Bit Preserve: A Sanctuary For Modern Captures Of Vintage Schematics

Vintage parts may be documented, but that doesn’t mean they’re particularly useful or accessible. If the phrase “eyestrain from unsearchable, badly-scanned PDF datasheets” makes your lower eyelid twitch in sympathy, read on.

While [Bald Engineer] was researching how he might make a portable Apple II, he was delighted to find that the vintage components he needed to examine were documented. However, he became frustrated with the seemingly endless number of poor quality PDF scans and the inability to search effectively. He decided to re-create the entire Apple IIgs schematic in KiCad, and in the process the Bit Preserve project was born. The goal is to act as a safe haven for modern and editable versions of vintage electronic schematics. The GitHub repository can be found here.

[Bald Engineer] talks a bit about his Apple II project, as well as the ideas behind the Bit Preserve project in his KiCon 2019 talk “Preserving History with KiCad”. KiCon was wild, and we have loads of photos of the projects and details so be sure to check it out.

Making An Update Server For PythonAnywhere And GitHub

Cloud based IDEs and development tools have grown over the years, though most have limitations in their free tiers and may not be fully compatible with other services such as GitHub. [Aadi Bajpai] loved using PythonAnywhere and to collaborate using GitHub, so he made a update server that automatically updates the running code once you make a push to Github

PythonAnywhere gives you access to a python shell over a web browser, and also lets you run a web app that can be accessed via a custom sub-domain. Even though it does not have direct integration with GitHub, you can drop to the bash shell to and get access to a git client.

For this hack, [Aadi Bajpai] utilizes the webhooks from GitHub that are triggered when a push event is detected. A flask server running on PythonAnywhere is written such that once triggered by the get POST request, it locally executes a git pull from the repository. There a bit more work that allows adding a bit of security sauce to the recipe but it is a pretty elegant solution and can be used for other cases as well.

Setting up alert notifications has been demonstrated to be an interesting task, though integrating Discord or Slack for notifications adds a little more bragging rights.

A Rough And Ready Pan & Tilt Mirror

There’s nothing quite like waking up on a warm and sunny morning, with the sun filtering in through the windows over a magnificent beach view. Of course, in real life, not every bedroom has access to beautiful natural vistas and abundant natural light. [Rue Mohr] decided to try and solve this issue with technology.

The initial write-up may be brief, but the pictures of the resulting project show a proper hacker’s build. A stand for an old office chair appears to serve as the base, and the mirror is mounted on a frame that allows for both pan and tilt to be adjusted. There’s a large gear to enable pan rotation, which meshes with a nifty old-school cage gear built out of what we suspect is plastic and welding rod. An AVR microcontroller is charged with running the show, with it interpolating a series of waypoints to set the mirror’s position throughout the day.

[Rue] reports that the project is nearing completion, and is soon to be fully automated. With the dark bedroom that spawned the project no longer a concern, the mirror will instead be pressed into service to provide sun to a row of bean plants.

If you’re looking for a pan-tilt mechanism, but something a little smaller, this 3D-printed mechanism might be just what you’re after.

Laser Cutting Wooden Pogo Pin Test Jigs

Now as far as problems go, selling so many products on Tindie that you need to come up with a faster way to test them is a pretty good one to have. But it’s still a problem that needs solving. For [Eric Gunnerson] the solution involved finding a quick and easy way to produce wooden pogo test jigs on his laser cutter, and we have a feeling he’s not the only one who’ll benefit from it.

The first step was exporting the PCB design from KiCad into an SVG, which [Eric] then brought into Inkscape for editing. He deleted all of the traces that he wasn’t interested in, leaving behind just the ones he wanted to ultimately tap into with the pogo pins. He then used the Circle tool to put a 0.85 mm red dot in the center of each pad.

You’re probably wondering where those specific parameters came from. The color is easy enough to explain: his GlowForge laser cutter allows him to select by color, so [Eric] can easily tell the machine to cut out anything that’s red. As for the size, he did a test run on a scrap of wood and found that 0.85 mm was the perfect dimensions to hold onto a pogo pin with friction.

[Eric] ran off three identical pieces of birch plywood, plus one spacer. The pogo pins are inserted into the first piece, the wires get soldered around the back, and finally secured with the spacer. The whole thing is then capped off with the two remaining pieces, and wrapped up in tape to keep it together.

Whether you 3D print one of your own design or even modify a popular development board to do your bidding, the test jig is invaluable when you make the leap to small scale production.

A Solar-Powered Box Of Sensors To Last 100 Years

It’s a simple goal: build a waterproof box full of environmental sensors that can run continuously for the next century. OK, so maybe it’s not exactly “simple”. But whatever you want to call this epic quest to study and record the planet we call home, [sciencedude1990] has decided to make his mission part of the 2019 Hackaday Prize.

The end goal might be pretty lofty, but we think you’ll agree that the implementation keeps the complexity down to a minimum. Which is important if these solar-powered sensor nodes are to have any chance of going the distance. A number of design decisions have been made with longevity in mind, such as replacing lithium ion batteries that are only good for a few hundred recharge cycles with supercapacitors which should add a handful of zeros to that number.

