See If Today’s Air Quality Will Conch You Out

January 20, 2020 by Kristina Panos 16 Comments

Air quality is one of those problems that is rather invisible and hard to grasp until it gets bad enough to be undeniable. By then, it may be too late to do much about it. But if more people were interested in the problem enough to monitor the air around them, there would be more innovators bringing more ideas to the table. And more attention to a problem usually means more accountability and eventual action.

This solar-powered particulate analyzer made by [rabbitcreek] is a friendly way to take the problem out of the stratosphere of ‘someday’ and bring it down to the average person’s backyard. Its modular nature makes it fairly simple to build, and the conch shell enclosure gives it a natural look. That shell also cleverly hides the electronics, while at the same time allowing air and particulates to reach the sensor. If you don’t like the shell enclosure, we think the right type of bird feeder could protect the electronics while allowing airflow.

[rabbitcreek] attached a sizeable solar panel to the shell on a GoPro mount so it can be adjusted to face the sun. The panel charges a Li-Po battery that gets boosted to 5V. Every two hours, a low-power breakout circuit wakes up the Feather ESP32 and takes a reading from the particulate sensor. [rabbitcreek] can easily see the data on his phone thanks to the Blynk app he created.

Why limit this to your yard? Bare ESP32s are cheap enough that it’s feasible to build a whole network of air quality sensors.

Living At The Close Of The Multiway Era

January 9, 2020 by Jenny List 97 Comments

After over a decade of laptop use, I made the move a couple of months ago back to a desktop computer. An ex-corporate compact PC and a large widescreen monitor on a stand, and alongside them a proper mouse and my trusty IBM Model M that has served me for decades. At a stroke, the ergonomics of my workspace changed for the better, as I no longer have to bend slightly to see the screen.

The previous desktop PC was from an earlier time. I think it had whatever the AMD competitor to a Pentium 4 was, and if I recall correctly, its 512 MB of memory was considered to be quite something. On the back it had an entirely different set of sockets to my new one, a brace of serial ports, a SCSI port, and a parallel printer port. Inside the case, its various drives were served by a set of ribbon cables. It even boasted a floppy drive. By contrast the cabling on its successor is a lot lighter, with much less bulky connectors. A few USB plugs and a network cable, and SATA for its disk drive. The days of bulky multiway interconnects are behind us, and probably most of us are heaving a sigh of relief. Continue reading “Living At The Close Of The Multiway Era” →

Reading Light Not Quite Powered By Your Favorite Hot Beverage

January 6, 2020 by Lewin Day 13 Comments

Thermoelectric devices are curious things, capable of generating electricity via the Seebeck effect from a temperature differential across themselves. The Seebeck effect does not produce a huge potential difference, but when employed properly, it can have some useful applications. [MJKZZ] decided to apply the technology to build a reading light, powered by a hot cup of coffee.

The build is based around four Peltier modules, 40mm x 40mm in size, sandwiched between a pair of copper sheets. The modules are wired in series to create a greater output voltage, and an aluminium heatsink is fitted to one side to create a higher temperature differential. The set-up produces just 230 mV from human body temperature, but over 8 volts when warmed directly with a heat gun. Boiling water in a mug produces a more restrained 2.1V output.

On its own, this voltage is a little weak to do anything useful. Thus, the electricity from the Peltier modules is fed through a joule thief, which helps step up the voltage to a more useful range to run an LED. With a mug of coffee on the copper plate, the assembly isn’t quite able to light the LED enough to allow the user to read comfortably. However, it flickers into life just a touch, demonstrating the basic concepts in action.

While it’s not the most practical build, and it’s likely to cool your coffee faster than you’d like, it’s a fun project that serves to educate about the mechanics of the Seebeck effect and using Peltier devices to generate it. Another fun application is to use them in a cloud chamber. Video after the break.

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DIY Trommel Sifts Compost In Style

January 2, 2020 by Kristina Panos 22 Comments

Composting is a great idea that helps you and the planet at the same time. But all that stuff is going to break down at different rates, and depending on what you put in there and how soon you want to use the compost, you’ll probably have to sift out some unwanted stuff first.

