Pad Presence Detection System

Abstract

An aspect of some embodiments of the present invention relates to a system configured to detect a connection between a pressure pad and a monitor. The system includes a pressure sensing circuit and a presence sensing circuit. The pressure sensing circuit is configured to sense whether pressure on the pad is above or below a threshold pressure. The presence sensing circuit is configured to determine whether the connection between the monitor and the pad is intact. The presence sensing circuit is configured to establish a high voltage state that occurs when the connection is broken in the middle of the presence sensing circuit, and a low voltage state that occurs when the presence sensing circuit is intact.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 004,574, filed April 3, 2020, which is incorporated herein by reference in its entirety. [Background technology]

[0002] A standard bed pad for sensing the presence of a person on the bed is wired to a 6-pin jack J1 or 4-pin jack J1 with an external pair of wires connected to the sensing material, as seen in Figure 1. This material acts as an open switch when no pressure is present on the pad and switches to a closed switch when weight is applied.

[0003] The sense line (e.g., pin 6 or pin 4 for pressure sensing, depending on whether the monitor's pin unit has six or four pins) is connected to a (weak) pull-up resistor R1 connected to a power source with a predetermined input voltage VIN (e.g., +5V) above ground, thereby establishing a predetermined high voltage state at pin 6 when the switch is open. The sense line is also connected to ground around pin 1. The ground connection is between pin 1 and the pad switch, and the power connection is between the pad switch and pin 6. Once the switch closes in the pad between pins 1 and 6 (for a six-pin unit, or pins 1 and 4 for a four-pin unit), the signal in the circuit between pins 1 and 6 is pulled to ground. Therefore, if the signal on pin 6 is measured and is high, the pad switch is inferred to be open, indicating that no pressure above a predetermined threshold is being applied to the pressure pad (no patient is present on the pad). The signal on pin 6 is measured and if it is in a low voltage state (at or near earth) the pad switch is assumed to be closed, which indicates that pressure above a predetermined threshold is being applied to the pressure pad. A measurement unit 50 is part of the monitor and is connected to jack J1 to measure the voltages on the different pins. Summary of the Invention

[0004] Overview of the embodiments of the present invention The inventors have discovered that the problem with the above design is what happens if the pad breaks during operation, which results in one of two scenarios.

[0005] 1. If the weight is applied before a disconnection occurs, the monitor will be armed and may incorrectly assume that the disconnection will cause a high voltage (e.g., +5V) condition, which will open the pad switch indicating a pressure release and activate the fall alert.

[0006] 2. If no weight is applied before the disconnection occurs, the monitor will be idle and measurements within the disconnected circuit will still indicate a high voltage condition (e.g. +5V), so the hardware disconnection may be missed. This could lead to a scenario where the next patient using the pads goes undetected unless staff notices the disconnected pads.

[0007] Accordingly, one aspect of some embodiments of the present invention relates to a system configured to detect a connection between a pressure pad and a monitor. The pressure pad includes a pressure-sensitive zone configured to function as an open switch when pressure on the pressure pad is below a threshold pressure and to function as a closed switch when pressure on the pressure pad is above the threshold pressure, wherein the monitor includes a jack having a first external pin, a second external pin, and one or more intermediate pins located between the external pins. The system includes a pressure-sensing circuit and a presence-sensing circuit. The pressure-sensing circuit is configured to sense whether pressure on the pad is above or below the threshold pressure. The pressure-sensing circuit begins with the first external pin and ends with the second external pin, connecting the first and second external pins in series with the pressure-sensing zone. The pressure-sensing circuit further includes a first connection to ground located on the monitor between the pressure-sensing zone and the first external pin, and a second connection to a power source having a predetermined input voltage higher than ground via a first weak pull-up resistor within the monitor, the second connection being located between the sensitive zone and the second external pin. The presence detection circuit is configured to determine whether a connection between the monitor and the pad is intact. The presence detection circuit starts from a first external pin and terminates at a selected intermediate pin from one or more intermediate pins, and shares a first path from the first external pin to the pad and a first connection to ground with the pressure detection circuit. The presence detection circuit includes a short connection in the first path before reaching the pressure sensitive zone, which leads to the selected intermediate pin via a second path not shared with the pressure detection circuit. The second path has a third connection to a power source via a second weak pull-up resistor in the monitor. The pressure sensing circuit is configured to establish a first high voltage state at the second external pin when the pressure sensitive zone functions as an open switch, and a first low voltage state at the second external pin when the pressure sensitive zone functions as a closed switch, and a measurement of the voltage at the second external pin can be used to determine whether the pressure sensitive zone functions as an open or closed switch, thereby indicating whether pressure on the pad is below or above a pressure threshold.The presence detection circuit is configured to establish a high voltage state at the selected intermediate pin when a connection is broken midway through the presence detection circuit, and a low voltage state at the selected intermediate pin when the presence detection circuit is intact.

