RU170020U1 - WIRELESS MULTIGAS SENSOR WITH REMOTE ACTIVATION BY RADIO SIGNAL - Google Patents

Abstract

The device relates to the field of monitoring the parameters of the gas environment and is intended for monitoring the concentration of explosive, fire and toxic hazardous gases in the atmosphere of residential premises, inside and on the territory of industrial facilities, as well as issuing not only individual alarms when the measured component reaches the set threshold values, but also transmitting data via a wireless sensor network to a control room. The device is a wireless multi-gas gas sensor with data transfer wirelessly IEEE 802.15.4 standard network operating in the end device mode. The device is designed to monitor toxic and explosive gases in the air and prevent emergency situations. The device works according to the algorithm stored in the memory of the microcontroller in the mode: operating mode - sleep mode - operating mode. To force the device to wake up from sleep mode in order to perform its prescribed functions (for example, to take measurements, transmit data, perform a device verification operation), the device is equipped with a passive RF circuit, including an antenna, a resonant circuit for tuning to a specific frequency, detector, and comparator . The technical result is to improve the design of the device due to the remote activation of the device by transmitting an external radio signal to it and expanding its function when performing monitoring the composition of the gas medium.

Description

The technical field to which the utility model relates.

The device relates to the field of monitoring the parameters of the gas environment and is intended for monitoring the concentration of explosive, fire and toxic hazardous gases in the atmosphere of residential premises, inside and on the territory of industrial facilities, as well as issuing not only individual alarms when the measured component reaches the set threshold values, but also data transmission over the wireless sensor network to the control room control.

In particular, the invention may find application:

- as a wireless gas sensor for monitoring methane leaks (СН ₄ ) in gasified apartment buildings and individual houses and at oil and gas facilities;

- as a wireless gas sensor for monitoring the chemical composition of air (in particular, for monitoring toxic gases, such as carbon monoxide CO, hydrogen sulfide H ₂ S, nitrogen dioxide NO ₂ );

- as a device for monitoring the gas composition of air in the construction of wireless sensor networks.

State of the art

A known wireless gas sensor containing gas sensors, an analog measuring part, a transceiver, a microprocessor module for controlling the operating modes of the device, a power supply circuit of the sensor and the device as a whole, autonomous power (RF patent 111675, IPC G01N 33/00, published on December 20, 2011) .

The disadvantage of this device is that the principle of operation of the device is based on firmware embedded in the microcontroller. In order to save energy, measurements of gas concentrations are carried out in a periodic mode: measurement mode - sleep mode - measurement mode. The duration of the sensor heating mode and the measurement time is about 1 s. The duration of sleep mode is determined by the technical requirements. Typical values are in the range from 10 to 60 s. At the same time, there is no possibility of waking the device from sleep mode by receiving a radio command from an external transmitter. In addition, the disadvantage of the known platform is the lack of integration of gas sensors of various types and the possibility of their joint and / or separate operation.

Closest to the described device is a wireless multisensor sensor (RF Patent No. 160116, IPC G01N 33/00, publ. 10.03.16) with autonomous power supply, containing gas sensors with analog and digital output connected to a switch, an analog measuring part, a transceiver, microprocessor module for controlling the operating modes of the device and the device power circuit from batteries, batteries, alternative energy sources and their combination.

This device allows you to monitor multicomponent gas mixtures. The principle of operation of the device is based on firmware embedded in the microcontroller. In order to save energy, measurements of gas concentrations by all sensors of the device are carried out in periodic mode: measurement mode - sleep mode - measurement mode. The duration of the sleep mode is set by the program and depends on the presence of the measured component in the air. In sleep mode, all functions are disabled, except for the built-in timer of the microcontroller. Initially, the sleep time is 1 minute for all sensors. If there is a measured component in the air, the duration of the sleep mode is reduced to 15 seconds for the sensor that detects this presence. Thus, most of the time the device is in sleep mode.

The disadvantage of this device is the inability to wake the device from sleep mode or transfer it from the operating mode (measurement mode) to the service mode (for example, to transmit data stored in the microcontroller memory or reprogramming) by command from an external radio transmitter.

