A water starting circuit

Abstract

The present invention discloses a water entry start-up circuit, comprising a first electronic switch, a first resistor, a third resistor, a third electronic switch, a first contact, a second contact, a second resistor, a second electronic switch, a power supply chip, and an MCU. When both the first and second contacts are submerged in water, the circuits conduct and trigger the second electronic switch, which is then powered by an external power supply. After the reset circuit is reset, the MCU starts by controlling the I / O1 pin to set to 1, grounding the third electronic switch, thereby turning off the first electronic switch and outputting a square wave signal from the first contact via the I / O2 pin. Furthermore, the signal voltage waveform is detected from the second contact via the I / O3 pin. When the waveform meets a preset condition, water entry is determined; when the waveform does not meet the preset condition, it is determined to be an interference signal. The present invention is small in size, light in weight, has a fast water entry start-up speed, requires low power, has excellent anti-false triggering capabilities, and can adapt to various harsh environments.

Description

Technical Field

[0001] The present invention belongs to the field of water entry detection, and in particular relates to a water entry starting circuit. Background Art

[0002] Currently, domestic water intrusion detection and activation circuits rely on two electrodes detecting whether a device has fallen into water and whether the circuit is activated. This circuit is always in standby mode. Although the current consumption is low, it is still constantly consuming current. If such devices are to operate for a long time, they need to be equipped with a large-capacity battery, which is unacceptable for portable or wearable devices. If a solution is to regularly replace the battery, such devices will hardly meet the three-proof performance requirements. Currently, domestic water intrusion detection and activation circuits are not designed for reliability, and the detection and activation logic is prone to interference and errors. Furthermore, such devices rarely have a full circuit self-test function, which is unacceptable for critical life-saving equipment. Summary of the Invention

[0003] The purpose of the present invention is to provide a water starting circuit with small size, light weight, and fast water starting speed; the circuit has low power supply requirements and can support its operation for more than 10 years with a conventional button battery; the circuit has excellent anti-false triggering capability and can adapt to various harsh environments; at the same time, the circuit has a key information recording function and a full circuit one-button self-test function, which is particularly suitable for making into portable or wearable devices.

[0004] In order to solve the above technical problems, the technical solution of the present invention is as follows: a water entry start circuit, comprising a first electronic switch, a first resistor, a third resistor, a third electronic switch, a first contact, a second contact, a second resistor, a second electronic switch, a power supply chip and an MCU; wherein the first electronic switch and the second electronic switch are both externally connected to a power supply input, the third electronic switch is grounded, the first electronic switch is externally connected to the first resistor, the control electrode is externally connected to the third resistor and the third electronic switch, the third electronic switch is set to an I / O1 pin, and the first resistor is set to an I / O2 pin; the MCU is externally connected to a reset circuit and pins connected to the I / O1 pin to the I / O8 pin; an I / O3 pin is set between the second contact and the second resistor; the first contact The first contact and the second contact are wirelessly connected. When both the first contact and the second contact are submerged in water, the two are conductive and the second electronic switch is triggered. The second electronic switch is powered by an external power input. After the reset circuit is reset, the MCU starts by controlling the I / O1 pin to be set to 1 to control the third electronic switch to be conductive and grounded, thereby controlling the first electronic switch to be closed and outputting a square wave signal from the first contact through the I / O2 pin. The signal voltage waveform is detected from the second contact through the I / O3 pin. When the waveform meets the preset conditions, it is determined that water has entered; when the waveform does not meet the preset conditions, it is determined that an interference signal has been detected. The device also includes a first self-test switch, which is connected in parallel to the trunk line formed by the wireless connection between the first contact and the second contact.

[0005] The device also includes an electric initiator circuit, which includes a fourth electronic switch, a fifth electronic switch, a sixth electronic switch, a seventh electronic switch, a boost chip, an electric initiator, and a second voltage acquisition circuit. Two ends of the electric initiator are connected in parallel to a branch formed by the seventh electronic switch and the energy storage capacitor. The fourth electronic switch controls grounding and is provided with an I / O4 pin. The fifth electronic switch is connected to an external power input. The sixth electronic switch controls the boost chip to be directly grounded and is provided with an I / O5 pin. The second voltage acquisition circuit is connected between the electric initiator and the energy storage capacitor and is provided with an I / O6 pin. The electric initiator circuit is connected to the MCU via the I / O4 pin to the I / O6 pin.

