阅读说明：本技术 一种压力检测的提示灯电路 (Prompting lamp circuit for pressure detection ) 是由 田勇 于 2020-06-22 设计创作，主要内容包括：一种压力检测的提示灯电路,包括压阻电桥电路、运算放大电路OP07、稳压芯片7805、单片机PIC12C508以及两组LED灯。压阻电桥电路的四个压阻首尾相连,运算放大电路OP07的引脚3连接第二电阻一端并与第七压阻与第八压阻相连端连接,OP07的引脚2连接第一电阻并与第九压阻与第十压阻相连端连接；7805的引脚Vin连接输出电压端口PRE,7805的引脚Vout连接电源输出正端,7805的GND引脚接地；PIC12C508的引脚VDD连接源输出正端,PIC12C508的引脚VSS接地,PIC12C508的引脚GP3连接第十二分压电阻一端和第十一分压电阻一端；LED灯p1的阴极连接PIC12C508的引脚GP0,LED灯p2的阴极连接PIC12C508的引脚GP1,LED灯p1和LED灯p2的阳极连接电源输出正端。(A pressure detection prompting lamp circuit comprises a piezoresistive bridge circuit, an operational amplifier circuit OP07, a voltage stabilizing chip 7805, a single chip microcomputer PIC12C508 and two groups of LED lamps. The four piezoresistors of the piezoresistive bridge circuit are connected end to end, a pin 3 of the operational amplifier circuit OP07 is connected with one end of the second resistor and connected with the connection ends of the seventh piezoresistor and the eighth piezoresistor, and a pin 2 of the OP07 is connected with the first resistor and connected with the connection ends of the ninth piezoresistor and the tenth piezoresistor; a pin Vin of 7805 is connected with an output voltage port PRE, a pin Vout of 7805 is connected with a positive power output terminal, and a GND pin of 7805 is grounded; pin VDD of PIC12C508 is connected to the positive output terminal, pin VSS of PIC12C508 is grounded, and pin GP3 of PIC12C508 is connected to one end of the twelfth divider resistor and one end of the eleventh divider resistor; the cathode of the LED lamp p1 is connected with a pin GP0 of the PIC12C508, the cathode of the LED lamp p2 is connected with a pin GP1 of the PIC12C508, and the anodes of the LED lamp p1 and the LED lamp p2 are connected with the positive end of the power supply output.)

1. A warning light circuit for pressure detection is characterized by comprising:

the operational amplifier circuit OP07 is characterized in that a pin 2 of an OP07 is connected with one end of a first resistor and one end of a fourth resistor, a pin 3 of an OP07 is connected with one end of a second resistor and one end of a third resistor, the other end of the third resistor is grounded, pins 1, 7 and 8 of an OP07 are connected with a fifth sliding resistor, a pin 6 of an OP07 is connected with the other end of the fourth resistor and one end of a sixth resistor, and the other end of the sixth resistor is connected with a first capacitor and an output voltage port PRE;

the piezoresistive bridge circuit comprises a seventh piezoresistive, an eighth piezoresistive, a ninth piezoresistive and a tenth piezoresistive, wherein the seventh piezoresistive, the eighth piezoresistive, the ninth piezoresistive and the tenth piezoresistive are connected end to end, the connected end of the seventh piezoresistive and the tenth piezoresistive is connected with +5V voltage, the connected end of the eighth piezoresistive and the ninth piezoresistive is grounded, the connected end of the ninth piezoresistive and the tenth piezoresistive is connected with the other end of the first resistor, and the connected end of the seventh piezoresistive and the eighth piezoresistive is connected with the other end of the second resistor;

the pin VDD of the single chip microcomputer PIC12C508 is connected with a source output positive terminal, the pin VSS of the PIC12C508 is grounded, and the pin GP3 of the PIC12C508 is connected with one end of a twelfth divider resistor and one end of an eleventh divider resistor; the other end of the twelfth voltage-dividing resistor is connected with an output voltage port PRE, and the other end of the eleventh voltage-dividing resistor is grounded;

