A Look Inside The Geochron Clock

May 31, 2024 by Dan Maloney 6 Comments

There are plenty of cool clocks out there, and maps by their very essence are cool, too. But a map that’s also a clock — or is it a clock that’s also a map? — has to be the coolest thing ever.

Of course we’re talking about the Geochron, a world clock that makes the relationship between the Earth and the Sun clear and has graced the offices of executives who want to impress visitors with the global nature of their importance for decades. [Attoparsec] has long coveted one of these electromechanical beauties, and when a used one popped up online for a pittance, at least compared to what they cost new, he jumped at the chance.

The Geochron he ended up with was in need of some TLC, but surprisingly little considering its mid-1980s vintage. The real treat in the video below is getting to see how these wonderful devices work. They’re basically simple slide projectors. While we here in the future would simply do everything in software on a nice flat-screen display, the base map, night-day terminators, and calendar are all contained on transparent elements that move under the power of a synchronous motor across a lighted platen. The analemma display is particularly cool; an indicator tracks the Sun’s position over the Earth with a cam that encodes the equation of time in its shape, moving through its familiar bi-lobed loop as the seasons progress.

Any clock that comes with a set of blueprints for installation purposes is alright in our book, and kudos to [Attoparsec] for landing this prize and getting it back in shape. His description of it as “the greatest clock of all time” is apt, but perhaps with a little competition. Or maybe a lot.

Continue reading “A Look Inside The Geochron Clock” →

Cockpit of a Hawker Siddeley Trident with the moving map display

A Live Map Display In A 1960s Airliner

January 23, 2024 by Danie Conradie 4 Comments

We tend take GPS navigation for granted these days, so it’s easy to forget that it became only available in the last few decades. Aviation navigation used to be significantly more challenging, so how was the Hawker Siddeley Trident, a 1960s airliner, fitted with a live updating map display? In a fascinating dive into aviation history the British Airliner Collection has spun up an insightful article on the magic behind these moving map displays.

Without access to satellite navigation or advanced electronics, engineers had to get creative. Enter the Trident’s moving map display, a marvel of ingenuity that predated the GPS systems. Using a combination of Doppler radar and some clever mechanics, pilots could accurately determine their position without relying on any external signals.

The system makes use of four Doppler radar beams, arranged in what was known as the Janus array. This configuration corrected for errors caused by changes in altitude or wind drift, ensuring accurate ground speed readings. The movable antennas mounted under the cabin floor could adjust its orientation to maintain alignment with the actual direction of travel, calculating drift angle precisely. Combined with compass information and flight time from a known start point to to indicate the current position with a pointer on a rolled paper map. The system was well ahead of it’s time, and significantly easier to use and more accurate than the Decca radio navigation system in use at the time.

It’s mind boggling to see the solutions engineers came up with without much of the digital technology we take for granted today. Gyroscopes for inertial navigation, the cavity magnetron for radar and radial engines were all building blocks for modern aviation.

Thanks for the tip [poiuyt]!

A Homebrew GPS Correction System For DIY Land Surveying

January 12, 2024 by Dan Maloney 60 Comments

For those of you rushing to the comment section after reading the title to tell [Ben Dauphinee] that his DIY land surveying efforts are for naught because only a licensed surveyor can create a legally binding property description, relax — he already knows. But what he learned about centimeter-resolution GPS is pretty interesting, especially for owners of large rural properties like him.

[Ben]’s mapping needs are less rigorous than an official survey; he just wants to get the locations of features like streams and wood lines, and to get topographic elevations so that he has a general “lay of the land” for planning purposes. He originally engaged a surveyor for that job, but after shelling out $4,600 to locate a single property line, he decided to see what else could be done. Luckily, real-time kinematics, or RTK, holds the key. RTK uses a fixed GPS station to provide correction signals to a mobile receiver, called a rover. If the fixed station’s position is referenced to some monument of known position, the rover’s position can be placed on a map to within a couple of centimeters.

To build his own RTK system, [Ben] used some modules from SparkFun. The fixed station has an RTK breakout board and a multi-band GNSS antenna to receive positioning data, along with a Raspberry Pi to run the RTK server. An old iPhone with a prepaid SIM provides backhaul to connect to the network that provides correction data. [Ben]’s rover setup also came mainly from SparkFun, with an RTK Facet receiver mounted on a photographer’s monopod. Once everything was set up and properly calibrated, he was able to walk his property with the rover and measure locations to within 4 centimeters.

This was not an inexpensive endeavor — all told, [Ben] spent about $2,000 on the setup. That’s a lot, especially on top of what he already paid for the legal survey, but still a fraction of what it would have cost to have a surveyor do it, or to buy actual surveyor’s equipment. The post has a ton of detail that’s worth reading for anyone interested in the process of mapping and GPS augmentation.

Carving Terrain Maps Into Plywood With Software Help

November 28, 2022 by Bryan Cockfield 20 Comments

CNC machines are incredibly versatile tools. At a machine shop, they can machine all kinds of metal and plastic parts. Beyond that, they can engrave various materials including glass, and even create PCBs. [Steve] has a CNC machine of his own creation in his shop, and while he might be employing it for those common uses, his artistic creations are on the showcase for today with these 3D topographic relief maps.