Utility Model Disclosure

The utility model is based on the task of improving the design of the known wireless multi-gas sensor to enable remote activation of the device by detecting an external high-frequency RF signal by it. To solve this problem, a circuit for converting a high-frequency signal to a constant voltage (HF circuit) is connected to the external interrupt input of the microcontroller, which allows the sensor to wake up from sleep mode or measurement mode when an external radio signal of a given power is detected and the sensor is switched to another operating mode, for example, transmission of data stored in the memory of the microcontroller. The ability to remotely activate by transmitting a radio signal to it allows you to change the algorithms and modes of operation of the device, in particular, to remove it from sleep mode.

The problem is solved in that a wireless multi-gas sensor containing sensors with analog and digital output connected to a switch, an analog measuring part, a transceiver, a microcontroller to control the operating modes of the device, the power supply circuit of the sensor and the device as a whole, an autonomous power source. At the same time, an RF circuit is connected to the external interrupt input of the microcontroller, which ensures that the sensor wakes up from sleep mode when an external radio signal of a given power is detected and the sensor is transferred to the data transfer mode of the microcontroller. In this case, the RF circuit consists of an antenna, a resonant circuit, a detector and a comparator; the sensor contains an electrochemical digital carbon monoxide sensor, a semiconductor hydrogen sulfide sensor, an electrochemical nitrogen dioxide sensor and a thermocatalytic catalytic methane sensor.

Since the wireless multi-gas sensor is made with the possibility of remote activation by transmitting an external radio signal to it, the device design is improved and its function is expanded when monitoring the composition of the gas medium.

In fact, a wireless multi-gas sensor becomes a radio-controlled device, which, when registering an external radio signal, can not only exit sleep mode, but also launch additional routines, as well as be reprogrammed.

Brief Description of the Drawings

In FIG. 1 is a schematic block diagram of a wireless multi-gas sensor. The device consists of a power source 1, a voltage converter 2, a transceiver 3, a microcontroller 4, a sensor switching unit 5, gas sensors 6-9, communication lines for transmitting data from the sensors to the microcontroller 10. To receive a radio signal from an external transmitter to the external interrupt input of the microcontroller connected to the RF circuit, including its own antenna 11, a resonant circuit for tuning to a specific frequency 12, the detector 13 and the comparator 14.

As a power source 1 can be used batteries, batteries, alternative energy sources and their combination. The microcontroller 4 performs device control, processing and data transfer. In addition, the measured values of the concentration of the corresponding gases are stored in the memory of the microcontroller. Data is transmitted wirelessly using a transceiver 3. The following types of sensors can be connected to the device: thermocatalytic 6, semiconductor 7, electrochemical 8 and any type of sensor with digital output 9. The device operates according to the program stored in the microcontroller's memory, which controls the connection (switching) of sensors 6-9, turning on and off. The included sensor is ready to take measurements. The output signal from sensors 6-9 can be received through communication lines 10. To increase the battery life, the device, most of the time, is in sleep mode, leaving it for measurements.

Implementation of a utility model.

The device is a wireless multi-gas gas sensor with data transmission over a wireless network of IEEE 802.15.4 standard operating in the end device mode. The device is designed to monitor toxic and explosive gases in the air and prevent emergency situations. The device works according to the algorithm stored in the memory of the microcontroller in the mode: operating mode - sleep mode - operating mode. In operating mode, gas composition measurements are performed. Data transfer is also carried out on command from the microcontroller, for which the device must be in working mode. Most of the time the device is in sleep mode. The device has autonomous battery power, and the device’s sleep mode provides extended battery life.

To force the device to wake up from sleep mode in order to perform the prescribed functions (for example, taking measurements, transmitting data, performing a device verification operation), the device is equipped with a passive RF circuit. Wakeup occurs in the presence of a beacon device in the immediate vicinity of the device. A beacon device transmits signal pulses at a given frequency and at a given frequency. When approaching a beacon device, the signals transmitted from the beacon arrive at the RF circuit of the device. If the signal power is sufficient, an output voltage is generated at the output of the RF circuit that is sufficient for the comparator to operate, which is responsible for the device leaving the sleep mode. In this case, the device software records the fact of a forced exit from sleep mode. After the forced exit from sleep mode, the device establishes a connection with the wireless sensor network, if necessary reconnects to the network, and performs the prescribed functions, for example, transfers the data stored in the microcontroller's memory to the control room control panel.

The implementation of the RF circuit includes an antenna, a resonant circuit for tuning to a specific frequency, a detector and a comparator. The resonant circuit provides amplification of the voltage of the incoming signal in the event that its frequency coincides with the resonant frequency or is close to it. The detector converts the RF signal into a DC signal. The comparator brings the level of the analog signal from the output of the detector to the levels of logic zero or unity and transmits this signal to the external interrupt input of the microcontroller.

