Converting A Porsche 944 To Run A MAF

Electronic fuel injection was a big leap forward for engine control. However, early implementations often left something to be desired. This was the case for [Rob] and his Porsche 944, which had relied on an old-fashioned mechanical air flow meter (AFM). He decided to replace this with a modern mass air flow (MAF) sensor instead, and documented the process online.

The output of the sensors was compared with a rig built using a vacuum cleaner to create air flow.

AFMs are often a target for replacement on old cars. They’re usually based on a flap that moves a potentiometer wiper across a carbon trace which wears out over the years. They can also present an air flow restriction in some cases, limiting performance. MAF sensors instead measure the amount of air flowing through with a hot wire. The amount of current required to maintain the temperature of the wire indicates the amount of air flowing through the sensor. They’re less restrictive and readily available as they’re used in many cars today.

To run a MAF in place of the AFM requires a circuit to emulate the AFM’s output. [Rob] used a STM32 Cortex-M0 to read the MAF, and then output the relevant voltage to the Porsche’s engine computer via PWM and a low pass filter. To figure out how to map the MAF’s output to match the AFM, [Rob] built a rig to blow air through both devices in series, and measuring their output on an oscilloscope. This data was used to program the STM32 to output the right emulated AFM voltage for the given MAF signal.

It’s a great piece of work from [Rob] that has his Porsche running happily on new parts. We’ve seen similar hacks done to other cars before, as well! Video after the break.

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Is That A Typewriter In Your Pocket Or Are You Just Pleased To See Me?

Don’t have the right milling tool? Just make one!

[Attoparsec] wondered what if you could carry a typewriter in your pocket, then followed through with that and built one. (Video, embedded below.) Kind of. The plan was to use an existing set of striker bars, but not wanting to destroy a perfectly good typewriter, they realised that you can easily source just the bar set on eBay.

The first problem was that the striker bars are shaped to allow the typewriter mechanism to operate, but that would not make for a compact arrangement. After a spot of straightening in a big vice, and drilling in a custom jig, they were in a suitable state to be arranged inside the case. The casing is milled from a chunk of aluminium, complete with a nice recess to hold an ink-impregnated felt pad. To prevent this pad from drying out when stowed, and to keep the whole thing clear of pocket lint, a U-shaped metal cover was bent from some sheet. This slides into a set of slots that are milled near the edges, in a very satisfying manner. This last bit was causing them a little trouble, so a custom slotting tool was created especially for the job. And a good job was indeed done. The final results look as you might expect from a manual ‘typewriter’ quirky, a bit wonky, but fabulous all the same.

If you have an old typewriter that needs some attention, here’s a quick guide for giving it a once-over. Some of you of a certain age may remember electronic typewriters with some fondness. They died a rapid death, but if you’ve still got one lurking, you could convert it into a Linux terminal for some clackity nostalgic fun.

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The Amateur Rocketry Hack Chat Reaches For The Stars

Hackaday has been around long enough to see incredible changes in what’s possible at the hobbyist level. The tools, techniques, and materials available today border on science-fiction compared to what the average individual had access to even just a decade ago. On a day to day basis, that’s manifested itself as increasingly elaborate electronic projects that in many cases bear little resemblance to the cobbled together gadgets which graced these pages in the early 2000s.

Kip Daugirdas

But these gains aren’t limited to our normal niche — hobbyists of all walks have been pushing their respective envelopes. Take for example the successful launch of MESOS, a homebuilt reusable multi-stage rocket, to the very edge of the Kármán line. It was designed and built by amateur rocket enthusiast Kip Daugirdas over the course of several years, and if all goes to plan, will take flight once again this summer with improved hardware that just might help it cross the internationally recognized 100 kilometer boundary that marks the edge of space.

We were fortunate enough to have Kip stop by the Hack Chat this week to talk all things rocketry, and the result was a predictably lively conversation. Many in our community have a fascination with spaceflight, and even though MESOS might not technically have made it that far yet (there’s some debate depending on who’s definition you want to use), it’s certainly close enough to get our imaginations running wild.

