Can You Really Use The Raspberry Pi 4 As A Desktop Machine?

September 9, 2019 by Jonathan Bennett 90 Comments

When the Raspberry Pi 4 was released, many looked at the dual micro HDMI ports with disdain. Why would an SBC like the Raspberry Pi need two HDMI ports? The answer was that the Pi 4 is finally fast enough to work as a desktop replacement, and the killer feature (for many of us) for a desktop is multiple monitors.

Now I know what many of you are thinking. There’s no way a $35, or even $55, credit-card-sized computer can replace a $1000+ desktop machine, right? Right? Of course not, but at the same time, yes, yes it can. So I tried to use the Pi as a desktop replacement for a week, and it worked. In fact, this article has been written almost entirely on the Pi 4 with 4 GB of memory, as well as a couple of my recent security columns. I could definitely continue working with the Pi as my daily driver for that purpose.

There are a few points of order to cover first. Initial reviews were based on the June 20th release of Raspbian, which in turn was based on the pre-release Debian Buster. Since then, Buster has released. Fixes that were queued up have landed now that the release freeze has ended. A new Raspbian image was released on July 10, and many of the initial release issues have been fixed.
Continue reading “Can You Really Use The Raspberry Pi 4 As A Desktop Machine?” →

Sensor Filters For Coders

September 6, 2019 by Pat Whetman 35 Comments

Anybody interested in building their own robot, sending spacecraft to the moon, or launching inter-continental ballistic missiles should have at least some basic filter options in their toolkit, otherwise the robot will likely wobble about erratically and the missile will miss it’s target.

What is a filter anyway? In practical terms, the filter should smooth out erratic sensor data with as little time lag, or ‘error lag’ as possible. In the case of the missile, it could travel nice and smoothly through the air, but miss it’s target because the positional data is getting processed ‘too late’. The simplest filter, that many of us will have already used, is to pause our code, take about 10 quick readings from our sensor and then calculate the mean by dividing by 10. Incredibly simple and effective as long as our machine or process is not time sensitive – perfect for a weather station temperature sensor, although wind direction is slightly more complicated. A wind vane is actually an example of a good sensor giving ‘noisy’ readings: not that the sensor itself is noisy, but that wind is inherently gusty and is constantly changing direction.

It’s a really good idea to try and model our data on some kind of computer running software that will print out graphs – I chose the Raspberry Pi and installed Jupyter Notebook running Python 3.

The photo on the left shows my test rig. There’s a PT100 probe with it’s MAX31865 break-out board, a Dallas DS18B20 and a DHT22. The shield on the Pi is a GPS shield which is currently not used. If you don’t want the hassle of setting up these probes there’s a Jupyter Notebook file that can also use the internal temp sensor in the Raspberry Pi. It’s incredibly quick and easy to get up and running.

It’s quite interesting to see the performance of the different sensors, but I quickly ended up completely mangling the data from the DS18B20 by artificially adding randomly generated noise and some very nasty data spikes to really punish the filters as much as possible. Getting the temperature data to change rapidly was effected by putting a small piece of frozen Bockwurst on top of the DS18B20 and then removing it again.

Continue reading “Sensor Filters For Coders” →

Hackaday Celebrates 15 Years And Oh How The Hardware Has Changed

September 5, 2019 by Mike Szczys 56 Comments

Today marks exactly 15 years since Hackaday began featuring one Hack a Day, and we’ve haven’t missed a day since. Over 5,477 days we’ve published 34,057 articles, and the Hackaday community has logged 903,114 comments. It’s an amazing body of work from our writers and editors, a humbling level of involvement from our readers, and an absolutely incredible contribution to open hardware by the project creators who have shared details of their work and given us all something to talk about and to strive for.

What began as a blog is now a global virtual hackerspace. That first 105-word article has grown far beyond project features to include spectacular long-form original content. From our community of readers has grown Hackaday.io, launched in 2014 you’ll now find over 30,000 projects published by 350,000 members. The same year the Hackaday Prize was founded as a global engineering initiative seeking to promote open hardware, offering big prizes for big ideas (and the willingness to share them). Our virtual connections were also given the chance to come alive through the Hackaday Superconference, Hackaday Belgrade, numerous Hackaday Unconferences, and meetups all over the world.

All of this melts together into a huge support structure for anyone who wants to float an interesting idea with a proof of concept where “why” is the wrong question. Together we challenge the limits of what things are meant to do, and collectively we filter through the best ideas and hold them high as building blocks for the next iteration. The Hackaday community is the common link in the collective brain, a validation point for perpetuating great ideas of old, and cataloging the ones of new.

Perhaps the most impressive thing about the last 15 years of Hackaday is how much the technological landscape has changed. Hackaday is still around because all of us have actively changed along with it — always looking for that cutting edge where the clever misuse of something becomes the base for the next transformative change. So we thought we’d take a look back 15 years in tech. Let’s dig into a time when there were no modules for electronics, you couldn’t just whip up a plastic part in an afternoon, designing your own silicon was unheard of, and your parts distributor was the horde of broken electronics in your back room.

Continue reading “Hackaday Celebrates 15 Years And Oh How The Hardware Has Changed” →

3D Printing May Be The Key To Practical Scramjets

September 3, 2019 by Tom Nardi 32 Comments

The first scramjet, an airbreathing jet engine capable of pushing an aircraft beyond Mach 5, was successfully flown in the early 1990s. But while pretty much any other technology you could imagine has progressed by leaps and bounds in the nearly 30 years that have passed, the state-of-the-art in hypersonic scramjets hasn’t moved much. We still don’t have practical hypersonic aircraft, military or otherwise, and any missiles that travel at those sort of speeds are rocket powered.

