You’ve Got Mail: Grilled, Scrambled, And Other Delicious Stamps

October 19, 2023 by Kristina Panos 8 Comments

Well, we’re just zipping right through this series, no? So far we’ve looked at various postal machines and how they work to flip mail around, cancel the postage, and sort it, all in a matter of seconds. We explored the first automated post office and found out why it was a failure, and we learned why it all depends on ZIP code. Now, it’s finally time for some really fun stuff: the stamp trivia.

Now I’m no philatelist by any standard, though I do have a few hundred stamps strewn about the house. The danger in philately is that you learn all sorts of cool things about stamps and their history, and you just want to buy more and more of them. So let’s go!

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2023 Hackaday Supercon Badge: Welcome To The Vectorscope

October 18, 2023 by Elliot Williams 48 Comments

This year, the Supercon badge goes analog! (Or at least fakes it pretty convincingly.) Taking inspiration from the phosphor scopes of yesteryear, the 2023 Vectorscope badge is part analog audio playground, part art project, and all about prototyping. Who doesn’t like the warm glow and lovely green fade of an old Tektronix tube scope? That’s what we’re after.

Conceptually, the badge is two separate devices in one. Most obvious is the vectorscope, which takes in voltages in the 0 V – 3 V range and plots them out in X-Y mode in glorious fake-phosphor effect on the lovely round IPS screen. We’ve also tied an audio amplifier to the Y input that plays whatever waveform you’re watching.

But you don’t have to bring your own waveforms with you – the other half of the badge is an arbitrary programmable waveform generator that drives two channels. Off the bat, it’s configurable with the front panel controls, so you’re obviously invited to make Lissajous figures and store them in the program memories.

Combining the two halves lets you draw in voltages and time, but not until you connect them together, naturally. You see, this isn’t an analog simulation – it’s the programmable equivalent of the real deal, courtesy of the AK4619 ADC/DAC. Voltages go out on one set of pins and come back in on the other.

And you get to play around with these voltages in through-hole space too, because we’ve included a very generous prototyping board for your analog explorations. Does this instantly suggest a curve tracer to you? Be our guest! Other forms of analog video-mangling? We want to see what you come up with. Make an audio filter and watch it work on the screen in front of your very eyes.

Of course we’re not leaving you code monkeys out in the cold. MicroPython puts the “programming” in the programmable waveform generator. If you’re not content with the four stock waveforms, you’re invited to write your own. And this is where it gets artsy.

You can upload your own repetitive waveforms to the onboard direct digital synth routine, but why stop there? We’ve left most of the processing power of the underlying RP2040 untouched, for you to use. And four buttons on the front panel let you store and play back your code, so you have space to stash your demos, and a sweet joystick with a custom keycap gives you control.

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The Pros And Cons Of Hydrofoils

October 17, 2023 by Lewin Day 25 Comments

Hydrofoils have fascinated naval architects and marine designers for years. Fitted with underwater wings, these designs traverse the waters at great speed with a minimum of drag. As with many innovative technologies, though, the use of hydrofoils is riddled with challenges that often offset the vast benefits they offer.

While hydrofoils promise a better marine transportation experience, their adoption hasn’t been smooth sailing. In this article, we’ll dive deep into the potential and pitfalls of hydrofoil designs, and look at the unique niches this technology serves today.

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Why The RP1 Is The Most Important Product Raspberry Pi Have Ever Made

October 16, 2023 by Jenny List 92 Comments

We’ve had about a week to digest the pending arrival of the Raspberry Pi 5, and it’s safe to say that the new board from Cambridge has produced quite some excitement with its enhanced specifications and a few new capabilities not seen in its predecessors. When it goes on general sale we expect that it will power a slew of impressive projects in these pages, and we look forward with keen anticipation to its companion Compute Module 5, and we sincerely hope eventually a Raspberry Pi 500 all-in-one. It’s the latest in a line of incrementally-upgraded single board computers from the company, but we think it conceals something of much greater importance than the improvements that marked previous generations. Where do we think the secret sauce lies in the Pi 5? In the RP1 all-in-one PCIe peripheral chip of course, the chip which provides most of the interfacing on the new board. Continue reading “Why The RP1 Is The Most Important Product Raspberry Pi Have Ever Made” →

USB-C For Hackers: Build Your Own PSU

October 12, 2023 by Arya Voronova 43 Comments

What if you wanted to build your own USB-C PSU? Good news – it’s easy enough! If you ever wanted to retrofit a decent DC PSU of yours to the USB-C standard, say, you got a Lenovo/HP/Dell 19V-20V charger brick and you’ve ever wished it were USB-C, today is the day when we do exactly that. To be fair, we will cheat a bit – but only a tiny bit, we won’t be deviating too much from the specification! And, to begin with, I’ll show you some exceptionally easy ways that you can turn your DC PSU into a USB-C compatible one, with a simple module or a few.

