Microelectric monitoring device
This is a continuation of U.S. patent application Ser. No. 07/998,332, filed Dec. 30, 1992, now abandoned which is a continuation-in-part application of U.S. Ser. No. 07/938,111, filed Aug. 31, 1992, now U.S. Pat. No. 5,290,191, which is a continuation-in-part application of U.S. Ser. No. 07/895,148, filed Jun. 5, 1992, now U.S. Pat. No. 5,181,859, which is a continuation application of U.S. Ser. No. 07/694,262, filed Apr. 29, 1991, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This invention relates to sensors and, more particularly, to power monitoring devices. 
     2. Discussion 
     A variety of applications exist for sensor devices which can detect characteristics of the electrical signals supplied by conventional electrical outlets. One such application is to detect the quality of the power supplied through the electrical outlet for powering electrical equipment. It is known that optimum performance of certain electrical equipment is conditioned on the reception of clean power, with spikes, sag, swell, harmonic distortion and other factors collectively referred to as power quality characteristics, held within acceptable limits. 
     Power quality monitors have been used in the past to detect power quality characteristics. However, they are generally bulky devices which are relatively expensive and difficult to install. Therefore, while it would be desirable in many instances to monitor power quality at a multitude of locations within a facility, it is impractical to do so because of cost and manpower limitations of the known power quality monitors. 
     SUMMARY OF THE INVENTION 
     In accordance with the teachings of the present invention, a wafer-like substrate is provided with holes therein aligned with the pins of the electrical plug for powering a variety of electrical equipment. The substrate carries at least one microelectronic device, such as a microprocessor. The substrate is sufficiently thin to allow the electrical plug to be normally mated with the electrical outlet. In operation, provision is made for using the microelectronic device to collect data about the electrical signals flowing from the outlet to the plug and then to the electrical equipment. This data can later be retrieved for further analysis, or collected in real-time, as desired. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The various advantages of the present invention will become apparent to those skilled in the art after reading the following specification and by reference to the drawings in which: 
     FIG. 1 is an exploded perspective view of the sensor device of the present invention, an electrical outlet and an electrical plug; 
     FIG. 2 is a plan view of the sensor device illustrating the layout of various components thereon; 
     FIG. 3 is a partial cross sectional view taken along the lines 3--3 of FIG. 2 which further illustrates the sensor device sandwiched between the plug and outlet when mated; 
     FIG. 4 is a schematic diagram of one embodiment of electrical circuitry on the sensor device; and 
     FIG. 5 is a perspective view illustrating the connection of the sensor device during retrieval of data therefrom by a computer. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In FIG. 1, the sensor device 10 of the present invention is shown in conjunction with a conventional electrical outlet 12 and conventional three-pronged electrical plug 14. Sensor device 10 includes holes 16, 18 and 20 which are aligned with the hot, neutral and ground pins 22, 24 and 26 of plug 14, respectively. Likewise, holes 16, 18 and 20 are aligned with the female sockets 28, and 32, respectively, of outlet 12. 
     Sensor device 10 includes a generally flat substrate which is sufficiently thin to allow the plug 14 to make normal mated connection with outlet 12 as shown in FIG. 3. In this embodiment, substrate 34 is a rigid nonconductive printed circuit board to which discrete components are mounted. However, it should be understood that substrate 34 can take the form of a plastic material which supports and encases a thin flex-circuit, such as Kapton, upon which the components are mounted and electrically connected. Substrate 34 has a thickness which is preferably less than about 15 percent the length of the plug pins in order to permit normal mated connection with outlet 12. In this example, substrate 34 is about 0.015-0.030 inch thick and its outer periphery is generally coextensive with the end face of plug 14. 
     Circuitry is provided on substrate 34 for performing the desired detection and storage of data containing information about the electrical signal characteristics flowing from outlet 12 through plug 14 and then to the electrical equipment 36. The circuitry includes one or more microelectronic devices ranging from simple rectifier/analog to digital converter combinations to programmable integrated circuit devices for collecting information about the electrical signals flowing to plug 14 and for storing the data in digital form for later retrieval. Microprocessors or programmable logic arrays could be used for the more complex applications. 