In addition, the signal at the input of the external interrupt of the microcontroller during the measurement, lead to the termination of the measurement and puts the device in the mode of execution of the prescribed functions.

The device can be used both as an individual wireless multi-gas sensor, and as part of wireless sensor networks that support Zigbee technology. When working as an individual wireless multi-gas sensor, the device can be equipped with a light alarm and an audible alarm.

Example. The device is a multi-gas sensor that autonomously measures the concentration of methane, nitric oxide, hydrogen sulfide and carbon monoxide at its location. The measured values are stored in the memory of the microcontroller until the activation signal arrives at the device. After that, the device establishes a network connection and performs the function of transmitting the accumulated data to the dispatching device.

The device operates as follows. After turning on the power, the voltage of the batteries 1 through a DC / DC converter (DS-DS converter) 2 is supplied to the microcontroller 4, the transceiver 3 and the switching unit 5 of the sensors 6-9. In this case, at the initial moment, the microcontroller 4, the transceiver 3 and the switching unit 5 are in the off state. When voltage is supplied to the microcontroller 4, the software is activated. The microcontroller 4 goes into active mode, puts the transceiver 3 into sleep mode (standby), and, according to a given algorithm, connects the power to the required sensor (by closing the contacts in block 5). Measurements are carried out sequentially by selecting the desired sensor. The device comprises an electrochemical digital carbon monoxide sensor 9, a semiconductor hydrogen sulfide sensor 7, an electrochemical nitrogen dioxide sensor 8 with an analog output, and a thermocatalytic catalytic methane sensor 6 with an analog output.

Sensors that are not used for measurements are in the off state or standby mode (depending on the measurement procedure). In order to save energy, measurements of gas concentrations by all sensors of the device are carried out in periodic mode: measurement mode-sleep mode-measurement mode. The duration of the measurement mode is the sum of the time taken by all sensors. The duration of the sleep mode is determined based on the specific conditions of the measurements. Most of the time the device is in sleep mode.

The measured gas concentration value is stored in the memory of the microcontroller. When an external signal from the beacon device of the required amplitude and predetermined frequency arrives at the antenna 11, the device leaves the sleep mode or interrupts the measurement process. The power of the external signal must exceed at the input of the RF circuit - 10 dBm at a frequency of 866 MHz. At the same time, a voltage equal to or more than 0.5 V is supplied from the detector 13 to the comparator 14. In turn, the comparator supplies a logical unit to the microcontroller, which displays it from sleep mode. When using a beacon device with a power of 30 dBm (or 1 W), a power value of 10 dBm will take place at a distance of 2.5-3 m from the beacon with a non-directional antenna and an antenna gain of 5 dBi. In this case, the microcontroller 4 gives a command to turn on the transceiver 3, which connects to the detected sensor network and transmits data to the dispatching device. There are several options for using a beacon device. It can be portable and then it is necessary to bring it a certain distance to the device, so that the power level of its radio emission brought the device out of sleep mode. The beacon device can be stationary and then the device must be brought closer to it.

After data transfer, the microcontroller puts the device into normal operation.

In addition, when measuring the concentration of methane, nitric oxide, hydrogen sulfide and carbon monoxide, the device operates as a two-threshold device. The first threshold is warning, the second is danger. The thresholds are set in accordance with table 1.

Exceeding the concentration of the warning threshold and the hazard threshold activates the sound and light alarms of the device.

Claims (3)

1. A wireless multi-gas sensor containing sensors with analog and digital output connected to a switch, an analog measuring part, a transceiver, a microcontroller for controlling the operating modes of the device, a power supply circuit for the sensors and the device as a whole, an autonomous power source, characterized in that to the external input microcontroller interruption An RF circuit is connected, which ensures that the sensor wakes up from sleep mode when an external radio signal of a given power is detected and the sensor is put into transmission mode PARTICULAR data in memory of the microcontroller. 2. The wireless multi-gas sensor according to claim 1, characterized in that the RF circuit consists of an antenna, a resonant circuit, a detector and a comparator. 3. The wireless multi-gas sensor according to claim 1, characterized in that the sensor comprises an electrochemical digital carbon monoxide sensor, a semiconductor hydrogen sulfide sensor, an electrochemical nitrogen dioxide sensor and a thermocatalytic methane sensor.

Images