Protect Your Tomatoes With A 9V Battery

December 19, 2020 by Lewin Day 57 Comments

Growing fresh vegetables at home is a popular pastime, even moreso in a year when we’ve all been locked inside. However pests can easily spoil a harvest, potentially putting a lot of hard work down the drain. [Matt] of [DIY Perks] isn’t one to give up his tomatoes without a fight, however, and came up with a solution to protect his plants.

The trick is to take advantage of the mildly conductive slime excreted by snails as they travel along the ground. To protect potted plants, [Matt] places two strips of copper tape around the perimeter of the pot, spaced about a centimeter apart. Each strip is connected to one terminal of a 9 V battery. When a snail attempts to cross the strips, it completes a circuit between the two, and the electrical current that flows irritates the snail, forcing it to retreat.

[Matt] notes that no snails were harmed in the making of the video, and that the solution is far kinder to the slimy critters than poisons or traps. He also goes so far as to demonstrate alternative solutions for garden beds, as well. We’ve more commonly seen [Matt] working with lighting, though it’s great to see he has a bit of a green thumb, too. Video after the break.

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Micro:bit Put On Plant Minding Duty

December 15, 2020 by Lewin Day 1 Comment

The BBC has a long history of supporting technology education in schools. The BBC Micro introduced a whole generation of students to computers, and more recently the Micro:bit is teaching today’s children about embedded systems. [Michael Klements] happens to be a grown adult, but has whipped up a project using the little board to build an automatic plant watering system.

Rather than a simple timer-based system, [Michael’s] build measures soil moisture using a capacitive sensor. This has the benefit of not needing to be in direct contact with the soil as resistive sensors do, and thus the sensor can be built in a fashion that minimises corrosion. The Micro:bit reads this sensor using an analog input, and displays the moisture level using its inbuilt LED matrix as a graph. Once levels dip below a set threshold, a pump is activated to deliver water to the plant until the soil is suitably moist again.

It’s a simple project, but one that would be a great way to teach students about interfacing with pumps and sensors, as well as the basics of control systems. [Michael] also notes that further work could involve interfacing multiple Micro:bits using their onboard wireless hardware. We’ve thus far seen the Micro:bit used for everything from handheld gaming to gumball delivery. Video after the break.

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Norway Leads The Charge To Phase Out Internal Combustion; China And The UK To Follow

December 7, 2020 by Lewin Day 194 Comments

Climate change promises to cause untold damage across the world if greenhouse gas emissions continue at current levels for much longer. Despite the wealth of evidence indicating impending doom, governments have done what humans do best, and procrastinated on solving the issue.

However, legislatures around the world are beginning to snap into action. With transportation being a major contributor to greenhouse gas emissions — 16% of the global total in 2016 — measures are being taken to reduce this figure. With electric cars now a viable reality, many governments are planning to ban the sale of internal combustion vehicles in the coming decades.

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Killing Mosquitoes With Cardi B

December 5, 2020 by Bryan Cockfield 31 Comments

Keeping a bird bath or a pond in your yard is a great way to add ambiance and style, but both of these things can be a haven for mosquitoes. Popular methods of getting rid of them are often with harsh pesticides, but [Shane] has brought us a more environmentally-friendly way of taking care of these disease-carrying insects by looping a Cardi B playlist underwater, killing the mosquito larvae.

While the build does include some other favorites such as “Baby Shark” and would probably work with any song (or audio of sufficient volume) the build is still pretty interesting. It’s based on a 555 timer circuit which powered an ultrasonic sound gun, but was repurposed for this build. The ultrasonic modules were replaced with piezo modules which were waterproofed with silicone. The sound produced vibrates at a frequency which resonates with the mosquito larvae and is fatal to them. [Shane] put the build into a small boat which can be floated in any pond, bird bath, horse trough, or water feature.

The major caveat to this build is that it may be damaging to other beneficial animals such as fish or frogs, so he suggests limiting its use to uninhabited stagnant water. Either way, though, it’s a pretty unique way of taking care of a mosquito problem not unlike another build which takes care of these insects in water a slightly different way.

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The Dark Side Of Solar Power

December 2, 2020 by Kristina Panos 302 Comments

Everybody loves solar power, right? It’s nice, clean, renewable energy that’s available pretty much everywhere the sun shines. If only the panels weren’t so expensive. Even better, solar is now the cheapest form of electricity for companies to build, according to the International Energy Agency. But solar isn’t all apples and sunshine — there’s a dark side you might not know about. Manufacturing solar panels is a dirty process from start to finish. Mining quartz for silicon causes the lung disease silicosis, and the production of solar cells uses a lot of energy, water, and toxic chemicals.

The other issue is that solar cells have a guanteed life expectancy of about 25 years, with average efficiency losses of 0.5% per year. If replacement begins after 25 years, time is running out for all the panels that were installed during the early 2000s boom. The International Renewable Energy Agency (IREA) projects that by 2050, we’ll be looking at 78 million metric tons of bulky e-waste. The IREA also believe that we’ll be generating six million metric tons of new solar e-waste every year by then, too. Unfortunately, there are hardly any measures in place to recycle solar panels, at least in the US.

How are solar panels made, anyway? And why is it so hard to recycle them? Let’s shed some light on the subject.

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Reduce, Reuse, Injection Mold

November 21, 2020 by Al Williams 34 Comments

Many people have the means now to create little plastic objects thanks to 3D printing. However, injection molding is far less common. Another uncommon tech is plastic recycling, although we do occasionally see people converting waste plastic into filament. [Manuel] wants to solve both of those problems and created an injection molder specifically for recycling.

The machine — Smart Injector — is automated thanks to an Arduino. It’s pretty complex mechanically, so in addition to CAD models there are several PDF guides and a ton of pictures showing how it all goes together.

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Mushroom Canoe Is Rooted In Nature

November 20, 2020 by Kristina Panos 38 Comments

Mushrooms might be the most contested pizza topping after pineapple, but can you build a boat from pineapples? Probably not, but you can from mushrooms. Mushrooms, or rather their mycelium root systems, can be used for things like packaging, insulation, and furniture, and it could be the next thing in floatation, too. Just ask [Katy Ayers], a Nebraska college student who built an eight-foot canoe molded almost entirely of mycelium.

[Katy] got into mushrooms when she was tasked with researching solutions to climate change. She loves to fish and has always wanted a boat, so when she found out that mycelium are naturally buoyant and waterproof, she decided to try using it as a building material.

[Katy] floated the idea by the owner of a local mushroom company and they got to work, building a frame suspended in the air by a hammock-like structure. Then they covered the boat’s skeleton with spores and let it proliferate in a hot, humid growing room. Two weeks later, they had a boat made of live mycelium, which means that every time it goes out on the water, it spawns mushrooms. The total cost including tools was around $500. The boat experiment spawned even more mycelium projects. [Katy] has since experimented with making lawn chairs and landscaping bricks from mycelium.

Don’t want to wait to grow your own mycelium boat? You can build one out of stretch wrap, packing tape, and tree branches.

Thanks for the tip, [ykr300]!

Main image by Katy Ayers via NBC News