Emerald Group Publishing Limited
Copyright © 2004, Emerald Group Publishing Limited
Brave new world
Brave new world
The theme of this issue is “Nanotechnology and sub-miniaturised sensors”. This is currently a hot topic in the sensor community which is probably reason enough that we should be covering it. But is it just another area that will be “famous for 15 min”?
I think not – but let us examine why making sensors smaller can be a good idea. The top reasons probably include:
getting more different sensors in a given space;
improved characteristics; and
new application areas.
If we look at these in turn – price may be a bit of a surprise because it is often harder to make things small, but with sensors it is the use of semiconductor fabrication technologies that makes the small size possible, and these lend themselves to high volumes and low unit cost.
Getting more sensors in a given space allows better quality measurements to be obtained. For example, if you want to measure temperature over a wide dynamic range a single sensor may have highly non-linear characteristics and be prone to errors caused by pressure or humidity. However, if a number of temperature sensors with different characteristics can be co-located and their signals processed intelligently then a greatly improved response can be achieved.
Improved characteristics can also be obtained that are directly attributable to the size of the sensor. For example, the frequency response of a pressure sensor or a temperature sensor is fundamentally affected by the mass of the sensor itself. Inertia – be it thermal or pure mass related, gets dramatically reduced as volumes fall.
All of the above are very useful, but it is the final category of new applications that I find especially interesting.
New applications can require lateral thinking.
Sometimes the application comes first and then the hard work goes into accomplishing it with the available technology. We published a good example of this in SR 23-2 “Wireless Capsule Endoscopy”, A Glukhovsky. In this development the goal was to create a capsule that could be swallowed and which would include a camera, light source and radio transmitter for sending images of the small intestine to a receiver adjacent to the patient.
In other cases the applications only get considered once the technology exists. The ubiquitous yellow Post-It Notes only came about after someone at 3M developed a low tack adhesive that left no residue.
Clearly good sense must prevail. There is no point for example, in developing a mobile phone the size of a coin if the buttons are so small that no one can press them.
Unless of course you do away with the buttons all together and use voice recognition, but then to work effectively it would probably need to be located close to the larynx, and you would need to be able to hear it as well, and so implanting on the shoulder blade may be the only option, and then it could get power by piezoelectric generators powered by muscle movements.
Well – perhaps not. But the above technologies could well find application in medical sensors systems or remote monitoring of moving objects.
Oh brave new world that has such sensors in it.