Abstract:
A multifunctional portable electronic device ( 100 ) that easily allows a user to test dangerous fumes level is described. A power module ( 10 ) supplies a working voltage to a gas-sensing module ( 12 ) and an output voltage of the gas-sensing module is generated after sensing gas. A signal processor converts the output voltage of the gas-sensing module into a digital signal and calculates a corresponding gas concentration value that can be displayed on a display module ( 18 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is related to a co-pending U.S. patent application (Attorney Docket No. [US15142]), entitled “MULTIFUNCTIONAL PORTABLE ELECTRONIC DEVICE”, by Tung-Lung Lee. Such application has the same assignee as the present application and is concurrently filed herewith. The disclosure of the above-identified application is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention generally relates to portable electronic devices, and more particularly to a multifunctional electronic device. 
         [0004]    2. Description of Related Art 
         [0005]    In our daily life, we may often be exposed to toxic fumes such as automobile exhaust or even flammable fumes. 
         [0006]    Although sensing devices are available for alerting to the presence of dangerous fumes they are not commonly used by people in their daily lives, like mobile phones are. And if people were concerned enough to carry a protective sensor it would be inconvenient. 
         [0007]    Therefore, a new multifunctional portable electronic device having a function of sensing dangerous fumes is desirable to overcome the above-described problems. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Many aspects of the multifunctional portable electronic device can be better understood with reference to the following drawings. Drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present multifunctional portable electronic device. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views, in which: 
           [0009]      FIG. 1  is a block diagram of a multifunctional portable electronic device according to an examplary embodiment of the invention; 
           [0010]      FIG. 2  is a first embodiment of a circuit diagram of a gas-sensing module of the multifunctional portable electronic device shown in  FIG. 1 ; 
           [0011]      FIG. 3  is a second embodiment of a circuit diagram of a gas-sensing module of the multifunctional portable electronic device shown in  FIG. 1 ; and 
           [0012]      FIG. 4  is an isometric view of the multifunctional portable electronic device shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0013]    Referring to  FIGS. 1 and 4 , an exemplary embodiment of a multifunctional portable electronic device  100  in the form of a mobile phone is shown. The multifunctional portable electronic device  100  includes a power module  10 , supplying power for a gas-sensing module  12 , an analog-to-digital converter  14 , a central processing unit (CPU)  16 , a display module  18 , a keypad  20 , an antenna  22  and a integrated telephone module  24 . The keypad  20  allows inputting information. The antenna  22  receives and transmits signals from/to a telephone module  24 . 
         [0014]    Referring to  FIG. 2 , in the first embodiment of present invention, the gas-sensing module  12  includes a gas-sensing portion  120  and a dividing resistor R. The gas-sensing portion  120  includes a heater  122  and a detector ( 124 , A, B). The heater  122  is an inductance, and when in use, the heater  122  radiates heat to achieve a temperature condition suitable for allowing gas sensing. The detector is a pair of electrodes  124  comprising a first electrode A and a second electrode B, and the heater  122  is positioned therebetween. The electrodes  124  have a conventional gas-sensitive material thereon for sensing gases, such as carbon dioxide (CO2), methyl hydride, chlorine, sulfide, oil-gas, and so on. 
         [0015]    The power module  10  supplies a first input voltage V in1  and a second input voltage V in2 . The V in1  is input on the heater  122  to form a loop as a heating circuit of the gas-sensing module  12 . The first input voltage V in1  is a working voltage of the heating circuit. 
         [0016]    The electrodes  124  and the resistor R are electronically connected in series. The second input voltage V in2  is input to the electrodes  124  and the resistor R to form a loop as a signal output circuit of the gas-sensing module  12 . The voltage at the resistor R is an output voltage V out  of the gas-sensing module  12 . The second input voltage V in2  is a working voltage for the signal output circuit. In general, the working voltage of the signal output circuit is about 5V. 
         [0017]    Referring to  FIG. 3 , in the second exemplary embodiment of present invention, the gas-sensing module  12   a  includes a gas-sensing portion  120   a , a first resistor R 1 , a second resistor R 2  and a third resistor R 3 . The gas-sensing portion  120   a  includes a heater  122  and a pair of electrodes  124  comprising a first electrode A and a second electrode B. The heater  122  is an inductor provided between the first electrode A and the second electrode B. When in use, the heater  122  radiates heat to achieve a temperature condition suitable for gas sensing. At least one of the first resistor R 1  and the second resistor R 2  is an adjustable resistor. 
         [0018]    The electrodes  124  and the third resistor R 3  are connected in parallel, and then connected in series to the first resistor R 1  and the second resistor R 2 , and then all the resistors are connected in parallel to the heater  122 . One end of the heater  122  is grounded, and the other end is connected to an input voltage V in . A voltage at the first resistor R 1  and the second resistor R 2  is an output voltage V out  of the gas-sensing module  12 . 
         [0019]    The heater  122  provided with an input voltage V in  is used as a heating circuit of the gas-sensing module  12 . The electrodes  124  and the third resistor R 3 , provided with the input voltage V in , are used as a signal output circuit of the gas-sensing module  12 . The first resistor R 1  and the second resistor R 2  are used as a voltage divider for adjusting the working voltage of the signal output circuit. The third resistor R 3  is a shunt resistor provided for optimizing the linear characteristics of the signal output circuit. 
         [0020]    Referring to  FIGS. 1 and 2 , or referring to  FIGS. 1 and 3 , the power module  10  supplies a working voltage for the heating circuit and the signal output circuit of the gas-sensing module  12 ,  12   a . When the working voltage is input, the heater  122  radiates heat to achieve a temperature condition of the electrodes  124  suitable for sensing gas. When a detectable gas is present in the air around the device  100 , it is adsorbed on a surface of the electrodes  124 , and the surface resistance R s  of the electrodes  124  changes accordingly. That is, the electrodes  124  have different resistance R s  corresponding to different sensed gas concentration values. The output voltage V out  of the gas-sensing module  12 ,  12   a  will then varies with the change of the surface resistance R s  of the electrodes  124 . The analog-to-digital converter  14  converts the analog signal of the output voltage V out  into a digital signal usable by the CPU  16 . 
         [0021]    The CPU  16  calculates a corresponding gas concentration value based on the received digital signal, and sends the gas concentration value to the display module  18 . The display module  18  includes a display screen of the multifunctional portable electronic device  100 . The sensed gas concentration value is displayed in the display module  18 . 
         [0022]    It should understood that, the multifunctional portable electronic device can be a mobile phone, a personal digital assistant (PDA), and so on. The analog-digital converter  14  and the CPU  16  can be replaced by a signal processor with analog-to-digital converting function and data processing function, such as a single chip, a integrate circuit, and so on. 
         [0023]    It is to be further understood that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.