Building Robots With A 20×20 Grid

February 5, 2024 by Danie Conradie 15 Comments

On autonomous robots, the most difficult challenges usually lie in the software and electronic realms, but the mechanics can also be very time consuming. To help address this challenge, [Nikodem Bartnik] is working on the Open Robotic Platform (ORP), a modular robotics chassis system designed to make prototyping as easy and affordable as possible. Video after the break.

The ORP is governed by a set of design rules to maintain interchangeability. Most of the design rules are very open, but the cornerstone of ORP is its standardized mounting plates featuring a 20 mm grid pattern of 3.5 mm mounting holes. These plates can be stacked using connecting rods, creating a versatile foundation upon which various components can be mounted.

[Nikodem] is on a mission to create and collect an entire library of these modular components. From custom 3D-printed holders that accommodate sensors, motors, wheels and dev boards to homemade PCBs that snap directly onto the chassis, everything to get your robot rolling as soon as possible. While manufacturing methods and materials are not limited, 3D printing and laser cutting will likely be the most popular manufacturing technologies for making your own parts.

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Arctic Adventures With A Data General Nova II — The Equipment

February 5, 2024 by Chris Lott 49 Comments

As I walked into the huge high bay that was to be my part-time office for the next couple of years, I was greeted by all manner of abandoned equipment haphazardly scattered around the room. As I later learned, this place was a graveyard for old research projects, cast aside to be later gutted for parts or forgotten entirely. This was my first day on the job as a co-op student at the Georgia Tech Engineering Experiment Station (EES, since renamed to GTRI). The engineer who gave me the orientation tour that day pointed to a dusty electronic rack in one corner of the room. Steve said my job would be to bring that old minicomputer back to life. Once running, I would operate it as directed by the radar researchers and scientists in our group. Thus began a journey that resulted in an Arctic adventure two years later.

The Equipment

The computer in question was a Data General (DG) mini computer. DG was founded by former Digital Equipment Corporation (DEC) employees in the 1960s. They introduced the 16-bit Nova computer in 1969 to compete with DEC’s PDP-8. I was gawking at a fully-equipped Nova 2 system which had been introduced in 1975. This machine and its accessories occupied two full racks, with an adjacent printer and a table with a terminal and pen plotter. There was little to no documentation. Just to turn it on, I had to pester engineers until I found one who could teach me the necessary front-panel switch incantation to boot it up. Continue reading “Arctic Adventures With A Data General Nova II — The Equipment” →

Starlink’s Inter-Satellite Laser Links Are Setting New Record With 42 Million GB Per Day

February 5, 2024 by Maya Posch 44 Comments

Slide from the SpaceX Starlink presentation on mesh routing via the laser links. (Credit: PCMag/Michael Kan)

Although laser communication in space is far from novel, its wide-scale deployment as seen with SpaceX’s Starlink satellite internet constellation has brought the technology to the forefront like never before. This was quite apparent during the SPIE Photonics West event on January 30th when [Michael Kan] and other journalists attended a presentation by SpaceX’s [Travis Brashears] on the inter-satellite laser communication performance that was first enabled with the Starlink v1.5 satellites.

Among currently active inter-satellite communication systems, Starlink is by far the most numerous and with the highest bandwidth, reaching over 42 PB per day across its over 9000 space lasers (yes, that is over 9000) for a 5.6 Tbps throughput. Since these satellites form a mesh network with their 100 Gbps laser transceivers, a big part of using it efficiently is to route any data with the least amount of latency while taking into account link distance (maximum of 5,400 km), link duration (up to multiple weeks) and presence of other Starlink satellites before they become within reach. With this complex mesh in LEO, this also means that a very high uptime can be accomplished, with a claimed 99.99% due to rapid route changing.

For the future, SpaceX has plans to not only keep upgrading its own Starlink satellites with better laser transceivers, but to also make them available to third-party satellites, as well as beam the lasers directly down to Earth for ground-based transceivers. The latter is still cutting edge, despite it being tested to beam cat videos to Earth from Deep Space.

Fail Of The Week: PCB LED Cube Fails Successfully

February 5, 2024 by Dan Maloney 24 Comments

Remember LED cubes? We sure do — they were all the rage for a while, and then it seemed like everyone just sort of lost interest in them. There are probably a lot of reasons for that, not least of which is likely the amount of work it takes to put one together from discrete LEDs and separate pieces of wire. Could there be a better way?

Of course there could, and [Sasa Karanovic] thought he had it all figured out with this PCB-based LED cube. At first glance, it seems to make perfect sense; after all, weren’t PCBs invented to take the place of all that pesky point-to-point wiring in the early days of electronics? The boards [Sasa] designed are pretty cool, actually. They’ve each got room for 16 addressable WS2812 LEDs in 5 mm packages, with every possible bit of substrate removed to block the minimum amount of light. That left very little room for traces on the 2-mm-wide arms, so the PCBs had to have four layers, which raised eyebrows at the PCB house when [Sasa] submitted the design.

Such an airy and open design obviously has the potential for mechanical issues, which [Sasa] addressed by adding pads at three corners of each board; a vertical PCB connects to each LED board to provide mechanical support and distribute signals to the LEDs. The cube seems solid enough as a result, and even when handled the LED boards don’t really flop around too much. See the cube in action in the video below.

What’s nice about this design is the perfect spacing between the LEDs in all three dimensions, and the way everything lines up nice and straight. That would be really hard to do with wire, even for the most practiced of circuit sculptors. [Sasa] seems to agree, but still deems the build a failure because the PCBs block too much of the view. We suppose he’s got a point, and we’re not sure how well this would scale to an 8×8 cube. We’re not sure how we’d feel about paying for PCBs that are mostly air either, but as failures go, this one still manages to be pretty successful. Continue reading “Fail Of The Week: PCB LED Cube Fails Successfully” →