CN113576226B

CN113576226B - Intelligent carpet based on capacitive sensor

Info

Publication number: CN113576226B
Application number: CN202110991469.6A
Authority: CN
Inventors: 刘红星; 程东; 刘乐
Original assignee: Nanjing University
Current assignee: Nanjing University
Priority date: 2021-08-26
Filing date: 2021-08-26
Publication date: 2023-02-28
Anticipated expiration: 2041-08-26
Also published as: CN113576226A

Abstract

An intelligent carpet based on a capacitive sensor is composed of a carpet body, an auxiliary ground mat and an above-ground sensing system, and is characterized in that (1) the above-ground sensing system is composed of a sensing node array based on the capacitive sensor, a routing node and an upper computer, wherein (2) the sensing node array based on the capacitive sensor of the above-ground sensing system is attached to the auxiliary ground mat and arranged below the carpet body, (3) each sensing node and one routing node of the sensing node array based on the capacitive sensor are connected through a 485 bus, (4) the routing node is connected to the upper computer in a wired or wireless mode, (5) the routing node is connected with a mains supply or indirectly connected with the mains supply through a 5v socket and supplies power to each sensing node of the sensing node array, and (6) each sensing node transmits capacitance values corresponding to different conditions on the ground to the upper computer through the routing node, and the upper computer judges whether a person is robbed or not.

Description

Intelligent carpet based on capacitive sensor

Technical Field

The application relates to an intelligent carpet based on a capacitive sensor.

The household and the rest homes gradually develop towards intellectualization, and the intellectualization of the carpet is also an important method because the method for automatically monitoring the video in real time needs to rely on a large amount of data accumulated in advance and machine learning. Compared with the traditional carpet, the intelligent carpet integrates various sensors to sense things happening on the ground, such as falling down of old people, burglary and the like.

Background

An implementation of an intelligent carpet is based on electromagnetic tomography. Electromagnetic Tomography (EMT) is a process Tomography technology based on the principle of Electromagnetic induction, and studies the spatial distribution of substances with Electromagnetic properties. A typical EMT system can be divided into four parts: the system comprises a sensor array (namely a detection and excitation coil), a system control circuit, a data acquisition and processing circuit and an image reconstruction and characteristic parameter extraction unit. The method is used for intelligent carpets, the coils need to be detected and excited, the resolution is related to the number of the coils, the technology is complex, and the adaptability and the robustness to the application field are not high.

One implementation of smart carpet is to use smart pressure sensitive flooring under traditional carpet. As the name suggests, the intelligent pressure sensing floor uses a pressure sensor, and judges the condition on the ground by detecting the pressure from the ground, such as whether the old falls down, whether people exist on the ground, and the like. The method has the defects that a special pressure-sensitive floor is needed, the floor has certain rigidity, the sensor needs to be embedded under the floor, and the applicability is limited.

One implementation of intelligent carpet is to place an array of electrostatic sensors under a conventional carpet to sense conditions on the floor, based on the principle that human activity on the carpet generates static electricity, with the closer sensors to the static electricity sensing the stronger the static signal. The method has the advantages of being sensitive to the action of people on the carpet (the action generates static electricity), and has the defects of no perception capability to the static condition on the ground and large influence by other external static electricity interference.

Therefore, there is a need for a more adaptable, robust, or applicable intelligent carpet solution.

Disclosure of Invention

The invention aims to provide a novel method.

A new intelligent carpet solution is proposed, which is based on a capacitive sensor and easy to apply and implement.

The technical scheme is as follows.

An intelligent carpet based on a capacitive sensor is characterized by comprising a carpet body (7), an auxiliary floor mat (2) and a ground sensing system; the ground sensing system consists of a sensing node array (3) based on a capacitive sensor, a routing node (5) and an upper computer (6); the sensing node array (3) based on the capacitive sensor of the ground sensing system is attached to and distributed on the auxiliary ground mat (2) and is arranged below the carpet body (7); each sensing node (3) of the sensing node array based on the capacitive sensor and one routing node (5) are connected through a 485 bus (4); the routing node (5) is connected to the upper computer (6) in a wired or wireless mode; the routing node (5) is connected with the commercial power or indirectly connected with the commercial power through a 5v socket and supplies power to each sensing node of the sensing node array; each sensing node (3) transmits the monitored capacitance values corresponding to different conditions on the ground to an upper computer (6) through a routing node (5), and the upper computer judges whether a person falls or enters a room for robbery according to the capacitance values; one sensing node (3) in the sensing node array comprises a capacitor plate pair, a capacitance value monitoring chip, a single chip microcomputer, a peripheral circuit and a power module, wherein one plate (1) in the capacitor plate pair is arranged on the auxiliary ground mat (2), the other plate in the capacitor plate pair is integrated in the capacitance value monitoring chip, and the capacitance value monitoring chip can adopt FDC2214; a sensing node (3) in the sensing node array shares a capacitance monitoring chip with a plurality of capacitance polar plate pairs under the condition that the capacitance monitoring chip supports, also shares a set of singlechip, peripheral circuit and power module, and thus the sensing node can correspond to polar plates (1) on a plurality of auxiliary ground mats and also correspondingly monitor a plurality of unit areas on the ground.

According to the intelligent carpet based on the capacitive sensor, one sensing node (3) in the sensing node array is provided, one polar plate (1) in one polar plate pair is attached to the auxiliary ground mat (2), and the intelligent carpet is characterized in that the polar plate attached to the auxiliary ground mat (2) can be made of copper foil (1).

