AI System Drops A Dime On Noisy Neighbors

April 25, 2024 by Dan Maloney 2 Comments

“There goes the neighborhood” isn’t a phrase to be thrown about lightly, but when they build a police station next door to your house, you know things are about to get noisy. Just how bad it’ll be is perhaps a bit subjective, with pleas for relief likely to fall on deaf ears unless you’ve got firm documentation like that provided by this automated noise detection system.

OK, let’s face it — even with objective proof there’s likely nothing that [Christopher Cooper] is going to do about the new crop of sirens going off in his neighborhood. Emergencies require a speedy response, after all, and sirens are perhaps just the price that we pay to live close to each other. That doesn’t mean there’s no reason to monitor the neighborhood noise, though, so [Christopher] got to work. The system uses an Arduino BLE Sense module to detect neighborhood noises and Edge Impulse to classify the sounds. An ESP32 does most of the heavy lifting, including running the UI on a nice little TFT touchscreen.

When a siren-like sound is detected, the sensor records the event and tries to classify the type of siren — fire, police, or ambulance. You can also manually classify sounds the system fails to understand, and export a summary of events to an SD card. If your neighborhood noise problems tend more to barking dogs or early-morning leaf blowers, no problem — you can easily train different models.

While we can’t say that this will help keep the peace in his neighborhood, we really like the way this one came out. We’ve seen the BLE Sense and Edge Impulse team up before, too, for everything from tuning a bike suspension to calming a nervous dog. Continue reading “AI System Drops A Dime On Noisy Neighbors” →

Custom Dog Door Prevents Culinary Atrocities

April 17, 2024 by Bob Baddeley 31 Comments

Riley, an 8 lb pug, has more beauty than brains, and a palate as unrefined as crude oil. While we hate criticizing others’ interests and tastes, his penchant for eating cat poop needed to stop. After a thorough exploration of a variety of options, including cat food additives that make its excrement taste worse (HOW? WHY? Clearly taste wasn’t the issue!), automatic litter boxes that stow the secretions, and pet doors that authenticate access to the room with the litter box, [Science Buddies] eventually settled on a solution that was amenable to all members of the family.

The trick was in creating a door mechanism with a blacklist of sorts rather than a whitelist. As the cat didn’t like to push the door open itself, the solution needed to have the pet door open by default. A magnet on Riley’s collar would trip a sensor attached to an Arduino that would control servos to swing the door shut immediately if he attempted to access the defecated delights. Of course safety was a consideration with the door swinging in Riley’s face.

We’ve covered a few pet screeners, including one for the same purpose that used IR sensors (but a much bigger dog also named Riley), and a flock of solutions for chickens. We’ve also seen [Science Buddies] in previous posts, so they’re not on the tips line blacklist.

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Arduino Gear Shift Indicator Finds ‘Em So You Won’t Grind ‘Em

March 20, 2024 by Dan Maloney 75 Comments

Now, it’s been a shamefully long time since we’ve driven a car with a manual transmission, but as we recall it was pretty straightforward. It certainly didn’t require a lot of help with the shifting pattern, at least not enough to require a technical solution to know what gear you’re in. But then again, we suspect that’s not really the point of [upir]’s latest build.

Oh sure, it’s pretty cool to display your current gear selection on a little LCD screen using an Arduino. And [upir] promises a follow-up project where the display goes inside the shifter knob, which will be really cool. But if you take a look at the video below, you’ll see that the real value of this project is the stepwise approach he takes to create this project. [upir] spends most of the time in the video below simulating the hardware and the code of the project in Wokwi, which lets him make changes and tune the design up before committing anything to actual hardware.

That turned out to be particularly useful with this build since he chose to use analog Hall sensors to detect the shift lever position and didn’t know exactly how that would work. Wokwi let him quickly build a virtual prototype for one sensor (using a potentiometer as a stand-in, since the simulator lacked a Hall sensor model), then quickly expand to the four sensors needed to detect all six gear positions.