a pin Vin of the voltage stabilizing chip 7805,7805 is connected with an output voltage port PRE, a pin Vout of the 7805 is connected with a power output positive terminal, and a GND pin of the 7805 is grounded;

in the two groups of LED lamps, the cathode of the LED lamp p1 is connected with a pin GP0 of the PIC12C508, the cathode of the LED lamp p2 is connected with a pin GP1 of the PIC12C508, and the anodes of the LED lamp p1 and the LED lamp p2 are connected with the positive end of the power supply output.

2. The warning light circuit for pressure detection as claimed in claim 1, wherein the pin 4 of the operational amplifier OP07 is connected to a voltage of-9V, and the pin 7 of the operational amplifier OP07 is connected to a voltage of + 9V.

3. The pressure detection warning light circuit according to claim 1, wherein a pin Vin of the voltage stabilizing chip 7805 is connected to one end of a filter capacitor C3, the other end of the filter capacitor C3 is grounded, a pin Vout is connected to one end of a filter capacitor C4 and one end of a power supply filter capacitor C2, the other end of the filter capacitor C4 is grounded, one end of a power supply filter capacitor C2 is connected to a positive power supply output terminal, and the other end of the power supply filter capacitor C2 is grounded; the filter capacitors C3 and C4 are both 47 μ F in size, and the power supply filter capacitor C2 is 100nF in size.

4. The pressure detection warning light circuit according to claim 1, wherein the size of the twelfth voltage dividing resistor is 200K ohms, and the size of the eleventh voltage dividing resistor is 100K ohms.

5. The pressure detection warning light circuit according to claim 1, wherein a switch is further connected in series between the one end of the twelfth voltage dividing resistor and the output voltage port PRE.

Technical Field

The invention relates to the field of pressure detection, in particular to a prompting lamp circuit for pressure detection.

Background

With the increasingly developed domestic traffic, freight vehicles carry goods more and more frequently, and whether the goods are overweight needs to be judged in many cases when the freight vehicles unload the goods. However, at present, the worker needs to weigh each piece of goods and then compare the weights to determine whether the goods are overweight, so that the unloading speed is greatly reduced, and when the worker fails to work, the worker may misjudge whether the goods are overweight, so that the technical problem needs to be solved.

Disclosure of Invention

The present invention provides a pressure detection warning light circuit, which comprises:

the operational amplifier circuit OP07 is characterized in that a pin 2 of an OP07 is connected with one end of a first resistor and one end of a fourth resistor, a pin 3 of an OP07 is connected with one end of a second resistor and one end of a third resistor, the other end of the third resistor is grounded, pins 1, 7 and 8 of an OP07 are connected with a fifth sliding resistor, a pin 6 of an OP07 is connected with the other end of the fourth resistor and one end of a sixth resistor, and the other end of the sixth resistor is connected with a first capacitor and an output voltage port PRE;

the piezoresistive bridge circuit comprises a seventh piezoresistive, an eighth piezoresistive, a ninth piezoresistive and a tenth piezoresistive, wherein the seventh piezoresistive, the eighth piezoresistive, the ninth piezoresistive and the tenth piezoresistive are connected end to end, the connected end of the seventh piezoresistive and the tenth piezoresistive is connected with +5V voltage, the connected end of the eighth piezoresistive and the ninth piezoresistive is grounded, the connected end of the ninth piezoresistive and the tenth piezoresistive is connected with the other end of the first resistor, and the connected end of the seventh piezoresistive and the eighth piezoresistive is connected with the other end of the second resistor;

the pin VDD of the single chip microcomputer PIC12C508 is connected with a source output positive terminal, the pin VSS of the PIC12C508 is grounded, and the pin GP3 of the PIC12C508 is connected with one end of a twelfth divider resistor and one end of an eleventh divider resistor; the other end of the twelfth voltage-dividing resistor is connected with an output voltage port PRE, and the other end of the eleventh voltage-dividing resistor is grounded;

