The Lunar Odyssey: Moon Landings From The 1960s To Today’s Attempts

March 20, 2024 by 21 Comments

With the recent string of lunar landing attempts, it’s interesting to consider how much things have changed – or stayed the same – since the first soft landing attempts in the 1960s with the US Ranger and USSR Luna landers. During the 1950s the possibility of landing a spacecraft on the Moon’s surface was investigated and attempted by both the US and USSR. This resulted in a number of lunar lander missions in the 1960s, with the US’s Ranger 3 and 5 missing the Moon, Ranger 4 nearly missing it but instead crashing into the far side of the Moon, and eventually the USSR’s Luna 9 making the first touchdown on the lunar surface in 1966 after a string of USSR mission failures.

What’s perhaps most interesting was how these first US and USSR spacecraft managed to touch down, with Luna 9 opting to inflate a landing airbag and bounce until it came to a halt. This approach had doomed Luna 8, as its airbag got punctured during inflating, causing a hard crash. Meanwhile the US’s Surveyor 1 was the first US spacecraft to land on the Moon, opting to use a solid-fuel retrorocket to slow the craft down and three liquid-fueled vernier thrusters to prepare it for a drop down from 3.4 meters onto the lunar surface.

Now, nearly 60 years later, the landers we sent regularly make it to the lunar surface, but more often than not end up crashing or toppling over into awkward positions. How much have lunar landings really changed?

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A Tape Echo For Anyone

March 20, 2024 by 8 Comments

If you’ve ever looked into how artists from the 1960s made their music, you’ll learn about the many inventive ways in which the tape recorder enabled new effects. One of the simplest of those is the tape echo, as distinct from a reverb which introduces the many delayed echoes of a large auditorium, an echo provides a single delayed version of the original. It’s something [Mark Gutierez] shows us as he makes a tape echo from a cheap Walkman-style cassette player. It’s hardly the highest quality of its ilk, but it does the job.

The player in question sports the ubiquitous Chinese mechanism that’s the last still in production. It has a radio incorporated which he doesn’t use, but for all that it has only a permanent magnet erase head rather than one driven from the bias oscillator. He first puts another head in the space between the record head and the pinch roller, then further modifies the cassette so a loop can be pulled out of the side of it, moving all heads off-board. As you can see in the video below the break it’s in no way high-fidelity, but with a couple of Eurorack mixer kits added on it makes for an interesting effect.

If you can lay your hands on a reel-to-reel machine, you can make a more traditional echo machine.

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The Hunt For Alien Radio Signals Began Sooner Than You Think

March 20, 2024 by 20 Comments

Every 26 months, Earth and Mars come tantalizingly close by virtue of their relative orbits. The closest they’ve been in recent memory was a mere 55.7 million kilometers, a proximity not seen in 60,000 years when it happened in 2003.

However, we’ve been playing close attention to Mars for longer than that. All the way back in 1924, astronomers and scientists were contemplating another close fly by from the red planet. With radio then being the hot new technology on the block, the question was raised—should we be listening for transmissions from fellows over on Mars?

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Commodore CHESSmate Replica Runs On The ESP32

March 20, 2024 by 9 Comments

The Commodore CHESSmate chess computer might not be terribly well known, but that doesn’t make it any less worthy of being reproduced. If anything it is more important, as it gives more people an opportunity to use one of these devices, yet beyond a purely emulated experience the real user interface is harder to experience.

Internals of the reproduction Commodore ChessMate (Credit: Michael Gardi)

This is where [Michael Gardi]’s modernized replica provides a highly accessible version, consisting of a custom PCB with an ESP32 as the brains of the system. Although decidedly overkill next to the 6502 in the original CHESSmate, it makes the project far easier for others to assemble as it contains few components that shouldn’t be readily available.

The ESP32 is mounted on a small daughterboard which plugs into the main PCB with the buttons, LEDs and indicators. The whole stack is then inserted into the 3D printed reproduction case. These 3D models along with the ESP32 port of the CHESSmate firmware can be found in the GitHub repository, along with a minimalist frame and a ‘CHESSmate Lite’ version as alternative enclosure options for those who somehow don’t appreciate the delightful 1980s aesthetics.

We covered the Commodore CHESSmate last year, including a highly faithful reproduction built by [Hans Otten], which [Michael] read the day after meeting [Peter Jennings], the author of MicroChess (which the CHESSmate uses internally) at an event at York University. Taking this as a sign, he set to work on this particular project.

