Monday, July 13, 2009

Smart clothes could take photos


Close-up of rope, Eyewire
The researchers stretch out large fibres to make thin threads

Clothes could one day take snaps of everything happening around whoever is wearing them.

US researchers have made smart fabric that can detect the wavelength and direction of light falling on it.

The research team has found a way to accurately place sensors in each fibre and co-ordinate the electrical signals they send when light falls on them.

The results were a step towards "ambient light imaging fabrics" said the researchers.

Led by Dr Yoel Fink from the Massachusetts Institute of Technology, the researchers have extended earlier work that placed sensors in relatively large polymer fibres.

Dr Fink and colleagues found a way to stretch the 25mm strands of polymer into much thinner fibres while maintaining the relative positions of the sensors.

This earlier work has led to the creation of very long and flexible light and temperature sensors that may find a role in smart fabrics for soldiers or those working in hostile environments.

In their latest work, described in a paper in Nano Letters, these thinner strands were woven into a 0.1m square section of fabric. The careful creation of the fibres and positioning of the light-sensitive elements meant that the team knew which signals were being sent by which sensors.

This enabled the team to reconstruct, albeit crudely, an image projected onto the small square of fabric. The researchers said their work was an "important step" towards finding ways to get many nanoscale devices working together.


Source: BBC news

Saturday, July 11, 2009

At this point, I don't feel like I need to burnish my eco-credentials, given that I write for CNET's Green Tech blog every day. But when it came to buying a car, I got the iconic, even cliched, 2010 Toyota Prius.

Having driven almost 2,500 miles on it so far, I like it, although I have not yet been able to get the advertised 50-plus miles per gallon when I go around town, which is the bulk of my driving. But it's early still, I tell myself, so maybe the Prius can show me the way. (See also CNET's review of the 2010 Toyota Prius.)

Buying a hybrid was not at all my plan. My wife and I were generally content with a 10-year-old Corolla that got us from point A to B with good mileage. As you can tell, fuel efficiency and reliability are high on my wish lists, not luxury features. In fact, what I really wanted to do was hold out for a plug-in electric vehicle.

But a few weeks ago, our well-maintained sedan was totaled by a teenager in an SUV (no serious injuries, thankfully). That meant I needed to get a new car--fast. We went from accident to test drive to transaction in about a week since we needed a new car before we left for a long-planned vacation. Nothing like a deadline to focus the mind.

I was surprised to see how few hybrid options there are. Certainly the Honda Insight was tempting and early reviews were positive. But reviews also said that space in the back seat isn't great, which was a priority for us, while the new Prius improves on interior space.

I also thought of the Ford Fusion hybrid, which I drove this spring. One advantage was the tax rebate I would have gotten for buying a fuel-efficient American car. It gets over 40 miles per gallon in city driving and I liked driving it a second time--it had a comfortingly familiar look and feel, both inside and out, even though it's a hybrid. But with the bigger battery, the trunk didn't seem very roomy and you can't push down the back seats for big loads.

Next stop was the Toyota dealership. The base price of the new Prius is a few thousand dollars higher than that of the Insight but less than the listed base of the Fusion. We took the Prius for a spin and were pleased.

There's not exactly a waiting list for the 2010 Prius, but each car is basically spoken for before it arrives, at least in the Boston area. Our sales guy had one coming in. We grabbed it. Did I mention we were in a hurry?

The day after delivery we started our long drive for vacation. Gas mileage for our roughly 2,000 miles of highway travel in total was about 51 miles per gallon. A limited sample of city driving (less than 100 miles) has me getting in the middle to high 40s.

Different state of mind
The biggest change with driving a hybrid is the feedback system. The 2010 Prius has a few different display options. It's interesting to know what's going on under the covers--how the gasoline engine, generator, and battery coordinate to maximize your mileage.

But so far what I've ended up using is the Eco dashboard, which tells you when you're driving just on the battery and when going out of the super-efficient zone. The big lesson here: don't accelerate aggressively. Picking up speed slowly is the key to fuel-efficiency nirvana, the Prius tells me.

What a difference from my old cars. I've always driven a stick shift, which means a direct sense of controlling your car's functions: put it in gear, hit the accelerator, and you're in control.

The Prius is fly by wire. You tell the computer what to do and it controls the car. The 2010 model has a few modes that you can put it in: all EV, which only works up to about 20 miles per hour; the Eco mode; and the Power mode.

I've used the Power mode to jump onto highways and it works fine. The Eco mode makes it harder to push on the accelerator so my preference is to only use that with cruise control on the highway. With my day-to-day driving, I've ended up not picking a specific mode and just eyeing the dashboard for feedback.

Show me the way, oh eco-indicator. The Hybrid System Indicator coaches you on how to sip gas.

(Credit: Corinne Schulze/CNET)

For a far more thorough run-through, I suggest this review by my colleague Wayne Cunningham at CNET Car Tech. If you want to know how the hybrid system works under the covers, check out this video from the CNET Green Show.

Of course, there's the cost of the car. I ended up with a relatively low-end model, which is fine because I don't rely on GPS or need a solar moonroof (the solar panel powers a fan to keep the car from heating up in the sun.)

I don't drive a whole lot of miles per year so I wasn't going to get out a calculator and run an ROI analysis on buying a Prius with 48/50 miles per gallon mileage versus something else.

Hybrid technology just makes sense and it's a feature I wanted, just like getting video on my digital camera. Why should my car be burning gas when it's standing still? And I think it's brilliant that I'm recouping energy for my battery when I'm decelerating or hitting the brake.

Now when I drive around I notice the other Priuses. And I keep wondering, are you getting over 50 miles per gallon? Any tips you can share?


Source: Cnet news