raspberry pi

1657 Articles

Weather Alert Lamp Keeps An Eye On What’s Brewing

October 2, 2019 by 2 Comments

Whether you’re getting ready for work in the morning, or heading out on a camping trip in the woods, it’s nice to know what to expect when the weather rolls over the horizon. To keep abreast of things, [natethecoder] built a lamp system to stay across weather alerts.

A Raspberry Pi 3 acts as the heart of the system, with Node Red responsible for running the show. Querying the web every 5 minutes for updated weather data, it keeps track of weather alerts, as well as incoming snowfall. For a basic weather watch, a yellow lamp is lit, while there’s a red lamp for more serious warnings. A Christmas decoration serves as the indicator for snow. The lamps are all controlled by mains-rated solid state relays, making it easy to swap out the lamps for other devices if so desired down the track. There’s also a lamp test subroutine that fires on startup to ensure everything is working correctly.

It’s a handy way to get your weather info at a glance, and would prove useful to anyone living in a storm-prone area. For something more portable, consider this umbrella that tells you the weather.

A Web API For Your Pi

October 1, 2019 by 29 Comments

There are many ways to attach a project to the Internet, and a plethora of Internet-based services that can handle talking to hardware. But probably the most ubiquitous of Internet protocols for the average Joe or Jane is the web browser, and one of the most accessible of programming environments lies within it. If only somebody with a bit of HTML and Javascript could reach a GPIO pin on their Raspberry Pi!

If that’s your wish, then help could be at hand in the form of [Victor Ribeiro]’s RPiAPI. As its name suggests, it’s an API for your Raspberry Pi, and in particular it provides a simple web-accessible endpoint wrapper for the Pi’s GPIO library from which its expansion port pins can be accessed. By crafting a simple path on the address of the Pi’s web server each pin can be read or written to, which while it’s neither the fastest or most accomplished hardware interface for the platform, could make it one of the easiest to access.

Security comes courtesy of Apache password protected directories via .htaccess files, so users would be well-advised to consider the implications of connecting this to a public IP address very carefully. But for non experts in security it still has the potential to make a very useful tool in the armoury of ways to control hardware from the little single board computer. It’s not the first try at this idea as we’ve seen a PHP example early in the Pi’s lifetime as well as one relying upon MySQL, but it does seem to be a simpler option than the others.

Meet MutantC: Raspberry Pi Sidekick Complete With Sliding Screen, QWERTY

September 30, 2019 by 29 Comments

Over the years we’ve seen the Raspberry Pi crammed into almost any piece of hardware you can think of. Frankly, seeing what kind of unusual consumer gadget you can shoehorn a Pi into has become something of a meme in our circles. But the thing we see considerably less of are custom designed practical enclosures which actually play to the Pi’s strengths. Which is a shame, because as the MutantC created by [rahmanshaber] shows, there’s some incredible untapped potential there.

The MutantC features a QWERTY keyboard and sliding display, and seems more than a little inspired by early smartphone designs. You know, how they were before Apple came in and managed to convince every other manufacturer that there was no future for mobile devices with hardware keyboards. Unfortunately, hacking sessions will need to remain tethered as there’s currently no battery in the device. Though this is something [rahmanshaber] says he’s actively working on.

The custom PCB in the MutantC will work with either the Pi Zero or the full size variant, but [rahmanshaber] warns that the latest and greatest Pi 4 isn’t supported due to concerns about overheating. Beyond the Pi the parts list is pretty short, and mainly boils down to the 3D printed enclosure and the components required for the QWERTY board: 43 tactile switches and a SparkFun Pro Micro. Everything is open source, so you can have your own boards run off, print your case, and you’ll be well on the way to reliving those two-way pager glory days.

We’re excited to see where such a well documented open source project like MutantC goes from here. While the lack of an internal battery might be a show stopper for some applications, we think the overall form factor here is fantastic. Combined with the knowledge [Brian Benchoff] collected in his quest to perfect the small-scale keyboard, you’d have something very close to the mythical mobile Linux device that hackers have been dreaming of.

Continue reading “Meet MutantC: Raspberry Pi Sidekick Complete With Sliding Screen, QWERTY” →

Using PoE With A Raspberry Pi 3 For About Two Bucks

September 30, 2019 by 33 Comments

When the Raspberry Pi 3 Model B+ was announced in March of 2018, one of its new features was the ability to be (more easily) powered via Power-over-Ethernet (PoE), with an official PoE HAT for the low price of just twenty-one USA bucks. The thing also almost worked as intended the first time around. But to some people this just isn’t good enough, resulting in [Albert David] putting out a solution he calls “poor man’s PoE” together for about two bucks.

His solution makes it extra cheap by using so-called passive PoE, which injects a voltage onto the conductors of the network cable being used for PoE, without bothering with any kind of handshake. In general this is considered to be a very reliable (albeit non-standard) form of PoE that works great until something goes up in smoke. It’s also ridiculously cheap, with a PoE injector adapter (RJ-45 plug & 2.1×5.5 mm power jack to RJ-45 jack) going for about 80 cents, and a DC-DC buck converter that can handle the input of 12V for about 50 cents.

