Wireless sensor node powered by radio frequency and its wake-up and self-driving method

Abstract

The present invention discloses a wireless sensor node powered by radio frequency energy and a wake-up and self-driving method thereof. PMIC performs voltage conversion on the radio frequency energy input, and then charges a super capacitor. After the charging voltage reaches the preset threshold of PMIC, the load switch connected to PMIC is turned on, and then the sensor, MCU and wireless communication module are powered. After the wireless communication module is connected to the host, it sends a connection indication to wake up the MCU, and the MCU collects sensor information and sends it to the host through the wireless communication module. The present invention realizes the storage of radio frequency energy through the cooperation of PMIC with threshold detection, low leakage current load switch and super capacitor; minimizes the discharge loss of radio frequency energy through the sleep wake-up mechanism; and realizes the self-driving of wireless sensor nodes powered by radio frequency energy through the fine management of radio frequency energy storage and release.

Description

Technical Field

[0001] The present invention belongs to the field of wireless sensor technology and specifically relates to a wireless sensor node powered by radio frequency energy and a wake-up and self-driving method thereof. Background Art

[0002] In recent years, with the development of microelectronics, wireless communication and low-power sensors, wireless sensor network technology has been greatly developed. Wireless sensor networks are composed of multiple wireless sensor nodes and hosts.

[0003] Wireless sensor networks have a wide coverage area and a large number of sensor nodes. Traditional battery-powered methods have limited lifespans, high labor costs for battery replacement, and environmental pollution problems caused by used batteries. Therefore, a self-driving wireless sensor node that does not require batteries has a wide range of application scenarios. Energy in nature includes solar energy, temperature difference energy, radio frequency energy, wind energy, vibration energy, etc. Among them, radio frequency energy is not affected by environmental changes and wiring, and is ubiquitous in space. Therefore, the collection and application of radio frequency energy has received more and more attention. Using radio frequency energy to build a self-driving wireless sensor node has a very broad application prospect. However, after the space loss of radio frequency energy collection, the power output is tens to hundreds of uW, which cannot directly drive common wireless sensor nodes.

[0004] If you want to use RF energy to drive common wireless sensor nodes, you need to use a storage medium to store the RF energy first. When the stored energy is sufficient, turn on the discharge switch to release the energy and drive the wireless sensor node to work. In addition, when RF energy drives the wireless sensor node to work, it is necessary to minimize unnecessary energy consumption. Summary of the invention

[0005] The present invention provides a wireless sensor node powered by radio frequency energy and a wake-up and self-driving method thereof, so as to solve the problem that the radio frequency energy is weak and cannot directly drive common wireless sensor nodes. The loss of radio frequency energy in applications can be reduced to the maximum extent, and the self-driving of the wireless sensor node powered by radio frequency energy can be realized through the coordinated application of three links: energy storage, energy release, and sleep wake-up.

[0006] The present invention is achieved through the following technical solutions:

[0007] A wireless sensor node powered by radio frequency energy, the wireless sensor node comprising a radio frequency energy input, a PMIC, a super capacitor, a load switch, a sensor, an MCU and a wireless communication module, the radio frequency energy input being connected to the PMIC, the PMIC being connected to the super capacitor and the load switch, the load switch being connected to the sensor, the MCU and the wireless communication module, the sensor being connected to the MCU, the MCU being connected to the wireless communication module, and the wireless communication module being wirelessly connected to a host.

[0008] A method for waking up and self-driving a wireless sensor node based on radio frequency energy supply, the method for waking up and self-driving a wireless sensor node comprising the following steps:

[0009] Step 1: RF input energy to the supercapacitor;

[0010] Step 2: Detect whether the supercapacitor reaches the high voltage threshold. If the high voltage threshold is reached, the sensor, MCU and wireless communication module are powered. If the high voltage threshold is not reached, the RF energy continues to charge the supercapacitor.

[0011] Step 3: The MCU collects sensor information and sends it to the host until the load switch is turned off and enters the next working cycle.

[0012] Furthermore, the step 1 specifically includes the following steps:

[0013] Step 1.1: PMIC converts the energy of RF input into voltage;

[0014] Step 1.2: Output the voltage converted in step 1 to the supercapacitor to charge it.

[0015] Furthermore, the step 2 specifically includes the following steps:

[0016] Step 2.1: PMIC detects the output voltage, i.e., the supercapacitor voltage. When the voltage does not reach the high-voltage threshold preset by PMIC, step 2.2 is performed. When the voltage reaches the high-voltage threshold preset by PMIC, step 2.3 is performed.

[0017] Step 2.2: The PMIC continues to convert the RF energy input to charge the supercapacitor, causing the voltage to rise.