[0006] When it is determined that water has entered the device, the MCU sets the I / O4 pin to 1, controls the fourth electronic switch to ground, and then activates the fifth electronic switch to supply power to the boost chip. The MCU also sets the I / O5 pin to 1, controls the sixth electronic switch to ground, and the boost chip rapidly boosts the voltage. The energy storage capacitor is charged through the activated electric initiator. When the energy storage capacitor is charged to the set voltage, the seventh electronic switch is triggered to turn on. At this time, the energy storage capacitor is rapidly discharged through the minimum loop formed by the electric initiator and the seventh electronic switch, activating the electric initiator. The MCU records the number of activations output in the E2PROM and controls the electric initiator circuit to power off.

[0007] When the first self-test switch is closed, the MCU collects the external power supply voltage through the I / O8 pin; the MCU controls the fourth electronic switch to be grounded by setting the I / O4 pin to 1, thereby starting the fifth electronic switch to power the boost chip, and the MCU starts timing internally. The boost chip slowly increases the voltage through the fourth resistor, and charges the energy storage capacitor through the electric initiator to be activated; the MCU collects the voltage of the positive electrode of the energy storage capacitor through the I / O6 pin; when the voltage of the positive electrode of the energy storage capacitor collected by the I / O6 pin of the MCU reaches the set value or the MCU starts timing internally and reaches the set time, the MCU sets the I / O4 pin to 0; when the external power supply voltage and the voltage of the positive electrode of the energy storage capacitor are both greater than the set value, the circuit self-test is judged to have passed, otherwise the circuit self-test is judged to have failed; the MCU records the self-test result in the E2PROM and indicates the result externally.

[0008] When the waveform does not meet the preset condition, it is determined whether the first self-test switch is closed. If the first self-test switch is not closed, it is determined to be an interference signal.

[0009] It also includes a first voltage acquisition circuit, which is arranged between the second electronic switch and the power supply chip, and the first power supply acquisition circuit is provided with an I / O8 pin.

[0010] It also includes determining whether the waveform meets a preset condition. If the condition is not met, the circuit waits for water to flow out of the first contact or the second contact, and the circuit automatically cuts off power.

[0011] The MCU is also connected to a second self-test circuit through the I / O7 pin for detecting whether the water entry starting circuit and the electric initiator circuit are intact.

[0012] A light emitting diode is provided on the second self-test circuit as an indicator light.

[0013] The first electronic switch, the second electronic switch and the third electronic switch are low-level trigger switches, the fourth electronic switch, the fifth electronic switch and the sixth electronic switch are high-level start switches, and the seventh electronic switch is a voltage-start switch.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention uses water immersion to power on, which greatly reduces current consumption; uses a square wave of a specific frequency to detect whether it is immersed in a liquid medium, which can prevent the electrode from being accidentally turned on by a metal conductor, and can also prevent it from being turned on in harsh environments such as rain, humidity, heat, and salt spray; adopts circuit boosting and capacitor energy storage solutions, which greatly reduces the power requirements of the power supply; the circuit has a one-button self-check function for the entire circuit, and can be indicated by an indicator light; the circuit also has the ability to record key information. The universal water immersion starting circuit is small in size, light in weight, and has a fast water immersion starting speed. The universal water immersion starting circuit can be widely used in fields where people accidentally fall into the water and need emergency rescue, and where equipment or equipment accidentally fall into the water and need to float immediately; it can also be used in fields where equipment or equipment starts working after falling into the water. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the structure of an embodiment of the present invention;

[0017] Figure 2 A circuit diagram of an embodiment of the present invention;

[0018] Figure 3 1 is a pin configuration diagram of the MCU in an embodiment of the present invention;

[0019] Figure 4 Schematic diagram of the operation flow of an embodiment of the present invention;

[0020] Figure 5 Schematic diagram of the working process of MCU in an embodiment of the present invention. DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions, and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0022] The purpose of the present invention is to provide a universal water-starting circuit. The circuit designed using this circuit design method is small in size, light in weight, and has a fast water-starting speed. The circuit has low power requirements and can support its operation for more than 10 years with a conventional button battery. The circuit has excellent anti-false triggering capability and can adapt to various harsh environments. At the same time, the circuit has a key information recording function and a full-circuit one-button self-test function, and is particularly suitable for making portable or wearable devices.

