A New Way To Heat People

December 16, 2013 by James Hobson 146 Comments

[Leigh Christie] is a researcher at MIT, and he’s developed an interesting solution to heating people, not buildings.

His TEDx talk, “Heating Buildings is Stupid,” demonstrates the MIT SENSEable City Laboratory’s efforts to tackle energy issues. Their research focuses on finding an alternative to the staggering waste of energy used to heat large spaces. Although TED talk articles are a rarity at Hackaday, we think this idea is both simple and useful. Also, [Leigh] is the same guy who brought us the Mondo Spider a few years ago for the Burning Man exhibition. He’s a hacker.

Anyway, what is it? The system he’s devised is so simple that it’s brilliant: a person-tracking infrared heat spotlight. Using a Microsoft Kinect, the lamp follows you around and keeps the individual warm rather than the entire space. [Leigh] has grand plans for implementing what he calls “Local Heating” in large buildings to save on energy consumption, but smaller-scale implementations could prove equally beneficial for a big garage or a workshop. How much does your workspace cost to heat during the winter? Hackerspaces seem like the perfect test environment for a cobbled-together “Local Heating” system. If anyone builds one, we want to hear about it.

Check out the full TEDx talk after the break.

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Peltier Joule Thief Power Supply

November 12, 2013 by Todd Harrison 20 Comments

[Steven] manages to power an LED for 15 minutes using hot and cold water as a battery. He does this using the thermoelectric effect also known as the Seebeck effect, Peltier effect or Thomson effect. This isn’t particularly new; in fact there are commercial products that you can use to charge a cell phone using a small campfire or internal burner that works on the same principle.

What is interesting about [Steven’s] device is that he uses a salvaged Peltier device not meant for generating electricity, coupled with a home built joule thief circuit. In the video he describes how the joule thief functions and powers the LED using the small voltage generated by the Peltier device. The energy for the thermoelectric effect is conducted from a hot water bath through aluminum plates, through the positive and negative sides of the Peltier device, through more aluminum plates and finally into a cold water bath. As the heat energy transfers through the Peltier device a small electric current is generated and flows in two small wires coming out the side of the device. The energy generated by the Peltier device is stored in the joule thief and periodically dumped at a voltage high enough to forward bias the LED “on” for a brief moment. Technically the LED is flashing but at a frequency too high for our eyes to see. As the hot water bath cools, the LED goes from very bright, to dim, to off in about 15 minutes.

Not a very practical power supply but still quite the parlor trick. He wraps up the tutorial specifying that a TEG thermoelectric generator would be a much better choice for generating power and can handle much higher temperatures. You can watch the video after the break.

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[Charles’s] Epic “Total-Recap” GoKart Post

October 27, 2013 by Marsh 11 Comments

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If you’ve built an electric vehicle in the past few years, you probably owe [Charles] a couple of beers. Now you can feel more indebted to him after you read his 17,500-word, 10-part post covering everything you need to know about electric go-kart design. You’ll want to grab a sandwich to keep you company.

You probably recall the Chibikart from posts earlier this summer, which is one of an endless list of EV projects [Charles] has up his sleeve. He’s been teaching MIT students how to build EV karts for a while now, and this total-recap “2.00gokart” novel is [Charles’s] way of sharing the wealth. This is more than a simple how-to guide, though. Instead, it reads like a teacher’s edition of GoKarting 101, with a few brief and important histories, walk-throughs of how the class evolved, exhaustive links to vendors, graphs, videos, and plenty of reference and documentation.

If you have even the slightest interest in electric vehicles, do yourself a favor and give it a browse. There are a couple of videos after the break, and if you need some more motivation, check out the EV skateboard that uses a lot of the same parts.

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Solar Camping On Steroids

October 19, 2013 by James Hobson 57 Comments

[Rick] does a lot of camping, but he loves his electronics. So he’s now on his third iteration of his solar-powered battery box, and it packs quite the punch!

It’s a pretty simple build, but very effective. [Rick] is using a 200W solar panel, a 20 Amp MPPT solar charge controller, a large 100Ah Military Spec Deka 6TMF deep cycle battery, three 12 volt car accessory outlets, and to box it all up — an inexpensive plastic tote from Walmart to keep it dry in bad weather. The only problem we can see with this is that since the battery isn’t a sealed gel cell, it could out gas inside the tote which might cause him problems down the road. He’s aware of this though so the lid is only on when it needs to be.

