model

88 Articles

Modeling Home Heating Systems With Circuit Simulation Software

July 1, 2024 by 6 Comments

Electricity flow is generally invisible, silent, and not something that most humans want to touch, so understanding how charge moves around can be fairly unintuitive at first. There are plenty of analogies to help understand its behavior, such as imagining a circuit as a pipe of water, with pressure standing in for voltage and flow standing in for current. But you can flip this idea in reverse and use electric circuits to model other complex phenomena instead. [Oxx], for example, is using circuit theory to model his home’s heating systems.

To build his model, he’s using LTSpice, a free circuit simulation program. Using voltage to model temperature and current to model heat flow, he’s set up a model for his home to compare the behavior of a heat pump and a propane furnace. A switch model already in LTSpice with built-in hysteresis takes the place of the thermostat. Using temperature data for a single day in January [Oxx] can see how each of his two heating systems might behave, and the model for the heat pump is incredibly close to how the heat pump behaved in real life.

The model includes all kinds of data about the system, including the coefficient of performance of the heat pump and its backup electric resistive heater, and the model is fairly accurate at predicting behavior. Of course, it takes a good bit of work to set up the parameters for all of the components since our homes and heating systems won’t be included in LTSpice by default, but it does show how powerful an electric circuit analog can be when building models of other systems. If you’ve never used this program before, we’ve featured a few guides to getting started that you can take a look at.

Thanks to [Jarvis] for the tip!

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RC Batwing Actually Flies

June 16, 2024 by 8 Comments

Batman is a compelling superhero for enough reasons that he’s been a cultural force for the better part of a century. His story has complex characters, interesting explorations of morality, iconic villains, and of course a human superhero who gets his powers from ingenuity instead of a fantastical magical force. There are a number features of the Batman universe that don’t translate well to the real world, though, such as a costume that would likely be a hindrance in fights, technology that violates the laws of physics, and a billionaire that cares about regular people, but surprisingly enough his legendary Batwing jet airplane actually seems like it might be able to fly.

While this is admittedly a model plane, it flies surprisingly well for its nontraditional shape. [hotlapkyle] crafted it using mostly 3D printed parts, and although it took a few tries to get it working to his standards, now shoots through the air quite well. It uses an internal electric ducted fan (EDF) to get a high amount of thrust, and has elevons for control. There are two small vertical stabilizer fins which not only complete the look, but allow the Batwing to take to the skies without the need for a flight controller.

Not only is the build process documented in the video linked below with some interesting tips about building RC aircraft in general, but the STL files for this specific build are available for anyone wanting to duplicate the build or expand on it. There are plenty of other interesting 3D-printed models on [hotlapkyle]’s page as well that push the envelope of model aircraft. For some other niche RC aircraft designs we’ve seen in the past be sure to check out this F-35 model that can hover or this tilt-rotor Osprey proof-of-concept.

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An Enigma Machine Built In Meccano

June 15, 2024 by 5 Comments

As far as model construction sets go, LEGO is by far the most popular brand for building not only pre-planned models but whatever the builder can imagine. There are a few others out there though, some with some interesting features. Meccano (or Erector in North America) is a construction set based around parts that are largely metal including its fasteners, which allows for a different approach to building models than other systems including the easy addition of electricity. [Craig], a member of the London Meccano Club, is demonstrating his model Enigma machine using this system for all of its parts and adding some electricity to make the circuitry work as well.

The original Enigma machine was an electronic cypher used by the German military in World War 2 to send coded messages. For the time, its code was extremely hard to break, and led to the British development of the first programmable electronic digital computer to help decipher its coded messages. This model uses Meccano parts instead to recreate the function of the original machine, with a set of keys similar to a typewriter which, when pressed, advance a set of three wheels. The wheels all have wiring in them, and depending on their initial settings will light up a different character on a display.

There are a few modifications made to the design (besides the use of a completely different set of materials) but one of the main ones was eliminating the heavy leaf springs of the original for smaller and easier-to-manage coil springs, which are also part of the electrical system that creates the code. The final product recreates the original exceptionally faithfully, with plans to create a plugboard up next, and you can take a look at the inner workings of a complete original here.