[0018] Step 2.3: The load switch is turned on, and the sensor, MCU and wireless communication module connected to the load switch are powered;

[0019] Furthermore, the step 3 specifically includes the following steps:

[0020] Step 3.1: After the sensor, MCU and wireless communication module are powered on, they are in sleep mode, and the host wakes them up by connecting to the wireless communication module;

[0021] Step 3.2: The awakened wireless communication module wakes up the MCU by sending a connection indication signal;

[0022] Step 3.3: Based on the MCU awakened in step 3.2, the sensor is awakened;

[0023] Step 3.4: MCU collects sensor information and sends it to the host through the wireless communication module;

[0024] Step 3.5: Repeat step 3.4 until the voltage on the supercapacitor drops to the PMIC preset low voltage threshold;

[0025] Step 3.6: After the voltage drops to the preset low-voltage threshold of the PMIC, the load switch is turned off and enters the next working cycle again.

[0026] Further, the threshold detection output of the PMIC is connected to the load switch enable pin;

[0027] When the output voltage of the PMIC reaches the preset high voltage threshold, the threshold detection output of the PMIC is set high and the load switch is controlled to be turned on;

[0028] When the output voltage of the PMIC drops to a preset low-voltage threshold, the threshold detection output of the PMIC is set low and the load switch is controlled to be turned off.

[0029] Furthermore, the connection indication output pin of the wireless communication module is divided into a connected state and an unconnected state, and the potential of the connected state is opposite to that of the unconnected state;

[0030] When the wireless communication module is connected to the host, the potential of the connected indication output pin is reversed, which serves as an interrupt signal to wake up the MCU.

[0031] The beneficial effects of the present invention are:

[0032] The present invention achieves storage of weak radio frequency energy through the cooperation of a low leakage current load switch and a supercapacitor. The supercapacitor is used as the energy storage medium, which can provide the system with hundreds of thousands of working cycles. Compared with traditional rechargeable battery power supply, the life of the wireless sensor system is greatly improved.

[0033] The MCU, sensor and wireless communication module of the present invention are all in sleep mode during their non-working phase. Only when the wireless communication module is connected to the host, the MCU and the sensor start working. The discharge loss of stored radio frequency energy is minimized through the sleep and wake-up mechanism.

[0034] The present invention controls energy precisely through the mechanisms of radio frequency energy storage, release, and load sleep and awakening, thereby realizing self-driving of wireless sensor nodes powered by radio frequency energy. Compared with wireless sensor nodes powered by traditional energy, the use of radio frequency energy for power supply has the advantages of being clean and not affected by the environment and wiring. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Attached Figure 1 A schematic diagram of the structure of the present invention.

[0036] Attached Figure 2 Flow chart of the method of the present invention. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] A wireless sensor node powered by radio frequency energy, the wireless sensor node comprising a radio frequency energy input, a PMIC, a super capacitor, a load switch, a sensor, an MCU and a wireless communication module, the radio frequency energy input being connected to the PMIC, the PMIC being connected to the super capacitor and the load switch, the load switch being connected to the sensor, the MCU and the wireless communication module, the sensor being connected to the MCU, the MCU being connected to the wireless communication module, and the wireless communication module being wirelessly connected to a host.

[0039] A wireless sensor node awakening and self-driving method based on radio frequency energy supply, the wireless sensor node awakening and self-driving method comprising the following steps:

[0040] Step 1: RF input energy to the supercapacitor;

[0041] Step 2: Detect whether the supercapacitor reaches the high voltage threshold. If the high voltage threshold is reached, the sensor, MCU and wireless communication module are powered. If the high voltage threshold is not reached, the RF energy continues to charge the supercapacitor.

[0042] Step 3: The MCU collects sensor information and sends it to the host until the load switch is turned off and enters the next working cycle.

[0043] Furthermore, the step 1 specifically includes the following steps:

[0044] Step 1.1: PMIC converts the energy of RF input into voltage;

[0045] Step 1.2: Output the voltage converted in step 1 to the supercapacitor to charge it.

[0046] Furthermore, the step 2 specifically includes the following steps:

[0047] Step 2.1: PMIC detects the output voltage, i.e., the supercapacitor voltage. When the voltage does not reach the high-voltage threshold preset by PMIC, step 2.2 is performed. When the voltage reaches the high-voltage threshold preset by PMIC, step 2.3 is performed.

[0048] Step 2.2: The PMIC continues to convert the RF energy input to charge the supercapacitor, causing the voltage to rise.