This unit can power pretty much anything that runs on 12 volts, from USB devices, to camping light batteries, air pumps for air mattresses, C-PAP machines via the included A/C inverter, and it can even run an EdgeStar FP-430 portable fridge/freezer for 3+ days before even needing to plug in the solar panel for recharging! Total system cost is a bit high at around $1000 — but that includes the portable fridge, solar panels, and all accessories and miscellaneous hardware that went into assembling the system.

Stick around after the break to see the video demonstration.

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Fully Automated Watering Robot Takes A Big Leap Forward Toward Greenhouse Automation

September 12, 2013 by Todd Harrison 44 Comments

Greenhouse owners might find [David Dorhout]’s latest invention a groundbreaking green revolution! [David]’s Aquarius robot automates the laborious process of precision watering 90,000 square feet of potted plants. Imagine a recliner sized Roomba with a 30 gallon water tank autonomously roaming around your greenhouse performing 24×7 watering chores with absolute perfection. The Aquarius robot can do it all with three easy setups; add lines up and down the aisles on the floor for the robot to follow, set its dial to the size of your pots and maybe add a few soil moisture sensors if you want the perfect amount of water dispensed in each pot. The options include adding soil moisture sensors only between different sized plants letting Aquarius repeat the dispensing level required by the first plant’s moisture sensor for a given series.

After also digging through a pair of forum posts we learned that the bot is controlled by two Parallax propeller chips and has enough autonomous coding to open and close doors, find charging stations, fill its 30 gal water tank when low, and remember exactly where it left off between pit stops. We think dialing in the pot size could easily be eliminated using RFID pot identification tags similar in fashion to the Science Fair Sorting Project. Adjusting for plant and pot size as well as location might easily be automated using a vision system such as the featured Pixy a few weeks back. Finally, here are some featured hardware hacks for soil moisture sensing that could be incorporated into Aquarius to help remotely monitor and attend to just the plants that need attention: [Andy’s] Garden sensors, [Clover’s] Moisture control for a DIY greenhouse, [Ken_S’s] GardenMon(itoring project)

[David Dorhout] has 14 years experience in the agriculture and biotech industry. He has a unique talent applying his mad scientist technology to save the future of mankind as seen with his earlier Prospero robot farmer. You can learn more about Aquarius’s features on Dorhout R&D website or watch the video embedded below.

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Compact Fluorescent Grow Light

August 19, 2013 by Mike Szczys 34 Comments

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Spring is on the way for our friends down under. With that in mind [x2Jiggy] built this compact fluorescent grow lamp to help start the seeds for his garden. He used materials that are easy to find, and multiple bulbs means that you can mix and match their color warmth in order to get the wavelengths of light best for plant growth.

He started by building the box out of MDF. It is lined mostly with a reflector meant to go in your car’s windshield when you leave it in a hot parking lot. He sealed the seams of the reflector using what he calls flashing tape. This is the rubbery type of stuff used as soft flashing around windows.

The bulb sockets came from an old string of party lights. Wiring is run through plastic junction boxes which keeps the setup code-compliant. Each of the CFLs draw 20 Watts for a total consumption of 160 Watts. Combine this with a DIY hydroponic tent and you’ll be eating fresh greens year round.

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Preserve Your Garden Bounty With A Solar Food Drier

August 17, 2013 by Mike Szczys 19 Comments

solar-food-drier

The [VelaCreations] family lives off the grid, getting the electricity that they actually use from solar and wind power. When they started looking for ways to preserve the fruit and vegetables now coming into harvest the electricity consumption and cost of a food dehydrator made them balk. What they do have plenty of at this time of year is sun and heat, so they built their own solar food drier.

The frame is made of welded square tube. They mention that you will have to alter it if you don’t have welding tools, but building your own MOT welder is just one more fun project to take on. The frame has wood rails to hold the trays of food. It is enclosed with translucent polycarbonate sheets. There is a vent in the top as well as the bottom. As the heat from the sun builds inside, it flows upward, sucking fresh air in the bottom. This carries away moisture from the food and can be regulated by adjusting the size of the bottom vent.