JPH0754735B2 - Rug electric heater - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rug-like electric heater such as an electric carpet or an electric cushion.

(B) Conventional technology Conventionally, in this type of electric carpet or electric cushion, a piezoelectric sensor (piezoelectric film) is arranged, the output of the piezoelectric sensor is amplified, and a person is placed on the heater from the change in the output. Whether or not the heater is present is determined, and the energization of the heater is controlled.

(C) Problems to be Solved by the Invention However, in the conventional heating device provided with the piezoelectric sensor, the piezoelectric sensor detects a large fluctuation in the power supply voltage of the heater and external noise superimposed on the heater. When the level was high, there was a malfunction in which the heater was energized even though there was no human body above the heater.

This invention was made in consideration of such circumstances,
(EN) A rug-like electric heater that does not malfunction even when strong noise from a power source or the like is superimposed on the output of a piezoelectric sensor.

(D) Means for Solving the Problem The present invention relates to a rug-shaped electric heater in which heaters are distributed and embedded in a rug, and a heating surface of the rug is divided into a plurality of areas, and a strip-shaped piezoelectric sensor is arranged on each heating surface. Control means for controlling the energization of the heater by receiving the output signal of each piezoelectric sensor, comparing means for comparing the phase of the output signal of each piezoelectric sensor, and the phase difference of the output signal of each piezoelectric sensor is less than a predetermined value. In this case, the rug-like electric heater is provided with a prohibiting means for prohibiting the energization of the heater by the output signals to the control means.

FIG. 1 is a block diagram showing the above-mentioned structure, 101 is a heater distributed and embedded in a rug, and 102a and 102b are strip-shaped piezoelectric elements arranged on each heating face by dividing the heating face of the rug into a plurality of parts. A sensor 103 is a control means for controlling the energization of the heater 101 by receiving the output signals of the piezoelectric sensors 102a and 102b.
04 is a comparison means for comparing the phases of the output signals of the piezoelectric sensors 102a and 102b, and 105 is the energization of the heater 101 by the output signals of the piezoelectric sensors 102a and 102b when the phase difference between the output signals is less than a predetermined value. It is a prohibition means for prohibiting the control by the control means 103.

(E) Action In FIG. 1, the power source and the external noise from the heater 101 are output from the piezoelectric sensors 102a and 102b as substantially in-phase signals. At that time, therefore, the inhibiting unit 105 operates by receiving the output of the comparing unit 104. However, the control unit 103 prohibits the energization control of the heater 101 by the output signals of the piezoelectric sensors 102a and 102b. Therefore, malfunction of the heater energization due to noise is prevented.

(F) Embodiment Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. This does not limit the present invention.

FIG. 2 is a perspective view of an embodiment of the present invention, where CP is a carpet in which heating wires for an electric heater (not shown in the figure) are distributed and embedded, and A and B are heating surfaces of the carpet CP. The divided heating surfaces Sa and Sb are piezoelectric sensors arranged together with heating wires for heating the heating surface A and the heating surface B, respectively.

FIG. 3 is a sectional view of a piezoelectric sensor applied to an embodiment of the present invention, in which 1 is a piezoelectric resin made of polyvinylidene fluoride having a thickness of 0.03 mm, and 2 is an aluminum electrode deposited on both sides of the piezoelectric resin 1. Reference numeral 4 is a polyester film for laminating the piezoelectric film 1, and reference numeral 3 is an adhesive layer inserted therebetween. The piezoelectric sensor thus constructed has dimensions of 0.1 mm in thickness and 10 mm in width.

FIG. 4 is a top view of the piezoelectric sensor shown in FIG. 3, in which a terminal block 6 is provided at one end thereof, and lead lines 7 from the electrodes 2 are fixed.

FIG. 5 is a circuit configuration diagram of the embodiment shown in FIG. The voltage generated in the piezoelectric sensors S1 and S2 by the movement of the person is waveform-shaped by the impedance conversion circuits 1a and 1b and the filter circuits 2a and 2b, and output as a voltage (several Hz component) corresponding to the movement of the person. The outputs of the filter circuits 2a and 2b are divided by resistors 3a and 4a and 3b and 4b, respectively, and are input to a microcomputer (hereinafter referred to as a microcomputer) MC as signals Va and Vb. The detection inputs Va and Vb of the microcomputer MC are normally about 2.5V when there is no movement of the person, but when a person moves, they change due to the expansion and return of the piezoelectric film, resulting in the voltage waveform as shown in Fig. 6. Become. In this voltage waveform, if both conditions of about 3.3 V or more and about 1.6 V or less occur within about 1.5 seconds, the microcomputer MC determines that there is a person on the electric carpet, and the heater control circuit Output to HC, and corresponding heating wire Ha or Hb is energized for 20 minutes from that time. And
The difference between the judgment time by the signal Va and the judgment time by the signal Vb
If it is 0.2 seconds or less, neither heating wire is energized.

