Month: May 2021

Teaching A USBasp Programmer To Speak TPI

May 3, 2021 by 20 Comments

Last Fall [Kevin] wanted to program some newer TPI-only AVRs using an old USBasp he had kicking around his lab. Finding an “odd famine of information” and “forums filled with incorrect information and schematics”, he decided to set the record straight and document things correctly. He sleuthed out the details and succeeded in reprogramming the USBasp, although he did end up buying a second one in the process.

Designers who use AVR microcontrollers have no shortage of programming interfaces — we count at least five different methods: ISP/SPI, JTAG, TPI, PDI, and UPDI. We’re not sure whether this is variety is good or bad, but it is what it is. [Kevin] discovers that for the particular family of Attiny devices he is using, the ATtiny20, TPI is the only option available.

While he normally builds his designs around ARM Cortex-M chips, [Kevin] needed some glue logic and decided to go with an ATtiny20 despite its unique programming requirements. He observes that the price of the ATtiny20, $0.53 last Fall, was cheaper than the equivalent logic gates he needed. This particular chip is also quite small — only 3 mm square (a 20-pin VQFN). We would prefer not to use different MCUs and tool chains on a single board, but sometimes the convenience and economics steer the design in that direction.

If you’re not familiar with the USBasp, our own [Mike Szczys] covered the breaking story over ten years ago. And if you have a lot of free time on your hands, ditch all these nicely packaged solutions and program your chips using an old USB Hub and a 74HCT00 NAND gate as described in this bizarre hack by Teensy developer [Paul Stoffregen].

After Years Of Uncertainty, Stratolaunch Flies Again

May 3, 2021 by 15 Comments

When Paul Allen founded Stratolaunch in 2011, the hope was to make access to space cheaper and faster. The company’s massive carrier aircraft, the largest plane by wingspan ever to be built, would be able to carry rocket-powered vehicles up into the thin upper atmosphere on short notice under the power of its conventional jet engines. The smaller vehicle, free of the drag it would incur in the denser atmosphere closer to the ground, could then be released and continue its journey to space using smaller engines and less propellant than would have been required for a conventional launch.

But Allen, who died in October of 2018, never got to see his gigantic plane fly. It wasn’t until April 13th, 2019 that the prototype carrier aircraft, nicknamed Roc, finally got to stretch its 117 meter (385 feet) wings and soar over the Mojave Desert. By that time, the nature of spaceflight had changed completely. Commercial companies were putting payloads into orbit on their own rockets, and SpaceX was regularly recovering and reusing their first stage boosters. Facing a very different market, and without Allen at the helm, Stratolaunch ceased operations the following month. By June the company’s assets, including Roc, went on the market for $400 million.

Finally, after years of rumors that it was to be scrapped, Allen’s mega-plane has flown for the second time. With new ownership and a new mission, Stratolaunch is poised to reinvent itself as a major player in the emerging field of hypersonic flight.

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Open-Source Oxygen Hack Chat

May 3, 2021 by 22 Comments

Join us on Wednesday, May 5 at noon Pacific for the Open-Source Oxygen Hack Chat with Maher Daoudi and the OxiKit Team!

In such tumultuous times, it may be hard to remember last week, let alone last year. But if you dig back a bit, you may recall what a panic the world was in at this point in 2020 about the ventilator crisis. With COVID-19 cases on the rise and the potential for great numbers of patients needing intensive care, everyone and their brother was hacking together makeshift ventilators, in the well-intentioned belief that their inventions would help relieve the coming shortage of these lifesaving medical mechanical miracles.

As it came to pass, though, more COVID-19 patients have benefited from high-flow oxygen therapy than from mechanical ventilation. That’s great news in places where medical oxygen is cheap and easily available, but that’s always the case. We’ve seen recent reports of hospitals in India running out of oxygen, and even rural and remote areas of the developed world can find themselves caught without enough of the vital gas.

To meet the world’s increasing demand for high-flow oxygen therapy, the team at OxiKit has developed an open-source oxygen concentrator that can be built for far less than what commercial concentrators cost. By filtering the nitrogen out of the air, the concentrator provides oxygen at 90% or higher purity, at a flow of up to 25 liters per minute.

Oxikit founder Maher Daoudi and some of the technical team will join us for this Hack Chat to discuss the details of making oxygen concentrators. We’ll learn about how they work, what the design process for their current concentrator was like, and how they got past the obstacles and delivered on the promise of high-flow oxygen for the masses.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, May 5 at 12:00 PM Pacific time. If time zones have you tied up, 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.
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I2C Paper Tape Reader Is Not What You Think

May 3, 2021 by 26 Comments

We’re not quite sure what drove the development of this project, but [shapoco] has put together an intriguing device that reads I2C signals (Japanese Twitter link) which have been printed as black and white rectangles on paper tape. He wrote a program that prints an I2C byte stream onto strips containing the SCL and SDA signal patterns. Once printed, you cut the strips from the paper and glue them together into one long piece, making a complete message — in this case, commands to a small LCD screen that will display the phrase “Hello, Tape I2C”.