At the most basic level, each node in the system consists of photovoltaic panels, the supercapacitors, and a “motherboard” based on the ATmega256RFR2. This single-chip solution provides not only an AVR microcontroller with ample processing power for the task at hand, but an integrated 2.4 GHz radio for uploading data to a local base station. [sciencedude1990] has added a LSM303 accelerometer and magnetometer to the board, but the real functionality comes from external “accessory” boards.

Along the side of the main board there’s a row of ports for external sensors, each connected to the ATmega through a UART multiplexer. To help control energy consumption, each external sensor has its own dedicated load switch; the firmware doesn’t power up the external sensors until they’re needed, and even then, only if there’s enough power in the supercapacitors to do so safely. Right now [sciencedude1990] only has a GPS module designed to plug into the main board, but we’re very interested in seeing what else he (and perhaps even the community) comes up with.

You’re Sitting On An Engineering Masterpiece: Chairs As A Design Challenge

If you move as a hardware hacker through the sometimes surprisingly similar world of artists, craftspeople, designers, blacksmiths, and even architects, there’s one piece of work that you will see time and time again as an object that exerts a curious fascination. It seems that designing and building a chair is a rite of passage, and not just a simple chair, but in many cases an interesting chair.

An American-made Windsor chair from the turn of the 19th century. Los Angeles County Museum of Art [Public domain]
An American-made Windsor chair from the turn of the 19th century. Los Angeles County Museum of Art [Public domain]
Some of the most iconic seating designs that you will be instantly familiar with through countless mass-produced imitations began their lives as one-off design exercises. Yet we rarely see them in our community of hackers and makers, a search turns up only a couple of examples. This is surprising, not least because there is more than meets the eye to this particular piece of furniture. Your simple seat can be a surprisingly complex challenge.

Moving Charis From Artisan to Mass Market

The new materials and mass production techniques of the 19th and 20th centuries have brought high-end design into the hands of the masses, but while wealthy homes in earlier centuries had high-quality bespoke furniture in the style of the day, the traditional furniture of the masses was hand-made in the same way for centuries often to a particular style dependent on the region in which it was produced.

Continue reading “You’re Sitting On An Engineering Masterpiece: Chairs As A Design Challenge”

Is 4 GB The Limit For The Raspberry Pi 4?

So you’ve rushed off to your favourite dealer in Raspberry Pi goodies and secured your shiny new Raspberry Pi 4. Maybe you’re anxiously waiting for the postie, or perhaps if you’re lucky enough to live near Cambridge you simply strolled into the Pi shop and bought one over the counter. You’ve got the best of the lot, the 4 GB model, and there’s nothing like the feeling of having the newest toy before everyone else does.

A scan of the Pi 4 user guide, with a tantalising 8GB at the bottom.
A scan of the Pi 4 user guide, with a tantalising 8GB at the bottom.

You open the box, pull out the Pi, and get busy. The instruction leaflet flutters to the floor, ignored and forgotten. If you’re our tipster [Eric van Zandvoort] though, you read it, notice something unexpected, and send a scan to your friends at Hackaday. Because there at the top, in the regulatory compliance information that nobody reads, is the following text:

Product name: Raspberry Pi 4 Model B 1 GB, 2 GB, 4 GB + 8 GB variants.

It’s not the lack of an Oxford comma that caught his eye, but the tantalising mention of an 8 GB Raspberry Pi 4. Could we one day see an extra model in the range with twice the memory? It would be nice to think so.

There are a couple of inevitable reactions when a new product comes out. First, everyone who has just bought the previous one will be upset, and second there will always be a group of people who say “Ah, don’t buy this one, wait for the super-duper upgrade model!” We’d like to suggest to anyone tempted into the latter group that this news should be no reason not to buy a Raspberry Pi 4 at the moment, because the prospect of an 8 GB variant should come as a shock to nobody.

It makes absolute sense that the Pi people will have equipped their SoC with as much address space as they can get into it, and equally as much sense that they will have fitted the final products with whatever memory chips keep it within their target price point. If you cast your mind back you’ll know that this isn’t the first time this has happened, early boards were shipped with 256 MB of RAM but later upgraded to 512 MB as the economics made it possible. Those with extreme knowledge of Pi trivia will also know that the original Model A was announced with 128 MB and released with 256 MB for the same reason.

There’s another question, would 8 GB make that much difference? The answer depends upon what you are doing with your Pi 4, but it’s worth remembering that this is no high-end workstation but a single-board computer with a stripped-down Linux distro for experimenters. You may be disappointed if you are pushing the limits of computational endeavour, but the majority of users will not be taxing Raspbian on the 4 GB model even if they install Chromium and open up all their favourite bloated social media sites. Perhaps we’ve become conditioned by the excessive demands of Windows on an x86 platform and forgotten just how powerful our computers really are. After all, as the apocryphal Bill Gates quote has it, “640k should be enough for anyone“, right?

We can look forward to an 8 GB Pi 4 then at some point in the future. We’d put our money on next year, since 2020 is a leap year and 2020-02-29 will be the Pi’s 2nd 8th birthday, it wouldn’t stretch the imagination to speculate around that date. But don’t bet on it, save your money for buying a 4 GB Pi 4 right now.