Guardin, Guarding The Garden: Turn Raspberry Pi Into A 3rd Eye

August 23, 2018 by Jenny List 16 Comments

If you are a gardener, you’ll know only too well the distress of seeing your hard work turned into a free lunch for passing herbivorous wildlife. It’s something that has evidently vexed [Jim], because he’s come up with an automated Raspberry Pi-controlled turret to seek out invading deer, and in his words: “Persuade them to munch elsewhere”.

Before you groan and sigh that here’s yet another pan and tilt camera, let us reassure you that this one is a little bit special. For a start, it rotates upon a set of slip rings rather than an untidy mess of twisted cables, so it can perfom 360 degree rotations at will, then it has a rather well-designed tilting cage for its payload. The write-up is rather functional but worth persevering with, and he’s posted a YouTube video that we’ve placed below the break.

This is a project that still has some way to go, for example just how those pesky deer are to be sent packing isn’t made entirely clear, but we think it already shows enough potential to be worthy of a second look. The slip ring mechanism in particular could find a home in many other projects.

It’s worth reminding readers that while pan and tilt mechanisms can be as impressive as this one, sometimes they are a little more basic.

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Cross-Correlation Makes Quick Work Of Ads

August 22, 2018 by Kerry Scharfglass 25 Comments

Once relegated to the proverbial Linux loving Firefox user, ad blocking has moved into public view among increased awareness of privacy and the mechanisms of advertising on the internet. At the annual family gathering, when That Relative asks how to setup their new laptop, we struggle through a dissertation on the value of ad blockers and convince them to install one. But what about mediums besides the internet? Decades ago Tivo gave us one button to jump through recorded TV. How about the radio? If available, satellite radio may be free of The Hated Advertisement. But terrestrial radio and online streams? [tomek] wasn’t satisfied with an otherwise sublime experience listening streaming Polish Radio Three and decided to build a desktop tool to detect and elide ads from the live audio stream.

[tomek] was aware of this hip knowledge domain called Digital Signal Processing but hadn’t done any of it themselves. Like many algorithmic problems the first step was to figure out the fastest way to bolt together a prototype to prove a given technique worked. We were as surprised as [tomek] by how simple this turned out to be. Fundamentally it required a single function – cross-correlation – to measure the similarity of two data samples (audio files in this case). And it turns out that Octave provides it in the box. After snipping the start-of-ad jingle out of a sample file and comparing it to a radio program [tomek] got the graph at the left. The conspicuous spike is the location of the jingle in the audio file.

At this point all that was left was packaging it all into a one click tool to listen to the radio without loading an entire analysis package. Conveniently Octave is open source software, so [tomek] was able to dig through its sources until they found the bones of the critical xcorr() function. [tomek] adapted their code to pour the audio into a circular buffer in order to use an existing Java FFT library, and the magic was done. Piping the stream out of ffmpeg and into the ad detector yielded events when the given ad jingle samples were detected.

[tomek] packaged that tool into a standalone executable, but the gem here is the followup post. After removing ads in the online stream they adapted a RaspberryPi to listen to an FM receiver and remote control their Yamaha tuner over the network. So when the tuner is playing Radio Three the Pi notices and ducks the audio appropriately to avoid those pesky ads. Video of this after the break.

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Blink A Pi, Win A Prize

August 21, 2018 by Brian Benchoff 5 Comments

You can plug in a Raspberry Pi, and you can blink a LED. You can visualize data, and now there’s a contest on Hackaday.io to show off your skills. Right now, we’re opening up the Visualize It With Pi contest on Hackaday.io. The challenge? Visualize data with LED strips and panels. Is that ‘data’ actually just a video of Never Gonna Give You Up? We’ll find out soon enough.

The goal of this contest is to combine a Raspberry Pi and its immense processing power and the blinky goodness of LED strips and panels to visualize and interpret data in novel and artistic ways. We’re looking for animation. clarity, and flamboyant flickering. Want some ideas? Check out the World of Light or the American Constitution Candle. We’re looking for the most blinky you can do with a Pi, and yes, there will be prizes.

Prizes

Prizes for the best blinky include, of course, more blinky. The best visualizations from a directly connected sensor, data from an Internet Source, and data from an esoteric data source will each receive some Blinkytape. This is a strip of WS2812b LEDs with an ATMega32u4 embedded on the end. Plug a USB power supply into the Blinkytape, and you get a strip of LEDs in whatever color you want with the ability to push animation frames to the chip on the strip. The Grand Prize winner for this contest will also receive Blinkytile Explorers Kit, a Serpentine LED strip, a LED ring, and two meters of ultra thin LED strip.

Let’s Do This!

The requirements for the contest are simple: just use a Raspberry Pi to drive LED strips or panels, post it as a new project on Hackaday.io, and submit the project to the contest. We’re looking for a full description, source, schematics, and photos and videos of the finished version of the project — do everything you can to show off your work! The contest is open right now, and ends at 08:00 Pacific on October 1st. We know you like to blink those LEDs, so get crackin’.

Installing LibreBoot The (Very) Lazy Way

August 20, 2018 by Tom Nardi 47 Comments

Recently I was given a somewhat crusty looking ThinkPad T400 that seemed like it would make a good knock around machine to have on the bench, if it wasn’t for the fact the person who gave it to me had forgotten (or perhaps never knew) the BIOS password. Cleaning the machine up, putting more RAM in it, and swapping the wheezing hard drive for an SSD would be a relatively cheap way to wring a few more years of life from the machine, but not if I couldn’t change the boot order in BIOS.

