Building A Small Gyro Stabilized Monorail

August 27, 2024 by Lewin Day 11 Comments

Monorails aren’t just the core reason why The Simpsons remains on air after thirty-six seasons, twenty-six of which are unredeemable garbage. They’re also an interesting example of oddball rail travel which has never really caught on beyond the odd gadgetbahn project here and there. [Hyperspace Pirate] recently decided to investigate the most interesting kind of monorail of all—the gyro stabilized type—on a small scale for our viewing pleasure.

The idea of a gyro-stabilized monorail is to use active stability systems to allow a train to balance on a single very thin rail. The benefits of this are questionable; one ends up with an incredibly expensive and complex rail vehicle that must always run perfectly or else it will tip over. However, it is charming to watch in action.

[Hyperspace Pirate] explains how the monorail vehicle uses control moment gyroscopes to keep itself upright. The video also explains the more common concept of reaction wheels so the two systems can be contrasted and compared. It all culminates in a wonderful practical demonstration with a small 3D printed version of a 20th-century gyro monorail running on a 24″ track.

If you’re studying mechanical engineering this is a great project to pore over to see theoretical principles put into obvious practice. Video after the break.

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Automatic Garbage Can Keeps Cooking Cleaner

July 23, 2024 by Bryan Cockfield 30 Comments

Over the last decade or so, we’ve been inundated with appliances with wireless or “smart” technology that is often of dubious utility. No one really needs a tablet in their refrigerator or Wi-Fi on their coffee maker. A less glamorous kitchen appliance that actually might benefit from some automation and connectivity is the garbage can, or “bin” for those speaking the Queen’s English, and [Mellow_Labs] is here to show off just how to get that done with this automatic garbage can lid.

As he explains, the real impetus behind this build is to not have to touch a dirty lid while cooking to avoid having to take time to wash one’s hands again afterwards. There are a few other design criteria as well; it has to be roommate-approved so nothing permanently attached to the lid, overly complicated, or with an unnecessary amount of wires or other fixtures. A servo with an extension sits on the lid itself, and when activated forces the lid open. A distance sensor provides basic gesture recognition and a microcontroller with wireless connectivity controls both and provides home automation integration as well. With a 3D printed case that includes a quick disconnect function for easy cleaning of the lid, the build was ready to be put into service.

The first iteration used an infrared distance sensor, but placing it by an open window caused it to continuously open and close since sunlight has the same wavelengths of light the sensor is tuned for. A quick swap with an ultrasonic sensor solved the problem, and the garbage can is working flawlessly in the kitchen now. Another appliance that is generally not targeted by off-the-shelf automation solutions is the range fume hood, but another build tackled that problem a while back.

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Photoresistor-based Single Pixel Camera

July 23, 2024 by Alexander Rowsell 18 Comments

[Hugh] has been going back through episodes of the Hackaday podcast, and Elliot mentioned in episode 67 that it can often be inspiring to go back through the archives of Hackaday to find ideas for new projects. Well, he did just that and came across a single-pixel camera made using an infrared photodiode. He decided to try and hack together his own single-pixel camera, but this time on the cheap and using an ever simpler component – a photoresistor!

His description of the project tickled me – “I’ve used an ESP32, MicroPython, two servos, a peanut butter jar lid, a toilet paper roll, a paper towel roll, magnets and scrap wood for this version.” That’s certainly a much simpler bill of materials than the original (which was written up by Hackaday way back in 2015), which used a nice metal frame to hold everything together. However, there’s absolutely nothing wrong with improvising with things you happen to have to hand.

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Vastly Improved Servo Control, Now Without Motor Surgery

March 21, 2024 by Donald Papp 13 Comments

Hobby servos are great, but they’re in many ways not ideal for robotic applications. The good news is that [Adam] brings the latest version of his ServoProject, providing off-the-shelf servos with industrial-type motion control to allow for much, much tighter motion tracking than one would otherwise be limited to.

Modifying a servo no longer requires opening the DC motor within.

The PID control system in a typical hobby servo is very good at two things: moving to a new position quickly, and holding that position. This system is not very good at smooth motion, which is desirable in robotics along with more precise motion tracking.

[Adam] has been working on replacing the PID control with a more capable cascade-based control scheme, which can even compensate for gearbox backlash by virtue of monitoring the output shaft and motor position separately. What’s really new in this latest version is that there is no longer any need to perform surgery on the DC motor when retrofitting a servo; the necessary sensing is now done externally. Check out the build instructions for details.