We’re not sure if there’s really a cosmic force directing [Michael] towards his next project, but if there is, we’d like to take this opportunity to thank it for doing a fantastic job so far.

Arduino Gear Shift Indicator Finds ‘Em So You Won’t Grind ‘Em

March 20, 2024 by 75 Comments

Now, it’s been a shamefully long time since we’ve driven a car with a manual transmission, but as we recall it was pretty straightforward. It certainly didn’t require a lot of help with the shifting pattern, at least not enough to require a technical solution to know what gear you’re in. But then again, we suspect that’s not really the point of [upir]’s latest build.

Oh sure, it’s pretty cool to display your current gear selection on a little LCD screen using an Arduino. And [upir] promises a follow-up project where the display goes inside the shifter knob, which will be really cool. But if you take a look at the video below, you’ll see that the real value of this project is the stepwise approach he takes to create this project. [upir] spends most of the time in the video below simulating the hardware and the code of the project in Wokwi, which lets him make changes and tune the design up before committing anything to actual hardware.

That turned out to be particularly useful with this build since he chose to use analog Hall sensors to detect the shift lever position and didn’t know exactly how that would work. Wokwi let him quickly build a virtual prototype for one sensor (using a potentiometer as a stand-in, since the simulator lacked a Hall sensor model), then quickly expand to the four sensors needed to detect all six gear positions.

By the time his simulation was complete, the code was almost entirely written. [upir] also walks us through his toolchains for both designing the graphics and laying out the PCB, a non-trivial task given the odd layout. We particularly enjoyed the tip on making smooth curved traces around the oval cutout for the shift lever in the board.

The video below is on the longish side, but it’s chock full of great little tips. Check out some more of [upir]’s work, like his pimped-out potentiometer or his custom animations on 16×2 LCDs.

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Repairing A Gear With A Candle (and Some Epoxy)

March 19, 2024 by 19 Comments

You have a broken gear you need to fix, but there’s no equivalent part available. That’s the issue [Well Done Tips] faced with a plastic gear from a lawnmower. While we’d be tempted to scan the gear, repair the damage in CAD and then 3D print a new one, we enjoyed hearing about his low-tech solution. In addition to the write up, there’s a video showing the process you can watch below.

The idea is pretty simple. Using a piece of pipe and melted candle wax, he prepared a mold of an undamaged section of the gear. Then he cast epoxy resin in place to recreate the missing pieces. There are a few tricks, like putting holes in the remaining part of the gear so the epoxy flows into the existing part. Depending on the gear’s purpose and original material, you might be able to just use it as-is. However, you could also use the repaired gear as a template to create another mold and then cast an entire gear from resin or even metal if you can cast metal.

You can argue whether resin is better or worse than PLA, but of course, it depends on the kind of resin—photopolymers are different from epoxy resins you’d use for this sort of thing. If you think you might like to make your new gear out of aluminum, you might find some inspiration in a previous post.

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Your Text Needs More JPEG

March 19, 2024 by 22 Comments

We’ve all been victims of bad memes on the Internet, but they’re not all just bad jokes gone wrong. Some are simply bad as a result of being copies-of-copies, as each reposter adds another layer of compression to an already lossy image format like JPEG. Compression can certainly be a benefit in areas like images and videos, but [Michal] had a bit of a fever dream imagining this process applied to text. Rather than let the idea escape, he built the Lossifizer to add JPEG-like compression to text.

JPEG compression uses a system similar to the fast Fourier transform (FFT) called the discrete cosine transform (DCT) to reduce the amount of data in an image by essentially removing some frequency information. The data lost is often not noticeable to the human eye, at least until it gets out of hand. [Michal]’s system performs the same transform on text instead, with a slider to control the “amount of JPEG” in the output text. The code for this script uses a “perceptual” character map, clustering similarly-looking and similarly-sounding characters next to each other, resembling “leet speak” from days of yore, although at high enough compression this quickly gets out of hand.

One of the quirks that [Michal] discovered is that certain AI chat bots have a much less difficult time interpreting this JPEG-ified text than a human probably would have, which provides a bit of insight into how some of these algorithms might be functioning under the hood. For some more insight into how JPEG actually works on images, we posted about a deep dive into the image format a while back.