[0049] Step 2.3: The load switch is turned on, and the sensor, MCU and wireless communication module connected to the load switch are powered;

[0050] Furthermore, the step 3 specifically includes the following steps:

[0051] Step 3.1: After the sensor, MCU and wireless communication module are powered on, they are in sleep mode, and the host wakes them up by connecting to the wireless communication module;

[0052] Step 3.2: The awakened wireless communication module wakes up the MCU by sending a connection indication signal;

[0053] Step 3.3: Based on the MCU awakened in step 3.2, the sensor is awakened;

[0054] Step 3.4: MCU collects sensor information and sends it to the host through the wireless communication module;

[0055] Step 3.5: Repeat step 3.4 until the voltage on the supercapacitor drops to the PMIC preset low voltage threshold;

[0056] Step 3.6: After the voltage drops to the preset low-voltage threshold of the PMIC, the load switch is turned off and enters the next working cycle again.

[0057] Further, the threshold detection output of the PMIC is connected to the load switch enable pin;

[0058] When the output voltage of the PMIC reaches the preset high voltage threshold, the threshold detection output of the PMIC is set high and the load switch is controlled to be turned on;

[0059] When the output voltage of the PMIC drops to a preset low-voltage threshold, the threshold detection output of the PMIC is set low and the load switch is controlled to be turned off.

[0060] Furthermore, the connection indication output pin of the wireless communication module is divided into a connected state and an unconnected state, and the potential of the connected state is opposite to that of the unconnected state;

[0061] When the wireless communication module is connected to the host, the potential of the connected indication output pin is reversed, which serves as an interrupt signal to wake up the MCU.

[0062] The radio frequency energy input includes an energy collection antenna, a rectifier circuit, and a filter circuit. The energy collection antenna collects radio frequency wireless energy in the environment and obtains a DC output through a rectifier and a filter circuit.

[0063] After the wireless communication module is powered on, it is in sleep mode by default. It still maintains the broadcast function in sleep mode, and the host can search it and connect to it.

[0064] After the wireless communication module is connected to the host, it enters the transparent transmission mode. In the transparent transmission mode, all data sent by the MCU to the wireless communication module will be transparently transmitted to the host via wireless.

[0065] After the host searches for the wireless communication module, it connects to it. The wireless communication module then inverts the level of its connection indication pin, and the inverted level is sent to the MCU as an interrupt signal.

[0066] In the MCU program, the MCU is configured to enter sleep mode after power-on and can be awakened by an interrupt signal. After the host is connected to the wireless communication module, the wireless communication module sends an interrupt signal to the MCU, and the MCU wakes up.

[0067] The sensor chip is in sleep mode by default when it is powered on, with low power consumption. After the MCU sends an acquisition instruction to it, the sensor collects information and stores it in an internal buffer. The MCU then reads the data in the buffer. After the data is read out, the sensor enters sleep mode and waits for the next acquisition instruction.

[0068] Figure 1 The solid lines represent energy flow, and the dashed lines represent signal transmission.

[0069] The RF energy input is connected to the PMIC, the PMIC is connected to the super capacitor and the load switch, and the high and low voltage threshold detection outputs of the PMIC are connected to the enable pin EN of the load switch.

[0070] The voltage output of the load switch is connected to the sensor, the MCU and the wireless communication module respectively.

[0071] The MCU performs data exchange with the sensor and the wireless communication module respectively, can collect data from the sensor, and send the data to the wireless communication module.

[0072] The wireless communication module has a connection indication pin, which is connected to the MCU as an interrupt input. After being connected to the host, the level of the connection indication pin is reversed to wake up the MCU.

[0073] Combination Figure 2 , S201: The power management IC (hereinafter referred to as PMIC) converts the RF energy input into a voltage, and the output voltage is connected to the super capacitor and the load switch to charge the super capacitor.

[0074] S202: The PMIC detects the output voltage, that is, the voltage on the supercapacitor. When the voltage reaches the high voltage threshold preset by the PMIC, the load switch is turned on, and the sensor, microcontroller unit (MCU) and wireless communication module connected to the output of the load switch are powered.

[0075] S203: The sensor, MCU, and wireless communication module are in sleep mode after being powered on. The host wakes up the wireless communication module after connecting to it, and the wireless communication module sends a connection indication signal to wake up the MCU.

[0076] S204: After MCU wakes up, it collects sensor information and sends it to the host through the wireless communication module.

[0077] S205: S204 will continue until the voltage on the super capacitor drops to the low voltage threshold preset by the PMIC, the load switch is turned off, and the process enters step S201 again.

[0078] The RF energy input is connected to the PMIC, and the output voltage converted by the PMIC is connected to the supercapacitor and the load switch to charge the supercapacitor. The PMIC has a threshold voltage detection function, and the level of this output pin will be reversed when it exceeds the high and low voltage thresholds.