FIG. 7 is a flowchart showing the operation of the microcomputer MC, and FIGS. 8 and 9 are flowcharts showing the subroutine of FIG.

In addition, Ia is a counter that counts up by 1 every 0.1 seconds after the signal Va becomes larger than 3.3V, Ja is 1 every 0.1 seconds after the signal Va becomes smaller than 1.6V.
The counter that counts up one by one, Ib is 1 every 0.1 seconds after the signal Vb becomes larger than 3.3V.
The counter that counts up one by one, Jb is 1 every 0.1 seconds after the signal Vb becomes less than 1.6V.
A counter that increments by one, Ta is a counter that increments by 1 every 0.1 seconds when the counts of counters Ia and Ja are both 1 or more, and Tb is 0.1 when the counts of counters Ib and Jb are both 1 or greater. It is a counter that counts up by 1 every second.

When all counters are reset in step 201 of FIG. 7, the microcomputer MC detects a detection input about every 0.1 seconds (step 202).

First, in step 203, that is, in the subroutine shown in FIG. 8, when it is detected that the detected voltage Va is about 3.3 V or more or about 1.6 V or less, from that time point, the reverse voltage (about 3.3 V last time) is detected. 1.6V or less if detected above, 1.6V last time
If the following is detected, it is about 0.
It is repeatedly determined up to 15 times per second, and if a reverse voltage is detected during that time, it is determined that there is a person on the electric carpet CP. If the reverse voltage cannot be detected while detecting the reverse voltage (up to 15 times), it is determined that there is no person on the electric carpet.

Next, in step 204, that is, in the subroutine shown in FIG. 9, similarly, the electric carpet CP is detected by the detected voltage Vb.
The presence or absence of the upper body is determined. And the human body is on the heating surface A
If it is determined that the heat is present on the heating surface B and is not present on the heating surface B (steps 205 and 206), the heat generation Ha is energized for 20 minutes from the determination time. In addition, the human body does not exist on the heating surface A,
When it is determined that the heating line B exists only on the heating surface B (steps 205 and 208), the heating wire Hb is energized for 20 minutes from the determination point. If it is determined that the human body exists on the heating surfaces A and B within the time of 0.2 seconds or less (step 20).
5,206), the routine returns to step 202 and the heating lines Ha, Hb
Are not energized together. Also, when it is determined that there is no human body on any of the heating surfaces A and B (step 210),
The heating lines Ha and Hb are not energized. By the way, the piezoelectric sensors Sa and Sb may induce a voltage not only by the movement of a person or an animal but also by a large fluctuation of the power supply voltage or noise such as radiated radio waves.

In this case, a voltage is simultaneously induced in the piezoelectric sensors Sa and Sb. Therefore, since these signals are input to the microcomputer MC within a fixed time (within 0.2 seconds), the signals are not discriminated as described above and the heating wires Ha and Hb are not energized. That is, malfunction of the electric carpet due to noise is prevented.

(G) Effect of the Invention According to the present invention, it is possible to accurately detect whether or not a human body is present on the heater without causing a malfunction due to noise, so that safe and efficient energization of the heater is performed. Be seen.

[Brief description of drawings]

1 is a block diagram showing the configuration of the present invention, FIG. 2 is a perspective view of an electric carpet to which an embodiment of the present invention is applied,
3 is a sectional view of the piezoelectric sensor used in the embodiment of FIG. 1, FIG. 4 is a top view of FIG. 3, and FIG. 5 is an electric circuit diagram of a control unit of the embodiment shown in FIG. FIG. 6 is a time chart showing the relationship of the signal waveforms of FIG. 5, and FIGS. 7 to 9 are flowcharts showing the operation of the main parts of the electric circuit shown in FIG. A, B ... Heating surface, CP ... Electric carpet, Ha, Hb ... Heating line, Sa, Sb ... Piezoelectric sensor, MC ... Microcomputer, HC ... Heater control circuit.

Claims (1)

[Claims] 1. In a rug-shaped electric heater in which heaters are distributed and embedded in a rug, a heating surface of the rug is divided into a plurality of zones, and strip-shaped piezoelectric sensors are provided on each heating surface, and output signals of the respective piezoelectric sensors are provided. In response to this, control means for controlling the energization of the heater, comparison means for comparing the phases of the output signals of the respective piezoelectric sensors, and those for the control means when the phase difference between the output signals of the respective piezoelectric sensors is below a predetermined value. A rug-like electric heater comprising a prohibition unit that prohibits energization of a heater by an output signal.