Arnis Brings The World To Minecraft: Bedrock Edition

January 17, 2026 by Ian Bos 2 Comments

A couple of years ago, we covered a project called Arnis, created by [Louis Erbkamm], which allowed you to generate any portion of Earth into Minecraft blocks and maps. It was already impressive, but since we last checked in the open source project has made some incredible progress.

When we first covered Arnis, it was stuck on the Java edition of Minecraft. But now the project has been updated to support the more modern Bedrock Edition, meaning you can put your home into any device’s version of Minecraft!

Beyond Bedrock version support, the actual tool has improved with proper elevation generation using data provided from NASA. This allows you to view the Alps or the Himalayas in all their voxel glory, or explore an entire map of the Moon. Perhaps what’s even more impressive is that the generation is accurate enough to be used in an actual research study involving flood mitigation education.

All of this has been made possible with help from a passionate community who have volunteered their time to assist [Louis] with the project — a testament to the power of open source.

The Sunchronizer Keeps Your Solar Panel Aligned

August 15, 2024 by Bryan Cockfield 35 Comments

In the past few years, the price-per-watt for solar panels has dropped dramatically. This has led to a number of downstream effects beyond simple cost savings. For example, many commercial solar farms have found that it’s now cheaper to install a larger number of panels in fixed positions, rather than accepting the extra cost, maintenance, and complexity of a smaller number panels that use solar tracking to make up the difference. But although this practice is fading for large-scale power production, there are still some niche uses for solar tracking. Like [Fabian], if you need to maximize power production with a certain area or a small number of panels you’ll wan to to build a solar tracker.

[Fabian]’s system is based on a linear actuator which can tilt one to four panels (depending on size) in one axis only. This system is an elevation tracker, which is the orientation generally with respect to latitude, with a larger elevation angle needed in the winter and a lower angle in the summer. [Fabian] also designs these to be used in places like balconies where this axis can be more easily adjusted. The actuator is controlled with an ESP32 which, when paired with a GPS receiver, can automatically determine the sun’s position for a given time of day and adjust the orientation of the panel to provide an ideal elevation angle on a second-by-second basis. The ESP32 also allows seamless integration with home automation systems like SmartHome as well.

Although this system only tracks the sun in one axis right now, [Fabian] is working on support for a second axis which mounts the entire array on a rotating table similar to an automatic Lazy Susan. This version also includes a solar tracking sensor which measures solar irradiance in the direction the panel faces to verify that the orientation of the panel is maximizing power output for a given amount of sunlight. Tracking the sun in two axes can be a complicated problem to solve, but some solutions we’ve seen don’t involve any GPS, programming, or even control electronics at all.

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Milspec Teardown: ID-2124 Howitzer Data Display

August 19, 2019 by Tom Nardi 29 Comments

It’s time once again for another installment in “Milspec Teardown”, where we get to see what Uncle Sam spends all those defense dollars on. Battle hardened pieces of kit are always a fascinating look at what can be accomplished if money is truly no object. When engineers are given a list of requirements and effectively a blank check, you know the results are going to be worth taking a closer look.

Today, we have quite a treat indeed. Not only is this ID-2124 Howitzer Deflection-Elevation Data Display unit relatively modern (this particular specimen appears to have been pulled from service in June of 1989), but unlike other military devices we’ve looked at in the past, there’s actually a fair bit of information about it available to us lowly civilians. In a first for this ongoing series of themed teardowns, we’ll be able to compare the genuine article with the extensive documentation afforded by the ever fastidious United States Armed Forces.

For example, rather than speculate wildly as to the purpose of said device, we can read the description directly from Field Manual 6-50 “TACTICS, TECHNIQUES, AND PROCEDURES FOR THE FIELD ARTILLERY CANNON BATTERY”:

The gun assembly provides instant identification of required deflection to the gunner or elevation to the assistant gunner. The display window shows quadrant elevation or deflection information. The tenths digit shows on the QE display only when the special instruction of GUNNER’S QUADRANT is received.

From this description we can surmise that the ID-2124 is used to display critical data to be used during the aiming and firing of the weapon. Further, the small size of the device and the use of binding posts seem to indicate that it would be used remotely or temporarily. Perhaps so the crew can put some distance between themselves and the artillery piece they’re controlling.

Now that we have an idea of what the ID-2124 is and how it would be used, let’s take a closer look at what’s going on inside that olive drab aluminum enclosure.

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Desktop Radio Telescope Images The WiFi Universe

June 20, 2018 by Dan Maloney 21 Comments

It’s been a project filled with fits and starts, and it very nearly ended up as a “Fail of the Week” feature, but we’re happy to report that the [Thought Emporium]’s desktop WiFi radio telescope finally works. And it’s pretty darn cool.

