Foreign body detecting
View Patent ↗A self-service terminal has a fascia 1 . A transmitter 18 sends a chirped ultrasonic pulse across a region R of the fascia. The pulse interacts with the region R and the region R responds by emitting an output. A receiver 20 receives the output and produces an electrical signal corresponding to the output. A frequency analysing module 24 transforms the electrical signal into a frequency response.
1. A self-service terminal comprising:
a fascia;
a transmitter sending a chirped ultrasonic pulse across a region of the fascia;
wherein the pulse interacts with the region;
a receiver receiving the pulse after the pulse has interacted with the region and produces an electrical output corresponding to the received pulse; and,
an analysing module converting the electrical output to a frequency domain, the analyzing module comparing the frequesncy domain converted electrical output to a baseline frequency response.
2. A self-service terminal according to claim 1 , where the frequencies of the pulse are in the range of 30 to 100 KHz.
3. A self-service terminal according to claim 1 , wherein the region comprises one or more parts of the fascia.
4. A self-service terminal according to claim 1 , further comprising a signal generator producing a chirped electrical pulse that the transmitter converts into a chirped ultrasonic pulse.
5. A self-service terminal according to claim 1 , further comprising a microprocessor controlling the signal generator and analysing module.
6. A self-service terminal according to claim 1 , further comprising a memory storing the baseline frequency response and/or frequency response characterisations.
7. A self-service terminal according to claim 1 , wherein the transmitter sends a succession of pulses.
8. A self-service terminal according to claim 1 , wherein the pulse is damped.
9. A self-service terminal according to claim 1 , wherein the transmitter and receiver are co-located.
10. A self-service terminal according to claim 1 , wherein the transmitter and receiver are combined as a single transducer unit.
11. A method of detecting foreign bodies at a self-service terminal, the method comprising:
sending a chirped ultrasonic pulse across a region of a fascia of the terminal so that the pulse interacts with the region, wherein the region is associated with a magnetic card slot of the self- service terminal;
receiving the pulse after the pulse has interacted with the region;
producing an electrical output corresponding to the received pulse; and,
analysing the electrical output by converting the electrical output to a frequency domain and comparing the frequency domain converted electrical output to a baseline frequency response.
12. A method according to claim 11 , further comprising determining the baseline frequency response in the absence of foreign bodies and subsequently comparing a determined frequency response with the baseline frequency response.
13. A method according to claim 12 wherein a succession of chirped pulses are sent across the fascia and the baseline frequency response is established on the basis of a historical average of frequency responses.
14. A method according to claim 12 , further comprising characterising a range of foreign bodies by determining a frequency response with each foreign body present, storing the frequency responses and subsequently comparing a determined frequency response with the stored frequency responses.
15. A method according to claim 11 wherein analysing the electrical output also, or instead of making the frequency domain analysis, includes making a time domain analysis of the electrical output.