, if you’re interested in the topic you might like to check out A Modest But Well-Assembled Home Hydropower Setup, Hydropower From A Washing Mashine, or Bicycle Hub Hydropower.

Continue reading “How To Convert A Drain Into A Hydropower Facility” →

COTS Components Combine To DIY Solar Power Station

June 12, 2025 by 20 Comments

They’re marketed as “Solar Generators” or “Solar Power Stations” but what they are is a nice box with a battery, charge controller, and inverter inside. [DoItYourselfDad] on Youtube decided that since all of those parts are available separately, he could put one together himself.

The project is a nice simple job for a weekend afternoon. (He claims 2 hours.) Because it’s all COTS components, it just a matter of wiring everything together, and sticking into a box.  [DoItYourselfDad] walks his viewers through this process very clearly, including installing a shunt to monitor the battery. (This is the kind of video you could send to your brother-in-law in good conscience.)

Strictly speaking, he didn’t need the shunt, since his fancy LiFePo pack from TimeUSB has one built in with Bluetooth connectivity. Having a dedicated screen is nice, though, as is the ability to charge from wall power or solar, via the two different charge controllers [DoItYourselfDad] includes. If it were our power station, we’d be sure to put in a DC-DC converter for USB-PD functionality, but his use case must be different as he has a 120 V inverter as the only output. That’s the nice thing about doing it yourself, though: you can include all the features you want, and none that you don’t.

We’re not totally sure about his claim that the clear cargo box was chosen because he was inspired by late-90s Macintosh computers, but it’s a perfectly usable case, and the build quality is probably as good as the cheapest options on TEMU.

This project is simple, but it does the job. Have you made a more sophisticated battery box, or other more-impressive project? Don’t cast shade on [DoItYourselfDad]: cast light on your work by letting us know about it!. Continue reading “COTS Components Combine To DIY Solar Power Station” →

Clickspring’s Experimental Archaeology: Concentric Thin-Walled Tubing

April 25, 2025 by 33 Comments

It’s human nature to look at the technological achievements of the ancients — you know, anything before the 1990s — and marvel at how they were able to achieve precision results in such benighted times. How could anyone create a complicated mechanism without the aid of CNC machining and computer-aided design tools? Clearly, it was aliens.

Or, as [Chris] from Click Spring demonstrates by creating precision nesting thin-wall tubing, it was human beings running the same wetware as what’s running between our ears but with a lot more patience and ingenuity. It’s part of his series of experiments into how the craftsmen of antiquity made complicated devices like the Antikythera mechanism with simple tools. He starts by cleaning up roughly wrought brass rods on his hand-powered lathe, followed by drilling and reaming to create three tubes with incremental precision bores. He then creates matching pistons for each tube, with an almost gas-tight enough fit right off the lathe.

Getting the piston fit to true gas-tight precision came next, by lapping with a jeweler’s rouge made from iron swarf recovered from the bench. Allowed to rust and ground to a paste using a mortar and pestle, the red iron oxide mixed with olive oil made a dandy fine abrasive, perfect for polishing the metal to a high gloss finish. Making the set of tubes concentric required truing up the bores on the lathe, starting with the inner-most tube and adding the next-largest tube once the outer diameter was lapped to spec.

Easy? Not by a long shot! It looks like a tedious job that we suspect was given to the apprentice while the master worked on more interesting chores. But clearly, it was possible to achieve precision challenging today’s most exacting needs with nothing but the simplest tools and plenty of skill. Continue reading “Clickspring’s Experimental Archaeology: Concentric Thin-Walled Tubing” →