Turning Glass Into A Touch-Sensitive Button

Although generally glass isn’t associated with touch-sensitive surfaces, the addition of an ITO (indium tin oxygen) coating adds the exciting property of not only being transparent to the visible light part of the electromagnetic spectrum, but also of being electrically conductive. The logical result is that fine folk like [Sokol] simply had to use their newly acquired ITO-coated glass to make a button out of.

Here the easy option is of course to just use it as a capacitive sensor where the conductive ITO layer is used for the capacitive charge and the glass provides the insulator, but here we see it demonstrated how to create a pressure-sensitive implementation instead.

The measured conductivity on the ITO-coated glass in the video is pretty good, at just over 20 Ohm. This thus makes said capacitive button very easy to achieve. To make it a touch-sensitive button, two pieces of glass are used, with the ITO sides facing. Paper is used to create a spacer, after which the slight flex of the glass allows for the two ITO surfaces to touch, completing the circuit.

This is somewhat similar to how resistive touch screens work, with the position of the finger or stylus determined by the resistance between the two sides. In a hobbyist setup this would make it fairly easy to create a multi-position touch screen using just two pieces of glass and some firmware.

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Thingino Teaches Cheap IP Cameras New Tricks

I recently found myself in the market for a few IP cameras to keep an eye on my Prusa 3D printers, and quickly found that the options on the market weren’t exactly ideal. Prusa does offer up an official camera, but the price for a pair of them was a bit more than I wanted to spend on the project. Conversely, there’s no shortage of cheap network-connected cameras available online, but they come with expenses of a different sort, namely proprietary software and cloud services I didn’t want or need.

Somewhere in the deep and dark recesses of this particular rabbit hole, I came across a Reddit post mentioning how a camera running the community-developed Thingino firmware could be plugged into Prusa’s remote printer monitoring scheme. It wasn’t a project I’d heard of previously, and sure enough, a search of the Hackaday back catalog showed we’d never come across it before.

My interest was already piqued, but the discovery that I already owned a supported camera sealed the deal. It was time to explore a new entry in one of my absolute favorite project categories: an open source replacement firmware that turns a cheap consumer device into something more than the sum of its parts.

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Filling High Pressure CO2 Tanks From Sugar Fermentation Gas

After previously using the fermenting of sugar to obtain ethanol fuel, [Hyperspace Pirate] figured that it’d be a waste to just blast the other half of the yeast production in the form of carbon dioxide into the air. This poses the slight problem that gaseous CO2 is fairly bulky, while compressing it into a liquid isn’t exactly for the faint of heart. This of course means that it’s a fun challenge, involving a beach ball, vapor-compression and various compressors.

Although at room temperature compressing CO2 into a liquid requires quite extreme pressures, if you lower it to freezing temperatures it becomes quite feasible to use more typical off-the-shell compressors.

In the video both oil-less and regular compressors are used, mostly because ultimately you want to get pure CO2 into the bottle, without oil or water. Here a few methods are explored, including a pre-cooler with the oil-less compressor as it cannot quite hit the same pressures. With a typical compressor linked to an oil-separator you can directly fill the tank, which is pretty nice, though even with this removal of water turned out to be a chore.

Desiccating the gas that comes out of the fermentation vat, is attempted using a converted water filter that’s filled with desiccant beads, but as the later tests show, this isn’t quite good enough to prevent moisture to make it into the bottle and clogging its nozzle. Of course, moisture here is more acceptable than oil for most applications, so with some more work this could be quite a feasible method to fill bottles with liquid CO2 for various nefarious applications like paintball guns and more.

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Using Your Own RBMK Reactor Control Center At Home

To give people the most intimate RBMK experience, the [Chornobyl Family] has been working tirelessly at not only replicating the original RBMK reactor control room and its SKALA industrial control system’s controls, but also to create a version that you could tinker with at home if you ever fancied getting your own RBMK operator license. This starts with the operator console, with its use demonstrated in a recent video including a range of common commands.

In this video the entering of codes on the console to interact with the system is detailed, including the logic behind it. In the absence of large displays to display many parameters and such, this way the operator could ‘talk’ with the control system, including obtaining current sensors readings and the setting and changing of setpoints. From the same console you can also select and run programs, which is useful for automating tasks, like monitoring coolant flows.