[0008] In a variant, the short connection is at the pad.

[0009] In some embodiments of the invention, the system further includes a connection device between the monitor and the pad, the connection device including a connector and an adapter configured to be removably coupled to each other to complete the pressure sensing circuit and the presence sensing circuit.

[0010] In a variant, the connector is connected to the monitor and includes a cavity for accommodating a number of male pins that are connected to corresponding pins of the jack, and the adapter is connected to the pad and includes a protruding adapter body having a number of female connectors, the connector cavity being configured to receive the adapter body such that the female connectors are configured to receive respective male pins to complete the pressure sensing circuit and the presence sensing circuit.

[0011] In another variation, the adapter includes a clip, while the connector includes a clip receptor configured to receive the clip, allowing the adapter and connector to be releasably locked together.

[0012] Another variation of some embodiments of the present invention relates to a system configured to detect pressure on a pressure pad. The system includes a pressure pad, a monitor, a pressure detection circuit, and a presence detection circuit. The pressure pad includes a pressure-sensitive zone configured to function as an open switch when pressure on the pressure pad is below a threshold pressure and to function as a closed switch when pressure on the pressure pad is above the threshold pressure. The monitor is configured to connect to the pressure pad and includes a jack having a first external pin, a second external pin, and one or more intermediate pins located between the external pins. The pressure detection circuit is configured to sense whether pressure on the pad is above or below the threshold pressure. The pressure detection circuit begins with the first external pin, ends with the second external pin, and connects the first and second external pins in series with the pressure-sensitive zone. The pressure sensing circuit further includes a first connection to ground located within the monitor between the pressure sensitive zone and the first external pin, and a second connection to a power source having a predetermined input voltage higher than ground via a first weak pull-up resistor within the monitor, the second connection being located within the monitor between the pressure sensitive zone and the external pin. The presence sensing circuit is configured to determine whether the connection between the monitor and the pad is complete. The presence sensing circuit begins at the first external pin and terminates at a selected intermediate pin from the one or more intermediate pins, and the presence sensing circuit shares a first path from the first pin to the pad with the pressure sensing circuit and the first connection to ground, and the presence sensing circuit includes a short connection in the first path before reaching the pressure sensitive zone. The short connection leads to the selected intermediate pin via a second path not shared with the pressure sensing circuit and has a third connection to the power source via a second weak pull-up resistor within the monitor.The pressure sensing circuit is configured to establish a high voltage state at the second external pin when the pressure sensitive zone functions as an open switch and a low voltage state at the second external pin when the pressure sensitive zone functions as a closed switch, such that a voltage measurement at the second external pin is used to determine whether the pressure sensitive zone functions as an open or closed switch, thereby indicating whether pressure on the pad is below or above a threshold pressure. The presence sensing circuit is configured to establish a second high voltage state at the selected intermediate pin when a connection is broken in the middle of the presence sensing circuit, and a low voltage state at the selected intermediate pin when the presence sensing circuit is intact.