We’re not sure exactly sure what’s inside that rectangular widget epoxied to the bottom of that perf board through which the tape passes. But clearly, it must contain a pair of LEDs to illuminate the tape and a pair of sensors to detect the reflection off the tape (looking at the wiring, it seems unlikely that anything is mounted underneath the tape). According to one machine-translated Twitter message, detection is done using a Schmitt trigger made from an LM393 comparator with hysteresis (see this TI app note for a review of this type of circuit). Here’s a scope capture of the resulting signals. [Shapoco] notes that the circuit can operate much faster — the tape is being pulled slowly in the video to make it easier to see.

This is not [shapoco]’s first experiment in optical I2C communications. Check out the second video down below where he’s reading I2C signals from a computer’s display. One person tweeted about how software source code was sometimes printed optically in old Byte magazines many years ago, a topic we talked about in Hackaday Podcast #049 last year when discussing Cauzin strips.

Besides just being cool, and possibly helpful as an educational device, does this technique have any real-world applications these days? Let us know your thoughts in the comment section below. Thanks to [Manawyrm] for sending us this tip.

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Genetically Modified Mosquitos: Biohacking For Disease Prevention

May 3, 2021 by 43 Comments

Many years ago, I took a summer trip to the Maryland shore with some friends. One of my buddies and I got bored with playing football on the beach, so we decided to take a hike on one of the many trails back into the wooded area behind the dunes. At the trailhead we noticed a prominent sign, warning about the presence of “very aggressive mosquitos” and not to enter without first applying ample insect repellent. We scoffed at the warning as only young idiots could and soldiered on, bare-legged and confident that we’d be fine.

About three minutes into our hike, a small group came pelting down the trail in a panic. “It’s true! Turn back!” they shouted as they flew past us. Undeterred, or at least unwilling to appear that way to each other, we pressed on, only to discover a few minutes later that we were making a substantial blood sacrifice to the next generation of mosquitos on Assateague Island. We couldn’t bear more than a few seconds before turning tail and running back to the beach and jumping into the ocean to get rid of the last few dozen bloodsuckers.

I learned a valuable lesson from that experience, as well as developing a deep and abiding hatred of mosquitos. It turns out I’m in good company — pretty much everyone hates mosquitos, which are not just a nuisance but can be downright dangerous to be around. But if tests with genetically engineered mosquitos currently underway in Florida turn out well, we may be able to finally turn the tide against mosquito-borne diseases, simply by killing all the females before they ever reach adulthood.

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Commodore 64 Emulator In VR Delivers A Full 80s Experience

May 3, 2021 by 18 Comments
The simulated color CRT monitor looks surprisingly convincing in VR.

One way to play with vintage hardware without owning the hardware is to use an emulator, but [omni_shaNker] announced taking it to the next level by using VR to deliver a complete Commodore 64 system, in its full glory, complete with a native 80s habitat playset! This is a pretty interesting angle for simulating vintage hardware, especially since the emulator is paired with what looks like a pretty convincing CRT monitor effect in VR, not to mention a virtual 5.25″ floppy drive that makes compellingly authentic sounds.

The project is hosted on GitHub and supports a variety of VR hardware, but for owners of Oculus headsets, the application is also available on SideQuest for maximum convenience. SideQuest is essentially an off-the-books app store for managing software that is neither approved nor distributed by Facebook. Oculus is owned by Facebook, and Facebook is keen to keep a tight grip on their hardware.

As functional as the application is, there are still improvements and optimizations to be made. To address this, [omni_shaNker] put out a call for beta testers on Reddit, so if that’s up your alley be sure to get in touch. A video demonstration and overview that is chock-full of technical details is also embedded below; be sure to give it a watch to see what the project is all about.

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Keep Livestock From Razing Your Field With An Overgrazing Shield

May 3, 2021 by 49 Comments

You know, not every solution needs to be complicated to be absolutely awesome. Take the humble clothespin, for example, two pieces of cleverly carved wood (or plastic; we won’t judge) and a spring. And yet, the service it provides is useful for many applications.

The same simple elegance is also present in [Anteneh]’s overgrazing shield. When sheep and other animals are allowed to eat the vegetation down to the soil, it leads to soil erosion if not kept in check with regular grazing location rotation. As it turns out, if you want to keep an animal from eating grass and plants down to the soil, just slip a leather harness over its neck with a piece of wood in the right place so it literally can’t graze any lower than the wood allows.

According to [Anteneh]’s prototype tests, it only takes a few seconds to fit the shield to the animal’s head and neck, and then they’re off to grazing to the prescribed depth. We think this is a great solution and hope to see it in wide use along with regular rotation.

Need a way to track your livestock? [Sean Boyce]’s experiments with subcutaneous pig tracking makes for a good read, but the reality of that system will probably have you looking for a simpler solution.