The rest of the $2 budget is mostly spent on wiring and heatshrink, resulting in a very compact PoE solution that plugs straight into the PoE header on the Raspberry Pi 3 board, with the buck converter outputs going into the ground and +5V pins on the Raspberry Pi’s GPIO header.

A fancier solution would implement any of the standard PoE protocols to do the work of negotiating a suitable voltage. Maybe this could be the high-tech, $5 solution featuring an MCU and a small PCB?

Maps To SMS, When You’re Really Far Away

September 28, 2019 by 32 Comments

GPS is available on most smart phones, which is all well and good unless you drive out into a place with weak service. Unless you want to go into the before-time and buy a standalone GPS (and try to update the maps every so often) or go even further back and print out MapQuest directions, you’ll need another solution to get directions. Something like this project which sends Google Maps directions over SMS.

The project is called RouteMe by [AhadCove]. It runs on a Raspberry Pi at his home which is constantly monitoring an email inbox. Using Google Voice to forward incoming text messages as emails to the Pi, the system works when your phone has a cell signal but no data connection. The Pi listens for specific commands in that SMS-to-Email connection and is able to send directions back to the phone via text message. That’s actually a neat hack you may remember from the olden days where you can send email as SMS using the phone number as the address.

If you find yourself lost in the woods with just your phone often enough, [AhadCove] has all of the code and detailed directions on how to set this up on his GitHub site. But don’t discount this particular task, anything you can script on the Pi can now be controlled via SMS without relying on a service like Twilio.

This maps hack is a pretty ingenious solution to a problem that more than a few of us have had, and it uses a lot of currently-available infrastructure to run as well. If you want another way of navigating without modern tech, have a go at dead reckoning in a car.

WiringPi Library To Be Deprecated

September 18, 2019 by 60 Comments

Since the release of the original Raspberry Pi single board computer, the WiringPi library by [Gordon] has been the easy way to interface with the GPIO and peripherals – such as I2C and SPI – on the Broadcom SoCs which power these platforms. Unfortunately, [Gordon] is now deprecating the library, choosing to move on rather than deal with a community which he no longer recognizes.

Among the points which he lists are the (commercial) abuse of his code, and the increasing amount of emails and messages on social media from folk who either failed to read the friendly manual, or are simply rude and inconsiderate. As [Gordon] puts it, WiringPi was never meant to be statically linked into code, nor to be used with anything other than C and RTB BASIC programmers. He never supported the use of the library with other languages, or having it statically integrated into some Java/JavaScript/NodeJS project.

As this secondary use is what’s draining the fun out of the project, he has decided to put out one final release, before making it a closed-source project, for use by himself and presumably paying clients. What the impact of this will be has to be seen. Perhaps a new fork will become the new ‘WiringPi’?

Suffice it to say, none of this is a good thing. The illegal use of open source code and the support nightmare that gets poured on the authors of said code by less than informed users is enough to drive anyone away from putting their projects out there. Fighting abuse and junking the ‘spam’ is one way to deal with it, but who has the time and energy (and money) for this?

What are your thoughts on this news, and this issue in general? How should an open source developer deal with it?

Thanks to [Dirk-Jan Faber] for sending this one in.

Keeping Clocks On Time, The Swiss Way

September 17, 2019 by 31 Comments

Could there be a worse fate for a guy with a Swiss accent than to be subjected to a clock that’s seconds or even – horrors! – minutes off the correct time? Indeed not, which is why [The Guy With the Swiss Accent] went to great lengths to keep his IKEA radio-controlled clock on track.

For those who haven’t seen any of [Andreas Spiess]’ YouTube videos, you’ll know that he pokes a bit of fun at Swiss stereotypes such as precision and punctuality. But really, having a clock that’s supposed to synchronize to one of the many longwave radio atomic clocks sprinkled around the globe and yet fails to do so is irksome to even the least chrono-obsessive personality. His IKEA clock is supposed to read signals from station DCF77 in Germany, but even the sensitive receivers in such clocks can be defeated by subterranean locales such as [Andreas]’ shop. His solution was to provide a local version of DCF77 using a Raspberry Pi and code that sends modulated time signals to a GPIO pin. The pin is connected to a ferrite rod antenna, which of course means that the Pi is being turned into a radio transmitter and hence is probably violating the law. But as [Andreas] points out, if the power is kept low enough, the emissions will only ever be received by nearby clocks.

With his clock now safely synced to an NTP server via the tiny radio station, [Andreas] can get back to work on his other projects, such as work-hardening copper wire for antennas with a Harley, or a nuclear apocalypse-Tweeting Geiger counter.

Continue reading “Keeping Clocks On Time, The Swiss Way” →