Keeping Streets Ice-Free With The Raspberry Pi

April 17, 2018 by Tom Nardi 33 Comments

[Revanth Kailashnath] writes in to tell us about an interesting project he and his team have been working on for their “Real Time Embedded Programming” class at the University of Glasgow. Intended to combat the harsh and dangerous winters in Glasgow, their system uses a Raspberry Pi and a suite of sensors to automatically deploy a brine solution to streets and sidewalks. While the project is still only a proof of concept and hasn’t been deployed, the work the team has done so far runs the gamut from developing their own PCBs to creating a web-based user interface.

The core idea is simple. If the conditions are right for ice to form, spray salt water. Using salt water is a cheap and safe way of clearing and preventing ice as it simply drops the temperature at which water freezes. The end result is that the ice won’t form until it gets down to 10F (-12C) or so. Not a perfect solution, but it can definitely help. Of course, you don’t want to spray people with salt water as they pass by, so there’s a bit more to it than that.

Using the venerable DHT22 sensor the team can get the current temperature and humidity, which allows them to determine when it’s time to start spraying. But to prevent any wet and angry pedestrians, a HC-SR501 PIR motion sensor is used. If the system sees motion it will stop for a while to let the activity quiet down.

Monitoring the sensors and controlling the pump is done by a daemon written in C++, which also logs data to an SQL database, which in turn feeds their PHP web interface. In the video after the break, [Revanth] demonstrates how the system is constantly making decisions based on the input of the various sensors. Environmental data and motion is analysed every few seconds to provide a real-time solution.

We’ve covered a few projects aimed at melting ice and snow by heating concrete, but it’s interesting to see a “smart” approach to this common winter annoyance.

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Polaroid Gets Thermal Printer And Raspberry Pi

April 16, 2018 by Tom Nardi 15 Comments

Despite what you may have read in the comments, we here at Hackaday are not unaware that there’s something of a “Pi Fatigue” brewing. Similar to how “Arduino” was once a dirty word around these parts, projects that are built around the world’s most popular Linux SBC are occasionally getting dismissed as lazy. Hacker crams Raspberry Pi into an old electronic device, applies hot glue liberally, posts a gallery on Imgur, and boom! Lather, rinse, repeat.

We only mention this because the following project, despite featuring the Raspberry Pi Zero grafted into a vintage Polaroid camera, is anything but lazy. In the impeccably detailed and photographed write-up, [mitxela] explains how the Pi Zero and a thermal camera recreated the classic Polaroid experience of going from shutter button to physical picture in seconds. The workmanship and attention to detail on this build is simply phenomenal, and should quell any doubts our Dear Readers may have about Raspberry Pi projects. For now, anyway.

The video after the break will show you the modded camera in operation and goes over a few highlights of the build, but for this one you really should take the time to read the entire process start to finish. [mitxela] starts off by disassembling the Polaroid camera, complete with plenty of fantastic pictures that show how this legendary piece of consumer electronics was put together. If you’ve never seen the inside of one of these cameras, you might be surprised to see what kind of interesting hardware is lurking underneath that rather unassuming exterior. From the screw-less construction to the circuits with paper substrate, a lot of fascinating engineering went into getting this camera to a mass-market price. Frankly, the teardown alone is worth checking out.

But once the camera has been stripped down to the bare frame, the real fun begins. At the conceptual level, [mitxela] replaces the camera optics with a cheap webcam, the “brains” with a Raspberry Pi Zero, and the film mechanism with the type of thermal printer used for receipts. But how he got it all connected is why this project is so impressive. Nearly every decision made during the design and construction of this camera was for the purposes of reducing boot-time. Nobody wants a camera that takes 30, 15, or even 10 seconds to boot. It has to be available as soon as you need it.

