3D Printed Cartilage Ushers In Ear-a Of Custom Body Parts

When it comes to repairing human bodies, there’s one major difficulty: spare parts are hard to come by. It’s simply not possible to buy a knee joint or a new lung off the shelf.

At best, doctors and surgeons have made do with transplants from donors where possible. However, these are always in short supply, and come with a risk of rejection by the patient’s body.

If we could 3D print new custom body par/ts to suit the individual, it would solve a lot of problems. A new ear implant pioneered by 3DBio Therapeutics has achieved just that.

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Reverse Engineering An Apollo-Era Module With X-Ray

The gear that helped us walk on the Moon nearly 60 years ago is still giving up its mysteries today, with some equipment from the Apollo era taking a little bit more effort to reverse engineer than others. A case in point is this radiographic reverse engineering of some Apollo test gear, pulled off by [Ken Shirriff] with help from his usual merry band of Apollo aficionados.

The item in question is a test set used for ground testing of the Up-Data Link, which received digital commands from mission controllers. Contrary to the highly integrated construction used in Apollo flight hardware, the test set, which was saved from a scrapyard, used more ad hoc construction, including cards populated by mysterious modules. The pluggable modules bear Motorola branding, and while they bear some resemblance to ICs, they’re clearly not.

[Ken] was able to do some preliminary reverse-engineering using methods we’ve seen him employ before, but ran into a dead end with his scope and meter without documentation. So the modules went under [John McMaster]’s X-ray beam for a peek inside. They discovered that the 13-pin modules are miniature analog circuits using cordwood construction, with common discrete passives stacked vertically between parallel PCBs. The module they imaged showed clear shadows of carbon composition resistors, metal-film capacitors, and some glass-body diodes. Different angles let [Ken] figure out the circuit, which appears to be part of a square wave to sine wave converter.

The bigger mystery here is why the original designer chose this method of construction. There must still be engineers out there who worked on stuff like this, so here’s hoping they chime in on this innovative method.

Shielding A Cheap RTL-SDR Stick

Even though not every Hackaday reader is likely to be a radio enthusiast, it’s a fair guess that many of you will have experimented with an RTL-SDR USB dongle by now. These super-cheap devices are intended for digital TV reception and contain an RTL2832 chip, which with the proper software, can be pushed into service as a general purpose software defined radio receiver. For around $10 USD they’re fantastic value and a lot of fun to play with, even if they’re not the best radio ever. How to improve the lackluster performance? One of the easiest and cheapest ways is simply to shield it from RF noise, which [Alan R] has done with something as mundane as a tubular fizzy orange tablet container.

This is probably one of the simpler hacks you’ll see on this site, as all it involves is making an appropriate hole in the end of the tube and shielding the whole with some aluminium foil sticky tape. But the benefits can be seen immediately in the form of reduced FM broadcast band interference, something that plagues the cheaper dongles.

Perhaps the value in this hack aside from how easy it is on a cheap dongle is that it serves to remind us some of the benefits of paying a little extra for a better quality device. If you’d like to know more about RTL-SDR improvements, it’s a topic we covered in detail back in 2019 when we looked at seven years of RTL-hackery.