Turning a 20 V PSU into a USB-C PSU feels natural if you want to charge a laptop – those tend to request 20 V from a USB-C PSU anyway, so what’s the big deal? However, you can’t just put 20 V onto a USB-C connector – you have to add a fair bit of extra logic to make your newly christened USB-C PSU safe to use with 5 V devices, and this logic also requires you go through a few extra steps before 20 V appears on VBUS. Any USB-C PSU has to output 5 V first and foremost whenever a device is connected, up until a higher voltage is negotiated digitally, and the PSU may only switch to a higher voltage output when it’s requested to do so.

Now, for that, a PSU offers a list of profiles, and we looked into those profiles in the Replying PD article – each profile is four bytes that contain information about the profile voltage, maximum current that the device may draw at that voltage, and a few other details. For a PSU to be USB-C compliant, the USB-C specification says that, in addition to 5 V, you may also offer 9 V, 15 V, and 20 V.

Also, the specification says that if a PSU supports certain in-spec voltage like 15 V, it’s also required by the spec to offer all of the spec-defined voltages below the maximum one – for 15 V, that also requires supporting 9 V. Both of these are UX requirements, as opposed to technical requirements – it’s easier for device and PSU manufacturers to work with a small set of pre-defined voltages that majority of the chargers will support, but in reality, you can actually offer any voltage you want in the PSU advertisement; at worst, a device is going to refuse and contend with slowly charging from the 5 V output that you’re required to produce.

I’d like to walk you through how off-the-shelf USB-C PSUs work, all of the options you can use to to create one, and then, let’s build our own USB-C PSU from scratch! Continue reading “USB-C For Hackers: Build Your Own PSU” →

You’ve Got Mail: It All Depends On ZIP Code

October 12, 2023 by Kristina Panos 26 Comments

Previously on You’ve Got Mail, we looked at a few services that were designed to speed up the mail at various points along the way. But these improvements were all taking place on the USPS’ side of the the fence. Was there anything the customer could be doing to help out?

As it turns out, yes. And it was almost too late. Whereas you could once address a letter or postcard simply to “Fred Minke, Somerset, Wis.” and it would reach him, the volume of mail was getting completely out of hand with the rise of computers, automated billing, and advertising. Something was needed to improve routing and speed up delivery.

We all know enough about ZIP codes to use them, but where did they come from? How many types are out there? What do they even mean? Let’s find out.

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Meshtastic And Owntracks To Kick Your Google Habit

October 11, 2023 by Jonathan Bennett 21 Comments

I have an admission to make. I have a Google addiction. Not the normal addiction — I have a problem with Google Maps, and the timeline feature. I know, I’m giving my location data to Google, who does who-knows-what-all with it. But it’s convenient to have an easy way to share location with my wife, and very useful to track my business related travel for each month. What we could really use is a self-hosted, open source system to track locations and display location history. And for bonus points, let’s include some extra features, like the ability to track vehicles, kids, and pets that aren’t carrying a dedicated Internet connection.

You can read the title — you know where we’re going with this. We’re setting up an Owntracks service, and then tying it to Meshtastic for off-Internet usability. The backbone that makes this work is MQTT, a network message bus that has really found its niche in the Home Assistant project among others. It’s a simple protocol, where clients send brief messages labeled by topic, and can also subscribe to specific topics. For this little endeavor we’ll use the Mosquito MQTT broker.

One of the nice things about MQTT is that the messages are all text strings, and often take the form of JSON. When trying to get two applications to talking using a shared MQTT server, there may need to be a bit of translation. One application may label a field latitude, and the other shortens it to lat. The glue code to put these together is often known as an MQTT translator, or sometimes an MQTT bridge. This is a program that listens to a given topic, ingests each message, and sends it back to the MQTT server in a different format and topic name.

The last piece is Owntracks, which has a recorder project, which pulls locations from the MQTT server, and stores it locally. Then there’s Owntracks Frontend, which is a much nicer user interface, with some nice features like viewing movement a day at a time. Continue reading “Meshtastic And Owntracks To Kick Your Google Habit” →