arduino

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Make Your Own Remy The Rat This Halloween

October 19, 2024 by 10 Comments

[Christina Ernst] executed a fantastic idea just in time for Halloween: her very own Remy the rat (from the 2007 film Ratatouille). Just like in the film Remy perches on her head and appears to guide her movements by pulling on hair as though operating a marionette. It’s a great effect, and we love the hard headband used to anchor everything, which also offers a handy way to route the necessary wires.

Behind Remy are hidden two sub-micro servos, one for each arm. [Christina] simply ties locks of her hair to Remy’s hands, and lets the servos do the rest. Part of what makes the effect work so well is that Remy is eye-catching, and the relatively small movements of Remy’s hands are magnified and made more visible in the process of moving the locks of hair.

Originally Remy’s movements were random, but [Christina] added an MPU6050 accelerometer board to measure vertical movements of her own arm. She uses that sensor data to make Remy’s motions reflect her own. The MPU6050 is economical and easy to work with, readily available on breakout boards from countless overseas sellers, and we’ve seen it show up in all kinds of projects such as this tiny DIY drone and self-balancing cube.

Want to make your own Remy, or put your own spin on the idea? The 3D models and code are all on GitHub and if you want to see more of it in action, [Christina] posts videos of her work on TikTok and Instagram.

[via CBC]

DIY 3D-Printed Arduino Self-Balancing Cube

October 13, 2024 by 16 Comments

Self-balancing devices present a unique blend of challenge and innovation. That’s how [mircemk]’s project caught our eye. While balancing cubes isn’t a new concept — Hackaday has published several over the years — [mircemk] didn’t fail to impress. This design features a 3D-printed cube that balances using reaction wheels. Utilizing gyroscopic sensors and accelerometers, the device adapts to shifts in weight, enabling it to maintain stability.

At its core, the project employs an Arduino Nano microcontroller and an MPU6050 gyroscope/accelerometer to ensure precise control. Adding nuts and bolts to the reaction wheels increases their weight, enhancing their impact on the cube’s balance. They don’t hold anything. They simply add weight. The construction involves multiple 3D printed components, each requiring several hours to produce, including the reaction wheels and various mount plates. After assembly, users can fine-tune the device via Bluetooth, allowing for a straightforward calibration process to set the balancing points.

If you want to see some earlier incarnations of this sort of thing, we covered other designs in 2010, 2013, and 2016. These always remind us of Stewart platforms, which are almost the same thing turned inside out.

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A Homebrew Gas Chromatograph That Won’t Bust Your Budget

October 13, 2024 by 17 Comments

Chances are good that most of us will go through life without ever having to perform gas chromatography, and if we do have the occasion to do so, it’ll likely be on a professional basis using a somewhat expensive commercial instrument. That doesn’t mean you can’t roll your own gas chromatograph, though, and if you make a few compromises, it’s not even all that expensive.

At its heart, gas chromatography is pretty simple; it’s just selectively retarding the movement of a gas phase using a solid matrix and measuring the physical or chemical properties of the separated components of the gas as they pass through the system. That’s exactly what [Markus Bindhammer] has accomplished here, in about the simplest way possible. Gas chromatographs generally use a carrier gas such as helium to move the sample through the system. However, since that’s expensive stuff, [Markus] decided to use room air as the carrier.

The column itself is just a meter or so of silicone tubing packed with chromatography-grade silica gel, which is probably the most expensive thing on the BOM. It also includes an injection port homebrewed from brass compression fittings and some machined acrylic blocks. Those hold the detectors, an MQ-2 gas sensor module, and a thermal conductivity sensor fashioned from the filament of a grain-of-wheat incandescent lamp. To read the sensors and control the air pump, [Markus] employs an Arduino Uno, which unfortunately doesn’t have great resolution on its analog-to-digital converter. To fix that, he used the ubiquitous HX7111 load cell amplifier to read the output from the thermal conductivity sensor.

After purging the column and warming up the sensors, [Markus] injected a sample of lighter fuel and exported the data to Excel. The MQ-2 clearly shows two fractions coming off the column, which makes sense for the mix of propane and butane in the lighter fuel. You can also see two peaks in the thermal conductivity data from a different fuel containing only butane, corresponding to the two different isomers of the four-carbon alkane.

[Markus] has been on a bit of a tear lately; just last week, we featured his photochromic memristor and, before that, his all-in-one electrochemistry lab.

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A Flip Digit Clock, Binary Style

October 8, 2024 by 7 Comments

Flip digit clocks are a prized piece of consumer electrical ephemera, providing as they do a digital display without significant electronics. Making your own flip digit display involves some drudgery in the production of all those flip cards, but how would it seem if the complexity was reduced? Go from base 10 to base 2 for example, and a binary flip digit display can be made from flip dot display parts. [Marcin Saj] has done just that, resulting in a timepiece that’s a few bits out of the ordinary.

