Relay Computer Consumes Six Years And 4.5 Suitcases

If you thought your home-brew project was taking a long time, [Jeroen Brinkman]’s MERCIA Relay Computer project probably has you beat. He began working on this impressive computer back in 2014, and has been at it ever since.  In fact, the ongoing nature of the project is embedded into the name itself — the English translation of the acronym MERCIA is “My Simple Relay Computer Under Construction”.  Being interested in old analog and relay computers from an early age, [Jeroen] took on this project to educate students about how computers work.  The entire computer is build only using relays, diodes, and capacitors, not to mention color-coded wire based on signal functions. Using relays as the primary switching elements is at the core of his educational goal — anyone can understand how a relay works.

Understandably, this thing is big.  But he has cleverly packaged it to visually show the major building blocks of a computer.  While the exact size isn’t stated, we can estimate based on the photo of [Jeroen] standing next to the modules that these panels are about 1.5 m tall and perhaps 60 cm wide.  The whole computer is nine panels wide, making it about 5 meters long.  Except for the ROM assembly, pairs of panels are hinged together and they fold like a book and carried like a suitcases when being moved.  If you enjoy the clickety-clack sound of relays, be sure to watch the relay longevity test in the video below and check out our article on the 1958 FACOM from last year.

This is a fascinating project, but unless you have a couple thousand relays laying around and a decade of free time, it’s probably better to just enjoy [Jeroen]’s work rather than build your own.  We hope he releases schematics and other documentation once the project is finished.  You can follow his Facebook build log if you want to keep track of the progress. Thanks to [David Gustafik] for the tip.

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Short Video Recaps A Long Tradition Of Space Hacks

Human spaceflight has always been, and still remains, a risky endeavor. We mitigate risk by being as prepared as we can. Every activity is planned, reviewed, and practiced long before any rocket engines are ignited. But space has a history of not cooperating with plans, and thus there is a corresponding history of hacks to get missions back on track. YouTube space fan [Scott Manley] recaps some of his favorites in How a $2 Toothbrush Saved the ISS and Other Unbelievable Space Hacks.

The introduction explained this compilation was motivated by the latest International Space Station drama, where an elusive air leak has finally been tracked down. Air leaks are obviously much more worrying in a space station than in, say, a bicycle tire. Thus there exists a wide array of tools to track down leaks but they couldn’t find this one. Reportedly the breakthrough came from an improvised airflow visualization tool: leaves from a cut-open tea bag. Normally small floating particles are forbidden in space because they might end up in troublesome places. (Eyes, noses, onboard equipment…) Apparently the necessity of the hack outweighed the rules here.

Tea leaves are but the latest in a long line of hacks devised in the course of space missions, because things don’t always go according to the original plan. Or even any of the large volume of contingency plans. Solutions have to be cobbled together from resources on hand, because when we’re in space, what we brought is all we have. From directly editing production code during Apollo 14, to a field-built replacement fender for the Apollo 17 Lunar Rover Vehicle (top picture), to the $2 toothbrush pressed into service as metal debris cleaner. The mission must go on!

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A Plethora Of Power Delivery Potential

Here at the Hackaday we’ve been enjoying a peculiar side effect of the single-port USB-C world; the increasing availability of programmable DC power supplies in the form of ubiquitous laptop charging bricks. Once the sole domain of barrel jacks or strange rectangular plugs (we’re looking at you Lenovo) it’s become quite common to provide charging via the lingua franca of USB-C Power Delivery. But harnessing those delectable 100W power supplies is all to often the domain of the custom PCBA and firmware hack. What of the power-hungry hacker who wants to integrate Power Delivery in her project? For that we turn to an excellent video by [Brian Lough] describing four common controller ICs and why you might choose one for your next project.

A superb illustration from the TS100 Flex-C-Friend documentation

[Brian] starts off with a sorely-needed explainer of what the heck Power Delivery is; a topic with an unfortunate amount of depth. But the main goal of the video is to dive into the inscrutable hoard of “USB C trigger boards.” Typically these take USB on one side and provide a terminal block on the other, possibly with a button or LED as user interface to select voltage and current. We’ve seen these before as laptop barrel jack replacements and TS100 power supplies but it’s hard to tell which of the seemingly-identical selection is most suitable for a project.

The main body of the video is [Brian’s] detailed walkthrough of four types of trigger boards, based on the IP2721, FUSB302, STUSB4500, and Cypress EZ-PD BCR. For each he describes the behaviors of it’s particular IC and how to configure it. His focus is on building a board to power a TS100 (which parallels his TS100 Flex-C-Friend) but the content is generally applicable. Of course we also appreciate his overview of the products on Tindie for each described module.

For another angle on Power Delivery, check out this series of posts by [jason cerudolo], a perennial favorite. And don’t miss his classic project, the USB Easy Bake Oven.