The above scheme stems from the assumption that: when a person appears or moves somewhere on the carpet, including falling, walking, etc., the original capacitance value of the underfoot capacitor array is changed. Also stems from the discovery and validation of the inventor's practice of the discipline of: the change in the value of the underfoot capacitor array is large enough to be utilized when a person is present or moving somewhere on the carpet.

Has the beneficial effects.

An intelligent carpet simple device based on a capacitance sensor is built, and the detailed implementation mode is shown in the following embodiment.

And (5) testing experiments. 8 copper foils are attached to 8 foam ground mats to form 8 capacitance sensors, and another 8 foam ground mats are placed on the capacitance sensors to serve as a carpet body. The testees stand on the intelligent carpet tiles 1#, 2#, 3#, 4#, 5#, 6#, 7#, and 8# respectively, and the corresponding capacitance values are found to be changed obviously. The corresponding capacitance value on the computer display is much larger when stepping on the electric blanket area. This demonstrates the effectiveness of the present invention in monitoring the condition of an above-ground person.

Drawings

Fig. 1 is an oblique view of the structure of the smart carpet based on capacitive sensors according to the present invention. In the figure 1, (1) is a capacitance polar plate, (2) is an auxiliary ground mat, (3) is a sensing node composed of a capacitance value monitoring chip, a single chip microcomputer, a peripheral circuit and a power module, (4) is an RS485 bus, (5) is a routing node, (6) is an upper computer, and (7) is a carpet body

Fig. 2 is a logic block diagram of an intelligent carpet circuit built in the embodiment.

Fig. 3 is a schematic diagram of the sensing result of stepping on the 1# sensing area.

Fig. 4 is a schematic diagram of the sensing result of stepping on the 7# sensing area.

Detailed Description

Examples are given. As mentioned above, 8 pieces of copper foil were attached to 8 foam mats to form 8 capacitive sensors, and another 8 foam mats were placed thereon to serve as a carpet body. As the capacitance value monitoring chip mentioned above, a capacitance sensor chip FDC2214 from TI corporation is used. FDC2214 is a 28-bit capacitance-to-digital conversion IC suitable for proximity sensing and liquid level sensing, introduced by TI corporation, and is a noise and EMI resistant, high resolution, high speed, multi-channel capacitance-to-digital converter facing capacitive sensing solutions. The device adopts an innovative architecture based on narrow bands, can highly suppress noise and interference, and simultaneously provides high resolution under high speed conditions. One chip of the chip and 4 copper foils are matched to construct 4 capacitors, and four capacitance values are monitored, so that only two sensing nodes are involved in the embodiment. The single-chip microcomputer of the sensing nodes adopts STM32F103 of ST company, the routing nodes also adopt STM32F103, and the single-chip microcomputer responsible for sending instructions to each sensing node collects capacitance data and uploads the data to the upper computer through WIFI. The capacitor plate is made of copper foil, so that the capacitor plate is cheap and convenient. The copper foil is attached to the ground mat, a lead is welded to the copper foil and connected to the sensing node, the sensing node collects capacitance values after receiving the collection command, sends the result to the routing node through a 485 bus and then to an upper computer PC, and the PC processes data and visually displays the data.

In fig. 3 and 4, the computer visually displays the capacitance values, each small gray block in the graph represents a carpet, the capacitance values are converted into gray values after being processed, and the larger the capacitance value is, the smaller the gray value is, and the whiter the small gray block is.

Claims

1. An intelligent carpet based on a capacitive sensor is characterized by comprising a carpet body (7), an auxiliary ground mat (2) and a ground sensing system; the ground sensing system consists of a sensing node array based on a capacitive sensor, a routing node (5) and an upper computer (6); the sensing node array based on the capacitive sensor of the ground sensing system is attached to and distributed on the auxiliary ground mat (2) and is arranged below the carpet body (7); each sensing node (3) of the sensing node array based on the capacitive sensor and one routing node (5) are connected through a 485 bus (4); the routing node (5) is connected to the upper computer (6) in a wired or wireless mode; the routing node (5) is connected with commercial power or indirectly connected with the commercial power through a 5v socket and supplies power to each sensing node of the sensing node array; each sensing node (3) transmits the monitored capacitance values corresponding to different conditions on the ground to an upper computer (6) through a routing node (5), and the upper computer judges whether a person falls or enters a room for robbery according to the capacitance values; one sensing node (3) in the sensing node array comprises a capacitor plate pair, a capacitance value monitoring chip, a single chip microcomputer, a peripheral circuit and a power module, wherein one plate (1) in the capacitor plate pair is arranged on the auxiliary ground mat (2), the other plate in the capacitor plate pair is integrated in the capacitance value monitoring chip, and the capacitance value monitoring chip can adopt FDC2214; a sensing node (3) in the sensing node array shares a capacitance monitoring chip with a plurality of capacitance polar plate pairs under the condition that the capacitance monitoring chip supports, also shares a set of singlechip, peripheral circuit and power module, and thus the sensing node can correspond to polar plates (1) on a plurality of auxiliary ground mats and also correspondingly monitor a plurality of unit areas on the ground.

2. Intelligent carpet based on capacitive sensors according to claim 1, one sensing node (3) of the array of sensing nodes, one plate (1) of its pair of plates being attached to the auxiliary floor mat (2), characterized in that the plate attached to the auxiliary floor mat (2) can be made of copper foil.