Interactive Plant Lamps for Quiet Spaces

If you’ve spent any serious time in libraries, you’ve probably noticed that they attract people who want or need to be alone without being isolated. In this space, a kind of silent community is formed. This phenomenon was the inspiration [MoonAnchor23] needed to build a network of connected house plants for a course on physical interaction and realization. But you won’t find these plants unleashing their dry wit on twitter. They only talk to each other and to nearby humans.

No living plants were harmed during this project—the leaves likely wouldn’t let much light through, anyway. The plants are each equipped with a strip of addressable RGB LEDs and a flex sensor controlled by an Arduino Uno. Both are hot glued to the undersides of the leaves and hidden with green tape. By default, the plants are set to give ambient light. But if someone strokes the leaf with the flex sensor, it sends a secret message to the other plant that induces light patterns.

Right now, the plants communicate over Bluetooth using an OpenFrameworks server on a local PC. Eventually, the plan is use a master-slave configuration so the plants can be farther apart. Stroke that mouse button to see a brief demo video after the break. [MoonAnchor23] also built LED mushroom clusters out of silicone and cling wrap using a structural soldering method by [DIY Perks] that’s also after the break. These work similarly but use force-sensing resistors instead of flex-sensing.

Networking several plants together could get expensive pretty quickly, but DIY flex sensors would help keep the BOM costs down. Continue reading “Interactive Plant Lamps for Quiet Spaces”

Pocket-Sized Multiduino Does it All

How many times have you wished for a pocket-sized multimeter? How about a mini microcontroller-based testing rig? Have you ever dared to dream of a device that does both?

Multiduino turns an Arduino Nano into a Swiss Army knife of portable hacking. It can function as an analog multimeter to measure resistance, voltage drop, and continuity. It can also produce PWM signals, read from sensors, do basic calculator functions, and display the health of its rechargeable battery pack.

Stick a 10kΩ pot in the left-side header and you can play a space shooter game, or make line drawings by twisting the knob like an Etch-A-Sketch. Be sure to check out the detailed walk-through after the break, and a bonus video that shows off Multiduino’s newest functions including temperature sensing, a monophonic music player for sweet chiptunes, and a virtual keyboard for scrolling text on the OLED screen. [Danko] has a few of these for sale in his eBay store. They come assembled, and he ships worldwide. The code for every existing function is available on his site.

More of a maximalist? Then check out this Micro-ATX Arduino.

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Hacking Balsa to Make it Stronger

Balsa wood has long been revered for its strength and lightweight composition, two properties that make it ideal for building model structures and airplanes. Researchers from the US and China have managed to make balsa even stronger and more useful. They’ve found a way to change its structure, turning it into a carbon sponge that’s strong enough to withstand repeated mechanical strain, but light enough to sit atop a dandelion gone to seed.

Using common chemicals like lye and hydrogen peroxide, the scientists burned the hemicellulose and lignin fibers that make up balsa’s rectangular cell walls. Then they incinerated the sample at 1,000°C, which morphed the cellular structure into a cross between a helical spring and a honeycomb.

Normally, carbonized wood just collapses under weight. But by first burning the cell fibers, the carbonization process results in a balsa carbon sponge capable of withstanding thousands of compressions before deforming. The researchers used the new material as part of a mechanical strain sensor prototype for wearable electronics, and they see a solid future for the material in water purification devices, supercapacitors, and rechargeable batteries.

This is big news for a society that’s trying to find more environmentally responsible ways to keep going full steam ahead in technological growth. Balsa trees grow fast, averaging 10+ feet per year, so this is a more sustainable alternative to graphene and carbon nanotubes. We’re excited to see what comes of this hack of nature. You can read the full paper here.

Even in its natural state, balsa is an interesting material. We once saw someone exploit its water retention abilities to make a rain-activated, shape-shifting prototype for roofing shingles.

Thanks for the tip, [Gervais].

An Old Way to Make a New Crank Handle

When the crank handle on [Eric Strebel]’s cheapo drill press broke in two, did he design and print a replacement? Nah. He kicked it old school and cast a new one in urethane resin.