[Minnear Knives] had a bunch of apricot stones in his compost pile, and it was the pits. He did some research and decided to build his own rotary trommel to tumble out the trash. As you will see in the video after the break, it works really well. All he has to do is turn on the motor and shovel raw compost or dirt into one end. Bad stuff tumbles out the other end into a wheelbarrow, while the good stuff is sifted down into a pile under the cylinder. Just look at that rich, fluffy compost.

The best part is that he was able to make it mostly from stuff he had lying around, though he did trade some beer for the v-belt pulley. The cylinder is essentially made from mesh that’s zip-tied to bicycle rims. A 1/4 horsepower motor mounted up top uses that v-belt pulley to spin the cylinder’s rims against casters that are mounted to the frame. Thanks to the pair of bike wheels on the back, he can cart it around the ranch unassisted.

Composting doesn’t have to be any more difficult than a pile in the backyard. But if you don’t have a backyard, why not build a rotating bin that you can monitor from your phone?

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Reducing The Risk Of Flying With Hydrogen Fuels

January 1, 2020 by Sharon Lin 91 Comments

Flight shaming is the hot new thing where people who take more than a handful of trips on an airplane per year are ridiculed for the environmental impact of their travels. It’s one strategy for making flying more sustainable, but it’s simply not viable for ultimately reducing the carbon impact that the airline industries have on the environment.

Electric planes are an interesting place to look for answers. Though carbon-free long haul travel is possible, it’s not a reality for most situations in which people travel today. Current battery technology can’t get anywhere near the energy density of fossil fuels and larger batteries aren’t an option since every pound matters when designing aircraft.

Even with land travel and electric grids improving in their use of renewables and electric power, aviation tends to be difficult to power with anything other than hydrocarbons. Student engineers in the AeroDelft program in the Netherlands have created Project Phoenix to develop an aircraft powered by a liquid hydrogen fuel cell, producing a primary emission of water vapor. So it is an electric plane, but leverages the energy density of hydrocarbons to get around the battery weight problem.

While the project may seem like an enormous reach peppered with potential safety hazards, redundant safety features are used such as sensors and vents in case of a hydrogen leakage, as well as an electric battery in case of failure. Hydrogen produced three times more energy per unit than kerosene, but is six times the volume in gas form and requires cumbersome compression tanks.

Even though hydrogen fuel only produces water vapor as a byproduct, it can still cause greenhouse effects if it is released too high and creates clouds. The team is exploring storage tanks for slow release of the water vapor at more optimal altitudes. On top of that, most hydrogen is produced using steam methane reforming (SMR), creating up to 150g of greenhouse gases per kWh, and electrolysis tends to be more costly and rarely carbon neutral. Alternatives such as solar power, biofuels, and electric power are looking to make headwind as well, but the technology is still far from perfected.

While it’s difficult to predict the success of the project so early on, the idea of reducing risk in hydrogen fuels may not be limited to a handful of companies for very long.

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The Hornsdale Power Reserve And What It Means For Grid Battery Storage

December 16, 2019 by Lewin Day 130 Comments

Renewable energy has long been touted as a major requirement in the fight to stave off the world’s growing climate emergency. Governments have been slow to act, but prices continue to come down and the case for renewables grows stronger by the day.

However, renewables have always struggled around the issue of availability. Solar power only works when the sun is shining, and wind generators only when the wind is blowing. The obvious solution is to create some kind of large, grid-connected battery to store excess energy in off-peak periods, and use it to prop up the grid when renewable outputs are low. These days, that’s actually a viable idea, as South Australia proved in 2017.

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Can You Piezo A Peugeot?

December 9, 2019 by Jenny List 55 Comments

Car manufacturers have a problem when it comes to climate change. Among the variety of sources for extra atmospheric CO₂ their products are perhaps those most in the public eye, and consequently their marketing departments are resorting to ever more desperate measures to sanctify them with a green aura. Among these are the French marque Peugeot, whose new electric version of their 208 model features in a slick video alongside a futuristic energy-harvesting billboard.

This is no ordinary billboard, nor is it a conventional wind turbine or solar array, instead it harvests ambient noise in one of the busiest parts of Paris, and turns it into electricity to charge the car with an array of piezoelectric energy capture units. This caught our eye here at Hackaday, because it seemed rather too good to be true. Is it a marketing stunt, or could you make a piezo billboard as a practical green energy device? Let’s take a closer look.

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