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Hackaday Podcast 195: No NABU For You, Self-Assembling 3D Prints, Black Hats Look At EV Chargers

This week, Editor-in-Chief Elliot Williams and Managing Editor Tom Nardi find themselves in the middle of a slow news week, so they dispense with the usual timely chit-chat and dive right into the results of a particularly tricky “What’s that Sound” challenge.

From there they’ll cover the new breed of ATtiny microcontollers (and why you probably won’t be buying them), a recently unearthed Z-80 consumer gadget that’s begging to be reverse engineered, the fine art of electrifying watercraft, and a particularly impressive speech recognition engine. Stick around till the end to hear about the potential dangers of unsecured EV chargers, and take a walk down memory lane to a time when soldering irons and paper schematics ruled the world.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Download the podcast for safe-keeping!

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Digital Taxidermy Spool Recycling concept art.

Spool Tower: Empty Filament Spool Or Base For Miniature Civilizations

While churning through rolls of FDM filament, there are these empty spools that remain at the end. These can be thrown out with the trash, or be used as a standard base for miniatures, for use with Dungeons & Dragons tabletop gaming or similar, or just as a display piece. The latter is what the blokes over at Digital Taxidermy ran with when they started their first Spool Tower Kickstarter campaign. Now they’re back with Spool Tower 2: The Re-Spoolening.

These are STL bundle packs that should contain all that’s needed to turn an empty filament spool into an art piece, minus of course the painting. To get a free taste of what the experience is like, Digital Taxidermy provides a few free STLs, such as for the Ye Olde Taxidermee Shoppee and the Hab Block from the new crowdfunding campaign.

This effort raises the interesting question of what other standard (plastic) shapes of packaging could conceivably be used in a similar manner. After all, why print the whole thing when half the model could be made from something you’d otherwise just toss into the trash bin?

Thanks to [scat happens] for the tip.

This Week In Security: Huawei Gets The Banhammer, Lastpass, And Old Code Breaking

While many of us were enjoying some time off for Thanksgiving, the US government took drastic action against Huawei and four other Chinese companies. The hardest hit are Huawei and ZTE, as the ban prevents any new products from being approved for the US market. The other three companies are Dahua and Hikvision, which make video surveillance equipment, and Hytera, which makes radio systems. FCC Commissioner Brendan Carr noted the seriousness of the decision.

[As] a result of our order, no new Huawei or ZTE equipment can be approved. And no new Dahua, Hikvision, or Hytera gear can be approved unless they assure the FCC that their gear won’t be used for public safety, security of government facilities, & other national security purposes.

There is even the potential that previously approved equipment could have its authorization pulled. The raw FCC documents are available, if you really wish to wade through them. What’s notable is that two diametrically opposed US administrations have both pushed for this ban. It would surely be interesting to get a look at the classified reports detailing what was actually found. Maybe in another decade or two, we can make a Freedom of Information Act request and finally get the full story.

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A Dead Photographic Format Rises From The Ashes

Sometimes we stumble upon a hack that’s not entirely new but which is still pretty exceptional. So it is with [Hèrm Hofmeyer]’s guide to recreating a film cartridge for the Kodak Disc photographic format. It’s written in 2020, but describing a project around a decade old.

The disc format was Kodak’s great hope in the 1980s, the ultimate in photographic convenience in which the film was a 16-shot circular disc in a thin cartridge. Though the cameras were at the consumer end of the market they were more sophisticated than met the eye, with the latest electronics for the time and some innovative plastic multi-element aspherical lenses. It failed in the face of better compact 35 mm cameras because the convenience of the disc wasn’t enough to make up for the relatively small negative and that few labs had the specialized printing equipment to get the best results from the format. The cameras faded from view, and the film ceased manufacture at the end of the 1990s.

The biggest hurdle to creating a Disc cartridge comes in the cartridge shells themselves. It’s solved by sourcing them second-hand from Film Rescue International, a specialist in developing expired photographic film. The stages follow the cutting of a film disc, perforating its edges, and fitting it into the cartridge. It’s an exact enough process in the pictures, and it’s worth remembering that in the real cartridges it must be done in the dark.

This is an interesting piece of work for anyone with an interest in photography, and while the Disc cameras were always a consumer snapshot camera we can see that it would appeal to those influenced by Lomography. We wish we could get our hands on a Disc cartridge, an maybe CAD up a 3D printable version to make it more accessible.