Retrotechtacular: Understanding Protein Synthesis Through Interpretive Dance

August 1, 2021 by 8 Comments

With the principles of molecular biology very much in the zeitgeist these days, we thought it would be handy to provide some sort of visual aid to help our readers understand the complex molecular machines at work deep within each cell of the body. And despite appearances, this film using interpretive dance to explain protein synthesis will teach you everything you need to know.

Now, there are those who go on and on about the weirdness of the 1960s, but as this 1971 film from Stanford shows, the 60s were just a warm-up act for the really weird stuff. The film is a study in contrasts, with the setup being provided by the decidedly un-groovy Paul Berg, a professor of biochemistry who would share the 1980 Nobel Prize in Medicine for his contributions to nucleic acid research. His short sleeves and skinny tie stand in stark contrast to the writhing mass of students capering about on a grassy field, acting out the various macromolecules involved in protein synthesis. Two groups form the subunits of the ribosome, a chain of ballon-headed students act as the messenger RNA (mRNA) that codes for a protein, and little groups standing in for the transfer RNA (tRNA) molecules that carry the amino acids float in and out of the process.

The level of detail, at least as it was understood in 1971, is impressively complete, with soloists representing things like T-factor and the energy-carrying molecule GTP. And while we especially like the puff of smoke representing GTP’s energy transfer, we strongly suspect a lot of other smoke went into this production.

Kitsch aside, and with apologies to Lewis Carroll and his Jabberwock, you’ll be hard-pressed to find a modern animation that captures the process better. True, a more traditional animation might make the mechanistic aspects of translation clearer, but the mimsy gyre and gimble of this dance really emphasize the role random Brownian motion plays in macromolecular processes. And you’ll never see the term “tRNA” and not be able to think of this film.

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Ostrich Robot Machine-Learns Itself To 5K

August 1, 2021 by 43 Comments

Ever since humanity has grasped the idea of a robot, we’ve wanted to imagine them into walking humanoid form. But making a robot walk like a human is not an easy task, and even the best of them end up with the somewhat shuffling gait of a Honda Asimo rather than the graceful poise of a balerina. Only in recent years have walking robots appeared to come of age, and then not by mimicking the human gait but something more akin to a bird.

We’ve seen it in the Boston Dynamics models, and also now in a self-balancing two-legged robot developed at Oregon State University that has demonstrated its abilities by completing an unaided 5 km run having used its machine learning skills to teach itself to run from scratch. It’s believed to be the first time a robot has achieved such a feat without first being programmed for the specific task.

The university’s PR piece envisages a time in which walking robots of this type have become commonplace, and when humans interact with them on a daily basis. We can certainly see that they could perform a huge number of autonomous outdoor tasks that perhaps a wheeled robot might find to be difficult, so maybe they have a bright future. Decide for yourself, after watching the video below the break.

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Hacking A PIC To Redefine A Microphone’s Transmit Frequency

August 1, 2021 by 1 Comment

Software defined radio and widespread software-controlled PLL synthesis for RF has been a game changer. Things like the RTL-SDR can be any kind of radio you like on almost any frequency you like. But not every SDR or PLL system opens the configuration doors to you, the end user. That was the problem [vgnotepad] faced when trying to connect a Sennheiser wireless microphone to some receivers. They didn’t use the same frequencies, even though the transmitter was programmable. The solution to that is obvious — hack the transmitter!

The post is only part one of several parts and if you read to the end, you’ll learn a lot about what’s inside the device and how to crack it. Luckily, the device uses a PIC processor, so getting to the software wasn’t a big issue.

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The O’Scope Restoration

August 1, 2021 by 8 Comments

These days, a pretty nice oscilloscope can fit in your toolbox and even a “big” instrument is probably something you can tuck under your arm. But that hasn’t always been the case. Consider this old HP 150A, restored by [USagi Electric]. (Video, embedded below.)

