Join us Wednesday at noon Pacific time for the ESP32 Video Tricks Hack Chat!
The projects that bitluni works on have made quite a few appearances on these pages over the last couple of years. Aside from what may or may not have been a street legal electric scooter, most of them have centered around making ESP32s do interesting tricks in the analog world. He’s leveraged the DACs on the chip to create an AM radio transmitter, turned an oscilloscope into a video monitor, and output composite video. That last one was handy for turning a Sony Watchman into a retro game console. He’s also found ways for the ESP32 to output VGA signals. Looks like there’s no end to what he can make the versatile microcontroller do.
Although the conversation could (and probably will) go anywhere, we’ll start with video tricks for the ESP32 and see where it goes from there. Possible topics include:
- Tricks for pushing the ESP32 DACs to their limits;
- When to use an external DAC;
- Optimizing ESP32 code by running on separate cores; and
- What about HDMI on the ESP32?
You are, of course, encouraged to add your own questions to the discussion. You can do that by leaving a comment on the ESP32 Video Tricks Hack Chat and we’ll put that in the queue for the Hack Chat discussion.
Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, March 27, at noon, Pacific time. If time zones have got you down, we have a handy time zone converter.
Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.
Jet engines are known to be highly demanding machines, requiring the utmost attention to tolerances, material specifications, and operating regimes. If any of these parameters are ignored, failures can be catastrophic and expensive. Despite these exacting requirements, it is possible to build a jet engine in the home workshop – and using a turbocharger is a great way to do that. (Video also embedded after the break.)
[Tech Ingredients] does a great job of discussing the basic concepts behind the turbocharger jet engine build, and how various parameters impact performance and efficiency. Through the use of various rules of thumb, developed over years of experimentation by home builders and engineers alike, it’s possible to whip up a functioning engine without too much trial and error. The video breaks down and discusses the thermodynamics at play, as well as practical considerations like cooling and lubrication, in several easy to digest steps.
Jet engines are a popular high-octane build, and we’ve seen it pulled off before by makers like [Colin Furze]. The trick is to pull it off without causing yourself serious injury.
Things aren’t looking good for NASA’s Space Launch System (SLS). Occasionally referred to as the “Senate Launch System”, or even less graciously, the “Rocket to Nowhere”, the super heavy-lift booster has long been a bone of contention for those in the industry. Designed as an evolution of core Space Shuttle technology, the SLS promised to reuse existing infrastructure to deliver higher payload capacities and lower operating costs than its infamous winged predecessor. But in the face of increased competition from commercial launch providers and proposed budget cuts targeting future upgrades and expansions of the core booster, the significantly over budget and behind schedule program is in a very precarious position.
Which is not to say the SLS doesn’t look impressive, at least on paper. In its initial configuration it would easily take the title as the world’s most powerful rocket, capable of lifting nearly 105 tons into low Earth orbit (LEO), compared to 70 tons for SpaceX’s Falcon Heavy. It would still fall short of the mighty Saturn V’s 155 tons to LEO, but the proposed “Block 2” upgrades would increase SLS payload capability to within striking distance of the iconic Apollo-era booster at 145 tons. Since the retirement of the Space Shuttle in 2011, NASA has been adamant that the might of SLS was the only way the agency could accomplish bigger and more ambitious missions to the Moon, Mars, and beyond.
Or at least, they were. On March 13th, NASA Administrator Jim Bridenstine testified to Congress that in an effort to avoid further delays, the agency is exploring the possibility of sending their Orion spacecraft to the Moon with a commercial launcher. The statement came as a shock to many in the aerospace community, as it would seem to call into question the future of the entire SLS program. If commercial rockets can do the job of SLS, at least in some cases, why does the agency need it?
NASA is currently preparing a report which investigates what physical and logistical modifications would need to be made to missions originally slated to fly on SLS; a document which is sure to be scrutinized by SLS supporters and critics alike. Until the report is released, we can speculate about what this hypothetical flight to the Moon might look like.A Drop in Replacement
Administrator Bridenstine didn’t specifically mention which commercial vehicle they were looking at during his Congressional testimony, but as the Falcon Heavy has the highest payload capacity of any currently operating launch platform, it would almost certainly be the focus of NASA’s report. It might seem like the considerably lower capacity of the Falcon Heavy would be a problem, but in reality, Orion’s proposed test flight to the Moon was never going to fully utilize the capability of the SLS to begin with.