Alright, that’s not entirely true. I could have installed an OS on the SSD from my desktop and then put it into the T400, but there was something else at play. The locked BIOS gave me the perfect excuse to install LibreBoot on it, which is one of those projects I’ve had in the back of my mind for years now. Replacing the BIOS with something entirely different would solve the password issue, but there was only one problem: the instructions for flashing LibreBoot onto the T400 are intimidating to say the least.

You’re supposed to take the entire machine apart, down to pulling the CPU cooler off and removing the display. All so you can flip the motherboard over to access a flash chip between the CPU and RAM that’s normally covered by a piece of the laptop’s frame. Oh how I hated that diabolical chunk of magnesium which kept me from my silicon quarry. Flashing the chip would take a few minutes, but YouTube videos and first hand accounts from forums told me it could take hours to disassemble the computer and then put it back together after the fact.

Deep into that darkness I peered, long I stood there, wondering, fearing, doubting. Then a thought came to me: maybe I could just cut the thing. If it was a success, it would save me hours of work. If it failed, well, at least the computer didn’t cost me anything. Time to roll the dice.

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An Upcycled Speaker Box With Hidden Features

August 20, 2018 by Tom Nardi 3 Comments

At first glance, this fire engine red speaker box built by [NoshBar] looks straightforward enough. Just an MDF case and couple of drivers recovered from a trashed stereo. But the array of controls and connectors on the front, and a peek on the inside, shows there’s more to this particular project than meets the eye.

Built almost entirely from parts [NoshBar] found in the trash, construction started with some salvaged MDF IKEA shelves and their corresponding twist lock cam fittings. We don’t usually see those style cam fittings used to build DIY enclosures, but if it works for all those furniture manufacturers why not?

A pair of Sony stereo speakers he found gave up their internals, and a TPA3116 amplifier board off of eBay drives them. He’s wired up an audio pass-through mode for using headphones when the amplifier is powered off, and dual inputs so he can switch between PC and PS4.

But the audio components are only half of what’s inside that shiny red exterior. [NoshBar] packed in an ATX PSU and broke out the 3.3 V, 5 V, and 12 V lines to the front panel so he can use it as a bench power supply for his Arduino projects. It’s also home to a gigabit Ethernet switch and a Raspberry Pi acting as a file server.

We’re always amazed at what hackers are able to accomplish with parts they’ve literally pulled out of the trash, from a waterwheel to charge your phone to a functional CNC router. It seems there’s plenty of treasure in your local dumpster if you’re willing to get a little dirty.

An Achievable Underwater Camera

August 18, 2018 by Jenny List 11 Comments

We are surrounded by sensors for all forms of environmental measurement, and a casual browse through an electronics catalogue can see an experimenter tooled up with the whole array for a relatively small outlay. When the environment in question is not the still air of your bench but the turbulence, sand, grit, and mud of a sea floor, that pile of sensors becomes rather useless. [Ellie T] has been addressing this problem as part of the study of hypoxia in marine life, and part of her solution is to create an underwater camera by encasing a Raspberry Pi Zero W and camera in a sturdy enclosure made from PVC pipe. She’s called the project LoBSTAS, which stands for Low-cost Benthic Sensing Trap-Attached System.

The housing is simple enough, the PVC has a transparent acrylic disk mounted in a pipe coupler at one end, with the seal being provided at the other by an expansion plug. A neopixel ring is mounted in the clear end, with the Pi camera mounted in its centre. Meanwhile the Pi itself occupies the body of the unit, with power coming from a USB battery bank. The camera isn’t the only sensor on this build though, and Atlas Scientific oxygen sensor completes the package and is mounted in a hole drilled in the expansion plug and sealed with silicone sealant.

Underwater cameras seem to have featured more in the earlier years of Hackaday’s existence, but that’s not to say matters underwater haven’t been on the agenda. The 2017 Hackaday Prize was carried off by the Open Source Underwater Glider.

Hanging, Sliding Raspi Camera Adds Dimension To Octoprint

August 16, 2018 by Kristina Panos 13 Comments

Are you using Octoprint yet? It’s so much more than just a way to control your printer over the internet, or to keep tabs on it over webcam when you’re off at work or fetching a beer. The 3D printing community has rallied around Octoprint, creating all sorts of handy plug-ins like Octolapse, which lets you watch the print blossom from the bed via time-lapse video.

Hackaday alum [Jeremy S Cook] wanted to devise a 3D-printable mount for a Raspi camera after finding himself inspired by [Tom Nardi]’s excellent coverage of Octoprint and Octolapse. He recently bought a wire shelving unit to store his printer and printer accessories, and set to work. We love the design he came up with, which uses the flexibility of the coolant hose to provide an endlessly configurable camera arm. But wait, there’s more! Since [Jeremy] mounted it to the rack with zip ties, the whole rig shimmies back and forth, providing a bonus axis for even more camera views. Slide past the break to see [Jeremy]’s build/demo video.

It’s great to be able to monitor a print from anywhere with internet access, but the camera is almost always set up for a tight shot on the print bed. How would you ever know if you’re about to run out of filament? For that, you need a fila-meter.

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