Using PoE With A Raspberry Pi 3 For About Two Bucks

September 30, 2019 by Maya Posch 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 Bryan Cockfield 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 Maya Posch 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 Dan Maloney 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” →

Wall-Mounted Ground Station Tames Unruly SatNOGS Node

September 12, 2019 by Dan Maloney 8 Comments

For many of us, ad hoc projects end up having a certain permanence to them. Think of the number of Raspberry Pis and RTL-SDRs that are just dangling from a USB cable under a desk or stuffed behind a monitor, quietly going about their business. If it ain’t broke, don’t fix it.

Some projects, though, just end up accreting past the acceptable point. This wall-mounted SatNOGS ground station is a great example of what happens when something needs to be done about the mess. The pile of stuff that [cshields] had cobbled together over time for his ground station needed tidying, so he laid hands on a new Pi 4 and a cool enclosure/breadboard called a Stegoboard. This is just a piece of acrylic with a variety of holes laid out to match every imaginable PC board, hard drive, PC motherboard, Arduino, and just about anything out there that needs mounting. To contain the mess, he mounted the Pi and a 7″ touchscreen to the Stegoboard, along with an RTL-SDR and an Arduino to control his antenna rotator. The ground station wiring is still a little rough, but worlds better than what it was, and now that it’s mounted on the wall it’ll be much easier to use.

For those not familiar with SatNOGS, check out our article back from when the Satellite Network of Ground Stations won the 2014 Hackaday Prize. In the half-decade since then, SatNOGS has only grown, with a huge following of dedicated enthusiasts pointing their antennas at the sky. We know how to pick ’em, and we’ll be selecting the 2019 Hackaday Prize winner very soon.

Thanks to [elkos] for the tip.

Warwalking For Radiation

September 10, 2019 by Elliot Williams 24 Comments

Can’t find a recently updated survey of radioactivity in your neighborhood? Try [Hunter Long]’s DIY scintillation counter warwalking rig. (Video also embedded below.) What looks like a paint can with a BNC cable leading to an unassuming grey box is actually a complete kit for radiation surveying.

Inside the metal paint can is a scintillation counter, which works by attaching something that produces light when struck by ionizing radiation on the end of a photomultiplier tube, to make even the faintest hits “visible”. And the BNC cable leads to a Raspberry Pi, touch screen, GPS, and the high-voltage converters needed to make the photomultiplier do its thing.

The result is a sensitive radiation detector that logs GPS coordinates and counts per second as [Hunter] takes it out for a stroll. Spoilers: he discovers that some local blacktop is a little bit radioactive, and even finds a real “hot spot”. Who knows what else is out there? With a rig like this, making a radiation map of your local environment is a literal walk in the park.

[Hunter] got his inspiration for the paint-can detector from this old build by [David Prutchi], which used a civil-defense Geiger counter as its source of high voltage. If you don’t have a CD Geiger detector lying around, [Alex Lungu]’s entry into the Hackaday Prize builds a scintillation detector from scratch.
Continue reading “Warwalking For Radiation” →

Machine Learning With Microcontrollers Hack Chat

September 9, 2019 by Dan Maloney 4 Comments

Join us on Wednesday, September 11 at noon Pacific for the Machine Learning with Microcontrollers Hack Chat with Limor “Ladyada” Fried and Phillip Torrone from Adafruit!

We’ve gotten to the point where a $35 Raspberry Pi can be a reasonable alternative to a traditional desktop or laptop, and microcontrollers in the Arduino ecosystem are getting powerful enough to handle some remarkably demanding computational jobs. But there’s still one area where microcontrollers seem to be lagging a bit: machine learning. Sure, there are purpose-built edge-computing SBCs, but wouldn’t it be great to be able to run AI models on versatile and ubiquitous MCUs that you can pick up for a couple of bucks?

We’re moving in that direction, and our friends at Adafruit Industries want to stop by the Hack Chat and tell us all about what they’re working on. In addition to Ladyada and PT, we’ll be joined by Meghna Natraj, Daniel Situnayake, and Pete Warden, all from the Google TensorFlow team. If you’ve got any interest in edge computing on small form-factor computers, you won’t want to miss this chat. Join us, ask your questions about TensorFlow Lite and TensorFlow Lite for Microcontrollers, and see what’s possible in machine learning way out on the edge.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, September 11 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.