The key to creating a good topographic relief map is good material stock. [Steve] is working with plywood because the natural layering in the material mimics topographic lines very well, especially with the high-quality marine-grade birch plywood he is using. Making sure to select pieces without knots improves the final product substantially, as does taking the time to fill any voids. Selecting good stock is only part of the process though. [Steve] is using TouchTerrain, an open source project helmed by [Dr. Chris Harding] of Iowa State University, to create the model which gets fed to the CNC machine. Originally intended for 3D printing applications, the web-based tool lets you easily select an area on the globe and export its topographical data to a standard STL or OBJ file.

With good stock and the ability to easily create 3D topographic maps, anyone with a CNC machine like this could easily reproduce their terrain of choice. We imagine the process might be easily ported to other tools like 3D printers, provided the resolution is high enough. We have also seen similar builds using laser cutters, although the method used is a little different.

An acrylic map of the state of Lagos. Each region is lit a different color by LEDs shining on the acrylic panels. The colors coorespond to the air quality index key which is lit in cooresponding colors to the value.

Hackaday Prize 2022: This Interactive Air Quality Map Makes The Invisible Visible

October 11, 2022 by Navarre Bartz 2 Comments

Air quality can have a big impact on your health, but it isn’t always something you can see. [Ahmed Oyenuga] wanted to make air quality something more tangible and developed an Interactive Air Quality Map.

Using addressable LEDs and acrylic panels, [Oyenuga]’s map lights up different regions of his state (Lagos) with colors that correspond to qualitative values of the air quality readings. The color key on the edge of the map becomes a readout when you touch a specific region of the map.

Most of the map’s functionality is handled by an Arduino WiFi 1010, but the capacitive touch is running on a custom board [Oyenuga] designed with an ATSAMD21J17. [Oyenuga] is getting air quality data via a DesignSpark Environmental Sensor Development Kit (ESDK) and then uses reverse geocoding to take the GPS data and turn it into a location the map will understand.

If you’re interested in different options for monitoring air quality that could feed into a map like this, why don’t you check out this LoRa Air Quality Monitor or even a Mobile Air Quality Monitor.

Continue reading “Hackaday Prize 2022: This Interactive Air Quality Map Makes The Invisible Visible” →

Washington, DC Finally Gets Its Own PCB Metro Map

July 19, 2022 by Tom Nardi 6 Comments

There was a time, not so long ago, when folks who wanted to make their own custom PCBs would have found themselves in the market for a bucket of acid and a second-hand laser printer. These days, all you have to do is click a few buttons in your EDA program of choice and send the files off for fabrication. It’s easy, cheap, and nobody ends up with chemical burns.

This has obviously had a transformative effect on the electronics hobby — when you can place traces on a PCB like an artist using a brush, it’s only a matter of time before you get projects like [Logan Arkema]’s DCTransistor. This open source board uses carefully arranged RGB LEDs to recreate the Washington Metropolitan Area Transit Authority (WMATA) metro map, and thanks to an ESP8266 connected to their API, can display the positions of trains in real-time.

If you’re getting a sense of déjà vu here, it’s not just in your head. We’ve seen similar maps created for other major metropolitan areas, and [Logan] certainly isn’t trying to take credit for the idea. In fact, he was a bit surprised to find that nobody had ever made one for the DC area — so he decided to take on the challenge himself. He reasoned it would be a good way to hone his PCB design skills and become more comfortable with embedded development. We’d say the end result proves his theory correct, and makes one more city that can boast about its IoT cartography.

Looking to hang a DCTransistor on your own wall? [Logan] says he’ll be dropping the board design files and schematics into the project’s GitHub repository soon, and he also plans on selling pre-made boards in the near future.

We covered this London “tube” map back in 2020, and were impressed by the attention to detail that went into similar displays for Tokyo, Singapore, and the San Francisco Bay Area a year later. Perhaps it’s time to map out your own hometown in LEDs?

Keep Tabs On Asteroids With Asteroid Atlas

March 20, 2022 by Bryan Cockfield 4 Comments

Keeping tabs on the night sky is an enjoyable way to stay connected to the stars, and astronomy can be accessible to most people with a low entry point for DIY telescopes. For those who live in areas with too much light pollution, though, cost is not the only issue facing amateur astronomers. Luckily there are more ways to observe the night sky, like with this open source software package from [elanorlutz] which keeps tabs on all known asteroids.

The software is largely based on Python and uses a number of databases from NASA to allow anyone with a computer to explore various maps of the solar system and the planetary and non-planetary bodies within it. Various trajectories can be calculated, and paths of other solar system bodies can be shown with respect to an observer in various locations. Once the calculations are made in Python it is able to export the images for use in whichever image manipulation software you prefer.

The code that [elanorlutz] has created is quite extensive and ready to use for anyone interested in tracking comets, trans-Neptunian objects, or even planets and moons from their own computer. We would imagine a tool like this would be handy for anyone with a telescope as well as it could predict locations of objects in the night sky with accuracy and then track them with the right hardware.