[0023] The technical solution of the present invention is as follows: a first electronic switch is connected in series with two open contacts to detect whether water has entered. When the contact enters water, the voltage divider on the contact triggers the second electronic switch, and the second electronic switch is connected to the power supply to the MCU circuit. The MCU is reset by the RC reset circuit. The MCU controls the third electronic switch to be turned on and grounded by setting the I / O1 pin to 1, thereby controlling the first electronic switch to be turned off. The MCU then outputs a square wave signal of a certain frequency from the first contact via the I / O2 pin via D1, and detects the signal voltage waveform from the second contact via the I / O3 pin. If the set conditions are met, it is determined that water has entered. If the set conditions are not met, it is determined whether the self-test switch is pressed. If not, it is determined as an interference signal. The circuit waits until water exits the two contacts or the self-test switch is disconnected, and the circuit automatically powers off.

[0024] If it is determined that it has entered water, the MCU sets the I / O4 pin to 1 to start the fourth electronic switch to ground, and then controls the fifth electronic switch to turn on and supply power to the boost chip. The MCU also controls the I / O5 pin to 1 to control the sixth electronic switch to ground. The boost chip quickly boosts the voltage and charges the energy storage capacitor through the electric initiator to be activated. When the energy storage capacitor is charged to the set voltage, the seventh electronic switch is triggered to turn on. At this time, the energy storage capacitor is quickly discharged through the minimum loop composed of the electric initiator and the seventh electronic switch, activating the electric initiator. The MCU is in E 2 The PROM records the number of activations of the output, and the MCU controls the electric initiator circuit to power off.

[0025] If it is determined that the self-test switch is pressed, the MCU collects the external power supply voltage through the I / O8 pin; the MCU controls the fourth electronic switch to be grounded by setting the I / O4 pin to 1, and then starts the fifth electronic switch to power the boost chip. The MCU starts timing internally, and the boost chip slowly increases the voltage through the fourth resistor, and charges the energy storage capacitor through the electric initiator; the MCU collects the voltage of the positive electrode of the energy storage capacitor through the I / O6 pin; when the voltage of the positive electrode of the energy storage capacitor collected by the I / O6 pin of the MCU reaches the set value of 11V or the MCU starts timing internally and reaches the set time of 3s, the MCU sets the I / O4 pin to 0; when the external power supply voltage and the voltage of the positive electrode of the energy storage capacitor are both greater than the set value, it is judged that the circuit self-test has passed, otherwise it is judged that the circuit self-test has failed. If the self-test passes, the MCU drives the light-emitting diode to flash 3 times through the I / O7 pin; if the self-test fails, the light-emitting diode will not be driven to flash. The MCU is in E2 The self-test results are recorded in the PROM.

[0026] The first, second, and third electronic switches are low-level trigger switches, turning on when an input of 0 is input. The fourth, fifth, and sixth electronic switches are high-level trigger switches, turning on when an input of 1 is input. The seventh electronic switch is a voltage-activated switch; when the voltage reaches the set threshold, the fourth electronic switch automatically turns on. I / O3, I / O6, and I / O8 are the MCU's A / D conversion pins. The circuit uses the MCU's internal oscillator as its clock.

