SemiSerious

The expression “turn off your clothes” might soon be applied more literally than it once was for the geeky guy wearing the bright yellow Hawaiian shirt. MIT Technology Review recently reported on a technology that might some day extract power from the clothes we wear. It’s all part of a new movement to harvest energy from the various sources of kinetic energy that surround us.

Georgia Tech materials science professor Zhong Lin Wang and his team have adapted their zinc oxide nanowire technology to a new way to generate power. They have grown the nanowires on top of a polymer surface a bit like hair. The flexing and movement of the hairs can generate electricity from the movement or even the breath or heartbeat of the person donning the new fabric. According the the MIT report, as much as 80mW are available per square metre of the fabric. The energy conversion ability of the nanowires has been known for some time, but their use in clothing is a new development.

One other source of power that has attracted the interest of the US military generates power from the motion of a person walking. Simon Fraser University professor, Max Donelan, is the lead researcher for this presently untapped source of portable power. For a 21st centruy soldier in the field, a few extra minutes of battery life in a GPS receiver might actually save his life.

The zinc oxide nanopartilce clothes and the SFU Biomechanical Energy Harvester represent the larger-scale devices within the broader field of environmental energy harvesters. I have previously posted (see “More Buzz” and “Nanotechnology from Gigatools”) about nanogeneration of power, and I believe this will be the enabling technology for a wide range of devices from wireless sensor networks to self-powering drug delivery robots and diagnostic devices inside our bodies.

In a somewhat related development, researchers are proposing self-cleaning clothes that harness the power of the sun to do the dirty work. The secret is in the titanium dioxide coats the textile fibers. According to this work, the titanium oxide spontaneously combusts, vaporizing the stain on top of it. Perhaps future developments will allow some of the heat of that combustion to be recycled so that the sloppiest among us will be able to get the best charge out of our clothes.

The Mobile World Congress has wrapped up, and there were plenty of interesting things to see and new announcements made.  But unfortunately I was stuck at SI’s booth fighting off the hordes of people clamoring to learn more about our semiconductor analyses   I did, however, make it out of the booth long enough to present with my Portelligent colleague, Jeff Brown, about the “Evolution of the Smart Phone - Systems to Semiconductors”.  While it started a bit slow with only two non-SI/Portelligent people there at the beginning, it was standing room only in a hot, noisy room by the time we concluded, which was fabulous!  A lot of questions were asked as well, which is always a good sign that people liked what you had to say instead of just wanting to bolt for the doors once you stopped speaking.
 
The presentation examined three smart phones from HTC (Universal, TyTN, and TyTN 2) and compared/contrasted them with three smart phones from Nokia (N90, N93, and N95).  Jeff covered the system level side of the presentation where he talked about the different feature sets and overall board sizes.  One of the interesting areas that he discussed was how HTC came into the smart phone market as a PDA vendor, so they had a full blown (and large) first offering, and then had to figure out how to meet the phone market criteria, the big one being size.  On the flip side, Nokia entered looking at a phone and had to grow to compete in the smart phone arena with the successive offerings, mostly in terms of functionality.  In the end, the two latest offerings from both companies are quite comparable from a system level point of view.
 
This is where I took over and looked at some of the components that made the phones functional.  One thing that surprised me was how loyal both companies were to the component manufacturers.  Many people think that cost is king in cell phones, and this may be true for entry- and mid-tier offerings, but other than changing the Bluetooth from TI to CSR, the major components for each company remained consistent.  Looking at the different chips that were used, my conclusion was that HTC had a very efficient design where they removed duplicate functionality from devices and were able to dramatically reduce the number of chips used in their phones while still increasing the functionality.  Nokia’s phones resulted in a very effective design, taking advantage of the economies of scale that a company of that size has at its power and they have a great opportunity to optimize in the future.
 
A copy of the slides can be downloaded at www.semiconductor.com/mwcpres.

- Gregory A. Quirk