Integration Taught Correctly

February 26, 2024 by Al Williams 31 Comments

[Math the World] claims that your calculus teacher taught you integration wrong. That’s assuming, of course, you learned integration at all, and if you haven’t forgotten it. The premise is that most people think of performing an integral as finding the area under a curve or as the “antiderivative.” However, fewer people think of integration as adding up many small parts. The video asserts that studies show that students who don’t understand the third definition have difficulty applying integration to real-world problems.

We aren’t sure that’s true. People who write software have probably looked at numerical integration like Simpson’s rule or the midpoint rule. That makes it pretty obvious that integration is summing up small bits of something. However, you usually learn that very early, so you’re forgiven if you didn’t get the significance of it at the time.

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The DeDeterminator Uses Quantum Physics To Make Decisions So You Don’t Have To

February 26, 2024 by Lewin Day 20 Comments

Are you making your own decisions and mainlining causality like a sucker? Why go through the agony, when you could hand over the railway switch of determinism to a machine that can decide things for you! Enter the DeDeterminator, a decision machine from [Oliver Child].

The construction is simple enough, being built inside a small tin. One kind of wishes it had a secret third “PERHAPS” bulb that illuminates only when the universe’s continued existence has been called into question.

The idea is simple. At the press of a button, the DeDeterminator illuminates a bulb—indicating either yes or no. The decision for which bulb to illuminate is truly random, as it’s determined by the radioactive decay of a Americium-241 alpha particle source. A Geiger-Muller tube is used to detect alpha particles, with the timing between detections used to determine the yes-or-no output of the device.

It’s a neat concept, and it’s kind of fun knowing that your decision is both out of your hands and as random as it could possibly be. Would the universe guide you wrong? Who could possibly question the reasoning of the particles? The only rational move could be to comply with whatever directive the box hath given. Just don’t ask it to make any decisions with dangerous outcomes.

We’ve featured other projects using radioactive decay for random number generation before, though they weren’t quite as philosophically intriguing as the DeDeterminator. Mostly they’re just about cryptographic security and such, but some do deal with causality in imaginary spaces, which has its own magic about it.

Meanwhile, if you’ve untangled the quantum chains of cause and effect, or you’ve just found a way to break RSA encryption using a Pi Pico, do drop us a line, won’t you?

TuneShroom Is An Artistic Mushroom-Themed MIDI Controller

February 25, 2024 by Lewin Day 1 Comment

Most MIDI controllers are modelled after traditional instruments, like pianos, flutes, or guitars. [Oliver Child] went in a different direction for the TuneShroom, instead modelling his DIY controller after the terrifying, unclassifiable living organism we call the mushroom.

The project was a fun way for [Oliver] to try creating a project with an artistic PCB design, and it worked out well in that regard. He penned a circuit board in the shape of a toadstool, with conductive pads serving as capacitive touch points to activate various notes.

The design is based around the Sparkfun Pro Micro, but it’s not programmed in Arduino. [Oliver] wanted to make full use of the ATmega32U4 microcontroller and have freedom to use the pins at will, so instead the project was programmed with a patched version of LUFA to handle the USB side of things. MIDI data is naturally piped out over this interface to an attached computer.

Files are on Github for the curious. Alternatively, contemplate turning an entire saxophone into a MIDI controller in your spare time. Video after the break.

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MovieCart Plays Videos On The Atari 2600

February 23, 2024 by Lewin Day 12 Comments

The original Xbox and PlayStation 2 both let you watch DVD movies in addition to playing games. Seldom few consoles before or since offered much in the way of media, least of all the Atari 2600, which was too weedy to even imagine such feats. And yet, as covered by TechEBlog, [Lodef Mode] built a cartridge that lets it play video.

It’s pretty poor quality video, but it is video! The MovieCart, as it is known, is able to play footage at 80×192 resolution, with a color palette limited by the capabilities of the Atari 2600 hardware. It’s not some sneaky video pass-through, either—the Atari really is processing the frames.

To play a video using the MovieCart, you first have to prepare it using a special utility that converts video into the right format for the cart. The generated video file is then loaded on a microSD card which is then inserted into the MovieCart. All you then have to do is put the MovieCart into the Atari’s cartridge slot and boot it up. Sound is present too, in a pleasingly lo-fi quality. Control of picture brightness and sound volume is via joystick. You could genuinely watch a movie this way if you really wanted to. I’d put on House of Gucci.

Thanks to the prodigious storage available on microSD cards, you can actually play a whole feature length movie on the hardware this way. You can order a MovieCart of your very own from Tindie, and it even comes with a public domain copy of Night of the Living Dead preloaded on a microSD card.