[0027] A thyristor first electronic switch Q1 is connected in series with two open contacts to detect water ingress. When water enters the contact, the low-level voltage divider on the first contact triggers the P-MOS tube second electronic switch Q2 to turn on power to the circuit. The reset circuit composed of R1 and R8 completes the reset of the MCU, and the MCU starts up. The MCU controls the N-MOS tube third electronic switch Q3 to ground through the I / O1 pin, thereby controlling the thyristor first electronic switch Q1 to turn off. The MCU then outputs a 1kHz frequency square wave signal with a duty cycle of 50% from the first contact through the I / O2 pin via diode D1. The signal voltage waveform is detected from the second contact through the I / O3 pin. If the set conditions are met, it is determined that water ingress has occurred. If the set conditions are not met, it is determined whether the self-test switch S1 is pressed. If not, it is determined to be an interference signal. The circuit waits until water exits the two contacts or the self-test switch is disconnected, and the circuit automatically powers off.

[0028] If water intrusion is determined, the MCU sets the I / O4 pin to 1, activating the N-MOS fourth electronic switch Q4 to ground, thereby controlling the P-MOS fifth electronic switch Q5 to turn on and power the boost chip U4. The MCU also sets the I / O5 pin to 1, controlling the N-MOS sixth electronic switch Q6 to ground. Boost chip U4 rapidly boosts the voltage, charging energy storage capacitor C7 through the activated electric initiator R. When energy storage capacitor C7 is charged to a set voltage above 15V, it triggers the voltage regulator D2, which in turn triggers the thyristor seventh electronic switch Q7 to turn on. At this point, energy storage capacitor C7 rapidly discharges through the minimum loop formed by the electric initiator R and the thyristor seventh electronic switch Q7, activating the electric initiator R. The MCU records the number of activations via 24C02 and controls the circuit of the electric initiator R to de-energize.

[0029] If self-test switch S1 is determined to be pressed, the MCU samples the external power supply voltage via pin I / O8. The MCU sets pin I / O4 to 1, grounding the N-MOS transistor fourth electronic switch Q4 and activating the P-MOS transistor fifth electronic switch Q5 to power boost chip U4. The MCU begins internal timing, and boost chip U4 slowly boosts the voltage via resistor R4, charging energy storage capacitor C7 via electric initiator R. The MCU samples the voltage at the positive terminal of energy storage capacitor C7 via pin I / O6. When the voltage at the positive terminal of energy storage capacitor C7 reaches the set value of 11V or the MCU timer expires after a set time of 3 seconds, the MCU sets pin I / O4 to 0. If the external power supply voltage VCC is ≥7V and the voltage at the positive terminal of energy storage capacitor C7 is ≥11V, the circuit self-test passes. Otherwise, the circuit self-test fails. If the self-test passes, the MCU drives LED D4 to flash three times via pin I / O7. If the self-test fails, LED D4 is not driven to flash. The MCU records the number of self-tests and the results in the 24C02.

[0030] Positive effects: The universal water starting circuit uses water immersion to power on, greatly reducing current consumption. It uses a square wave of a specific frequency to detect whether it is immersed in a liquid medium, which can prevent the electrodes from accidentally being turned on by metal conductors. It can also prevent it from being turned on in harsh environments such as rain, humidity, and salt spray. The circuit uses a circuit boost and capacitor energy storage solution, which greatly reduces the power requirements of the power supply. The circuit has a one-button self-test function for the entire circuit, which can be indicated by an indicator light. The circuit also has the ability to record key information. The universal water starting circuit is small in size, light in weight, and has a fast water starting speed. The universal water starting circuit can be widely used in fields where people accidentally fall into the water and need emergency rescue, and where equipment or equipment accidentally falls into the water and needs to be immediately floated. It can also be used in fields where equipment or equipment begins to work after falling into the water.

