2024 Home Sweet Home Automation: Spray Bottle Turret Silences Barking

Ah, dogs. They sure like to bark, don’t they? [rrustvold]’s dog likes to bark at the door when a package arrives. Or when someone walks by the house, or whenever the mood strikes, really. To solve the barking issue, at least near the front door, [rrustvold] built a spray bottle turret to teach the dog through classical conditioning.

As you can see from the image, it’s all about pulling the trigger on a standard spray bottle at the right time. This machine only sprays when two conditions are met: it hears noise (like barking) and detects motion (like overzealous tail wagging). It also has heat-seeking abilities thanks to a Raspberry Pi thermal camera.

To do the actual spraying, there’s a DC motor mounted behind the bottle which turns a pulley that’s mounted to its shaft. Around the pulley is a string that wraps around the spray bottle’s trigger. To complete the build, everything is mounted on a lazy Susan so there’s nowhere for Fido to hide-o.

If you’ve a dog whose bite is worse than its bark, consider building a custom dog door to keep it out of the cat box.

The 2024 Home Sweet Home Automation contest has officially wrapped — we’re counting the votes now, so stay tuned for an announcement about the winners shortly.

A red 3D-printed Raspberry Pi-based document scanner

Raspberry Pi Scanner Digitizes On The Cheap

It’s pretty important in 2024 to be able digitize documents quickly and easily without necessarily having to stop by the local library or buy an all-in-one printer. While there are plenty of commercial solutions out there, [Caelestis Cosplay] has created a simple document scanner that takes documents, as [Caelestis Cosplay] puts it, from papers to pixels.

The build is probably what you’re expecting — it’s essentially a Raspberry Pi (in this case a 4B), a V2 Pi camera, and a handful of custom 3D-printed parts. [Caelestis Cosplay] says they had never designed anything for printing before, and we think it looks great. There’s also a buzzer to indicate that the scan is starting (one beep) or has completed (two beeps), a ‘ready’ indicator, and a ‘working’ indicator.

Everything you’d need to build your own is available over on Instructables, including document scanner and controller scripts. Be sure to check it out in action after the break, and see it quickly scan in a document and put it on a thumb drive.

Looking for a 3D scanner? Check out the OpenScan project.

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FLOSS Weekly Episode 778: OctoPrint — People Are Amazing At Breaking Things

This week Jonathan Bennett and Katherine Druckman sit down with Gina Häußge to talk OctoPrint! It’s one of our favorite ways to babysit our 3D printers, and the project has come a long way in the last 12 years! It’s a labor of love, primarily led by Gina, who has managed to turn it into a full time job. Listen in to hear that story and more, including how to run an Open Source project without losing your sanity, why plugins are great, and how to avoid adding a special services employee as a co-maintainer!

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Get Today’s Forecast In Classic 90s Weather Channel Style

Remember when The Weather Channel actually had weather? It’s been a while, but we sure remember what a boon Local on the 8’s was when getting ready for the day. Not having to wait for the low-information national forecast on the morning shows or putting up with the antics of [Willard Scott] or [Al Roker] was just icing on the cake.

Recreating the retro look and feel of the Weather Channel experience is what this 1990s-style weather feed is all about, and we have to say that [Mitchell Scott] knocked it out of the park. Luckily, a lot of the heavy lifting was done already thanks to the WeatherStar 4000+ emulator project, which renders forecasts using online weather APIs in the distinctive retro graphics The Weather Channel used back in the day. He combined the graphics with the original smooth jazz soundtracks that TWC used back then; they’re online, because of course they are.

To really sell the look, [Mitchell] tracked down a period-correct Zenith TV with a 9″ CRT to display the feed from a Raspberry Pi 4’s composite video output. Why such a small screen? Easy. [Mitchell] wanted it on a shelf behind him to be visible during videoconferences. It’s a bit of a weird flex, but we respect it. Getting the composite video output working was a bit of a chore, as was tricking the TV into starting up on channel 14 so the feed is instantly visible.

The nostalgia is strong with this one, especially for weather geeks. For a more in-depth look at how The Weather Channel brought those local forecasts to cable, make sure you check out how the WeatherStar box was reverse-engineered.

Thanks to [USA-RedDragon] for the tip.

anfractuosity's test setup showing the Pi under test and a few pieces of equipment used to perform the attack

Cold Boot Attack You Can Do With A Pi

A cold boot attack is a way to extract RAM contents from a running system by power cycling it and reading out RAM immediately after loading your own OS. How easy is it for you to perform such an attack? As [anfractuosity] shows, you can perform a cold boot attack with a Raspberry Pi, with a reasonably simple hardware setup and a hefty chunk of bare-metal code.

[anfractuosity]’s setup is simple enough. The Pi 4 under attack is set up to boot from USB drive, and a relay board has it switch between two possible USB drives to boot from: one with a program that fills RAM with , and another with a program that extracts RAM out through UART. The process is controlled by another Pi controlling the relays through GPIOs, that also monitors the target Pi’s UART and uses it as a channel to extract memory.

The outcomes are pretty impressive. After 0.75s of power-down, most of the image could be extracted. That’s without any cooling, so abusing a can of electronics duster is likely to improve these results dramatically. Want to play with cold boot attacks? [anfractuosity]’s code is great for getting your feet wet. Furthermore, the code examples provided serve as a wonderful playground for general memory attack research.

Raspberry Pi not fun enough for you anymore? Well then, you can always start playing with Android phones!

Video Killed The Radio Alarm Clock

For decades now, MTV has been on a bizarre trajectory given its original name was an acronym for Music Television. In the original days in the 80s and 90s it kept mostly true to its name, but starting around two decades ago they expanded into reality and other non-musical television programming and have now left it largely behind. Plenty of those who grew up in its heyday have an understandable amount of nostalgia for the channel as a cultural touchstone, and [Derf] used MTV archival footage to build a video alarm clock which helps him keep in tune with the past.

To keep the appropriate 80s aesthetic, the build uses a portable TV from the late 80s with its original CRT. The video files are hosted on more modern technology though, in this case a Raspberry Pi. The Pi is set up to run a python script which launches the VLC media player with a playlist loaded with video files, in this case a long list of MTV shows. Some configuration needs to be done to get it to output to the old CRT properly which depends on the hardware used, but once that’s in place it’s ready to be used as an alarm. [Derf] is using a smart outlet to power the TV at the appropriate time, and a cron job which starts the video player simultaneously at a somewhat random point in the playlist.

As far as retro TVs go, having one as an alarm clock is certainly a novel idea. We have seen a few others in the past, though, one to play the golden age of The Simpsons, and another that recreates the nostalgia of 90s cable television complete with a preview channel and era-appropriate commercials.

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Automatic Position Reporting Over HF Radio

While most of us carry cell phones that have GPS and other location services, they require a significant amount of infrastructure to be useful. Drive from Washington to Alaska like [Lonney] did a while back, where that infrastructure is essentially nonexistent, and you’ll need to come up with some other solutions to let friends and family know where you are.

A tool called the Automatic Packet Reporting System (APRS) is fairly robust in the very high frequency (VHF) part of the amateur radio spectrum, but this solution still relies on a not-insignificant amount of infrastructure for the limited distances involved with VHF. [Lonney] adapted a few other tools to get APRS up and running in the HF range, letting his friends keep tabs on him even from the most remote locations.

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