In his newest video, [Eric] shows us his approach to molding and casting a handle that’s likely stronger than the original. The old crank handle attached to the shaft with a brass collar and a grub screw, so he planned around their reuse. After gluing the two pieces together and smoothing the joint with body filler, he packs the back of the handle with clay. This is a great idea. The original handle just has hollow ribbing, which is probably why it broke in the first place. It also simplifies the cast a great deal.

Here’s where things get really interesting. [Eric] planned to make a one-piece mold instead of two halves. At this point it becomes injection molding, so before he gets out the reusable molding box, he adds an injection sprue as an entry point for the resin, and a plug to support the sprue and the handle. Finally, [Eric] mixes up some nice bright Chevy orange resin and casts the new handle. A few hours later, he was back to drilling.

Crank past the break to watch [Eric]’s process, because it’s pretty fun to watch the resin rise in the clear silicone mold. If you want to take a deeper dive into injection molding, we can fill that need.

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What is Twitter Without the Numbers?

How many people liked your last tweet? Oh yeah? Didja get any retweets? Was it enough to satisfy your need for acceptance, or were you disappointed by the Twitterverse’s reaction?

If you couldn’t see the number of likes, retweets, or followers you had, would you still even use Twitter?

[Ben Grosser] wants to know. He’s trying to see if people will look their relationship with social media squarely in the eye and think honestly about how it affects them. After all, social media itself isn’t the bad guy here—we are all responsible for our own actions and reactions. He’s created a browser extension that demetricates Twitter by removing any bluebird-generated quantifier on the page. It works for tweets, retweets, and the number of tweets playing the trending tag game. Numbers inside of tweets and on user profiles aren’t hidden, however, so you’ll still be able to see, for example, tweets containing Prince lyrics.

The Twitter Demetricator is available as a Chrome extension, and as a userscript for Tampermonkey for the other browsers people actually use (read: no IE support). Here’s what we want to know: Can he gamify it? Can he make a game out of weaning ourselves off of these meaningless metrics and inflated sense of self and FOMO and whatever marketing guff they come up with next to describe the modern human condition? We’re getting low on dopamine over here.

This isn’t [Ben]’s first foray into the social aspects of social media. We covered his Facebook demetricator way back in ’12.

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DIY Text-to-Speech with Raspberry Pi

We can almost count on our eyesight to fail with age, maybe even past the point of correction. It’s a pretty big flaw if you ask us. So, how can a person with aging eyes hope to continue reading the printed word?

There are plenty of commercial document readers available that convert text to speech, but they’re expensive. Most require a smart phone and/or an internet connection. That might not be as big of an issue for future generations of failing eyes, but we’re not there yet. In the meantime, we have small, cheap computers and plenty of open source software to turn them into document readers.

[rgrokett] built a RaspPi text reader to help an aging parent maintain their independence. In the process, he made a good soup-to-nuts guide to building one. It couldn’t be easier to use—just place the document under the camera and push the button. A Python script makes the Pi take a picture of the text. Then it uses Tesseract OCR to convert the image to plain text, and runs the text through a speech synthesis engine which reads it aloud. The reader is on as long as it’s plugged in, so it’s ready to work at the push of a button. We can probably all appreciate such a low-hassle design. Be sure to check out the demo after the break.

If you wanted to use this to read books, you’d still have to turn the pages yourself. Here’s a BrickPi reader that solves that one.

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Finding Noise with an Antenna

[K5ACL], aka [SignalSearch], recently brought his active receive loop antenna in off the roof to give it a checkup and perform any necessary maintenance. While it was in the shack, he took the opportunity to discuss how well it would perform indoors. The verdict? Not ideal. He’d mount it 50 feet away from the house if the HOA would let him.

Houses, and subsequently most ham shacks, are filled with noise sources that interfere badly with HF. So after spending a minute or so listening on an SDR, [K5ACL] demonstrates another use for this type of tightly-tuned antenna—as a noise detector.

The main culprit in [K5ACL]’s house is the ceiling light that’s right there in the shack. You can see the noise striping the waterfall as he turns it on and off. But the noise from the light is small potatoes compared to some other common household items, like those power line adapters that turn house wiring into networking cable. Those produce so much noise that even an active loop is really no match. Stay tuned after the break to watch [K5ACL] work the bands through the noise.

Loop antennas are great if you’re stuck in an apartment building or a congested city. They’re easy enough to make, whether you want a portable loop or a permanent installation.

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