[0079] As the PMIC charges the supercapacitor, the output voltage rises. When the output voltage rises to the high-voltage threshold preset by the PMIC, the PMIC threshold detection output is set high, the load switch is turned on, and the sensors, MCU, and wireless communication modules connected to the load switch are powered and enter sleep mode.

[0080] The wireless communication module is in sleep mode until the host connects to it. After the connection, the wireless communication module wakes up from sleep mode, reverses the level of the connection indication pin, and sends a connection indication signal to the MCU.

[0081] The MCU is awakened by the connection indication signal sent by the wireless communication module and collects sensor information. During the collection process, the sensor enters the normal working mode from the sleep mode. After the collection is completed, the sensor continues to enter the sleep mode. After the MCU collects the sensor information, it sends the collected information to the host through the wireless communication module. This process will continue. The electric energy stored in the supercapacitor after the PMIC continues to be consumed, and the voltage continues to decrease until the PMIC low voltage threshold. The PMIC threshold detection output is reversed, the level is set low, the load switch is turned off, and the system enters the next working cycle.

Claims

1. A method for waking up and self-driving a wireless sensor node based on radio frequency energy supply, characterized in that: The wireless sensor node includes a radio frequency energy input, a PMIC, a super capacitor, a load switch, a sensor, an MCU and a wireless communication module, wherein the radio frequency energy input is connected to the PMIC, the PMIC is connected to the super capacitor and the load switch, the load switch is connected to the sensor, the MCU and the wireless communication module, the sensor is connected to the MCU, the MCU is connected to the wireless communication module, and the wireless communication module is wirelessly connected to the host; The wireless sensor node awakening and self-driving method comprises the following steps: Step 1: RF input energy to the supercapacitor; Step 2: Detect whether the supercapacitor reaches the high voltage threshold. If the high voltage threshold is reached, the sensor, MCU and wireless communication module are powered. If the high voltage threshold is not reached, the RF energy continues to charge the supercapacitor. Step 3: MCU collects sensor information and sends it to the host until the load switch is turned off and enters the next working cycle; The step 3 specifically includes the following steps: Step 3.1: After the sensor, MCU and wireless communication module are powered on, they are in sleep mode, and the host wakes them up by connecting to the wireless communication module; Step 3.2: The awakened wireless communication module wakes up the MCU by sending a connection indication signal; Step 3.3: Based on the MCU awakened in step 3.2, the sensor is awakened; Step 3.4: MCU collects sensor information and sends it to the host through the wireless communication module; Step 3.5: Repeat step 3.4 until the voltage on the supercapacitor drops to the PMIC preset low voltage threshold; Step 3.6: After the voltage drops to the preset low-voltage threshold of the PMIC, the load switch is turned off and enters the next working cycle again.

2. According to claim 1, a method for waking up and self-driving a wireless sensor node based on radio frequency energy supply, characterized in that: The step 1 specifically includes the following steps: Step 1.1: PMIC converts the energy of RF input into voltage; Step 1.2: Output the voltage converted in step 1 to the supercapacitor to charge it.

3. According to claim 1, a method for waking up and self-driving a wireless sensor node based on radio frequency energy supply, characterized in that: The step 2 specifically includes the following steps: Step 2.1: PMIC detects the output voltage, i.e., the supercapacitor voltage. When the voltage does not reach the high-voltage threshold preset by PMIC, step 2.2 is performed. When the voltage reaches the high-voltage threshold preset by PMIC, step 2.3 is performed. Step 2.2: The PMIC continues to convert the RF energy input to charge the supercapacitor, causing the voltage to rise. Step 2.3: The load switch is turned on, and the sensor, MCU and wireless communication module connected to the load switch are powered.

4. The method for waking up and self-driving a wireless sensor node based on radio frequency energy supply according to claim 1, characterized in that: The threshold detection output of the PMIC is connected to the load switch enable pin; When the output voltage of the PMIC reaches the preset high voltage threshold, the threshold detection output of the PMIC is set high and the load switch is controlled to be turned on; When the output voltage of the PMIC drops to a preset low-voltage threshold, the threshold detection output of the PMIC is set low and the load switch is controlled to be turned off.

5. The method for waking up and self-driving a wireless sensor node based on radio frequency energy supply according to claim 1, characterized in that: The connection indication output pin of the wireless communication module is divided into a connected state and an unconnected state, and the potential of the connected state is opposite to that of the unconnected state; When the wireless communication module is connected to the host, the potential of the connected indication output pin is reversed, which serves as an interrupt signal to wake up the MCU.

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