Talking Ohmmeter Also Spits Out Color Bands For You

December 24, 2023 by 13 Comments

If you’ve got a resistor and you can’t read the color bands (or they’re not present), you can always just grab a multimeter and figure out its value that way. [Giacomo Yong Cuomo] and [Sophia Lin] have built an altogether different kind of ohmmeter, that can actually spit out color values for you, and even read the resistance aloud. It’s all a part of their final project for their ECE 4760 class.

The build is based around a Raspberry Pi Pico. It determines the value of a resistor by placing it in a resistor divider, with the other reference resistor having a value of 10 kΩ. The resistor under test is connected between the reference resistor and ground, while the other leg of the reference resistor is connected to 3.3 V. The node between the two resistors is connected to the Pi Pico’s analog-to-digital converter pin. This allows the Pico to determine the voltage at this point, and thus calculate the test resistor’s value based on the reference resistor’s value and the voltages involved.

A large fake resistor provides user feedback. It’s filled with addressable LEDs, which light up the appropriate color bands depending on the test resistor’s value. It’s capable of displaying both 3-band, 4-band, and 5-band color configurations. While six-band resistors do exist, the extra band is typically used for denoting temperature coefficients which can’t readily be determined by this simple test. It can also play audio files to announce the resistance value over a speaker.

It’s a neat project that surely taught the duo many useful skills for working with microcontrollers. Plus, it’s kinda fun — we love the big glowing resistor. We’ve featured some other fancy resistors before, too!

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Photoshop image of the NES game Metroid on a Super Nintendo cartridge.

NES Classic Metroid Ported To Equally Classic Super Nintendo

December 24, 2023 by 8 Comments

There was a time early in the development of the Super Nintendo (SNES) where the new console was to feature backwards compatibility with NES games. The solution would have required a cumbersome cartridge adapter and a hard switch on every console to flip the CPU into 8-bit mode. Unfortunately, it was not meant to be — outside of the first public demo of the console, little evidence exists to suggest the gamers would have been able to supercharge their old NES carts on their Super Nintendo.

But thanks to the impressive port of Metroid to the SNES by [infidelity], we can imagine what such a capability might have been like. There’s more on offer here than reduced sprite flicker. There are additional frames of animation compared to the original, so now Samus’ arm cannon stays consistent rather than magically switching arms when turning around. A complete save game system from the Famicom Disk System version has also been implemented as well, with the traditional three slots. Although purists can still utilize the password system if they so choose.

Ultimately the most impressive inclusion of [infidelity]’s work is the MSU-1 enhancement chip implementation. Fun video intro sequences lead into the main menu where players can select the accompanying soundtrack. There’s the original 8-bit music remapped onto the SNES sound chip, the expanded 8-bit version from the Famicom Disk System, the reimagined sound of Metroid Zero Mission, or a full orchestral score. It really is the sort of situation where there are no wrong answers.

While you’re here, check out this post about bringing Poke’mon ROM hacks into physical cartridge form.

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Mailblocks Makes Your Phone Work More Like The Post, Kinda?

December 23, 2023 by 3 Comments

Phones can be distracting, with notifications popping up all the time to snare our attention and maybe even ruin our lives. [Guy Dupont] wishes to be no slave to the machine, and thus built a solution. Enter Mailblocks.

The concept is simple. It’s a physical mailbox which [Guy] can put his phone in. All notifications on the phone are blocked unless he puts his phone into the box. When the phone is inside and the box is closed, the little red flag goes up, indicating “DOPAMINE” is available, and [Guy] can check his notifications.

To achieve this, [Guy] is running a custom DNS server. It redirects all the lookups for push notifications on Android so they go nowhere. Placing the phone in the mailbox turns the re-directions off, so the phone can contact the usual servers and get its notifications as normal.

It’s a novel way of fighting against the constant attention suck of modern smartphones. Rather than being bombarded by notifications in real time, [Guy] instead has to take a significant intentional physical action to check the notifications. It cuts the willpower required and the interruptions to his work in a fell swoop.

We’ve featured [Guy’s] innovative and outside-the-box projects before, too. His smart pants were an absolute tour de force, I might add.

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Dial Up Over Discord

December 23, 2023 by 17 Comments

Some hacks are useful and some are just… well… for the fun of it, and we can appreciate that. Take, for example, [Cool Blog’s] recent experiments with dialup networking. If you think about it, the BBS systems of yesterday have been replaced with more modern tools like Discord. So why not run modems using audio chat over Discord and get the best of both worlds?

This was both easier and harder than we would have expected. The first hurdle was the lack of any actual modems. Luckily, there are software modem emulators like minimodem that makes a PC soundcard work like a modem. It supports some basic protocols, and that’s probably a good thing since the digital audio channel is probably unable to support anything too sophisticated.