[0031] The above descriptions are merely embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A water starting circuit, characterized in that: The invention comprises first to third electronic switches, first to third resistors, first to second contacts, a power supply chip and an MCU; wherein the first electronic switch and the second electronic switch are both externally connected to a power supply input, the third electronic switch is grounded, the first electronic switch is externally connected to the first resistor, the control electrode is externally connected to the third resistor and the third electronic switch, the third electronic switch is set to the I / O1 pin, and the first resistor is set to the I / O2 pin; the MCU is externally connected to a reset circuit and pins connected to the I / O1 pin to the I / O8 pin; the I / O3 pin is set between the second contact and the second resistor; the first contact and the second contact are wirelessly connected, and when the first contact and the second When both contacts are submerged in water, they are conductive and trigger the second electronic switch, which is powered by an external power input. After the reset circuit is reset, the MCU starts by controlling the I / O1 pin to be set to 1 to control the third electronic switch to be conductive and grounded, thereby controlling the first electronic switch to be closed and outputting a square wave signal from the first contact through the I / O2 pin. The signal voltage waveform is detected from the second contact through the I / O3 pin. When the waveform meets the preset conditions, it is determined that water has entered; otherwise, it is determined to be an interference signal. The device also includes a first self-test switch, which is connected in parallel to the trunk line formed by the wireless connection between the first contact and the second contact. The device also includes an electric initiator circuit, which includes fourth to seventh electronic switches, a boost chip, an electric initiator, and a second voltage acquisition circuit. Both ends of the electric initiator are connected in parallel to a branch formed by the seventh electronic switch and the energy storage capacitor. The fourth electronic switch controls grounding and is provided with an I / O4 pin. The fifth electronic switch is connected to an external power input. The sixth electronic switch controls direct grounding of the boost chip and is provided with an I / O5 pin. The second voltage acquisition circuit is connected between the electric initiator and the energy storage capacitor and is provided with an I / O6 pin. The electric initiator circuit is connected to the MCU via the I / O4 pin to the I / O6 pin. When water intrusion is detected, the MCU sets the I / O4 pin to 1, controls the fourth electronic switch to ground, and then activates the fifth electronic switch to supply power to the boost chip. The MCU sets the I / O5 pin to 1, controls the sixth electronic switch to ground, and the boost chip rapidly boosts the voltage. The activated electric initiator charges the energy storage capacitor. When the energy storage capacitor is charged to the set voltage, the seventh electronic switch is turned on. The energy storage capacitor discharges through the minimum loop formed by the electric initiator and the seventh electronic switch, activating the electric initiator. The MCU outputs the activation count, and the MCU controls the electric initiator circuit to power off. When the first self-test switch is closed, the MCU collects the external power supply voltage through the I / O8 pin; the MCU controls the fourth electronic switch to be grounded by setting the I / O4 pin to 1, thereby starting the fifth electronic switch to power the boost chip. The MCU starts timing internally, and the boost chip slowly increases the voltage through the fourth resistor. The electric initiator to be activated charges the energy storage capacitor; the MCU collects the voltage of the positive electrode of the energy storage capacitor through the I / O6 pin; when the voltage of the positive electrode of the energy storage capacitor collected by the I / O6 pin of the MCU reaches the set value or the MCU starts timing internally and reaches the set time, the MCU sets the I / O4 pin to 0; when the external power supply voltage and the voltage of the positive electrode of the energy storage capacitor are both greater than the set value, it is determined that the circuit self-test has passed.

2. The water entry starting circuit according to claim 1, characterized in that: When the waveform does not meet the preset condition, it is determined whether the first self-test switch is closed. If the first self-test switch is not closed, it is determined to be an interference signal.

3. The water entry starting circuit according to claim 1, characterized in that: It also includes a first voltage acquisition circuit, which is arranged between the second electronic switch and the power supply chip, and the first power supply acquisition circuit is provided with an I / O8 pin.

4. The water entry starting circuit according to claim 1, characterized in that: It also includes determining whether the waveform meets a preset condition. If the condition is not met, the circuit waits for water to flow out of the first contact or the second contact, and the circuit automatically cuts off power.

5. The water entry starting circuit according to claim 1, characterized in that: The MCU is also connected to a second self-test circuit through the I / O7 pin for detecting whether the water entry starting circuit and the electric initiator circuit are intact.

6. The water entry starting circuit according to claim 5, characterized in that: A light emitting diode is provided on the second self-test circuit as an indicator light.

7. The water entry starting circuit according to claim 1, characterized in that: The first electronic switch, the second electronic switch and the third electronic switch are low-level trigger switches, the fourth electronic switch, the fifth electronic switch and the sixth electronic switch are high-level start switches, and the seventh electronic switch is a voltage-start switch.

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