[0013] In a variant, the short connection is in the pad.

[0014] In some embodiments of the invention, the system further includes a connection device between the monitor and the pad, the connection device including a connector and an adapter configured to be removably coupled to each other to complete the pressure sensing circuit and the presence sensing circuit.

[0015] In a variant, the connector is connected to the monitor and includes a cavity for accommodating a number of male pins connected to corresponding pins of the jack, and the adapter is connected to the pad and includes a protruding adapter body having a number of female connectors, the connector cavity being configured to receive the adapter body such that the female connectors are configured to receive respective male pins to complete the pressure sensing circuit and the presence sensing circuit.

[0016] In another variation, the adapter includes a clip, while the connector includes a clip receptor configured to receive the clip, allowing the adapter and connector to be releasably locked together. [Brief explanation of the drawings]

[0017] [Figure 1]1 shows a circuit diagram of a monitor and pressure pad, as known in the art, configured to determine whether pressure above a predetermined threshold is being applied to the pad. [Figure 2a] FIG. 1 shows a circuit diagram of a monitor and pressure pad configured to determine whether pressure above a predetermined threshold is being applied to the pad and to detect disconnection between the monitor and the pressure, according to some embodiments of the present invention. [Figure 2b] 2b shows the circuit diagram of FIG. 2a with the connector and adapter disconnected, according to some embodiments of the present invention. [Figure 3] 10A-10C illustrate an adapter configured to connect to a pressure pad and to connect to a monitor, according to some embodiments of the present invention. [Figure 4] 10A-10C illustrate a connector of a monitor configured to connect to an adapter of a pad according to some embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention is sometimes described herein in terms of example environments. The description in terms of these environments is provided so that various features and embodiments of the invention can be depicted in the context of exemplary applications. After reading this description, it will become apparent to one skilled in the art how the present invention may be implemented in different and alternative environments.

[0019] Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. All patents, patent applications, published applications, and other publications referenced herein are incorporated herein by reference in their entirety. To the extent that a definition set forth in this section conflicts with or is otherwise inconsistent with a definition set forth in a patent application, published application, or other application incorporated herein by reference, the definition set forth in this text shall take precedence over the definition incorporated herein by reference.

[0020] To account for the above situation regarding disconnection between the pads and the monitor, one aspect of some embodiments of the present invention relates to adding a tamper sensor circuit to each monitor pad connection as well as adding a pin short within the pad to enable the tamper sensor circuit to detect the disconnection. To implement this feature, two circuit updates are provided, one in the monitor circuit and one in the pad circuit.

[0021] Monitor Circuit As shown in Figures 2a and 2b, the pressure sensing circuitry required for the monitor is identical to standard pad pressure sensing known to those skilled in the art, as it is intended to sense an open or closed switch. In the present invention, presence circuitry is added to sense the connection of the pad to the monitor. Measurement unit 50 is part of the monitor and connects to jack J1 to measure the voltages at various pins on jack J1. In some embodiments of the present invention, measurement unit 50 includes a microcontroller that measures the voltages at various pins on jack J1 using General Purpose Input / Output (GPIO) pins connected to the desired pins.

[0022] The monitor includes a jack J1 having at least three (e.g., three, four, six) pins, two of which are outer pins and at least one of which is an intermediate pin. J1 may be, for example, a female RJ-11 or female RJ-12 phone jack. The monitor and pads are optionally connected via a connector arrangement 202 configured to allow for removal and replacement of the pads. The connector arrangement 202 includes a connector 202a and an adapter 202b, which are configured to be selectively coupled (FIG. 2a) and separated (FIG. 2b).

