NES Zapper Becomes Telephone

May 25, 2025 by Bryan Cockfield 9 Comments

Although there was a time in the 80s (and early 90s for fans of the SuperScope) where light guns were immensely popular, with games like DuckHunt cultural touchstones, their time in the video game world has largely come to an end. We might occasionally pick up a Zapper for the NES and play this classic out of nostalgia, but plenty of people are looking for other things that these unique video game controllers can do instead. [Nick] has turned one of his old NES peripherals into a wireless phone.

The way the original Zapper worked was by looking for a certain pattern of pixels that displayed for a fraction of a second whenever the trigger was pulled. Bypassing the anti-cheat mechanism that looks only for qualities of light coming from CRT screens of the day effectively turns the light gun into an analog light sensor which is used for receiving the audio from the phone’s base station via a laser. Of course there were no microphones present within the original hardware so one is added, wiring its output to another laser that communicates to the base station. With the light gun pointed directly at this base station, audio is communicated back and forth by varying the strengths of these small lasers and listening to them on the other end with photodiodes.

[Nick] does point out that this isn’t a great phone, largely because it needs to be pointed exactly at the right spot to work at all, although we do agree that it’s an interesting project that demonstrates what the original hardware could do with a few of its limitations removed. There are a few other ways of bringing these devices into the modern world, with one of our favorites being this laser pointer with additional hardware from a Wiimote that could also function as a mouse.

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Who Needs 100K Speakers When You’ve Got A 3D Printer?

May 24, 2025 by Tyler August 64 Comments

The B&W Nautilus is, depending who you ask, either infamous or an icon of modern design. Want the look but don’t have a hundred grand to spare? [Every Project All at Once] has got a Nautilus-inspired design on printables you can run off for pennies. He also provides a tutorial video (embedded below) so you can follow along with his design process and get build instructions.

The model was done in Blender, and is designed to contain a 3.5″ full-range driver by Dayton Audio — a considerable simplification from the array of woofers and tweeters in the original Nautilus. On the other hand, they cost considerably less than a car and have no production wait list. [Every Project All At Once] is apparently working on a matching woofer if that interests you, but unless he invests in a bigger printer it seems we can safely say that would require more assembly than this project.

Of course it would also be possible to copy B&W’s design directly, rather than print a loose inspiration of it as makers such as [Every Project All At Once] have done, but what’s the fun in that? It’s a much more interesting hack to take an idea and make it your own, as was done here, and then you can share the design without worrying about a luxury brand’s legal team.

Desktop 3D printing offers a wealth of possibilities for would-be speaker makers, including the possibility of rolling your own drivers.

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Round Displays Make Neat VU Meters

May 5, 2025 by Lewin Day 11 Comments

You can still get moving-needle meters off the shelf if you desire that old school look in one of you projects. However, if you want a more flexible and modern solution, you could use round displays to simulate the same thing, as [mircemk] demonstrates.

At the heart of the build is an ESP32 microcontroller, chosen for its fast clock rate and overall performance. This is key when drawing graphics to a display, as it allows for fast updates and smooth movement — something that can be difficult to achieve on lesser silicon. [mircemk] has the ESP32 reading an audio input and driving a pair of GC9A01 round displays, which are the perfect form factor for aping the looks of a classic round VU meter. The project write-up goes into detail on the code required to simulate the behavior of a real meter, from drawing the graphics to emulating realistic needle movements, including variable sweep rates and damping.

The cool thing about using a screen like this is the flexibility. You can change the dials to a different look — or to an entirely different kind of readout — at will. We’ve seen some of [mircemk]’s projects before, too, like this capable seismometer. Video after the break.

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All-Band Radio Records Signals, Plays MP3s

May 4, 2025 by Tyler August 9 Comments

In these days of everything-streaming, it’s great to see an old school radio build. It’s even better when it’s not old-school at all, but packed full of modern ICs and driven by a micro-controller like the dsPIC in [Minh Danh]’s dsMP3 build. Best of all is when we get enough details that the author needs two blog posts — one for hardware, and one for firmware — like [Minh Danh] has done.

This build does it all: radio, MP3 playback, and records incoming signals. The radio portion of the build is driven by an Si4735, which allows for receiving both in FM and AM — with all the AM bands, SW, MW and LW available. The FM section does support RDS, though because [Minh Danh] ran out of pins on the dsPIC, isn’t the perfect implementation.

