At the end of the project, having developed the PEM markers, the possibilities of acoustic emission and the receiver, the developed theories presented by the means of laboratory tests showed their limitation on the ground.
Indeed, we forecasted to use the answering frequency of the electric piezo and the liberated energy in order to convert it into electro magnetically energy by the mean of an adapted antenna.
The experience and the ground tests (all types of grounds) proved that following the environment, the perturbations, the piezo specifications… the obtained frequencies were submitted to important variations.
During those 24 months of study, we tested the feasibility of a PIEZO ELECTRIQUE component used as an energy source in order to power electromagnetic emission electronics.
Manipulations in labs and tests in the field clearly demonstrated the impossibility to merely use the electric Piezo on its resonance frequency as a frequency source (the frequency varying in great proportions) in accordance with the environment.
Thus we introduced, in the PEM marker emission chain, an electronic as a “loading pump” and an oscillator accurate in frequency. An antenna constituted of a coil enables a capacity of emission of about 1m50.
This demonstrated the technical feasibility we expected and, unfortunately, the different disadvantages of the PEM device :
- On the one hand, for the users the mechanic shock excitation is very constraining. More over, the markers tests buried under a bitumen coating show a huge diminution of the shock wave. This is due to the impedance ruptures in a heterogeneous soil. The shock wave transmitted by the mass does not arrive.
On the other hand, as we indicated in the Mid-Term report, the mass-manufacturing of the PEM markers significantly changed.
The manufacturing price prevision has gone up from 0.5€ to 2.5€ for a basic marker. This is an important obstacle for the targeted market.
We thus can say that his programme will not lead to a commercial success.
Funding SchemeCRS - Cooperative research contracts
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