During “Exploration Mission 1”, the SLS is only responsible for getting the Orion, its Service Module, and the Interim Cryogenic Propulsion Stage (ICPS) into orbit around the Earth; it actually separates from the spacecraft at an altitude of just 157 kilometers. From that point on, Orion operates independently, and the ICPS is what actually propels the craft towards the Moon.
The Orion and Service Module together weigh in at around 57,000 lbs, and the ICPS itself tips the scales at roughly 66,000 lbs. So at least in theory, any booster that can lift around 125,000 lbs into orbit should be able to stand in for the SLS on this first mission. That’s well within the capabilities of the Falcon Heavy, even if we assume a few thousand extra pounds for ancillary hardware and whatever adapters it would take to bolt everything together. A new fairing would need to be designed and manufactured to encapsulate such a large payload, but all things considered, it seems like it would be a fairly straightforward process.Taking the Falcon Express
Interestingly, some quick back of the envelope math seems to indicate there’s another option on the table. Assuming NASA is willing to make some substantial deviations from the original mission parameters, it looks like the Falcon Heavy alone could potentially push the Orion most of the way towards the Moon itself without using the ICPS at all. This would not only make it easier to integrate the Orion hardware onto the Falcon Heavy, but would save the non-reusable ICPS for a future mission.
According to SpaceX, the Falcon Heavy is capable of lifting a bit more than 58,000 lbs into a geosynchronous transfer orbit (GTO). As you may recall our last lesson in “Beginner’s Orbital Mechanics”, a GTO orbit is the first half of an orbital transfer from a low Earth orbit to the geosynchronous equatorial orbit (GEO) altitude of 35,786 kilometers. Once the spacecraft has been placed into GTO by the Falcon’s upper stage, onboard propulsion would raise its perigee to circularize the orbit and complete the transfer.
This means the Falcon Heavy should just be able to put the Orion and its Service Module into GTO. Of course that doesn’t get you to the Moon, but it’s not quite that far off either. To reach GTO from Earth orbit, a spacecraft must increase its velocity by roughly 2.5 kilometers per second. By comparison, for lunar injection it needs to be accelerated by around 3.2 km/s. So how do we get the last 700 meters per second of acceleration? From the Orion itself.
As per the design specifications, the Orion Service Module is able to provide 1.8 km/s of delta-v. In theory, it should be able to complete the trans-lunar injection maneuver with enough propellant in reserve to perform any necessary course corrections. In this theoretical scenario, there may not be enough propellant to actually slow down and enter a lunar orbit as originally intended. In which case, Orion could simply make a loop around the far side of the Moon and then return to Earth. This “free return” flight path was previously used as a contingency for the early Apollo missions; had the spacecraft been unable to perform the lunar orbit insertion maneuver, it would have allowed the crew to essentially “drift” home.NASA Plays it Safe
These are interesting thought experiments, but unfortunately, the reality is likely to be quite a bit less exciting. Some believe that the statements made to Congress were essentially a threat directed at Boeing, the prime contractor on the Space Launch System. A not so subtle signal that the agency is getting tired of the delays and cost overruns. Indeed, just two days after his testimony, Administrator Bridenstine Tweeted that Boeing teams were working to accelerate the SLS timetable.
Good news: The @NASA and Boeing teams are working overtime to accelerate the launch schedule of @NASA_SLS. If achievable, this is the preferred option for our first exploration mission that will send the @NASA_Orion capsule around the Moon. Still looking at options.
— Jim Bridenstine (@JimBridenstine) March 15, 2019
Even if the Orion does fly on a commercial rocket, Administrator Bridenstine said the agency believes the mission would best be served by utilizing two launches and assembling the spacecraft in orbit. Until the final report is released, it’s unclear why NASA would select such a complicated path to the Moon. Especially considering that the Orion currently has no provision for orbital assembly, and this technology would have to be integrated into the vehicle on exceptionally short notice to meet the planned launch date of June 2020.
If we’ll allow one last bit of conspiracy theory, some in the community have put forward the idea that NASA is proposing the most expensive and complex possible way to launch Orion on a commercial rocket to help bolster the idea that the SLS is indispensable. If the world sees Orion’s Exploration Mission 1 completed on the back of just a single Falcon Heavy, at 1/10th the cost of flying on the SLS, it would arguably be more humiliating for the agency than simply scrapping the mission entirely.