Under the hood though it’s slightly more conventional, with the trusty ATmega328 and Arduino bootloader, whose software drives the dot electromagnets via a set of MOSFET drivers. It’s a nice project which if you want there’s a Kickstarter to buy one, but the files are also available from a GitHub repository if you’d like to have a go for yourself. Meanwhile you can see it in action in the video below the break.

We like this clock, as it’s different from the norm in Arduino clocks. It’s not however the first flip dot clock we’ve seen, this one has a full dot matrix display.

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Quake In 276 KB Of RAM

October 5, 2024 by 20 Comments

Porting the original DOOM to various pieces of esoteric hardware is a rite of passage in some software circles. But in the modern world, we can get better performance than the 386 processor required to run the 1993 shooter for the cost of a dinner at a nice restaurant — with plenty of other embedded systems blowing these original minimum system requirements out of the water.

For a much tougher challenge, a group from Silicon Labs decided to port DOOM‘s successor, Quake, to the Arduino Nano Matter Board platform instead even though this platform has some pretty significant limitations for a game as advanced as Quake.

To begin work on the memory problem, the group began with a port of Quake originally designed for Windows, allowing them to use a modern Windows machine to whittle down the memory usage before moving over to hardware. They do have a flash memory module available as well, but there’s a speed penalty with this type of memory. To improve speed they did what any true gamer would do with their system: overclock the processor. This got them to around 10 frames per second, which is playable, but not particularly enjoyable. The further optimizations to improve the FPS required a much deeper dive which included generating lookup tables instead of relying on computation, optimizing some of the original C programming, coding some functions in assembly, and only refreshing certain sections of the screen when needed.

On a technical level, Quake was a dramatic improvement over DOOM, allowing for things like real-time 3D rendering, polygonal models instead of sprites, and much more intricate level design. As a result, ports of this game tend to rely on much more powerful processors than DOOM ports and this team shows real mastery of their hardware to pull off a build with a system with these limitations. Other Quake ports we’ve seen like this one running on an iPod Classic require a similar level of knowledge of the code and the ability to use assembly language to make optimizations.

Thanks to [Nicola] for the tip!

A black OLED screen with a happy face displayed upon it is situated at the top of a squarish calculator with a 5x6 grid of white calculator keys. It floats above a graphing calculator, Nintendo Switch, aigo numpad, and an Arduino Mega on a white table. A handful of differently-colored kalih choc switches are in various places around the table.

Mechanical Switch Sci-Calc Is Also A Macropad

October 4, 2024 by 6 Comments

Smartphones have replaced a desktop calculator for most folks these days, but sometimes that tactility is just what you need to get the mathematical juices flowing. Why not spruce up the scientific calculator of yore with the wonders of modern microcontrollers?

While you won’t be able to use Sci-Calc on a standardized test, this classy calculator will let you do some pretty cool things while clacking on its mechanical choc switches. Is it a calculator? Obviously. Is it an Arduboy-compatible device that can play simple games like your TI-84? Yes. Is it also a macropad and ESP32 dev board? Why not? If that isn’t enough, it’s also takes both standard and RPN inputs.

[Shao Duan] has really made this device clean and the menu system that rewrites main.bin based on the program selection is very clever. Escape writes main.bin back into the ROM from the SD card so you can select another application. A few classic games have already been ported, and the process looks fairly straightforward for any of your own favorites.

If you’re hankering for more mathy inputs, checkout the Mathboard or the MCM/70 from 1974.

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Reverse Time Back To The Days Of RPN

September 26, 2024 by 68 Comments

While Texas Instruments maintains dominance in the calculator market (especially graphing calculators), there was a time when this wasn’t the case. HP famously built the first portable scientific calculator, the HP-35, although its reverse-Polish notation (RPN) might be a bit of a head-scratcher to those of us who came up in the TI world of the last three or four decades. Part of the reason TI is so dominant now is because they were the first to popularize infix notation, making the math on the calculator look much more like the math written on the page, especially when compared to the RPN used by HP calculators. But if you want to step into a time machine and see what that world was like without having to find a working HP-35, take a look at [Jeroen]’s DIY RPN calculator.

Since the calculator is going to be RPN-based, it needs to have a classic feel. For that, mechanical keyboard keys are used for the calculator buttons with a custom case to hold it all together. It uses two rows of seven-segment displays to show the current operation and the results. Programming the Arduino Nano to work as an RPN calculator involved a few tricks, though. [Jeroen] wanted a backspace button, but this disrupts the way that the Arduino handles the input and shows it on the display but it turns out there’s an Arudino library which solves some of these common problems with RPN builds like this.

One of the main reasons that RPN exists at all is that it is much easier for the processor in the calculator to understand the operations, even if it makes it a little bit harder for the human. This is because early calculators made much more overt use of a stack for performing operations in a similar way to Assembly language. Rather than learning Assembly, an RPN build like this can be a great introduction to this concept. If you want to get into the weeds of Assembly programming this is a great place to go to get started.