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AI System Drops A Dime On Noisy Neighbors

April 25, 2024 by 4 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” →

Reggaeton-Be-Gone Disconnects Obnoxious Bluetooth Speakers

February 23, 2024 by 29 Comments

If you’re currently living outside of a Spanish-speaking country, it’s possible you’ve only heard of the music genre Reggaeton in passing, if at all. In places with large Spanish populations, though, it would be more surprising if you hadn’t heard it. It’s so popular especially in the Carribean and Latin America that it’s gotten on the nerves of some, most notably [Roni] whose neighbor might not do anything else but listen to this style of music, which can be heard through the walls. To solve the problem [Roni] is now introducing the Reggaeton-Be-Gone. (Google Translate from Spanish)

Inspired by the TV-B-Gone devices which purported to be able to turn off annoying TVs in bars, restaurants, and other places, this device can listen to music being played in the surrounding area and identify whether or not it is hearing Reggaeton. It does this using machine learning, taking samples of the audio it hears and making decisions based on a trained model. When the software, running on a Raspberry Pi, makes a positive identification of one of these songs, it looks for Bluetooth devices in the area and attempts to communicate with them in a number of ways, hopefully rapidly enough to disrupt their intended connections.

In testing with [Roni]’s neighbor, the device seems to show promise although it doesn’t completely disconnect the speaker from its host, instead only interfering with it enough for the neighbor to change locations. Clearly it merits further testing, and possibly other models trained for people who use Bluetooth speakers when skiing, hiking, or working out. Eventually the code will be posted to this GitHub page, but until then it’s not the only way to interfere with your neighbor’s annoying stereo.

Thanks to [BaldPower] and [Alfredo] for the tips!

Modeling A Guitar For Circuit Simulation

August 19, 2023 by 20 Comments

Guitar effects have come a long way from the jangly, unaltered sounds of the 1950s when rock and roll started picking up steam. Starting in large part with [Jimi Hendrix] in the 60s, the number of available effects available to guitarists snowballed in the following decades step-by-step with the burgeoning electronics industry. Now, there are tons of effects, from simple analog devices that would have been familiar to [Hendrix] to complex, far-reaching, digital effects available to anyone with a computer. Another thing available to modern guitarists is the ability to model these effects and guitars in circuit simulators, as [Iain] does.

[Ian] plays a Fender Stratocaster, but in order to build effects pedals and amplifiers for it with the exact desired sound, he needed a way to model its equivalent circuit. For a simple DC circuit, this isn’t too difficult since it just requires measuring the resistance, capacitance, and inductance of the overall circuit and can be done with something as simple as a multimeter. But for something with the wide frequency range of a guitar, a little bit more effort needs to go into creating an accurate model. [Iain] is using an Analog Discovery as a vector network analyzer to get all of the raw data he needs for the model before moving on to some in-depth calculations.

[Iain] takes us through all of the methods of figuring out the equivalent impedance of his guitar and its cabling using simple methods capable of being done largely by hand and more advanced techniques like finding numerical solutions. By analyzing the impedance of the pickup, tone and volume controls, and cable, this deep dive into the complexities of building an accurate equivalent circuit model for his guitar could be replicated by anyone else looking to build effects for their specific guitars. If you’re looking for a more digital solution, though, we’ve seen some impressive effects built using other tools unavailable to guitarists in days of yore, such as MIDI and the Raspberry Pi.

Making A Kid-Scale Apollo 11 Lunar Lander

August 5, 2023 by 21 Comments

If you’d like to see what goes into making a 1/3-scale Apollo 11 Lunar Module, [Plasanator]’s photos and build details will show off how he constructed one for a kid’s event that was a hit!

The photo gallery gives plenty of ideas about how one would approach a project like this, and readers will surely appreciate the use of an old frying pan as a concrete mold to create the lander’s “feet”. Later, a little paint makes the frying pan become a pseudo-antenna mounted on the lander’s exterior.

Inside, the lander has a control panel with a lot of arcade-style buttons and LED lighting. It’s pretty simple stuff, but livens things up a lot. Bright red lighting for the engine combined with a couple of slow strobe lights really makes it come alive in the dark. The gold foil? Emergency thermal blankets wrapped around the frame.

We happen to have the perfect chaser for this kid-scale lunar module: the Apollo 11 moon landing, recreated with animatronics and LEGO.

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