Getting this Linux-powered camera boot up in as little as 2 seconds took a lot of clever software hacks that you’ll absolutely want to check out if you’ve ever considered building an embedded Linux device. You can’t just throw a stock Raspbian image on an SD card and hope for the best. [mitxela] used buildroot to craft a custom Linux image containing only what was needed for the camera to operate, plus a bunch of esoteric tweaks that the Junior Penguin Wrangler would likely never consider. Like shaving a full second off of the boot time by disabling dumping kernel messages to the serial port during startup.

[mitxela] brought his camera to show off at the recent Hackaday London meetup, but it was far from the first time we’ve come across his handiwork. From his servo-powered music box earlier this year to his penchant for tiny MIDI devices, he’s consistently impressed our cold robot hearts.

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Custom Built Vacuum Tube Cassette Player

April 16, 2018 by Tom Nardi 40 Comments

As we’ve said many times here on Hackaday, it’s not our place to question why people make the things they make. There’s a legitimate need or utility for many of the projects we cover, no doubt about it. But there’s also a large number of them which are so convoluted that they border on absurd. Not that we love the crazy ones any less, in fact, we usually like those the best.

So when we saw this incredible modification to a Panasonic RN-404 microcassette recorder which replaces the audio hardware with a custom built vacuum tube amplifier, we didn’t bother asking what the point was. Perhaps it’s an attempt to make the most impractical method for recording and playing back audio, or maybe it was just to see if it was possible. No matter why it was done, it’s here now and it’s absolutely glorious.

If the look of the hardware didn’t tip you off that this project makes use of old Soviet-era components, the video after the break certainly will. Specifically, it’s using 1ZH25R and 1S38A tubes which were originally intended for military use. Just like all cool old Soviet tech was. Say what you will about the Cold War, it certainly got the engineering juices flowing.

There’s quite a bit of information about how these ancient tubes were brought back to life by way of this gorgeous home-etched PCB. Suffice to say, working with tubes is an art to begin with, but working with such small and unique ones is on a whole new level.

This isn’t the first time we’ve seen some tiny tubes make their way into a piece of consumer audio equipment, but this one certainly takes the top spot in terms of professional final results.

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Visualizing Blocked Ads With The Pi Sense Hat

April 14, 2018 by Tom Nardi 13 Comments

Pi-hole is an open source project to turn that Raspberry Pi collecting dust in your drawer into a whole-network ad blocking appliance. Not only does it stop ads from showing up on all your computers and mobile devices, it also keeps track of how many ads have been blocked and where they came from. Just in case you wanted to know how many thousands of ads you missed out on for a given time period.

While the graphs generated in the web interface of Pi-hole are slick and all, what if you just wanted a quick way of visualizing how effective your ad blocking system is? You’re not so much worried about the exact figures, you just want something to blink away on your desk and let you know all those ads are going to /dev/null. Enter the aptly named pi-hole-visualizer by [simianAstronaut].

With the addition of a Sense HAT to the Pi running the ad blocking, this Python script will generate an animated visualization that can be easily interpreted even from a distance. The primary display is a bar graph of DNS traffic, where the height and color of each column indicate relative activity within a specific time interval. A second screen shows a spiral graph which gives you an idea of what percentage of ads were blocked before they hit your devices.

An array of options can be given to the script from the command line; controlling both physical aspects of the display like orientation and LED brightness, as well the configurable parameters for the different available visualizations. As an added bonus, there’s also support for using the Sense HAT joystick to switch between modes interactively.

Turning the Raspberry Pi into an ad blocking appliance goes back to the olden days of the original Raspberry Pi, but it’s interesting to see how advanced the concept has become. Just remember, not all ads are bad.

Portable DVD Player Gets Raspberry Pi Zero Upgrade

April 13, 2018 by Tom Nardi 24 Comments

You might remember a time when people thought portable DVD players were a pretty neat idea. In the days before netbooks, cheap tablets, and arguably even the widespread adoption of smartphones, it seemed perfectly reasonable to lug around a device that did nothing but play movies. Today we look back at them as we would flip phones: a quaint precursor to the technology overload we find ourselves in currently. But the fact remains that millions of these comical little devices were pumped into the greedy maw of the consumer electronics market. They’re ripe for the hacking, all you need is some inspiration.

