Object Detection, With TensorFlow

July 31, 2018 by Bryan Cockfield 11 Comments

Getting computers to recognize objects has been a historically difficult problem in computer science, but with the rise of machine learning it is becoming easier to solve. One of the tools that can be put to work in object recognition is an open source library called TensorFlow, which [Evan] aka [Edje Electronics] has put to work for exactly this purpose.

His object recognition software runs on a Raspberry Pi equipped with a webcam, and also makes use of Open CV. [Evan] notes that this opens up a lot of creative low-cost detection applications for the Pi, such as setting up a camera that detects when a pet is waiting at the door to be let inside or outside, counting the number of bees entering and exiting a beehive, or monitoring parking spaces at an office.

This project uses a number of other toolkits as well, including Protobuf. It also makes extensive use of Python scripts, but if you’re comfortable with that and you have an application for computer vision, [Evan]’s tutorial will get you started.

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GTA: San Andreas Radio Earns Six-Star Wanted Level

July 25, 2018 by Kristina Panos 14 Comments

[Raphaël Yancey] wanted to be able to jam to Bounce FM and Radio:X all the time, without having to steal a car or a street sweeper in San Andreas. As people who like to put on the sad piano building music from The Sims and write Hackaday posts, we can totally relate.

But this isn’t just another one of those jam-a-Pi-into-a-vintage-radio-and-call-it-a-sandwich projects (not that there’s anything wrong with those). This thing acts like a real radio. All the stations play continuously whether you’re tuned in or not, and they bleed into each other as you go up and down the dial.

After much trial and error, [Raphaël] found a Python mixer that would work, but it was no longer maintained. He forked it, squashed a bug or two, and wrote a module for KY040 rotary encoders to make them play nice with the Pi. The snake charming doesn’t stop there: the rock star of this project is [Raphaël]’s virtual radio software, which handles the audio blending as he tunes between stations. A step-by-step tutorial is coming soon, so watch [Raphaël]’s site for updates. Tune past the break to give it a listen.

Adventures in Raspi radio-ing don’t have to be one-way. Here’s how you can turn one into an AM/FM+ transmitter using a DVB-T dongle and SDR.

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Hands On With Python 3.7: What’s New In The Latest Release

July 23, 2018 by Ben James 42 Comments

Used for general purpose programming, data science, website backends, GUIs, and pretty much everything else; the first programming language for many, and claimed to be the fastest growing in the world, is of course Python. The newest version 3.7.0 has just recently been released.
Naturally any release of Python, no matter how small, undergoes meticulous planning and design before any development is started at all. In fact, you can read the PEP (Python Enhancement Proposal) for Python 3.7, which was created back in 2016.

What’s new in 3.7? Why should you upgrade? Is there anything new that’s actually useful? I’ll answer these questions for you by walking through some examples of the new features. Whilst there’s not much in this release that will make a difference to the Python beginner, there’s plenty of small changes for seasoned coders and a few headline features you’ll want to know about.

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Conquering The Earth With Cron

June 25, 2018 by Tom Nardi 15 Comments

The GOES-R series of Earth observation satellites are the latest and greatest NASA has to offer. As you might expect, part of the GOES-R job description is imaging Earth at high-resolution, but they also feature real-time lighting monitoring as well as enhanced solar flare and space weather capabilities. Four of these brand new birds will be helping us keep an eye on our planet’s condition into the 2030s. Not a bad way to spend around 11 billion bucks.

To encourage innovation, NASA is making the images collected by the GOES-R satellites available to the public through a collaboration with Google Cloud Platform. [Ben Nitkin] decided to play around with this data, and came up with an interactive website that let’s you visualize the Earth from the perspective of GOES-R. But don’t let those slick visuals fool you, the site is powered by a couple cron jobs and some static HTML. Just as Sir Tim Berners-Lee intended it.

But it’s not quite as easy as scheduling a wget command; the images GOES-R collects are separated into different wavelengths and need to be combined to create a false-color image. A cron job fires off every five minutes which downloads and merges the raw GOES-R images, and then another cron job starts a Python script that creates WebM time-lapse videos out of the images using ffmpeg. All of the Python scripts and the crontab file are available on GitHub.

Finally, with the images merged and the videos created, the static HTML website is served out to the world courtesy of a quick and dirty Python web server. The site could be served via something more conventional, but [Ben] likes to keep overhead as low as possible.

If you want to take the more direct route, we’ve covered plenty of projects focused on pulling down images from weather satellites; from using old-school “rabbit ears” to decoding the latest Russian Meteor-M N2 downlink.

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This Robot Barfs Comics!

May 25, 2018 by Rich Hawkes 7 Comments

If there’s one thing that’s more fun than a comic, it’s a randomly generated comic. Well, perhaps that’s not true, but Reddit user [cadinb] wrote some software to generate a random comic strip and then built a robot case for it. Push a button on the robot and you’re presented with a randomly generated comic strip from the robot’s mouth.

The software that [cadinb] wrote is in Processing, an open source programming language and “sketchbook” for learning to code if you’re coming from a visual arts background. The Processing code determines how the images are cropped and placed and what kind of background they get. Each image is hand drawn by [cadinb] and has information associated with it so the code knows what the main focus of the image is. Once the panels are created, the final image is passed on to a thermal printer for printing. Everything is controlled from a Python script running on a Raspberry Pi and the code, strip artwork, and case is all available online to check out.

Now that the comic can print, a case is needed for the printer and controls. [cadinb] designed a case in Illustrator after creating a prototype out of foam core. The design was laser cut and then coloured – the main body with fabric dye and the arms stained with coffee!

Now [cadinb] has a robot that can sit on his table at conventions and a fan can press a button and have a randomly generated comic strip printed out before their eyes! We have a neat article about printing a comic on a strand of hair, and one about bringing the Banana Jr. 6000 to life!

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Welcome To The Internet Of Hamsters

May 16, 2018 by Tom Nardi 8 Comments

It was only a matter of time. Everything else is getting its data logged and reported to the Internet for detailed analysis, so why should our rodents be any different? The cover story is that [Nicole Horward] hooked her pet hamster Harold up to the web because she wanted to see if he was getting as much exercise as he should. The real reason is, of course, that Harold wanted to show off to his “friends” on Hamsterbook. (Editor’s note: dead link, but take a look at the Wayback Machine.)

The hardware side of this hack is very simple, a magnetic door sensor (like the kind used in alarm systems) is used to detect each time the wheel makes a complete rotation. The sensor is hooked up to the GPIO pins of a Raspberry Pi, where it’s read by a Python script. A small LCD screen was added to give some visual feedback on Harold’s daily activity, and the whole thing was boxed up in a laser cut enclosure.

That gave [Nicole] a cute little display next to Harold’s cage, but it didn’t do much for analyzing his activity. For that, a script is used to upload the data every minute to a ThingSpeak channel via MQTT. This automatically generates attractive graphs from the raw data, making it much easier to visualize what’s happening over the long term.

Now might be a good time to brush up on your MQTT knowledge, so that your pet could be the next to join the IoT revolution.

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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.