a pin Vin of the voltage stabilizing chip 7805,7805 is connected with an output voltage port PRE, a pin Vout of the 7805 is connected with a power output positive terminal, and a GND pin of the 7805 is grounded;

in the two groups of LED lamps, the cathode of the LED lamp p1 is connected with a pin GP0 of the PIC12C508, the cathode of the LED lamp p2 is connected with a pin GP1 of the PIC12C508, and the anodes of the LED lamp p1 and the LED lamp p2 are connected with the positive end of the power supply output.

In the pressure detection warning light circuit of the present invention, the pin 4 of the operational amplifier circuit OP07 is connected to a voltage of-9V, and the pin 7 of the operational amplifier circuit OP07 is connected to a voltage of + 9V.

Furthermore, in the pressure detection prompting lamp circuit, a pin Vin of a voltage stabilizing chip 7805 is connected with one end of a filter capacitor C3, the other end of the filter capacitor C3 is grounded, a pin Vout is connected with one end of a filter capacitor C4 and one end of a power supply filter capacitor C2, the other end of the filter capacitor C4 is grounded, one end of a power supply filter capacitor C2 is connected with a positive power supply output terminal, and the other end of the power supply filter capacitor C2 is grounded; the filter capacitors C3 and C4 are both 47 μ F in size, and the power supply filter capacitor C2 is 100nF in size.

Furthermore, the size of a twelfth voltage-dividing resistor in the pressure detection prompting lamp circuit is 200K ohms, and the size of an eleventh voltage-dividing resistor is 100K ohms.

Furthermore, in the pressure detection warning light circuit of the present invention, a switch is connected in series between the one end of the twelfth voltage-dividing resistor and the output voltage port PRE.

The implementation of the prompting lamp circuit for pressure detection has the following beneficial effects: when the weight of the weighed goods is lower than a set threshold value, the goods are not overweight, and the LED lamp is not on. When the weight of the weighed goods is higher than a set threshold value, the goods are overweight, and the staff can be reminded by lighting the LED lamp.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a circuit schematic diagram of an embodiment of a pressure detection warning light circuit of the present invention.

Detailed Description

For a more clear understanding of the technical features, objects and effects of the present invention, embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

Referring to fig. 1, the prompting lamp circuit for pressure detection in this embodiment specifically includes: piezoresistive bridge circuit, voltage regulation chip 7805, singlechip PIC12C508, switch S1 and 2 luminous groups. Each light emitting group comprises a triode and an LED lamp, wherein the total number of the triodes Q1 and Q2 is 2, and the total number of the LED lamps P1 and P2 is 2.

Pin 2 of the operational amplifier circuit OP07 is connected to one end of the first resistor and one end of the fourth resistor, pin 3 of OP07 is connected to one end of the second resistor and one end of the third resistor, the other end of the third resistor is grounded, pins 1, 7 and 8 of OP07 are connected to the fifth sliding resistor, pin 6 of OP07 is connected to the other end of the fourth resistor and one end of the sixth resistor, and the other end of the sixth resistor is connected to the first capacitor and the output voltage port PRE. The pin 4 of the operational amplifier circuit OP07 is connected with a voltage of-9V, and the pin 7 of the operational amplifier circuit OP07 is connected with a voltage of + 9V.