The 10 MHz dual channel scope might not seem very high-tech today, but when HP rolled it out in the 1950s to challenge Tektronix, it was quite respectable. The $1,000 price tag just for the mainframe was pretty respectable, too. Unfortunately, the scope wasn’t very reliable with more than 50 tubes in it, and HP quickly had to develop new entries in the scope market.

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Stereo Recording Made Easy With A 3D-Printed Mount

August 1, 2021 by 15 Comments

When making a recording it can be surprisingly difficult to capture a good stereo image. A well-known technique is the ORTF microphone arrangement in which two cardoid microphones sit at 110 degrees to each other and 17cm apart, and thus pick up a readily reproducible stereo separation. It’s something that we’ve been known to do in our student days with a pair of Shure SM58s and a stack of Post Office elastic bands, but [marsairforce] has done a much nicer job with a very neat 3D-printed microphone clip.

Designed in OpenSCAD, the first iteration printed on a resin printer proved to be too brittle for the task, so a second version was printed on an FDM machine. This incorporated significant strengthening, as well as a screw mount for a microphone stand. The result is an extremely useful and cheap addition to any recording set-up, and anyone who has wrestled with achieving a good stereo image will appreciate it. You can see some of what went into it in the video below the break.

If this is your field of interest, you might also wish to look at a binaural microphone.

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An Epic Tale Of Reset Line Detective Work

July 31, 2021 by 10 Comments

The Pine64 folks have given us so many tasty pieces of hardware over the last few years, but it’s fair to say that their products are for experimenters rather than consumers and can thus be a little rough around the edges at times. Their Clusterboard for example is a Mini-ITX PCB which takes up to seven of their SOPINE A64 compute modules, and networks them for use as a cluster by means of an onboard Gigabit Ethernet switch. It’s a veritable powerhouse, but it has an annoying bug in that it appears reluctant to restart when told. [Eric Draken] embarked upon a quest to fix this problem, and while he got there in the end his progress makes for a long and engrossing read.

We journey through the guts of the board and along the way discover a lot about how reset signals are generated. The eventual culprit is a back-EMF generated through the reset distribution logic itself causing the low-pulled line to never quite descend into logic 0 territory once it has been pulled high, and the solution an extremely simple application of a diode. For anyone who wishes to learn about logic level detective work it’s well worth a look. Meanwhile the board itself with its 28 ARM cores appears to have plenty of potential. It’s even a board we’ve mentioned before, in a personal supercomputer project.

A Satellite Upconverter Need Not Be Impossible To Make

July 31, 2021 by 8 Comments

Those readers whose interests don’t lie in the world of amateur radio might have missed one of its firsts, for the last year or two amateurs have had their own geostationary satellite transponder. Called Es’hail-2 / AMSAT Phase 4-A / Qatar-OSCAR 100, it lies in the geostationary orbit at 25.9° East and has a transponder with a 2.4 GHz uplink and a 10.489 GHz downlink. Receiving the downlink is possible with an LNB designed for satellite TV, but for many hams the uplink presents a problem. Along comes [PY1SAN] from Brazil with a practical and surprisingly simple solution using a mixture of odd the shelf modules and a few hand-soldered parts.

An upconverter follows a simple enough principle, the radio signal is created at a lower frequency (in this case by a 435 MHz transmitter) and mixed with a signal from a local oscillator. A filter then picks out the mixer product — the sum of the two — and amplifies it for transmission. [PY1SAN]’s upconverter takes the output from the transmitter and feeds it through an attenuator to a MiniCircuits mixer module which takes its local oscillator via an amplifier from a signal generator module. The mixer output goes through a PCB stripline filter through another amplifier module to a power amplifier brick, and thence via a co-ax feeder to a dish-mounted helical antenna.

The whole thing is a series of modules joined by short SMA cables, and could probably be largely sourced from a single AliExpress order without too much in the way of expenditure. It’s by no means easy to get on air via Es’hail-2, but at least now it need not be impossibly expensive. Even the antenna can be made without breaking the bank.

We covered Es’hail-2 when it first appeared. May it long provide radio amateurs with the chance to operate worldwide with homebrew microwave equipment!

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