Would you react the same when someone touches you slightly and when you get pushed hardly?
The pressure force you will receive will not be the same and you might get angry if you get pushed hardly!
On this planet, many other organisms, such as plants and animals also react to different touch pressures. Mimosa pudica is perfect example of a sensitive prudish plant! Look at this short vidéo below, it’s amazing:
Here is also a scientific article about how Mimosa Puda bends with pressure:
As it can sense touch pressures, this plant is a biological sensor.
Biological sensors are not the only ones that can sense forces: tactil smartphone screens are also sensitive to touch pressures, for example. They are perfect examples of electronic force sensors!
So which between the biological and electronic sensors can best sense touch pressures?
Last week, we (a team of scientific students of an interdisciplinary programme) developed a project to compare biological and electronic force sensors: We studied Mimosa pudica’s behavior to different touch pressures and compared it to the electronic FSR sensor, which is found in…… . So we tried to answer this question:
“Which between Mimosa pudica and the FSR sensor is the most precise reacting to pressures of different weights?”
But, how does the FSR work?
It simply detects physical pressures, squeezing and weight. When the FSR sensor is plugged to an electrical circuit and to a computer, we can then read pressure intensities values (arbitrary units) given from the FSR sensor on the computer. These values are low when the sensor is in presence of no or low pressures and they are high when the sensor is pushed or squeezed hardly (between 0 and 1024).
So to answer are big question above, we performed series of experiments on 9 Mimosa pudica (MP) plants and with 1 FSR sensor:
- we observed and compared MP and FSR’s reaction and values when in contact of pressures from 3 objects of different weights: a smartphone, a coffee bag and a bottle of water,
- we observed and compared MP and FSR’s reaction and values when in contact of no pressures.
Here is a drawing showing our experiments:
And below is a very simple graph showing are results: it represents the average closing times of the plants (left blue axis) and the average values given by the FSR sensor (right red axis) in function of the objects’ weight (bottom axis).
So, as you can see, the values given by the FSR seem to increase as the objects’ weight increase from 153,7 g to 403 g. But the closing times of the plants do not follow the same pattern: the objects’ weight do not seem to influence the leafs’ reaction.
As our datas are not précise enough, we cannot conclude from these results, eventhow we got the results expected for the FSR sensor. Indeed, we had a few precision problems during our experiments: the objects were not perfectly dropped at 1 cm from the FSR or the Mimosa pudica. Also, we could not control precisely the dropping.
So it would be great to do these experiments again with a more precise set up, more FSR sensors (to compare their values) and more Mimosa pudica (more values again!).
It is always very interesting to study plants because it can help for many disciplines: theoretical knowledges as well as applied knowledges, in drugs for example. Also, observing how the leafs close could serve as an example for biomimetic objects.
Hanaé, Loïc, Floriane and Louis,
L2 students from LFDV
Our ressources:
No comments:
Post a Comment