We don’t see a big market for Atari 2600 movies, but it’s neat to see it done. Somehow it reminds us of the hacked HitClips carts from a while ago. Video after the break.

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No Inductors Needed For This Simple, Clean Twin-Tee Oscillator

February 18, 2024 by Dan Maloney 11 Comments

If there’s one thing that amateur radio operators are passionate about, it’s the search for the perfect sine wave. Oscillators without any harmonics are an important part of spectrum hygiene, and while building a perfect oscillator with no distortion is a practical impossibility, this twin-tee audio frequency oscillator gets pretty close.

As [Alan Wolke (W2AEW)] explains, a twin-tee oscillator is quite simple in concept, and pretty simple to build too. It uses a twin-tee filter, which is just a low-pass RC filter in parallel with a high-pass RC filter. No inductors are required, which helps with low-frequency designs like this, which would call for bulky coils. His component value selections form an impressively sharp 1.6-kHz notch filter about 40 dB deep. He then plugs the notch filter into the feedback loop of an MCP6002 op-amp, which creates a high-impedance path at anything other than the notch filter frequency. The resulting sine wave is a thing of beauty, showing very little distortion on an FFT plot. Even on the total harmonic distortion meter, the oscillator performs, with a THD of only 0.125%.

This video is part of [Alan]’s “Circuit Fun” series, which we’ve really been enjoying. The way he breaks complex topics into simple steps that are easy to understand and then strings them all together has been quite valuable. We’ve covered tons of his stuff, everything from the basics of diodes to time-domain reflectometry.

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Star Wars-Inspired Cosplay Prop Uses Old Vintage Camera

February 17, 2024 by Lewin Day 9 Comments

Lots of people make replica lightsabers from Star Wars or tricorders from Star Trek. Not so many people have tried to recreate the binoculars from The Last Jedi, but [The Smugglers Room] whipped up a pretty rad pair from old parts.

It’s more of an inspired build rather than screen-accurate, but they’re still pretty neat. A Bell & Howell camera was the basis for the binoculars used in the film, in fact, and this build starts with the same tri-lens model. Found vintage objects are often used in sci-fi with some modifications, but more commonly in lower-budget productions. Star Wars can do it too, though, it seems.

Turning them into binoculars requires the construction of a viewfinder, which was made out of hand-cut Sintra PVC foam board. Lots of leather wrap had to be removed from the camera, too, which offered a happy accident—it left a heavily-weathered aluminum surface that looked great for a Star Wars prop. A few random controls were then added to disguise the camera as an advanced pair of futuristic binoculars. LED lighting was also installed internally to make the build glow as if it actually contained some powered sci-fi optics. It also got a hand-made leather strap for that rugged aesthetic so fitting for the film.

It’s not a functional build; we’d love to see someone build a set of AR or rangefinder binoculars that still look the part. However, this would be a great addition to any Poe Dameron costume you might have planned for the next upcoming Comic Con.

Here’s our question, though. Does it suck you out of your suspension of disbelief when filmmakers use found objects as the basis for props? Or is it a neat thing when you spot such an example? Video after the break.

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Salvaged Meter Movements Really Pop In This DIY VU Meter Bridge

February 17, 2024 by Dan Maloney 3 Comments

If you’re going to build a nice VU meter bridge for the recording studio, the first thing you need is a nice pair of VU meters. But lest you think it’s as easy as putting some meters into a nice box and calling it a day, think again.

This project comes to us from [Frank Olson], whose projects usually incorporate wood as part of the mechanism, as with his famous wooden ribbon microphone. This build does indeed use wood, and to excellent effect, but only in the project’s final enclosure. Before that, [Frank] had salvaged a pair of good-looking moving coil meters from an old tape recorder. He muddled through some ideas before settling on a design. A NE5532 dual-channel audio buffer module is used as a preamp, with each channel feeding into a bridge rectifier before heading to the meter. Wisely, [Frank] chose to illuminate the meters with their existing incandescent bulbs, so a small DC-DC supply was added to provide the necessary 8 volts.

As for the enclosure, that’s where [Frank]’s experience working with veneers paid off. He chose mahogany, carefully cut all the pieces to shape with a knife, and glued it all up with CA glue — at least we assume it was CA; based on previous efforts, he uses a lot of the stuff. The tung oil finish looks fantastic, and the completed build aesthetic looks great! The video below shows it all.

If you need some backstory on the VU meter, we can help with that.

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