[0023] The pressure-sensing circuit measures the diameter of the outer pins of jack J1 (pins 1 and 6 for a 6-pin jack, or pins 1 and 4 for a 4-pin jack), while the presence circuit measures the diameter of the outer pin (e.g., pin 1) and the middle pin (e.g., pin 2). The sense lines (e.g., pressure-sensing pin 6 or 4, depending on whether the monitor's pin unit has six or four pins, and presence-sensing pin 2) can be connected to respective (weak) pull-up resistors (R1, R2) that connect a predetermined input voltage, VIN, to a power source higher than ground (e.g., +5 V), thereby establishing a predetermined high-voltage state. The sense lines are also connected to ground near pin 1. Once a switch is closed on the pad between pins 1 and 6 (for a 6-pin unit), the signal in the circuit between pins 1 and 6 is pulled to ground. Therefore, if the signal on pin 6 is measured to be in a high-voltage state, the pad switch is inferred to be open, indicating that no pressure above a predetermined threshold is being applied to the pressure pad (no patient is present). If the signal on pin 6 is measured to be in a ground state, the pad switch is inferred to be closed and pressure above a predetermined threshold is recognized on the pressure pad (patient present).

[0024] VIN can vary depending on the monitor's operating voltage. For example, in most battery-powered units, VIN will be 3.3V or 5V Transistor-Transistor Logic (TTL) levels.

[0025] R1 and R2 are weak pull-up resistors and may have very large resistances. For example, R1 and R2 may have resistances greater than 10 kOhms but less than 100 kOhms. If the resistance of R1 and R2 is too low (for example, less than 10 kOhms), the resistors become strong pull-up resistors and may have a negative effect on the input signal.

[0026] Pad Circuit The necessary addition of a second circuit is a connection 100 inside the sensor pad that shorts the outer pin together with the middle pin (e.g., pins 1 and 2). This provides a permanent physical closure that can be detected once the sensor pad is connected to a monitor.

[0027] If there is no break, the signal at pin 2 is pulled to ground, thereby establishing a second low voltage state (near or at ground) indicating an intact connection. If a break occurs, regardless of the state of the pad switch, the short between pins 1 and 2 is broken, and another high voltage state powered by VIN is sensed on pin 2. This high voltage indicates that the short is broken, and even if the present circuit is intact, the voltage of the present circuit, as sensed by pin 2, is being pulled to ground by the short at connection 100 to pin 1.

[0028] The short connection 100 is optionally placed as far down as possible in the wire harness or sensor pad material. If the short is established high in the wire harness (near the connector unit 202) and if the break occurs far below the sensor pad, the break in the sensor pad will be falsely detected as an opening in the pad switch. By placing the short connection 100 as far away as possible from the connector unit 202 (i.e., near or within the pad sensor material), the monitor-side circuitry will not only detect a break due to a separation at the connector unit 202 between the monitor and the pressure pad, but will also detect a critical wire harness break, such as a cut wire between the pad and connector due to bed or chair movement. This is due to the fact that a break anywhere along the wire harness will cause the short to break, thereby activating the presence circuitry in the monitor.

[0029] Dongle connection In some embodiments of the present invention, the pad also includes a connector arrangement 202 between the sensor pad and the monitor, as shown in FIGS.

[0030] The connector device includes a connector 202a (FIG. 4) connected to the monitor and an adapter 202b (FIG. 3) connected to the pad. The connector and adapter are detachably coupled to each other. When the connector and adapter are coupled together, the pressure sensing circuit and the presence circuit are completed. The connector 202a has a number of male pins that correspond to and connect to pins on the monitor's jack J1 and are located in a recess in the connector. Specifically, the male pins of the connector each correspond to and connect to at least all of the first external pin, the middle pin that is part of the presence circuit, and the second external pin. More male pins may be present in the connector to connect to other middle pins of the jack J1 that are not used in the pressure sensing circuit and the presence circuit. The adapter 202b has a protruding adapter body configured to fit into the recess in the connector, thereby coupling the adapter and the connector. The adapter body includes a female connector that connects to portions of the pressure sensing circuit and the presence sensing circuit on the pad. The female connector is configured to receive the male pins of the connector to complete the pressure sensing circuit and the presence circuit, as shown in FIGS. 2a and 2b. The number of female connectors in the adapter may exceed the number of portions of the pressure and presence sensing circuitry located on the pad, but only three of the female connectors connect to the portions of the pressure and presence sensing circuitry that are on the pad.