Don’t Guess, Listen To Your Plants’ Pleas For Water

Plants are great to have around, but they all have different watering needs. If only they could cry out when they’re thirsty, right? Well, now they can. All you need to hear them suffer is your very own Klausner Machine. [RoniBandini] based the Klausner machine on one of Roald Dahl’s short stories, which features an inventor who builds a machine that can make audible the sound of plants shrieking whenever they’re cut.

In [RoniBandini]’s version of the Klausner Machine, the point is to judge the plant’s feelings based on its soil moisture content. An Arduino Nano reads in from the soil moisture sensor, and if the soil is dry, the plant screams. If the soil is moist, the plant emits happy sounds from DF Player Mini and SD card.  We think the analog meters are a great touch, and the jumping needles really anthropomorphize the plant.

Go forth and gain a better appreciation for your plants’ feelings, because this project is wide open. Maybe it will help you water them more often. Some plants need to be cut back, so we think it would be cool if you could make it scream when you take a cutting. Check out the demo after the break.

This is isn’t the first time we’ve seen an analog meter used in conjunction with soil moisture. What is a VU meter, anyway? Our own [Dan Maloney] really moved the needle on the subject a while back.

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The Adorable Robot Spot, Now In Affordable Form

If you’ve been following the Boston Dynamics project Spot, you’ve seen its capabilities and how we’re starting to see it being used in public more since its official release last year. But in a true display of how hobbyist electronics have been evolving and catching up with the big companies over the past few years, [Miguel Ayuso Parrilla] shows us his own take on the walking robot with CHOP, one of the finalists in this year’s Hackaday Prize.

CHOP is a DIY quadruped robot that works much in the same way as Spot, although in a smaller form-factor and, perhaps most impressive of all, a bill of materials that can be all acquired for under $500. The entire project is open source, meaning that anyone can built their own version of it with off-the-shelf parts and some 3D printing. If you can’t get the hardware however, you can still play with the PyBullet simulation of the mechanics that were used during the debugging process.

Running the show are two main components, a Raspberry Pi 4B and an Arduino Mega. While the Mega interfaces with the servo controllers and provides filtering for sensors like the inertial measurement unit, the Pi takes all that data in and uses a series of Python scripts in order to determine the gait of the robot and which way the servos should move through an inverse kinematics model. To control the direction in which the body of the robot should accelerate, a Bluetooth remote controller sends commands to the Raspberry Pi.

We’re excited to see home-grown projects rise to this level of complexity, which would be mostly unheard of a few years ago in the maker scene, and only presented by large tech companies with tons of money to spend on research and development. There are other quadruped robots to inspire yourself on than Spot though, like this one with a spherical design and fold-out legs. Check this one in action after the break.

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Tesla Begins “Full Self Driving” Public Beta As Waymo And Cruise Go Unattended

Self-driving technology is a holy grail that promises to forever change the way we interact with cars. Thus far, there’s been plenty of hype and excitement, but full vehicles that remove the driver from the equation have remained far off. Tesla have long posited themselves as a market leader in this area, with their Autopilot technology allowing some limited autonomy on select highways. However, in a recent announcement, they have heralded the arrival of a new “Full Self Driving” ability for select beta testers in their early access program.

Taking Things Up A Notch

Telsa’s update notes highlight the new “Full Self-Driving” capabilities. Drivers are expected to pay continuous attention and be prepared to take over at any time, as the system “may do the wrong thing at the worst time.”

The new software update further extends the capabilities of Tesla vehicles to drive semi-autonomously. Despite the boastful “Full Self Driving” moniker, or FSD for short, it’s still classified as a Level 2 driving automation system, which relies on human intervention as a backup. This means that the driver must be paying attention and ready to take over in an instant, at all times. Users are instructed to keep their hands on the wheel at all times, but predictably, videos have already surfaced of users ignoring this measure.

The major difference between FSD and the previous Autopilot software is the ability to navigate city streets. Formerly, Tesla vehicles were only able to self-drive on highways, where the more regular flow of traffic is easier to handle. City streets introduce far greater complexity, with hazards like parked cars, pedestrians, bicycles, and complicated intersections. Unlike others in the field, who are investing heavily in LIDAR technology, Tesla’s system relies entirely on cameras and radar to navigate the world around it. Continue reading “Tesla Begins “Full Self Driving” Public Beta As Waymo And Cruise Go Unattended”

Hackaday Podcast 090: DIY Linux SBC, HDMI CEC, Fake Bluepills, And SCARA Arms

Hackaday editors Elliot Williams and Mike Szczys chat about our favourite hacks from the past week. We start off with a bit of news of the Bennu asteroid and the new Raspberry Pi Compute Module. We drive ourselves crazy trying to understand how bobbin holders on sewing machines work, all while drooling over the mechanical brilliance of a bobbin-winding build. SCARA is the belt and pulley champion of robot arms and this week’s example cleverly uses redundant bearings for better precision. And we wrap up the show looking in on longform articles about the peppering of microcontrollers found on the Bluepill and wondering what breakthroughs are left to be found for internal combustion.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (~60 MB)

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