The video (embedded just below) briefly shows how a modified servo can perform compared to a stock one, and gives a good look at the modifications involved. There’s still careful assembly needed, but unlike the previous version there is no longer any need to actually open up and modify the DC motor, which is a great step forward.

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Cute CO2 Gauge Tells You When To Crack A Window

March 19, 2024 by Kristina Panos 25 Comments

[Cyrill] has a good home automation scheme going: there are a number of physical switches set around the place that control the essential functions. The only problem is that in the winter time, this results in a great deal of phone checking as [Cyrill] tries to monitor the CO₂ level. Tired of all this screen time, [Cyrill] set about to create an incredibly cute (and useful) Co₂ monitor that plainly shows the current level and how bad it is, relatively speaking.

A large servo and an ESP32-S2 make up the guts of an analog CO2 sensor.

Behind that adorable face is a DS3225 servo being driven by a Wemos S2 mini, both of which [Cyrill] happened to have handy. Although the 25 Kg servo may be complete overkill for the situation, [Cyrill] reports that it is quieter than your average AliExpress alternatives, which makes it well worth it in our book. Then it was on to Inkscape to make the gauge itself. [Cyrill] says they’re an Inkscape noob, but that face could have fooled us.

Finally, it was time to integrate it into Home Assistant to get readings from the CO₂ sensors. This was easier said than done, but [Cyrill] does a nice job of explaining how to get the ESP32-S2 up and working.

If you’re out there monitoring CO levels in your home, beware of fake sensors that cropped up during the height of the pandemic and are likely still at large.

Swapping Nunchucks For A Steering Wheel

January 30, 2024 by Bryan Cockfield 4 Comments

Rather than chasing pure performance and high quality graphics like other gaming companies, Nintendo has made a name for themselves over the last few decades by favoring not only artistic design and gameplay, but the physical design of the game systems. Of course the hybrid handheld Switch console is among these, but it also includes things like the novel design of the Nintendo 64 controller and, of course, the Wii nunchuck controllers. They’re not always met with resounding approval, though. Some of us tend to prefer more traditional gamepad design, and will go to extreme lengths to get it like this D-pad for playing Mario Kart Wii.

Rather than simply building a compatible controller for the Wii, or even using a GameCube controller, this controller setup takes a more roundabout approach. A Wiimote is placed in a holster built from Lego, and the game is set up to recognize it as if it were being used in its steering wheel mode. The Lego holster has a servo attached which can tilt the Wiimote from side to side, mimicking a player holding it to play the game, with another set of servos set up to press the various buttons. To control the controller, a homebrew D-pad built on perfboard with an Arduino at its core is used to send commands to the servos, allowing for a more standard controller layout to be used for the classic kart racing game than the steering wheel Wiimote allows.

While it’s quite obvious that there are simpler, easier solutions that avoid the sometimes awkward nature of using Wiimotes, we certainly appreciate the Rube Goldberg-like approach to setting up your gaming experience exactly the way you like. Whether that’s setting up an antique CRT effect for the authentic retro gaming experience or building a complete racing simulator from scratch, the gaming experience is ripe for personalization and unique builds like this one.

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Robotic Rose Of Enchantment Drops Petals On Command

December 19, 2023 by Kristina Panos 2 Comments

In Disney’s 1991 film Beauty and the Beast, an enchantress curses the young (10 or 11-year-old) prince to beast-hood for spurning her based solely on her appearance. She gives him a special rose that she says will bloom until his 21st birthday, at which time he’ll be turned back into a prince, provided that he learned to love by then. If not, he’ll be a beast for eternity. As the years go by, the rose drops the occasional petal and begins to wilt under the bell jar where he keeps it.

[Gord Payne] was tasked with building such a rose of enchantment for a high school production and knocked it out of the park. With no budget provided, [Gord] used what he had lying about the house, like nylon trimmer line. In fact, that’s probably the most important part of this build. A piece of trimmer line runs up through the stem made of tubing and out the silk rose head, which connects with a custom 3-D printed part.

Each loose petal hangs from the tubing using a short length of wire. Down at the base, the trimmer line is attached to a servo horn, which is connected to an Adafruit Circuit Playground. When the button is pressed on the remote, the servo retracts the trimmer line a little bit, dropping a petal. Be sure to check out the demo after the break.

Dropping petals is an interesting problem to solve. Most of the flower hacks we see around here involve blooming, which presents its own set of troubles.

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