About a year ago when Hackaday and Tindie were at Maker Faire UK in Newcastle, we were shown an interesting retrocomputer by a member of York Hackspace. The Gigatron is a fully functional home computer of the type you might have owned in the early 1980s, but its special trick is that it does not contain a microprocessor. Instead of a 6502, Z80, or other integrated CPU it only has simple TTL chips, it doesn’t even contain the 74181 ALU-in-a-chip. You might thus expect it to have a PCB the size of a football pitch studded with countless chips, but it only occupies a modest footprint with 36 TTL chips, a RAM, and a ROM. Its RISC architecture provides the explanation, and its originator [Marcel van Kervinck] was recently good enough to point us to a video explaining its operation.
It was recorded at last year’s Hacker Hotel hacker camp in the Netherlands, and is delivered by the other half of the Gigatron team [Walter Belgers]. In it he provides a fascinating rundown of how a RISC computer works, and whether or not you have any interest in the Gigatron it is still worth a watch just for that. We hear about the design philosophy and the choice of a Harvard architecture, explained the difference between CISC and RISC, and we then settle down for a piece-by-piece disassembly of how the machine works. The format of an instruction is explained, then the detail of their 10-chip ALU.
The display differs from a typical home computer of the 1980s in that it has a full-color VGA output rather than the more usual NTSC or PAL. The hardware is simple enough as a set of 2-bit resistor DACs, but the tricks to leave enough processing time to run programs while also running the display are straight from the era. The sync interval is used to drive another DAC for audio, for example.
The result is one of those what-might-have-been moments, a glimpse into a world in which RISC architectures arrived at the consumer level years earlier than [Sophie Wilson]’s first ARM design for an Acorn Archimedes. There’s no reason that a machine like this one could not have been built in the late 1970s, but as we know the industry took an entirely different turn. It remains then the machine we wish we’d had in the early 1980s, but of course that doesn’t stop any of us having one now. You can buy a Gigatron of your very own, and once you’ve soldered all those through-hole chips you can run the example games or get to grips with some of the barest bare-metal RISC programming we’ve seen. We have to admit, we’re tempted!
We see our share of pitches for perpetual motion machines in the Hackaday tips line, and we generally ignore them and move along. And while this magnetic levitation motor does not break the laws of thermodynamics, it can be considered a perpetual motion machine, at least for certain values of perpetuity.
The motor that [lasersaber] presents in the video below is unconventional, to say the least. It’s not a motor that can do any useful work, spinning at a stately pace beneath its bell-jar enclosure as it does. The design is an extension of [lasersaber]’s “EZ-Spin” motor, which we’ve featured before, and has the same basic layout – a ring of coils wired in series forms the stator, while a disc bearing permanent magnets forms the rotor. The coils, scavenged from those dancing flowerpot solar ornaments, are briefly energized by the rotor passing over a reed switch, giving the rotor a little boost.
The difference here is that rather than low-friction sapphire bearings, this motor uses zero-friction magnetic levitation using pyrolyzed graphite discs. The diamagnetic material hovers above a rare-earth ring magnet, supporting a slender vertical shaft that holds the rotor and another magnetic bearing at the top. It’s fussy to adjust, but once it’s stable, the only friction in the system should be the drag caused by air in the bell jar. [lasersaber]’s current measurements of the motor running at slow speed are hard to believe – 150 nanoamps – leading to an equally jaw-dropping calculated run-time on a single AA battery of 89 millennia.
[lasersaber] is the first to admit that he’s not confident with his measurements, but it seems clear that his motor will likely outlive any chemical battery used to power it. Whatever the numbers are, we like the styling of the thing, and the magnetic bearings are cool too.
Spring started for real, so it was time for some early-spring cleaning and I managed to complete two webinars during last week:
- We covered the gory details of LISP and layer-2 data center interconnects on Tuesday;
- The third Ansible for Networking Engineers update session on Thursday covered network device configuration management (merge, fetch, compare, replace, rollback and save) and declarative configuration modules.
Both webinars are part of standard ipSpace.net subscription
MIDI has been a remarkably popular interface since its inception way back in 1983. Based on existing serial interfaces, and with a broad enough set of features, it remains the defacto standard for communication between musical gear. However, older gear and many modular synths simply don’t grok digital data, instead using analog control voltages to get the job done. Never fear, though – you can convert from one to the other with the goMIDI2CV.
It’s a simple device, hewn from an ATTINY microcontroller. MIDI signals are received at TTL voltage levels, and converted to output voltages by the ATTINY via use of the PWM hardware. A lowpass filter is added to remove the high-frequency content from the output signal. A 6N138 optocoupler completes the project, to comply with the MIDI standard and ensure the device is not subject to any dangerous voltages from the hardware plugged in.
