Abstract:
A system is devised for utilizing the speaker in a mobile phone or other appliance as a transducer for monitoring the shock to which the appliance is subjected. The shock signal is processed and stored signals relative to said shock and providing means to access said stored data.

Description:
BACKGROUND OF THE INVENTION 
     Mobile phones are rapidly becoming an article for every day use. To accommodate this fact, manufacturers have reduced the size of such phones to make them easy to carry at all times. This has resulted in the mobile phone being subject to all of the hazards of the user&#39;s work and play. Similar to a watch, the mobile phone must now be shock resistant to an ever increasing standard. This increased exposure has strained the warranty services of the manufacturers because the phones are damaged in ways not contemplated on normal warranty conditions. Since there are circumstances beyond which damage is not covered by warranty, an issue arises with respect to the determination of excessive force. 
     It is a purpose of this invention to provide a simple and inexpensive means of monitoring the shock to which a mobile phone is subjected. 
     SUMMARY OF THE INVENTION 
     The dynamic speaker provided as standard equipment on most mobile phones is used as a transducer to sense the shock experienced by the phone. Movement of the speaker core by an external force will produce a signal that is recorded in the memory of the phone. This can be accessed during service to determine if the phone was subjected to excessive force which may negate the warranty. The shock signal from the speaker is filtered and compared to a predetermined threshold. Therefore only the data relating to substantial force are recorded. 
    
    
     DESCRIPTION OF THE DRAWING 
     The invention is described in more detail below with reference to the attached drawing in which: 
     FIG. 1 is a block diagram of the monitoring system of this invention; 
     FIG. 2 is a block diagram of the sensor portion of this invention; 
     FIG. 3 is a circuit diagram of the sensor portion of this invention; 
     FIG. 4 is a schematic diagram of a speaker used as part of the subject invention; and 
     FIG. 5 is a graph showing the relationship V REF , V OUT , and V TRIGGER . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The basic system of this invention is shown in FIG. 1. A sensor circuit  1  has its output connected to the microprocessor control unit  2  of a mobile phone. The analog signal from the sensor  1  is converted to a digital signal in the analog to digital converter  3  for storage in a random access memory  4  within the microprocessor control unit  2 . Memory  4  maybe accessed by a service processor  5  through the use of service software designed for that purpose. 
     The components of the sensor circuit  1  are shown in FIG.  2  and include a dynamic speaker  6  connected to a amplifier/filter circuit  7  and a comparator circuit  8 . The amplifier/filter circuit  7  provides buffer impedance for the low impedance signal from the speaker  6  and if necessary may also provide amplification. Comparator circuit  8  receives a reference voltage V REF  from the microprocessor control unit  2  which is compared to the signal from speaker  6 . In this manner, an output threshold is set to limit the shock signals to those greater than a minimum value, as it is only the extremes of shock forces that it is desired to record. 
     Although the signal from speaker  6  may be processed in a variety of ways to achieve the monitoring purpose of this invention, a specific sensor processing circuit  1  is shown in FIG. 3 for the purpose of illustration. In general because of the significant voltages generated by the speaker  6  when it receives a significant physical shock, amplification will not normally be required. 
     In the sensor circuit  1  shown in FIG. 3, the signal from the speaker  6  is passed through an amplifier/filter circuit  7  which provides buffer impedance for the low impedance signal of speaker  6  and filters out environmental disturbances. Circuit  7  includes an amplifier  9  and a filter  10 . A voltage reference V REF  is set by microprocessor control unit  2 , through a digital to analog converter  16  which facilitates alignment of the reference voltage during production. V REF  is compared to the output signal V OUT  of the amplifier/filter circuit  7  in comparator circuit  8 , which includes an amplifier  17 . Comparator circuit  8  is designed to generate a trigger pulse V TRIGGER  when V OUT  is greater than V REF . This requires significant peaks of voltage which indicate extraordinary shocks received by the mobile phone. As shown in FIGS. 3 and 5, V TRIGGER  will go to the positive supply voltage (+5 V)of amplifer  17  and will be detected as an interrupt by microprocessor control unit  2  to initiate the storing of the value of V out . 
     A unique feature of this invention is the use of the dynamic speaker of the mobile phone as a transducer to sense when the mobile phone is subjected to significant shock. A schematic of a typical speaker is shown in FIG.  4 . In this illustration, speaker  6  is comprised of a cone  11  connected to a moveable core or diaphragm  12  which is mounted for movement within a wire coil or winding  13 . The diaphragm  12  contains a permanent magnet  14  which, in normal use, is caused to move within the winding  13  in response to voice signals from a receiver in the mobile phone. In this instance, however, the speaker  6  is also used as a transducer by reversing its operation. Violent movement of the mobile phone will jar the diaphragm  13  and cause the magnet  14  to move within winding  13 . This will induce a voltage in the winding  13  which acts as a pickup coil of a typical transducer. The output voltage V SHOCK  of the transducer/speaker  6  will appear at output terminals  15  and be proportional to the force to which the mobile phone is subjected. V SHOCK  is processed by amplifier/filter  9  and comparator  10 . 
     The shock signal is processed to eliminate spikes of voltage which may be caused by environmental disturbances or by minimal jarring during normal use. Peak signals are stored in the random access memory  4 . When a mobile phone is submitted for warranty repair with, for example, the case damaged, but is otherwise servicable, the service technician may access the random access memory through an access port and, using a tool designed for this purpose download the shock signal record for analysis. Warranty service may be refused if the record indicates a misuse of the mobile phone. 
     In this manner a system for utilizing the transducer characteristics of a mobile phone ins constructed. This system may be used in other devices which employ dynamic speakers such as portable radios, cordless phones, beepers and the like.