By the time his simulation was complete, the code was almost entirely written. [upir] also walks us through his toolchains for both designing the graphics and laying out the PCB, a non-trivial task given the odd layout. We particularly enjoyed the tip on making smooth curved traces around the oval cutout for the shift lever in the board.

The video below is on the longish side, but it’s chock full of great little tips. Check out some more of [upir]’s work, like his pimped-out potentiometer or his custom animations on 16×2 LCDs.

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Creating A Numbers Station Of Your Very Own

March 17, 2024 by Lewin Day 13 Comments

Numbers stations are a weird phenomenon where odd voices read out long strings of numbers or random codewords to the confusion of the vast majority of the listening audience. If you’ve ever wanted to build one of your own, you could follow the example of [AudioWanderer].

NumberMumble, as it’s called, is a numbers station emulator. It doesn’t signal spy networks or reveal national secrets. Instead, it randomly plays audio samples using an Arduino, including characteristic bursts of white noise that make it sound more authentic. It relies on the Mozzi library to help with audio tasks, including generating white noise and playing back samples. It’s also kitted out with a filter knob for varying the tone. Audio output is via PWM.

If you want to confuse your neighbours with oddball audio, put this thing on a radio transmitter and get broadcasting. But don’t, because that’s illegal without the proper licenses or — you know — if you happen to be a real spy. Video after the break.

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A new display wedged into a car-based fridge

New Brains Save 12 V Fridge From The Scrap Heap

March 14, 2024 by Dave Rowntree 17 Comments

Recently [nibbler]’s Evakool 55L vehicle fridge started to act strangely, reporting crazy temperature errors and had no chance of regulating. The determination was that the NTC thermistor was toast, and rather than trying to extricate and replace this part, it was a lot easier to add a new one at a suitable location

A straight swap would have been boring, so this was a perfect excuse for an overboard hack. Reverse engineering the controller wouldn’t be easy, as the data wasn’t available, as is often the case for many products of this nature.

While doing a brain transplant, the hacker way, we can go overboard and add the basics of an IoT control and monitoring system. To that end, [nibbler] learned as much as possible about the off-the-shelf ZH25G compressor and the associated compressor control board. The aim was to junk the original user interface/control board and replace that with a Raspberry Pi Pico W running CircuitPython.

For the display, they used one of the ubiquitous SH1106 monochrome OLED units that can be had for less than the cost of a McDonald’s cheeseburger at the usual purveyors of cheap Chinese electronics. A brief distraction was trying to use a DS18B20 waterproof thermometer probe, which they discovered didn’t function, so they reverted to tried and trusted tech — a simple NTC thermistor.

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Custom Mouse-Making: Clay Is The Way

March 10, 2024 by Kristina Panos 10 Comments

For something that many of us handle all day long, it sure would be nice if mice came in more sizes and shapes, wouldn’t it? Until that day, we’ll just have to find something passable or else design and build a custom-shaped mouse from scratch like [Ben Makes Everything] did.

First, [Ben] played around with some modelling clay until he had a shape he was happy with, then took a bunch of pictures of it mounted on a piece of wood for easy manipulation and used photogrammetry to scan it in for printing after cleaning it up in Blender. About six versions later, he had the final one and was ready to move on to electronics.

That’s right, this isn’t just mouse guts in an ergonomic package. Inside is Arduino Pro Micro and a PMW 3389 optical sensor on a breakout board. [Ben] was going to use flexible 3D printed panels as mouse buttons, but then had an epiphany — why not use keyboard switches and keycaps instead? He also figured he could have two buttons per finger if he wanted, so he went with Kailh reds for the fingers and and whites in the thumb.

Speaking of the thumb, there was no room for a mouse wheel in between those comparatively huge switches, so he moved it to the the side to be thumb-operated. [Ben] got everything working, and after all this, decided to make it wireless. So he switched to an Adafruit Feather S3 and designed his first PCB for both versions. Ultimately, he found that the wireless version is kind of unreliable, so he is sticking with the wired one for now.

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