It’s a simple way to control older non-MIDI compliant hardware, and might make an old modular rig just that much more useful in the studio of today. We’ve seen similar builds before, like this combined CV and Gate converter.
We see a lot of retrocomputing projects here at Hackaday that take devices from the 8-bit era and re-create them in the 21st century. Sometimes they remain period-accurate and stick to all contemporary devices, but in other cases they take full advantage of four decades of advancing technology. [Pkiller]’s Z80 console is one of this later category, creating peripherals for the classic CPU using microcontrollers in the place of the banks of 74 logic or ULA chips that might have graced a 1980s machine.
The video generation hardware produces a PAL signal using an interesting technique involving two RAM buffers. An ATmega644 microcontroller composites a single frame into one of the buffers while another ATmega644 is generating the previous frame of video from the other buffer. On each change of frame the buffers are switched between the two microcontrollers, requiring some extra 74 logic chips. Another AtMega chip provides the Z80 with I/O interfacing, and the sound comes via another dual-buffer microcontroller setup and a quick return to classic hardware with a YM3438 FM synthesis chip. The result can be seen in the video below, and would have not looked out of place in a late-’80s or even early-’90s living room.
Some people might ask why so much trouble should be gone to in the pursuit of a project like this one, but to do so is to miss the point. Sure, a Sega Master System can be had from the usual sources, but in creating project such as this one the builder has to truly understand the technologies such as PAL generation or the internals of a Z80 in great detail. The result while it is undeniably impressive is almost secondary to the process of reaching it.
Via Hacker News, and thanks [Adam Munich] for the tip.
It has come to my attention that a few of you don’t know about Crystalfontz, an online store where you can find displays of all types, from USB LCD displays to I2C OLEDs, to ePaper displays. Thanks to [arthurptj] for that tip. Yes, Crystalfontz is cool, but have you ever heard of Panelook? Oh boy are there some displays at Panelook. Here’s a 1024 by 768 resolution display that’s less than half an inch across.
The comments section of Hackaday has been pretty tame as of late, so here’s why Apple is the king of design. It’s a question of fillets. There are a few ways to add a fillet to the corner of an icon or a MacBook. The first is to draw two perpendicular lines, then add a fixed radius corner. The Apple way is to make everything a squircle. The ‘squircle’ way of design is that there are no sudden jumps in curvature, and yes, you can do this in Fusion360 or any other design tool. This is also one of those things you can’t unsee once you know about it, like the arrow in the FedEx logo.
The ESP8266 simply appeared one day, and it changed everything. The ESP32, likewise, also just arrived on the Internet one day, and right now it’s the best solution for a microcontroller, with WiFi, that also does things really fast. Someone over at Espressif is dropping hints of a new microcontroller, with a possible release on April 1st (the same date that Apple released their competitor to the Raspberry Pi). Is it RISC-V? Is it 5V tolerant? Who knows! (Editor’s note: it’s not RISC-V. Though they’re saying that’s in the pipeline.)
The Verge got their hands on an original iPhone engineering validation unit. It’s a breakout board for an iPhone.
There’s a screwdriver in your toolbox that has a cast clear handle, a blue ferrule surrounding the shaft, and red and white lettering on the side. Go check, it’s there. It’s a Craftsman screwdriver. It’s an iconic piece of design that’s so ubiquitous that it’s unnoticeable. It’s just what a screwdriver is. It’s a prototypical screwdriver. Thanks to the rise of resin and turning craftsmanship, there’s now a gigantic version of this screwdriver.
[The 8-Bit Guy] posted the following message on his Facebook on March 19th: “Just FYI – somebody hacked and totally erased my website. So, it’s going to be down for a while.” At the time of this writing, everything looks okay, which brings up the larger question of why Facebook is still a thing. We’re on a gradient of coolness here, and the sooner you delete your Facebook, the cooler you are. I, for example, deleted my Facebook during the Bush administration, and we all know how cool I am. I’ll never get to the singularity of coolness of kids who never had a Facebook in the first place, but the point remains: delete your Facebook old man.
[SirEdmar] wants to bring Fusion 360 to Linux users. Autodesk wants the same, and they tried a web-based version of Fusion 360, but… it’s a web version of Fusion 360. Right now the best solution is Wine, and thanks to [SirEdamr] 360 works in Wine.
Bing translate does Klingon! How well does it work? Not bad, it could use some work, mostly with non-standard vocabulary: