At present, the sensor has become one of the widely used magnetic sensors. As the three pillar technology of modern information society, sensor technology has been widely used in various fields of national economy.
This paper briefly introduces the effect of the sensor, and designs the automatic controller circuit of the toilet based on the sensor. In the electronic circuit of the automatic control system, the Holzer switch is widely used. It can sense the change of the flux near the object, and use this sensor to control the switching and breaking of the switch. The linear device has high accuracy and good linearity. The switch device has no contact, no wear, clear output waveform, no jitter, no rebound, and high repeatability (up to mu m level). The operating temperature range of Holzer devices with various compensation and protection measures is wide, and can reach -55 to 150 degrees Celsius. Because the potential difference between the Holzer components is very small, the Holzer element and amplifier circuit, the temperature compensation circuit and the regulated power supply circuit are usually integrated on a chip, which is called Holzer sensor. When a current I flows through a thin slice, an electromotive force EH will be generated in the direction perpendicular to the current and magnetic field. This phenomenon is called the “effect”. The electromotive force is called the “EMF”, and the semiconductor thin plate is called the “element”. The toilet control device has the automatic control function of lighting and toilet. When the toilet door is opened, the door is opened once, the lighting switch is turned on, and the lighting lamp automatically lights up; after closing the door at any time, the lighting lamp automatically goes out. When using the toilet, the toilet flushes automatically and can be controlled manually. CD4013 is a double D flip-flop consisting of two identical and independent data flip-flops. Each trigger has independent data, placement, reset, clock input and Q and Q* output. This device can be used as a shift register, and by connecting Q output to data input, it can be used as a calculator and trigger. When the rising edge of the clock is triggered, the logic level added to the D input is transmitted to the Q output. The placement and reset are independent of the clock, and are accomplished by the high level on the placement or reset line, respectively. The bidirectional thyristor is also a three-terminal device with two main electrodes T1, T2 and gate G. The equivalent circuit and electrical symbols of the bidirectional thyristor are shown in Figure 4. The bidirectional thyristor can be regarded as composed of two ordinary thyristors in reverse parallel.
The trigger signal is added between gate G and main electrode T2. The main electrode can be triggered by the same gate under both positive and negative voltage. Bidirectional thyristor gate plus positive and negative pulses can be triggered. But when UT1T2 0, positive and negative pulses can be used to trigger; when UT1T2 < 0, only negative pulses can be used to trigger. The whole circuit needs a 12 V DC power supply to provide direct current. If DC battery is supplied, it will not be able to meet long time working requirements. Therefore, the capacitor step-down DC regulated power supply circuit is selected to generate DC power supply. The power supply has been converted into a stable 12 V DC voltage through capacitance step-down, thermostatic element half-wave rectifier circuit, filter circuit and voltage stabilization circuit. This part of the circuit is composed of C1, R1, VD1, VD2 and C2. Among them, capacitor C1 is used to reduce voltage and limit current, and diode VD1 is used to rectify. The switch is an application form of switch mode integrated circuit. First, the output of the switch type integrated circuit is the digital signal. The “0” represents the low level, and the “1” stands for the high level. Secondly, the Holzer device is a magnetoelectric conversion magnetic sensor, it can feel the change of magnetic field, so we need to use magnetic object as its proximity object, through the Holzer switch to detect the existence of magnetic objects, so as to achieve the purpose of controlling switch on and off. According to the first function of the toilet automatic control device, when a person opens the toilet door, the lamp will automatically light up; when a person leaves the toilet and closes the door, the lamp will go out. IC1-IC2 is a D flip-flop.
The transient steady-state time of IC1 is determined by R 3 and C3. Generally, 3-5s. If the door is opened several times during this period, the output of IC1 remains unchanged. LED 1 is a bathroom light with no one in it. LED 1 lights up to indicate that there is someone in the bathroom and EL is lit. When LED 1 goes out, no one in the bathroom and EL is extinguished, SB is a manual button, which is set for the requirements of some special circumstances. Among them, IC1 is connected to a monostable circuit, and Q1 outputs a low level due to its S-state grounding at the positioning end. At the moment when the power supply is switched on, a positive spike pulse differentiated by C4 and R5 acts on the reset end R, forcing IC2 to reset, Q2 to output low level, and VT1 to cut off. The bidirectional thyristor VS1 is blocked and the lamp EL is not on. At the same time, LED 1 does not emit light. In normal times, the bathroom door is always closed. The Holzer sensor B installed above the door is close to the magnetic pole on the doorframe below, and the B output is low. No pulse trigger. IC1 and IC2 are not flipped, VT1 and VS1 are cut off, EL and LED 1 are extinguished. Another function of phototransistor is to transmit signal. Optical coupler is also called photoelectric isolator, or photocoupler for short. Optical couplers transmit electrical signals through optical media. It has a good isolation effect on the input and output electrical signals, so it is widely used in various circuits. At present, it has become one of the most diverse and widely used optoelectronic devices. The light-emitting device of the optical coupler used to transmit analog signals is a diode and the light receiver is a phototransistor. When a current passes through the light-emitting diode, a light source is formed.
The light source irradiates the surface of the phototransistor and makes the phototransistor produce collector current. The current is proportional to the intensity of the light, that is, the positive current flowing through the diode. Because the optical signal transmits between the input and output of the optical coupler, the two parts are completely separated in electricity, and there is no feedback and interference of the electric signal, so the performance of the optical coupler is stable and the anti-interference ability is strong. The common mode rejection ratio (CMRR) is high because of the small coupling capacitance (about 2pf) and high voltage withstand (about 2.5KV) between the luminescent tube and the photosensitive tube. LED 2 is an infrared light emitting diode driven by 12V constant DC voltage, and R8 is its current limiting resistor. LED 2 and phototransistor VT2 constitute a contra-radiation infrared light control circuit. VT2 is low resistor by infrared light emitted by LED. The crystal transistor VT3 is cut off. Its emission level is very low. There is no pulse triggering IC3 Q3 terminal. That is to say, one input terminal with gate F is low level. The photosensitive transistor VT4 and crystal transistor VT5 form another light-controlled circuit. Because the door is closed, VT4 has no light, high resistance, VT5 cuts off, and its collector is high level. One input is connected with the other input of gate F, and the other is charged to C5 via resistor R11. Therefore, f output low level, transistor VT6, bidirectional thyristor VS2 are all cut off, electromagnet km is not closed, and toilet is not flushed. When a person leaves the toilet and closes the door, because of the automatic extinguishing of the lamp EL, the VT4 has no illumination and the VT5 cuts off, the collector potential is high, so that both input terminals of F are high level. VS2 is driven by VT6 amplification, and the electromagnet KM is electrified, so that the toilet flushes. At the same time, the collector level of VT5 is charged to C5 by R11. When the voltage of both ends of C5 rises to the R-terminal threshold level of IC3, IC3 is reset. Q3 terminal becomes low level, stop flushing, and prepare for the next toilet. It can be seen that the flushing time of the toilet is controlled by a delay circuit composed of R11 and C5. Automatic switching lights and automatic flushing control circuit of toilet not only save resources but also facilitate people’s life. Through the application of the sensor in the bathroom automatic control circuit, I have a deeper understanding and understanding of the sensor. It is not only very important in industry, but also widely used in human life.