- Bio sensors result from the merging of a biological component, like an enzyme, an antibody, a microorganism, a cell with an electronic part that converts into data what the biological part has “sensed”. What started two decades ago as a laboratory exercise is now becoming an industry that will be worth 22 billion $ by decade end. At the same time it is no longer a niche endeavour by a few highly specialised researchers: by decade end biosensing may enter into the open source community.
Nature has had 3 billion years of evolution to try different ways of detecting molecules and biological organisms have developed very sophisticated solutions. Researchers are exploiting Nature’s result by using its solutions and coupling them to a transducer that can transform the detection into a data. When the bio-component “captures” (senses) a certain molecule it alters its structure (it can change its Ph, it can heat up, it can emit light, it can change its mass and in some cases it can even generate and electrical spike) and this alteration can be detected by the electronic part. Depending on the type of change the bio component has, an appropriate transducer is used to generate the electrical signal coding the data (respectively: a semiconductor Ph electrode, a thermistor, a photon counter, a piezoelectric device, an electrode).
In the last ten years researchers have been able to program bacteria and algae (more recently using the CRISPR technology) by altering their genes to sense specific substances and to generate a specific signal upon detection. This area of bio-engineering is bound to grow in the coming years and in the next decade the programming of bio-cells (and possibly of multicellular organisms) to create sensors with desired properties will become more and more common.
It is no longer science fiction to imagine that a city can have trees programmed to detect noxious substances and provide an early warning. Will we be able to know the quality of the air we breath just by looking at the colour of the foliage in the city park or looking at plants covering our building? The trend, in my view, is towards a growing synergy between bio and cities.
- So far I have discussed various classes of sensors with the assumption that a sensor is something very specific that has been designed to deliver that specific functionality. It is separate from everything else. Once I have a sensor I need to find “a place” to put it.
In talking about the bio-sensors I have started to hint that we may end up using bio entities, like plants, as sensors by programming the sensing functionality. This is going to happen, sooner, with objects by using materials that have been “programmed” to sense the environment. Enter “smart materials”. Scientists have started to program materials to have the characteristics they desire. Rather than creating a sensor to detect light, or temperature, you may design a material for manufacturing an object that has the property of detecting light, temperature… You no longer need a separate sensor: in a way you can “program” the sensing capability in the materials you will use to manufacture an object. Buildings windows can become sensors, or building bricks can become sensors. The light poles can become sensors by having them manufactured with appropriate material. The age of smart materials has already started and it will dominate the next decade. For a city planner there will be the possibility of designing a virtual sensing environment and then ask engineers, constructors to create that virtual sensing environment in the physical world they build.
Particularly in the safety area smart materials with sensing capabilities will become common. Buildings and bridges that can report the strain on their structure will be a given, rail tracks sensing anomalies in train circulation in the metro system, sidewalks detecting someone has fallen and he is not standing up… Smart materials will be an essential tile in the quilt of smart city awareness.
- As final type of sensors let me talk about “virtual sensing”. Virtual sensing is what our brain does when it sees the fridge empty and knowing it was full in the morning “senses” that the kids have been home earlier from school and helped themselves for a quick bite. By correlating a number of data (no more food in the fridge, there was food few hours ago, the kids may get home earlier some days, the kids like to scavenge the fridge….) it derives a new data: the kids have been home.
This is virtual sensing: by analysing independent data sets one can sense something that is not directly related to one single set of data but emerges once we consider the whole data sets.
This class of sensors is particulalry important for two reasons: there are more and more data sets available that can be used as virtual sensor feeds AND it is way cheaper to use virtual sensors than real ones. Technologies for virtual sensing are getting better and better, the most recent falling in the area of artificial intelligence. Deep learning approaches let the software learn from previous data exploration so that it gets better and better. It can also readjust as the context changes.
Municipalities should invest in making virtual sensing possible by promoting data accessibility.
Smart cities and Tech Evolution - VII Leveraging on sensors (d)
Tuesday, August 23 2016