SAFEMETAL

The key scientific and technical objectives of the project are:

• Development of techniques for measurement of electrical conductivity of coinsized copper-alloy specimens. Targeted uncertainty within ±1% from DC to 1MHz and ±4% to 10MHz with measurements traceable to international standards.
• Development of mathematical models and numerical techniques to define the interaction of broad-band electromagnetic fields with objects of finite size, such as coins, and of bi-metallic/ layered construction.
• Detailed characterisation of the electromagnetic properties for euro coins of all denominations and a selection of other coins.
• Investigation of eddy current signal interaction with bi-metallic, layered construction of euro coins at a range of frequencies from DC up to 10MHz.
• Investigation of the effect of surface finish, plating, tarnishing/ oxidation and embossing patterns (for both the common and country-specific sides of a coin) on conductivity across the range of frequencies.
• Development of theory to model electro-magnetic planar sensors, enabling use as improved alternative to conventional coil sensors.
• Development of the theory for pulse-based/ broad-band eddy-current conductivity measurements.
• Development and application of novel signal processing techniques to extract useful information from the complex electromagnetic signals using low-cost and low-power hardware.
• Development and optimisation of sensors to measure other parameters of coins — diameter, thickness, weight, etc.
• Development and application of novel data fusion methodologies to combine information from the electromagnetic and other sensors.
• Design, realisation and evaluation of validator prototypes based on the innovations applicable to vending, service automation and amusement machines. The requirement of these high volume market sectors are for high security and reliability coin validation combined with low cost.
• Design, realisation and evaluation of validator prototype based on the innovations applicable to high speed coin sorting and counting machines used by banks. In addition to high speed operation (targeted at up to 3,500 coins per minute), high discrimination between genuine, counterfeit and foreign coins is necessary with accurate, traceable calibration of the machines.
• Design, realisation and evaluation of prototype conductivity measurement and calibration system based on the innovations applicable to the needs of mints, coin blank suppliers and banks.