If you’ve been following along with the build like we have, you’ll know that this stems from a previous, much larger radio telescope that [Justin] used to visualize the constellation of geosynchronous digital TV satellites. This time, he set his sights closer to home and built a system to visualize the 2.4-GHz WiFi band. A simple helical antenna rides on the stepper-driven azimuth-elevation scanner. A HackRF SDR and GNU Radio form the receiver, which just captures the received signal strength indicator (RSSI) value for each point as the antenna scans. The data is then massaged into colors representing the intensity of WiFi signals received and laid over an optical image of the scanned area. The first image clearly showed a couple of hotspots, including a previously unknown router. An outdoor scan revealed routers galore, although that took a little more wizardry to pull off.

The videos below recount the whole tale in detail; skip to part three for the payoff if you must, but at the cost of missing some valuable lessons and a few cool tips, like using flattened pieces of Schedule 40 pipe as a construction material. We hope to see more from the project soon, and wonder if this FPV racing drone tracker might offer some helpful hints for expansion.

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Start Tracking Satellites With This Low-Cost Azimuth-Elevation Positioner

November 26, 2017 by Dan Maloney 28 Comments

Tracking satellites and the ISS is pretty easy. All you really need is an SDR dongle or a handheld transceiver, a simple homebrew antenna, and a clear view of the sky. Point the antenna at the passing satellite and you’re ready to listen, or if you’re a licensed amateur, talk. But the tedious bit is the pointing. Standing in a field or on top of a tall building waving an antenna around gets tiring, and unless you’re looking for a good arm workout, limits the size of your antenna. Which is where this two-axis antenna positioner could come in handy.

While not quite up to the job it was originally intended for — positioning a 1.2-meter dish antenna — [Manuel] did manage to create a pretty capable azimuth-elevation positioner for lightweight antennas. What’s more, he did it on the cheap — only about €150. His design seemed like it was going in the right direction, with a sturdy aluminum extrusion frame and NEMA23 steppers. But the 3D-printed parts turned out to be the Achille’s heel. At the 1:40 mark in the video below (in German with English subtitles), the hefty dish antenna is putting way too much torque on the bearings, delaminating the bearing mount. But with a slender carbon-fiber Yagi, the positioner shines. The Arduino running the motion control talks GS232, so it can get tracking data directly from the web to control the antenna in real time.

Here’s hoping [Manuel] solves some of the mechanical issues with his build. Maybe he can check out this hefty dish positioner for weather satellite tracking for inspiration.

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See Satellites With A Simple Radio Telescope

March 23, 2017 by Dan Maloney 17 Comments

Have you got a spare Dish Network antenna lying about? They’re not too hard to come by, either curbside on bulk waste day or perhaps even on Freecycle. If you can lay hands on one, you might want to try this fun radio telescope build.

Now, don’t expect much from [Justin]’s minimalist build. After all, you’ll be starting with a rather small dish and an LNB for the Ku band, so you won’t be doing serious radio astronomy. In fact, the BOM doesn’t include a fancy receiver – just a hacked satellite finder. The idea is to just get a reading of the relative “brightness” of a radio source without trying to demodulate the signal. To that end, the signal driving the piezo buzzer in the sat finder is fed into an Arduino through a preamp. The Arduino also controls stepper motors for the dish’s azimuth and elevation control, which lets it sweep the sky and build up a map of signal intensity. The result is a clear band of bright spots representing the geosynchronous satellites visible from [Justin]’s location in Brazil.

Modifications are definitely on the docket for [Justin], including better equipment that will allow him to image the galactic center. There may be some pointers for him in our coverage of a tiny SDR-based radio telescope, or from this custom receiver that can listen to Jupiter.

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Junkyard Dish Mount Tracks Weather Satellites

January 2, 2017 by Dan Maloney 11 Comments

There’s a magnificent constellation of spacecraft in orbit around Earth right now, many sending useful data back down to the surface in the clear, ready to be exploited. Trouble is, it often takes specialized equipment that can be a real budget buster. But with a well-stocked scrap bin, a few strategic eBay purchases, and a little elbow grease, a powered azimuth-elevation satellite dish mount can become affordable.

The satellites of interest for [devnulling]’s efforts are NOAA’s Polar-orbiting Operational Environmental Satellites (POES), a system of low-Earth orbit weather birds. [devnulling] is particularly interested in direct reception of high-definition images from the satellites’ L-band downlink. The mount he came up with to track satellites during lengthy downloads is a tour de force of junkyard build skills.

The azimuth axis rotates on a rear wheel bearing from a Chevy, the elevation axis uses cheap pillow blocks, and the frame is welded from scrap angle iron and tubing. A NEMA-23 stepper with 15:1 gearhead rotates the azimuth while a 36″ linear actuator takes care of elevation. The mount has yet to be tested in the wind; we worry that sail area presented by the dish might cause problems. Here’s hoping the mount is as stout as it seems, and we’ll look forward to a follow-up.

It would work for us, but a 4-foot dish slewing around in the back yard might not be everyone’s taste in lawn appurtenances. If that’s you and you still want to get your weather data right from the source, try using an SDR dongle and chunk of wire.

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