So if this grafting of a portable DVD player and the Raspberry Pi Zero W created by [nutsacrilege] doesn’t get you sniffing around your local second-hand store for a donor device, nothing will. By integrating a Pi running Kodi, the player gets a multi-media kick in the pants that arguably makes up for the rather archaic form factor. Not only can it play a wide array of local and online content, but it could even be used as portable game system if you were so inclined.

Rest assured, this isn’t some lazy five-minute mod. All of the original physical controls have been made functional by way of a MCP3008 ADC connected to the Pi’s GPIO and some clever Python scripting. Even the headphone jack was made functional by wiring it up to a USB sound card, and by integrating a tiny stripped down hub he was also able to add an external USB port. Who needs discs when you can plug in a flash drive full of content?

Speaking of which, [nutsacrilege] reports that the original functions of the device are still intact after all his modifications. So if you can get the museum to loan you one, you can even play a DVD on the thing as its creators intended.

With luck, this project will help spur on some more portable DVD player hacking, which we’ve seen precious little of so far. Frankly, it would be nice to see people cramming Raspberry Pi’s into something other than Game Boys for once.

[via /r/raspberry_pi]

A Hacker’s Epic Quest To Keep His Son Entertained

April 13, 2018 by Tom Nardi 22 Comments

Little humans have a knack for throwing a wrench in the priorities of their parents. As anyone who’s ever had children will tell you, there’s nothing you wouldn’t do for them. If you ever needed evidence to this effect, just take a gander at the nearly year-long saga that chronicles the construction of an activity board [Michael Teeuw] built for his son, Enzo.

Whether you start at the beginning or skip to the end to see the final product, the documentation [Michael] has done for this project is really something to behold. From the early days of the project where he was still deciding on the overall look and feel, to the final programming of the Raspberry Pi powered user interface, every step of the process has been meticulously detailed and photographed.

The construction methods utilized in this project run the gamut from basic woodworking tools for the outside wooden frame, to a laser cutter to create the graphical overlay on the device’s clear acrylic face. [Michael] even went as far as having a custom PCB made to connect up all the LEDs, switches, and buttons to the Arduino Nano by way of an MCP23017 I2C I/O expander.

Even if you aren’t looking to build an elaborate child’s toy that would make some adults jealous, there’s a wealth of first-hand information about turning an idea into a final physical device. It isn’t always easy, and things don’t necessarily go as planned, but as [Michael] clearly demonstrates: the final product is absolutely worth putting the effort in.

Seeing how many hackers are building mock spacecraft control panels for their children, we can’t help but wonder if any of them will adopt us.

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Dumping Arcade ROMs The Hard Way

April 12, 2018 by Tom Nardi 13 Comments

Nostalgia is a funny thing. That desire we all get to relive past memories can make you do things that in any other scenario would be out of the question. The effect seems even stronger when it comes to old video games. How else can you explain buying the same games over and over every time they get “remastered” for the next generation of consoles? But what if those remasters aren’t good enough?

If you have a burning desire to play a 100% accurate version of certain old arcade games, you might have your work cut out for you. Getting precise ROMs from some of these machines is exceptionally difficult, and as explained on the [CAPS0ff] blog, sometimes requires nearly superhuman feats of engineering.

As explained in the blog post, less invasive methods of getting inside the Taito C-Chip had already been examined and come up lacking. Despite best efforts, sending the unlock command to the chip didn’t yield the desired effect. If you can’t read the ROM the usual way, you need to get a little creative.

The process starts by milling down the case of the chip until the integrated circuit is just starting to become visible. Then acid is used to fully expose the traces. The traces are then tinned, and some very fine soldering is done to get the chip wired up to the reader. All told it takes about three hours from start to finish to pull a ROM using this method. But it’s all worth it in the end when you can play that 100% accurate version of Rainbow Islands. Or so we’ve been told.

If you couldn’t tell, this isn’t the first time a chip has been flayed open like this on the [CAPS0ff] blog.