This is somewhat surprising since, at least on paper, the operating principle of the scramjet is simplicity itself. Air rushing into the engine is compressed by the geometry of the inlet, fuel is added, the mixture is ignited, and the resulting flow of expanded gases leaves the engine faster than it entered. There aren’t even any moving parts inside of a scramjet, it’s little more than a carefully shaped tube with fuel injectors and ignitors in it.

Unfortunately, pulling it off in practice is quite a bit harder. Part of the problem is that a scramjet doesn’t actually start working until the air entering the engine’s inlet is moving at around Mach 4, which makes testing them difficult and expensive. It’s possible to do it in a specially designed wind tunnel, but practically speaking, it ends up being easier to mount the engine to the front of a conventional rocket and get it up to speed that way. The downside is that such flights are one-way tickets, and end with the test article crashing into the ocean once it runs out of fuel.

But the bigger problem is that the core concept is deceptively simple. It’s easy to say you’ll just squirt some jet fuel into the stream of compressed air and light it up, but when that air is moving at thousands of miles per hour, keeping it burning is no small feat. Because of this, the operation of a scramjet has often been likened to trying to light a match in a hurricane; the challenge isn’t in the task, but in the environment you’re trying to perform it in.

Now, both Aerojet Rocketdyne and Northrop Grumman think they may have found the solution: additive manufacturing. By 3D printing their scramjet engines, they can not only iterate through design revisions faster, but produce them far cheaper than they’ve been able to in the past. Even more importantly, it enables complex internal engine geometries that would have been more difficult to produce via traditional manufacturing.

Continue reading “3D Printing May Be The Key To Practical Scramjets” →

CCCamp: 5,000 Hackers Out Standing In Their Field

August 30, 2019 by Elliot Williams 12 Comments

What do hackers do on vacation? What do hackers do whenever they have free time? What do you love to do? That’s right. But how much more fun would it be if you could get together with 5,000 other hackers, share your crazy projects and ideas, eat, drink, dance, swim, and camp out all together for five days, naturally with power and Internet? That’s the idea of the Chaos Communication Camp, and it’s a once-in-four-years highlight of hacker life.

Held not too far outside of Berlin, the Camp draws heavily on hackers from Europe and the UK, but American hackers have been part of the scene since almost the beginning. (And Camp played an important role in the new-wave hackerspaces in the US, but that’s another story.) It’s one thing to meet up with the folks in your local hackerspace and work together on a project or brainstorm the next one, but it’s entirely a different thing when you’re drawing on hackers from all over the world. There was certainly more to see and do at Camp than you could in a month, not to mention in only five days, and this could be overwhelming. But if you dig in, the sense of community that came from shared effort and shared interests was the real take-home. And nearly everything at Camp should have its own article on Hackaday.

Continue reading “CCCamp: 5,000 Hackers Out Standing In Their Field” →

Kilopower: NASA’s Offworld Nuclear Reactor

August 28, 2019 by Tom Nardi 107 Comments

Here on Earth, the ability to generate electricity is something we take for granted. We can count on the sun to illuminate solar panels, and the movement of air and water to spin turbines. Fossil fuels, for all their downsides, have provided cheap and reliable power for centuries. No matter where you may find yourself on this planet, there’s a way to convert its many natural resources into electrical power.

But what happens when humans first land on Mars, a world that doesn’t offer these incredible gifts? Solar panels will work for a time, but the sunlight that reaches the surface is only a fraction of what the Earth receives, and the constant accumulation of dust makes them a liability. In the wispy atmosphere, the only time the wind could potentially be harnessed would be during one of the planet’s intense storms. Put simply, Mars can’t provide the energy required for a human settlement of any appreciable size.

The situation on the Moon isn’t much better. Sunlight during the lunar day is just as plentiful as it is on Earth, but night on the Moon stretches for two dark and cold weeks. An outpost at the Moon’s South Pole would receive more light than if it were built in the equatorial areas explored during the Apollo missions, but some periods of darkness are unavoidable. With the lunar surface temperature plummeting to -173 °C (-280 °F) when the Sun goes down, a constant supply of energy is an absolute necessity for long-duration human missions to the Moon.

Since 2015, NASA and the United States Department of Energy have been working on the Kilopower project, which aims to develop a small, lightweight, and extremely reliable nuclear reactor that they believe will fulfill this critical role in future off-world exploration. Following a series of highly successful test runs on the prototype hardware in 2017 and 2018, the team believes the miniaturized power plant could be ready for a test flight as early as 2022. Once fully operational, this nearly complete re-imagining of the classic thermal reactor could usher in a whole new era of space exploration.

Continue reading “Kilopower: NASA’s Offworld Nuclear Reactor” →

The Satellite Phone You Already Own: From Orbit, UbiquitiLink Will Look Like A Cell Tower

August 26, 2019 by Dan Maloney 54 Comments

For anyone that’s ever been broken down along a remote stretch of highway and desperately searched for a cell signal, knowing that a constellation of communications satellites is zipping by overhead is cold comfort indeed. One needs specialized gear to tap into the satphone network, few of us can justify the expense of satellite phone service, and fewer still care to carry around a brick with a chunky antenna on it as our main phone.

But what if a regular phone could somehow leverage those satellites to make a call or send a text from a dead zone? As it turns out, it just might be possible to do exactly that, and a Virginia-based startup called UbiquitiLink is in the process of filling in all the gaps in cell phone coverage by orbiting a constellation of satellites that will act as cell towers of last resort. And the best part is that it’ll work with a regular cell phone — no brick needed.

Continue reading “The Satellite Phone You Already Own: From Orbit, UbiquitiLink Will Look Like A Cell Tower” →