The audio section is a good intro to audio engineering if you’ve never done a project like this: he’s using a TDA1308 for headphones, which feeds into a NS8002 to drive some hefty stereo speakers– and he tells you why he selected those chips, as well as providing broken-out schematics for each. Really, we can’t say enough good things about this project’s documentation.

That’s before we get to the firmware, where he tells us how he manages to get the dsPIC to read out MP3s from a USB drive, and write WAVs to it. One very interesting detail is how he used the dsPIC’s ample analog inputs to handle the front panel buttons on this radio: a resistor ladder. It’s a great solution in a project that’s full of them.

Of course we’ve seen radio receivers before, and plenty of MP3 players, too — but this might be the first time we’ve seen an electronic Swiss army knife with all these features, and we’re very glad [Minh Danh] shared it with us.

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Crossing Commodore Signal Cables On Purpose

April 29, 2025 by Bryan Cockfield 19 Comments

On a Commodore 64, the computer is normally connected to a monitor with one composite video cable and to an audio device with a second, identical (although uniquely colored) cable. The signals passed through these cables are analog, each generated by a dedicated chip on the computer. Many C64 users may have accidentally swapped these cables when first setting up their machines, but [Matthias] wondered if this could be done purposefully — generating video with the audio hardware and vice versa.

Getting an audio signal from the video hardware on the Commodore is simple enough. The chips here operate at well over the needed frequency for even the best audio equipment, so it’s a relatively straightforward matter of generating an appropriate output wave. The audio hardware, on the other hand, is much less performative by comparison. The only component here capable of generating a fast enough signal to be understood by display hardware of the time is actually the volume register, although due to a filter on the chip the output is always going to be a bit blurred. But this setup is good enough to generate large text and some other features as well.

There are a few other constraints here as well, namely that loading the demos that [Matthias] has written takes so long that the audio can’t be paused while this happens and has to be bit-banged the entire time. It’s an in-depth project that shows mastery of the retro hardware, and for some other C64 demos take a look at this one which is written in just 256 bytes.

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DIY Record Cutting Lathe Is Really Groovy

April 22, 2025 by Tyler August 12 Comments

Back in the day, one of the few reasons to prefer compact cassette tape to vinyl was the fact you could record it at home in very good fidelity. Sure, if you had the scratch, you could go out and get a small batch of records made from that tape, but the machinery to do it was expensive and not always easy to come by, depending where you lived. That goes double today, but we’re in the middle of a vinyl renaissance! [ronald] wanted to make records, but was unable to find a lathe, so decided to take matters into his own hands, and build his own vinyl record cutting lathe.

photograph of [ronald's] setup — [ronald’s] record cutting lathe looks quite professional.

It seems like it should be a simple problem, at least in concept: wiggle an engraving needle to scratch grooves in plastic. Of course for a stereo record, the wiggling needs to be two-axis, and for stereo HiFi you need that wiggling to be very precise over a very large range of frequencies (7 Hz to 50 kHz, to match the pros). Then of course there’s the question of how you’re controlling the wiggling of this engraving needle. (In this case, it’s through a DAC, so technically this is a CNC hack.) As often happens, once you get down to brass tacks (or diamond styluses, as the case may be) the “simple” problem becomes a major project. Continue reading →

Designing A Tone Control Properly

April 8, 2025 by Jenny List 12 Comments

Many years ago, audio equipment came with a tone control, a simple RC filter that would cut or boost the bass to taste. As time passed, this was split into two controls for bass and treble, and then finally into three for bass, mid, and treble. When audiophile fashion shifted towards graphic equalisers, these tone controls were rebranded as “3-band graphic equalisers”, a misleading term if ever we heard one. [Gabriel Dantas] designed one of these circuits, and unlike the simple passive networks found on cheap music centres of old, he’s doing a proper job with active filters.

The write-up is worth a read even if you are not in the market for a fancy tone control, for the basic primer it gives on designing an audio filter. The design contains, as you might expect, a low-pass, a bandpass, and a high-pass filter. These are built around TL072 FET-input op-amps, and an LM386 output stage is added to drive headphones.

The final project is built on a home-made PCB, complete with mains power supply. Audiophiles might demand more exotic parts, but we’re guessing that even with these proletarian components it will still sound pretty good. Probably better than the headphone amplifier featured in a recent project from a Hackaday writer, at least. There’s a build video, below the break.

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