The piezoresistive bridge circuit comprises a seventh piezoresistive, an eighth piezoresistive, a ninth piezoresistive and a tenth piezoresistive, wherein the seventh piezoresistive, the eighth piezoresistive, the ninth piezoresistive and the tenth piezoresistive are connected end to end, the connected end of the seventh piezoresistive and the tenth piezoresistive is connected with +5V voltage, the connected end of the eighth piezoresistive and the ninth piezoresistive is grounded, the connected end of the ninth piezoresistive and the tenth piezoresistive is connected with the other end of the first resistor, and the connected end of the seventh piezoresistive and the eighth piezoresistive is connected with the other end of the second resistor;

a pin VDD of the singlechip PIC12C508 is connected with a source output positive terminal, a pin VSS of the PIC12C508 is grounded, and a pin GP3 of the PIC12C508 is connected with one end of a twelfth divider resistor and one end of an eleventh divider resistor; the other end of the twelfth voltage-dividing resistor is connected with the output voltage port PRE, the other end of the eleventh voltage-dividing resistor is grounded, the size of the twelfth voltage-dividing resistor is 200K ohms, and the size of the eleventh voltage-dividing resistor is 100K ohms.

A pin Vin of the voltage stabilizing chip 7805 is connected with an output voltage port PRE, a pin Vout of the 7805 is connected with a power output positive terminal, and a GND pin of the 7805 is grounded; a pin Vin of the voltage stabilizing chip 7805 is connected with one end of a filter capacitor C3, the other end of the filter capacitor C3 is grounded, a pin Vout is connected with one end of a filter capacitor C4 and one end of a power supply filter capacitor C2, the other end of the filter capacitor C4 is grounded, one end of a power supply filter capacitor C2 is connected with a positive power supply output terminal, and the other end of the power supply filter capacitor C2 is grounded; the filter capacitors C3 and C4 are both 47 μ F in size, and the power supply filter capacitor C2 is 100nF in size.

In the two groups of LED lamps, the cathode of the LED lamp p1 is connected with a pin GP0 of the PIC12C508, the cathode of the LED lamp p2 is connected with a pin GP1 of the PIC12C508, and the anodes of the LED lamp p1 and the LED lamp p2 are connected with the positive end of the power supply output.

The working principle of the circuit is as follows: the piezoresistance in the piezoresistance bridge is connected with a strain gauge, and an elastic element is pasted on the strain gauge. When the goods weighed, the elastic element was deformed due to pressure, and the resistance value of the piezoresistor was changed through the foil gage again, wherein the resistance values of the seventh piezoresistor and the ninth piezoresistor increased, and the resistance values of the eighth piezoresistor and the tenth piezoresistor decreased, thereby producing the piezoresistive bridge output voltage, and specific formula is:

wherein, V is the output voltage of the piezoresistive bridge, E is the constant voltage power supply of the piezoresistive bridge, R is the initial resistance of the piezoresistive bridge, and R is the resistance variation when the piezoresistive bridge receives pressure.

The output voltage generated by the piezoresistive bridge circuit is amplified by the signal amplifying part and is input into the single chip microcomputer PIC12C508, wherein the signal amplifying part adopts an OP07 operational amplifier with the first power consumption, small input offset voltage and good linearity, the output offset voltage can be adjusted by the fifth slide rheostat, the voltage stability of the voltage port PRE is guaranteed, and further, the voltage stabilizing chip 7805 is adopted to guarantee that the voltage port PRE can stabilize the output voltage.

The voltage input into the single chip microcomputer PIC12C508 is detected through a pin CP3, if the voltage is larger than a threshold value (1.37V in the embodiment), the weighed goods are overweight, the pins GP0 and GP1 output low level or no output, and the LED lamps p1 and p2 are lightened, so that the staff are reminded that the goods are overweight; when the voltage input into the single-chip microcomputer PIC12C508 is detected to be smaller than or equal to the threshold value through the pin CP3, the pins GP0 and GP1 output high levels, so that the LED lamps p1 and p2 are not lightened, and the condition that goods are not overweight is indicated. The lighting means that the p1 and the p2 are continuously lighted or continuously flash, and when the pins are continuously flash, the pins GP0 and GP1 can be signal lamps which output sinusoidal signals or square waves, for example. And preferably, the LED lamps p1 and p2 are lighted synchronously.

While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.