Arduino Turned Into Something Kinda Like A Pager

Video may have killed the radio star, but cell phones and smart phones all but killed the pager. They still exist, of course, but only in very niche applications. [João Santos] wanted a pager-like experience for himself, though, so he enlisted an Arduino and got to work. Watch a video of the system working below.

The build uses an Arduino Uno to drive a simple HD44780 LCD display with 16 characters each across two lines of text. It’s hooked up to a Wemos D1, which uses its WiFi connection to get online. To this end, it’s capable of talking to a web application which allows users to enter text messages. It receives these messages, passes them to the Arduino Uno over I2C, and then the Uno shuttles the message to the display. It’s overkill, but [João] just found it quicker to get everything up and running via this route.

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diagram of the radicle node-to-node connectivity

Radicle: An Open-Source, Peer-to-Peer, GitHub Alternative

The actions of certain large social networks have recently highlighted how a small number of people possess significant power over the masses and how this power is sometimes misused. Consequently, there has been a surge in the development of federated (or decentralized) services, such as Mastodon and Matrix.  But what about development? While GitHub and similar services are less likely to be used for political manipulation, they are still centralized services with a common failure point. Radicle is an open-source, peer-to-peer collaboration stack built on top of Git but backed with public key cryptography as a standard and a gossip protocol to ensure widespread data sharing across the network and, thus, some fault tolerance.

Essentially, code and associated documentation are secured cryptographically with an identity. The Git protocol is used for actual data transfer from peer-to-peer, which means that updates are only sent as deltas, not complete copies, maximizing channel bandwidth efficiency. A custom gossip protocol is used for metadata transfer around the network of peers. The projects had a local-first ideology, with users running a full-stack node on their hardware and all features available, even offline, which is great for laptop users who move around locations with sporadic access to the internet.

Judging from their Zulipchat instance, this is a highly active space, so perhaps it is worth diving in and seeing if it floats your boat. Fancy getting onto the Fediverse, but only have a spare MS-DOS machine to try it on? We’ve got it covered. Want to use Git but not online? You need a private Git server. Finally, too much Git? How about Gitless?

Thanks [Anonymous] for the tip! No, that wasn’t lost on us :D

NASA Engineers Poke Voyager 1 And Receive Memory Dump

For months, there has been a rising fear that we may have to say farewell to the Voyager 1 spacecraft after it began to send back garbled data. Now, in a sudden twist, Voyager 1 sent back a read-out of the Flight Data Subsystem (FDS) memory after a “poke” command, which both gives some hope that the spacecraft is in a better condition than feared while also allows engineers to dig through the returned memory read-out for clues. Although this data was not sent in the format that the FDS is supposed to use when it’s working correctly, it’s nevertheless readable.

It was previously suspected that the issue lay with the telemetry modulation unit (TMU), but has since been nailed down to the FDS itself.  This comes after NASA engineers have been updating the firmware on both spacecraft to extend their lifespan, but it’s too early to consider this as a possible reason. Now, as a result of the “poke” instruction – which commands the computer to try different sequences in its firmware in case part of it has been corrupted – engineers can compare it to previous downloads to hopefully figure out the cause behind the FDS problems and a possible solution.

Inspired by this news of the decoded memory download, Nadia Drake – daughter of Frank Drake – wrote about how it affects not only the engineers who have worked on the Voyager mission for the past decades but also her own thoughts about the two Voyager spacecraft. Not only do they form a lasting reminder of her father and so many of his colleagues, but the silence that would follow if we can no longer communicate with these spacecraft would be profound. Still, this new hope is better than the earlier news about this plucky little spaceship.

Thanks to [Mark Stevens] for the tip.

A Simple Seismometer You Can Build Yourself

If you’re a child, there are certain things you’re taught even though they’re probably not directly relevant to your life. We teach young kids all about dinosaurs, and we teach older kids all about how the mitochondria is the powerhouse of the cell. We also teach kids about natural phenomena like earthquakes, and the equipment used to measure them. Namely, seismometers. You might like to satisfy your own child-like curiosity by building one of your own, like [mircemk] did.