In the second video not only the construction of the control panel is covered, but also a visual representation of the simulated reactor core which is displayed on a connected monitor. Although not a part of the original SKALA system as such, a much larger version existed as a wall-sized physical version inside the control room, so it’s definitely more home-simulator friendly.

We previously covered this SKALA system that controls RBMK reactors, as well as the 1990s modernization of the Chornobyl Nuclear Power Plant.

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Fixing A Warped Paperback Spine With Gentle Heating

Although paperbacks are a much-loved aspect of the literary world, they are not really intended to last the decades the way that hardcover books are. Beyond the typical ravaged covers, paperbacks also tend to suffer from a warped spine, where the formally flat spine gets a definite inwards curve due to the ravages of moisture, temperature, failing glue and the passing of time in general. If this bothers you, then [Book Care Studio] shows a simple technique using which these spines can be flattened again.

All that you need for this approach are two cutting boards and two clamps to provide some clamping force on the book, along with a heat gun and some patience.

The book is clamped between the two boards with the spine sticking out. By putting said spine flat on e.g. a table and pushing on the opposite side while alternatingly briefly releasing the clamps, the spine can be forced into a flatter state. Without forcing this and then flipping the paperback sandwich around to heat the spine with the heat gun, the glue of the binding in the spine can then be softened sufficiently that a few of these push-heat cycles should be enough to straighten the spine.

Other than rebinding the book as for example public libraries are wont to do with a hardcover conversion of flimsy paperbacks, this simple approach should clean up a ratty-looking paperback collection. While one can definitely argue that half the charm of old paperbacks are the wrinkles, curves and intense smell of acidifying paper, it’s always good to have options like this at one’s disposal.

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Adding Weight To A 3D Print With Plaster Of Paris, Cleanly

Sometimes it’s useful to add extra mass to a 3D print, and [Joe Fedewa] shared a simple and effective technique that uses plaster of Paris. Rather than pause the print and insert hardware or weighted bits inside, he designed the base as hollow. Not in the sense of zero infill, but in the sense of modeling a cavity into the open bottom of the object.

An open cavity in the base is perfect for filling with plaster of Paris.

After the print is complete, he mixes the dry plaster with water until it creates a thick but pourable mixture. Then the object gets turned upside-down and the cavity filled. In about an hour, it will have set up enough to be handled and worked.

Plaster of Paris has a good heft to it, but more importantly it can be made perfectly presentable thanks to being very friendly to post-processing. Any rough spots can be easily sanded and the whole bottom smoothed, so one doesn’t even need to cap it off. Completely cured plaster can be sealed with a clear coat for a more durable finish, if desired.

This basic concept has been used in other ways, such as reinforcing prints with concrete to yield parts solid enough to make tools out of. But using plaster of Paris not just to add mass, but specifically to create a presentable surface that doesn’t need covering up is a neat and highly economical adaptation of the idea.

Other methods of adding mass to a 3D print include inserting metal balls or chunky nuts, bolts, or other hardware, but this method doesn’t require pausing prints to insert things. Nor does it require sealing off or capping the print, messing with goopy epoxies or resins, or spending a lot of money — making it a good one to keep in mind in case it comes in handy someday.

Using A Mirror To 3D Scan Both Sides Of An Object At Once

Photogrammetry is the process of 3D scanning an object by taking a lot of photographs, then using software to turn those into a 3D model. But the process can only scan what the camera can see, and one can’t always get a good view of every part of an object. To solve this, [Thomas Megel] shared an experiment in using a mirror to capture the underside of an object simultaneously with its top. The results were encouraging!

Using a mirror as the turntable allows the camera to image the underside at the same time.

To do this he perched a small tabletop gaming mini on a mirror serving as a turntable platform in his self-designed OpenScan Mini machine, which is designed to take highly structured photos of small objects for scanning purposes. This produced a single scan with two objects, the original and its mirror image, together in one file.

Aligning separate models and combining them into one is a common way to deal with partial or incomplete scans. The idea here is to get two scans at once, instead of separately with a reposition of the object in between. Additionally, it should be possible for the software to automatically separate, align, and combine the two since it is known exactly where the mirror plane is.

As far as a proof of concept, it’s encouraging. [Thomas] is still playing with the idea and looking for suggestions, so if you have any insights be sure to share them.

3D scanning can be a very useful tool, and while photogrammetry can be done with little more than your mobile phone’s camera, in some ways the concept is over a hundred years old.