Using some crude audio routing 300 baud data did flow. Increasing the baud rate all the way to 2,100 worked reliably. Combining some more sophisticated audio flows and managing sockets with systemd made the process easier. The goal was to, eventually, telnet over the link but that never worked. We would guess that it could work if you spent enough time.

But the proof is in the pudding, and the basic idea works. Why do it? We can’t think of a good reason. But if you want to give it a shot, you can find what you need on GitHub.

Hams still use modems. While we tend to have a soft spot for retrocomputing gear, we don’t miss acoustic couplers at all.

DIY Pneumatic Actuator Does Great In Action

December 23, 2023 by 5 Comments

Pneumatic actuators can be powerful and fast, making them very useful for all kinds of mechanical jobs. [Michael Rechtin] decided that while he could buy them off-the-shelf, he preferred to see if he could make his own via 3D printing. Despite the challenges, he succeeded!

Part of his success is because he knew when to take advantage of the strengths of 3D printed parts, and where they wouldn’t perform so well. To that end, the main body of the cylinder is actually a piece of PVC pipe. That’s because manufactured PVC pipe is far smoother and more regular than what you could reasonably achieve with a most 3D printers. The end caps, however, were printed and tapped to take standard air fittings. The piston was printed too, fitted with a steel cylinder rod and O-rings for sealing.

The double-acting cylinder performed remarkably well in testing, easily skewering an orange. The initial version did leak a touch, but later revisions performed better. Springs were also fitted for damping hits at either end which improved longevity, with a test rig racking up over 10,000 cycles without failure.

We love a design that is both easy to build at home and capable of great performance. We’ve featured some neat open-source pneumatic builds before, too.

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Mega-CNC Router Carves Styrofoam Into A Full-Size Flying Delorean

December 23, 2023 by 18 Comments

When you own an enormous CNC router, you’ve got to find projects that justify it. So why not shoot for the sky — literally — and build the 1980s-est possible thing: a full-scale flying Delorean.

Attentive readers will no doubt remember [Brian Brocken] from his recent attempt to bring a welding robot out of retirement. That worked quite well, and equipped with a high-speed spindle, the giant ABB robot is now one of the biggest CNC routers we’ve ever seen. As for the flying Delorean, short of the well-known Mr. Fusion mod, [Brian] had to settle for less fictional approaches. The project is still in its early phase, but it appears that the flying car will basically be a huge quadcopter, with motors and propellers hidden under the chassis. That of course means eschewing the stainless steel of the OEM design for something lighter: expanded polystyrene foam (EPS).

The video below shows the fabrication of most of the body, which starts as large blocks of EPS and ends up as shaped panels and an unthinkable amount of dust. Individual pieces are glued together with what looks like plain old PVA adhesive. The standard Delorean “frunk” has been replaced by a louvered assembly that will act as an air intake; we presume the rear engine cover will get the same treatment. Interestingly, the weight of the finished model is almost exactly what Fusion 360 predicted based on the 3D model — a mere 13.9 kg.

[Brian] is currently thrust-testing motors and propellers and has some interesting details on that process in his write-up. There’s obviously a lot of work left on this project, and a lot more dust to be made, and we’ll be eagerly following along. Continue reading “Mega-CNC Router Carves Styrofoam Into A Full-Size Flying Delorean” →

Infrared Following Robot Built As Proof-of-Concept For Autonomous Luggage

December 23, 2023 by 7 Comments

Once upon a time, the poor humans of the past had to lug around suitcases and trunks with their own arms. Then, some genius figured out that you could just put wheels on and make everyone’s life a million times easier. Now, what if you didn’t even have push, because your luggage could just follow you instead? Well, students [Yuqiang Ge] and [Yiyang Zhao] have figured out a proof of concept for how that could work.

Their build is a small robotic platform that they assembled for their ECE5730 final project. The tiny wheeled robot is programmed to rotate on the spot until its infrared sensors pick up a signal. In turn, the user is intended to carry an infared beacon for it to lock onto. A pair of sensors are used on the robot platform, separated by a board to serve as a blind. The robot determines the relative signal strength from each sensor, and uses that to vary PWM signals to the two DC drive motors to steer the robot platform to seek and follow the infrared beacon.

It’s a neat idea, and looks to work pretty well in a university corridor. It even has an ultrasonic range sensor to (ideally) stop when it gets too close to the user. Whether it would survive the tumult of a crowded airport is another thing entirely, but that’s what the engineering process is about. Indeed, the very concept has been commercialized already!

Following-robots are a common student project, and one well worth exploring if you’re new to the robotic field.

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