Output from the build showing tremors in the Earth.

The build starts with a sensitive geophone of [mircemk’s] own design. That’s basically a microphone but it’s for picking up vibrations in the ground, not in the air. However, a geophone is not enough. You need to be able to pick up the signals from the geophone and then plot them if you want a seismometer.

First, the signals from the geophone must be amplified, which is achieved with a small circuit based around the LM358 op-amp. From there, the signal is sent to an Arduino where the output is captured via the analog-to-digital converter. This passes the signal to an attached PC which plots the results using a piece of software called NERdaq, which was developed for schools that built their own slinky-based seismometers.

[mircemk] reports that this setup has served as a reliable tool for visualizing earthquake activity for over 6 years. Though, it bears noting, it’s not calibrated so don’t expect to get science grade results out of it. Regardless, though, it’s a super cool way to understand more about what is going on with the geology around us. Video after the break.

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A SPIF-fy Way Of Forming Metal

Thanks to 3D printing, most of us are familiar with the concept of additive manufacturing, and by extension, subtractive manufacturing. But what is it when you’re neither adding material nor taking it away to create something? Generally speaking, that’s called forming, and while there are tons of ways to do it, one you might not have heard of is single-point incremental forming (SPIF), and it’s pretty cool.

To explore SPIF as a method for making small parts, [Russell Makes] gave it a go on a small CNC mill. The idea is pretty simple, and the video below makes it pretty clear what’s going on. A forming tool is moved over a sheet metal blank that’s held very securely to the mill’s table. The tool has no cutting edges, just a smooth, hard, spherical tip — [Russell] made his own by brazing a carbide ball to a piece of drill rod. The tool is driven slightly into the blank along the Z-axis, while simultaneously tracing out a tool path in the XY plane. The tool spins, but very slowly; ideally, the spindle speed is controlled to keep a single point of contact with the metal as the tool works around its tool path. The tool steps downward incrementally, drawing the metal down with it as it forms the desired shape.

[Russell]’s experiments were pretty promising. He started with titanium sheet, which behaved pretty well except for some galling thanks to lack of lubrication. Aluminum and stainless worked pretty well too, at least for simple hemispherical and cone shapes. More complex shapes proved trickier, but with time he was able to figure out the correct speeds and feeds to keep the metal intact. The amount of tension built up in the metal is impressive, though, and is especially evident when cutting the finished part free from the blank.

Could this work with a hobbyist-grade machine? Possibly, but we’d be afraid that the forces involved might be a bit much for light-duty machines, especially in the Z-axis. And it’s a slow process, so it’s probably only good for one-offs and low-volume work. Once you’ve got a prototype, die stamping might be a more efficient way to go.

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Cheap DIY Microscope Lamp Makes Tiny Macro Shots Look Great

For optical microscopes, light is everything. If you don’t have a good amount of light passing through or bouncing off your sample, you’ve got nothing for your eyeballs or a camera to pick up. To aid in this regard, [Halogenek] whipped up a nifty microscope lamp with some LEDs.

The build uses a neat arch-shaped PCB with a hole in the middle for the microscope’s optics to pass through. Surrounding this are the LEDs, which provide a circle of light focused on the sample, akin to the ring lights so favored by today’s online influencers. The LEDs are powered via USB C, so the lamp can be run off of any garden-variety phone charger you might have lying around.

[Halogenek] reports that the lamp has proven useful for extreme macro shots of PCBs. It’s an easy build to replicate or redesign your own way if you’re doing similar work.

Microscopes are super useful, and there are all kinds of hacks you can do to make them perform better in your quest for science. Meanwhile, if you’ve been jazzing up your own lab hardware, let us know—we’d love to hear about it!