METHOD AND SYSTEM FOR DIGITAL PEN ASSEMBLY

1 . A receiving unit for receiving an acoustic signal from a digital pen, comprising:

a housing;

at least two ultrasound receivers, for receiving ultrasound signals from the digital pen, the ultrasound receivers comprising electret microphones, the electret microphones being located in location holes in the housing;

an electric circuit connected to said electret microphones, and configured to extract ultrasound signals received by said ultrasound receivers, and

at least one attachment device, for removably attaching the receiving unit to a further item.

2 . The receiving unit of claim 1 , further comprising a printed circuit board, wherein said extraction is carried out on said printed circuit board and comprises at least one member of the group comprising:

frequency down conversion, signal filtration, and signal amplification techniques.

3 . The receiving unit of claim 1 , wherein said extraction comprises referencing a reference model comprising data pertaining to expected reference signals.

4 . The receiving unit of claim 1 , wherein said at least two ultrasound receivers are positioned less than 65 mm apart from each other.

5 . The receiving unit of claim 1 , wherein said receiving unit further comprises a housing, configured to house said ultrasound receiver and having a changeable cover element.

6 . The receiving unit of claim 1 , connected to a pad and a clip to form a clipboard.

7 . The receiving unit of claim 1 , wherein said attachment device is configured such that said further item is a sheet of paper or a pad of paper, said attachment device being configured to locate said sheet of paper thereby to track movement of said pen over said sheet of paper or over said pad of paper.

8 . A digital pen system comprising:

a digital pen having an electric circuit, an acoustic transmitter configured to transmit acoustic signals, detached from said electric circuit, and a resilient holder, configured to press said electric circuit into contact with said transmitter upon applying a mechanical pressure to said resilient holder, so as to electrically connect said electric circuit and said transmitter;

the receiving unit of claim 1 ; and

a processor, associated with said receiving unit, configured to process said received acoustic signals for determining location of said digital pen.

9 . The digital pen system of claim 8 , wherein said processor is configured to process said received acoustic signal, for determining presence of said digital pen in a predefined area, and to trigger a predefined functionality upon said determining presence; and further comprising a map, configured to graphically map said predefined area, so as to assist a user in positioning the digital pen in said predefined area.

10 . A digital pen system of claim 8 , wherein

said digital pen comprises a switch assembly having two switching points for pressing said assembly to achieve first and second switching modes respectively, said assembly further having a third mode selectable upon said two switching points being pressed substantially simultaneously.

11 . The digital pen system of claim 10 , wherein said processor is further configured to detect a mode of said digital pen.

12 . The digital pen system of claim 8 , wherein:

said digital pen comprises a smooth contact switch configured to actuate the digital pen upon applying a pressure on said smooth contact switch; the resilient element being mounted on a first side of an open electric circuit and disconnected from a second side of said electric circuit, said resilient element being compressible into a position where said resilient element contacts said second side of said electric circuit, thereby closing said electric circuit, upon applying a writing pressure compressing said resilient element into said position.

13 . The digital pen system of claim 8 , wherein said extraction comprises referencing a reference model comprising data pertaining to expected reference signals.

14 . The digital pen system of claim 13 , further comprising at least one attachment device, for removably attaching said receiving unit to a further item.

15 . The digital pen system of claim 14 , wherein said attachment device is configured such that said further item is a sheet of paper or a pad of paper, said attachment device being configured to locate said sheet of paper thereby to track movement of said pen over said sheet of paper or said pad of paper.

16 . A digital pen system according to claim 8 , wherein said electret microphones are positioned inside said housing, less than 60 mm apart from each other, and configured to receive an acoustic signal from said digital pen.

17 . The digital pen system of claim 16 , wherein said housing comprises a changeable cover element.

18 . A method of manufacturing a receiving unit for receiving ultrasonic signals from a digital pen and determining a location of said pen, the method comprising:

providing a housing having two dedicated microphone holes;

inserting into each of said microphone holes an electret microphone;

mounting onto a printed circuit board processing electronics for locating said digital pen based on electronic decoding of said ultrasonic signals;

inserting said printed circuit board into said housing;

connecting said electret microphones to predetermined signal input points on said printed circuit board, said connecting being carried out while said electret microphones are within said microphone holes in said housing; and

providing an attachment device, for removably attaching the receiving unit to a further item.

19 . The method of claim 18 , wherein said inserting said printed circuit board comprises fixing said printed circuit board to said housing prior to said connecting said microphones.

20 . The method of claim 18 , wherein said attachment device is configured such that said further item is a sheet of paper or a pad of paper, said attachment device being configured to locate said sheet of paper thereby to track movement of said pen over said sheet of paper or over said pad of paper.