[0031] This provides one standard adapter on the pad and a dongle "pigtail" that converts adapter 202b to connector 202a, providing the pin requirements of jack J1 of the consumption monitor (i.e., 4-pin RJ11, 6-pin RJ11, mini-stereo, etc.). In some embodiments of the invention, a frangible part, such as a clip, is located on adapter 202b, while a clip receptor is located on connector 202a to receive a clip that removably locks the adapter and connector together. This allows the adapter to be replaced without discarding the pad in the event of damage. The scope of the invention also extends to embodiments in which the clip is located on connector 202a and the clip receptor is located on adapter 202b.

[0032] When the adapter and connector are connected together, the pressure sensing circuit and presence circuit are complete. In this scenario, a short connection in the presence circuit sense between pin 1 and pin 2 is placed between adapter 202b and the pad or inside the pad, so that the monitor can detect a scenario where the adapter is still connected to the monitor via the connector, but a disconnect occurs between adapter 202b and the pad or inside the pad.

[0033] Connector Array In the examples of Figures 3 and 4, a 4-pin connector is shown, but only three conductors are used. The techniques of the present invention can be used with any connection with at least three lines, such as a 6-pin or 4-pin RJ11 style plug, 1 / 4 inch audio, mini-audio, micro-audio, or other custom connector.

[0034] While the present invention has been described above in terms of various exemplary embodiments and implementations, it should be understood that the various features, aspects, timing, and functionality described in one or more of the individual embodiments are not limited in their applicability to the particular embodiment described, but instead may be applied to one or more other embodiments of the invention, either alone or in various combinations, regardless of whether such embodiment is described and whether such features are presented as part of the described embodiment. Thus, the breadth and scope of the present invention should not be limited by any of the exemplary embodiments described above.

Claims

1. 1. A system configured to detect a connection between a pressure pad and a monitor, the pressure pad including a pressure sensitive zone configured to function as an open switch when pressure on the pressure pad is below a threshold pressure and to function as a closed switch when pressure on the pressure pad is above the threshold pressure, the monitor including a jack having a first external pin, a second external pin, and one or more intermediate pins located between the external pins, the system comprising: a pressure sensing circuit configured to sense whether a pressure on the pressure pad is above or below the threshold pressure, the pressure sensing circuit starting from the first external pin and ending at the second external pin, the first external pin and the second external pin being connected in series with the pressure sensitive zone, the pressure sensing circuit further including a first connection to ground located on the monitor between the pressure sensitive zone and the first external pin, and a second connection via a first weak pull-up resistor to a power source having a predetermined input voltage higher than ground, the second connection being located on the monitor between the pressure sensitive zone and the second external pin; a presence detection circuit configured to determine whether a connection between the monitor and the pressure pad is intact, the presence detection circuit starting from the first external pin and terminating at one intermediate pin of the one or more intermediate pins, the presence detection circuit sharing with the pressure detection circuit a first path from the first external pin to the pressure pad and the first connection to ground, including a short connection in the first path before reaching the pressure sensitive zone, the short connection leading to the one intermediate pin via a second path not shared with the pressure detection circuit, and a third connection to the power source via a second weak pull-up resistor in the monitor; the pressure sensing circuit is configured to establish a first high voltage state at the second external pin when the pressure sensitive zone functions as an open switch and a first low voltage state at the second external pin when the pressure sensitive zone functions as a closed switch, wherein a measurement of the voltage at the second external pin can be used to determine whether the pressure sensitive zone functions as an open or closed switch, thereby indicating whether pressure on the pressure pad is below or above the threshold pressure; and The system, wherein the presence detection circuit is configured to establish a second high voltage state at the one intermediate pin when a connection is broken in the presence detection circuit, and a second low voltage state at the one intermediate pin when the presence detection circuit is intact.