     In this particular example, the circuitry is designed to monitor the quality of the power supplied from outlet 12 through plug 14 to the electrical equipment shown schematically by the numeral 36. Examples of power quality characteristics that can be monitored include voltage spikes, sag, swell, harmonic distortion and other similar characteristics which may be desired to be monitored. In FIGS. 2 and 4 the circuitry is employed to detect the voltage levels of the supplied power on a timed basis. In such manner, it can be determined when abnormally low voltage levels have been applied to the electrical equipment 36. Thus, electrical disturbances which can affect the performance of equipment 36 can be analyzed and corrected, as needed. 
     As shown in FIGS. 2 and 3, the upper surface of the substrate 34 includes a plurality of conductive traces thereon. Two of the traces terminate in bendable finger contacts 38 and 40 for making electrical connection to the pins 24 and 22 when the plug 14 is mated with outlet 12. With additional reference to FIG. 4, the hot electrical contacts 40 and neutral electrical contacts 38 are connected to a diode 42 and capacitor 44 network which serves to rectify and smooth the alternating current line voltage applied to pins 22 and 24 through outlet 12. The rectified line voltage is coupled to a +5 volt regulator 46 which provides the necessary operating voltage for microprocessor 48. A resistor-divider network provided by resistors R1 and R2 is employed to suitably condition the rectified line voltage to a level compatible with the onboard analog to digital converter 52 of microprocessor 48. Microprocessor 48 is, in this example, a Motorola MC68HC11microprocessor which further includes a clock 54 and nonvolatile memory 56. 
     If necessary, the various components can be recessed in pockets in substrate 34 to maintain the desired thin profile for the device 10. In FIG. 3, this is illustrated by recess or pocket 58 that receives microprocessor 48. Suitable electrical connection can be made between the component and the traces on the substrate 34. In FIGS. 2 and 3 this is illustrated by a plurality of wire bonds 60. Other well known connection techniques such as Tape Automated Bonding (TAB) or &#34;Flip-Chips&#34; could be used, as well. 
     Device 10 further includes two serial data transmission output ports 62 and 64 which, along with auxiliary +5 volt input 50, terminate in pads located conveniently near an edge of the substrate 34. The auxiliary +5 volt input 50 accepts +5 volt power from the querying computer 66 (FIG. 5), to power the device&#39;s circuitry when disconnected from line power. A protective coating (not shown), such as Kapton, can be applied to the upper and lower surfaces of substrate 34 as necessary to insulate and protect the components and traces carried by the substrate. 
     In operation, the device 10 is slipped over the male pins of the electrical plug 14 which is then mated with electrical outlet 12 in the normal fashion. The circuitry on device 10 monitors the power quality supplied to equipment 36 on a time-tagged basis. The AC line voltage from outlet 12 is tapped by plug contacts 38 and 40, rectified and converted to digital form by A/D converter 52. The converted digital data is stored in memory 56 under the control of microprocessor 48. Clock 54 provides clock pulses or other suitable signals which the microprocessor 52 uses to tag the sensed characteristics with indicia of when the data sampling took place. As shown in FIG. 5, the stored data can be read from memory 56 for further analysis by computer 66. Electrical connection between device 10 and computer 66 is made by way of a suitable patch cord 68 having a connector 70 which mates with the output pads 62, 64 and 50. 
     It should become apparent to those skilled in the art that the present invention provides a low cost and easily installed technique for monitoring various low voltage power characteristics. No modification of existing hardware is necessary and the device 10 is small enough so that it can be easily transported to various locations for use and/or analysis of its stored data. Various modifications of the particular example just described will become apparent to those skilled in the art. For example, sensors could be included for detecting other data such as temperature, vibration and the like, instead of electrical characteristics. Therefore, no limitation is intended thereby except as defined by the following claims.