Piccolo-stick and PCB-coil based simple coin validator

TMS320F29069 Piccolo-stick is an ideal platform to make a low-cost and simple demonstrator of various sensor signal processing solutions, for example of an eddy current-based coin validator, as described in the current paper. Inductive sensor array is made in the form of the PCB-coils. Proposed solution includes hardware and embedded software for generation of the two simultaneous excitation sine-waves (of 100 and 200 kHz, generated by PWM outputs of the 'F069 and a simple external analogue low-pass filter) and complex discrete Fourier transform calculation algorithm for acquired (by internal 12-bit ADC) signal. Also test-benches for passing the coins by the PCB-coil-sensors have been implemented. Internal software (in the Piccolo stick) finds also the peak values of the sum of the components of the complex impedance deviation, as the coin is passing and sends these peak values via RS232/USB link to a PC. In LabView environment a coin recognition/validation and counting demo-software (user interface) has been developed, for PC. Performed work shows the advantages and simplicity of making of such solutions on the Piccolo-low-cost and simple platform.