2. The system of claim 1 , wherein the short connection is within the pressure pad.

3. 10. The system of claim 1, further comprising a connection device between the monitor and the pressure pad, the connection device comprising a connector and an adapter configured to be removably coupled to one another to complete the pressure sensing circuit and the presence sensing circuit.

4. the connector is connected to the monitor and includes a cavity for receiving a number of male pins corresponding to and connected to at least the first external pin, the one intermediate pin, and the second external pin of the jack; the adapter is connected to the pressure pad and includes a protruding adapter body having a plurality of female connectors; 4. The system of claim 3, wherein the connector cavity is configured to receive the adapter body and the female connector is configured to receive each of the male pins to complete the pressure sensing circuit and the presence sensing circuit.

5. the adapter includes a clip; The system of claim 3 , wherein the connector includes a clip receptor configured to receive the clip to releasably lock the adapter and the connector together.

6. 1. A system configured to sense pressure on a pressure pad, the system comprising: a pressure pad including a pressure sensitive zone configured to function as an open switch when pressure on the pressure pad is below a threshold pressure and to function as a closed switch when pressure on the pressure pad is above the threshold pressure; a monitor configured to connect to the pressure pad, the monitor including a jack having a first external pin, a second external pin, and one or more intermediate pins located between the external pins; a pressure sensing circuit configured to sense whether a pressure on the pressure pad is above or below the threshold pressure, the pressure sensing circuit beginning at the first external pin and ending at the second external pin, the first external pin and the second external pin being connected in series with the pressure sensitive zone, the pressure sensing circuit further including a first connection to ground located on the monitor between the pressure sensitive zone and the first external pin, and a second connection via a first weak pull-up resistor to a power source having a predetermined input voltage higher than ground, the second connection being located on the monitor between the pressure sensitive zone and the second external pin; a presence detection circuit configured to determine whether a connection between the monitor and the pressure pad is intact, the presence detection circuit starting at the first external pin and terminating at one intermediate pin of the one or more intermediate pins, the presence detection circuit sharing with the pressure detection circuit a first path from the first external pin to the pressure pad and the first connection to ground, including a short connection in the first path before reaching the pressure sensitive zone, the short connection leading to the one intermediate pin via a second path not shared with the pressure detection circuit, and a third connection to the power source via a second weak pull-up resistor in the monitor; the pressure sensing circuit is configured to establish a first high voltage state at the second external pin when the pressure sensitive zone functions as an open switch and a first low voltage state at the second external pin when the pressure sensitive zone functions as a closed switch, wherein a measurement of the voltage at the second external pin can be used to determine whether the pressure sensitive zone functions as an open or closed switch, thereby indicating whether pressure on the pressure pad is below or above the threshold pressure; and The system, wherein the presence detection circuit is configured to establish a second high voltage state at the one intermediate pin when a connection is broken in the presence detection circuit, and a second low voltage state at the one intermediate pin when the presence detection circuit is intact.

7. The system of claim 6 , wherein the short connection is within the pressure pad.

8. 7. The system of claim 6, further comprising a connection device between the monitor and the pressure pad, the connection device comprising a connector and an adapter configured to be removably coupled to one another to complete the pressure sensing circuit and the presence sensing circuit.

9. the connector is connected to the monitor and includes a cavity for receiving a number of male pins corresponding to and connected to at least the first external pin, the one intermediate pin, and the second external pin of the jack; the adapter is connected to the pressure pad and includes a protruding adapter body having a plurality of female connectors; 9. The system of claim 8, wherein the connector cavity is configured to receive the adapter body and the female connector is configured to receive each of the male pins to complete the pressure sensing circuit and the presence sensing circuit.

10. the adapter includes a clip; The system of claim 8 , wherein the connector includes a clip receptor configured to receive the clip to releasably lock the adapter and the connector together.

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