Hydroponic Strawberries Sweeten Up Winter Dolldrums

February 8, 2012 by Mike Szczys 31 Comments

Add some fruit to your indoor bounty with this hydroponic strawberry farm. [Dino] whipped this up as his 45th hack a week episode (getting pretty close to his year-long goal). He used parts you probably already have sitting around the house somewhere. But even if you bought everything and used it once you still wouldn’t be out much.

A plastic storage container serves as the base. [Dino] also grabbed four identical plastic containers (large yogurt containers would work here) to host the plants. He cut off the bottom half and inserted some netting to keep the plant from falling through. After tracing the size of the container on the enclosure’s lid he cut out holes which will host each plant. This provides a way to dangle the roots into the nutrient solution which is kept oxygen rich with an aquarium pump and two air stones. It certainly deserves a place next to that salad farm you threw together. Don’t miss [Dino’s] build video after the break.

Continue reading “Hydroponic Strawberries Sweeten Up Winter Dolldrums” →

A.R.T. Sorts Your Recyclables For You

February 4, 2012 by Mike Szczys 21 Comments

[Yuhin Wu] wrote in to let us know about the Automated Recycling Sorter that was built with a group of classmates at the University of Toronto. They entered it the school’s student design contest and we’re happy to report that it took first place.

The angled sled has been designed to separate glass, plastic, and metal containers. The first sorting happens at the intake area. A set of moment arms are used to weed out the glass bottles. Since there are several of them in a row, a larger and heavier plastic container will not be falsely sorted and the same goes for smaller glass bottles.

With the glass out of the mix the team goes on to separate metal and plastic. An Arduino was used for this purpose. It senses an electrical disturbance caused by a metal can passing through the chute and actuates a trap door to sort it. Plastic has no effect on this sensor and slides past the trap to its own sorting bin.

Don’t miss both demo videos which we’ve included after the break.

Continue reading “A.R.T. Sorts Your Recyclables For You” →

Reviewing The Numbers From One Month Of Solar Harvesting

January 23, 2012 by Mike Szczys 19 Comments

[Mathieu] just finished analyzing the numbers from a month of solar energy harvesting. You may remember that he was curious to see what kind of energy can be collected from small solar cells used indoors. He built several copies of a test platform which collected data between December 16th and January 16th.

First of all, it’s not shocking to find out that rooms with no sunlight produced negligible energy during that time. When you think about it, if they had been gathering a statistically significant amount wouldn’t that mean the lighting used in those rooms was incredibly inefficient? In other words, there’s no way you need to be making that much light.

But he did find that proper positioning in rooms that catch sunlight during the day can result in usable energy for small loads. He established that a 0.5 Watt panel harvested just a bit more than half of what a 1 Watt panel did. But perhaps the most useful discovery was that it’s quite a bit more efficient to have a charging circuit store energy in a battery rather than directly powering a fixed load.

It will take us a few more viewings to really decide what we can take away from the experiment for our own projects. But we appreciate [Mathieu’s] quest for knowledge and his decision to put this information out there so that others can learn from it.

Crunching The Numbers: Using Solar Cells Indoors

December 12, 2011 by Mike Szczys 27 Comments

[Mathieu] was interested in using more solar cells for his everday electronics. He looked around but couldn’t find much information about using pholovoltaic for small indoor devices. We remember hearing some of the same things from [Dave Jones] in one of his EEVblog installments from a few years ago which looked at solar calculators; the only indoor solar gadget we can think of.

The quest for knowledge was on and [Mathieu] decided to build this indoor solar cell test platform. It’s a stable piece of hardware that allows him to run reliable tests in many different conditions. It’s designed to compare two identical cells. One is charging the Lithium cell, the other is driving a load directly. A second battery powers the platform separately from the solar circuits so that it can be used as a data logger. He collects, dumps, and graphs info from his test runs, then discusses his findings. We won’t spoil it, but the results are not great. Mostly you need sunlight to get real results as it’s just so much more powerful than artificial lighting.

Printable Solar Cells That Can Be Folded Up When Not In Use

December 2, 2011 by Mike Szczys 59 Comments

Here’s a photovoltaic cell that can be printed onto paper. The manufacturing technique is almost as simple as using an inkjet printer. The secret is in the ink itself. It takes five layers deposited on the paper in a vacuum chamber. But that’s a heck of a lot easier than current solar cell fabrication practices. In fact, is sounds like the printing process is very similar to how potato chip bags are made. This is significant, because it could mean a fast track to mass production for the technology.

It isn’t just the easy printing process that excites us. Check out the video after the break where a test cell is placed on top of a light source while being monitored by a multimeter. It’s been folded like a fan and you can see a researcher sinch up the cell into a small form for storage. It’s a little counter-intuitive; for instance, you wouldn’t want to make a window shade out of it because it would have to be down during the day to get power. Be we think there’s got to be some great use for these foldable properties. Continue reading “Printable Solar Cells That Can Be Folded Up When Not In Use” →

Camping Light Retrofitted As A Solar Recharging Station

November 4, 2011 by Mike Szczys 8 Comments

With grand plans of tenting out for several days at a music festival [Josh] needed a way recharge his portable devices. In the past he’s lugged around a 12V battery with him, but this year he wanted to make things easier. He ended retrofitting a camping light to do the job with the help of the summer sun.

The first step of the project was to source some rechargeable batteries. He toyed with the idea of Li-Ion cells but ended up going with NiMH because the charging is more forgiving and he got them at a great price. Because of the lower operating voltage (1.2V versus Alkaline’s 1.5V) he needed to squeeze two more into the lamp housing. Here you can see that he just managed to get them to fit in the wire-run area down the middle of the case.

Next comes the recharging circuit. He based his design around an ATmega44, using a voltage divider and the ADC to detect when the batteries are topped off. During the day this is connected to an external solar panel and it’s ready to charge his phone when he gets back at night.

Occupy Rigs Up Human-power After Generators Are Confiscated

November 2, 2011 by Mike Szczys 261 Comments

Looks like New York’s fire brigade confiscated all of the gas (or bio-diesel) generators from Occupy Wall Street protesters in Zuccotti Park. Apparently the Fire Chief cites the generators as a fire hazard. This seems a dubious claim. One of the shots in the video after the break clearly shows fire extinguishers close at hand, but we’re no experts on fire code. We’d bet the concern is having combustibles around if the scene turns violent… or just wanting to pressure the group with the loss of a heat source.

Instead of going without, the movement received help from a neighboring protest group in Boston. Bicycle power replaces the missing generators as volunteers pedal to produce electricity. Students from MIT plied their skills to help design multiple charging stations that can be used by the community. It won’t be enough to provide heat for the ongoing occupiers, but it does let them charge their electronic devices which helps ensure that current information is still flowing out of this epicenter of activity.

Does anyone have any ideas for hacking up a heat source that won’t ruffle the feathers of local officials? If so, leave a comment. And if you’ve already got a post written up on the topic don’t be afraid to send in a tip about it. Continue reading “Occupy Rigs Up Human-power After Generators Are Confiscated” →