DE102024102532A1 - Sensor unit and method for level monitoring - Google Patents

Abstract

The disclosure relates to a sensor unit comprising a housing insertable into the through-opening of a wall, in particular the wall of a container, wherein a first circuit board with at least one sensor and at least one second circuit board with at least one solar cell are arranged in the housing.

Description

Field of the invention

The invention relates to a sensor unit. In particular, the invention relates to a sensor unit for monitoring the fill level in a container and to a container equipped with the sensor unit. Furthermore, the invention relates to a method for monitoring fill levels in containers.

Background of the invention

The disclosure document DE 10 2022 116 041 A1 (Inventor Chris Möbus) shows a monitoring device for the fill level of a container, in particular a waste container, which comprises at least one ToF sensor (Time of Flight sensor) with a plurality of pixels for fill level monitoring.

A node module is connected to a host module. The node module contains the ToF sensor. The node module includes a battery for power supply and a radio transmitter unit based on the LoRa standard.

It has been proven that reliable and precise fill level monitoring is possible with a ToF sensor. The use of low-power wireless technology also ensures that the battery only needs to be replaced infrequently. However, regular battery replacement is still necessary. Furthermore, depending on the installation situation, installing the modules connected by cables can be complex.

Object of the invention

The invention is based on the object of providing a sensor unit which is easy to install and/or in which the required maintenance and configuration effort is further reduced.

Summary of the invention

The object of the invention is already achieved by a sensor unit and a method for level monitoring according to one of the independent claims and by a container equipped with the sensor unit.

Preferred embodiments and further developments of the invention can be found in the subject matter of the dependent claims, the description and the drawings.

The sensor unit comprises a housing that can be inserted into the opening in a wall.

The wall can in particular be the through hole of a container, in particular in the wall of the lid of a container.

In order to be inserted into the through hole, the housing may include a thread.

For installation, either a thread is drilled into the wall and the sensor unit is then mounted, or the sensor unit is secured in a hole using a lock nut. The housing preferably includes a gasket that seals it against the through hole.

Preferably, the housing is circularly cylindrical, at least in sections. The housing may include a collar, particularly designed as an upper housing part, which rests against the wall when mounted.

Inserting the sensor unit into a through hole in the container ensures a high level of security against deliberate damage. This aspect is particularly important in municipal waste disposal.

The housing can be made of plastic or metal, for example aluminum or stainless steel.

Preferably, the housing has a diameter of 40 to 70 mm, at least in the area of the thread.

The sensor unit's housing is preferably hermetically sealed. This can be achieved, in particular, with a potting compound.

A transparent potting compound is used to seal the second circuit board.

The space between the two boards can also be filled with an opaque potting compound.

It is understood that in addition to screwing in according to another embodiment, other mounting options are also available, for example riveting, welding or gluing.

A first circuit board with at least one sensor is arranged in the housing. When used as intended, the sensor is directed toward the interior of the container.

On the opposite side, especially on the outside, there is a second circuit board with at least one solar cell.

The sensor unit can be powered by at least one solar cell. The sensor unit is preferably not equipped with a battery.

The division into a first circuit board with at least one solar cell and a second circuit board, which is designed as a measuring and transmitting electronics assembly, enables a particularly simple and compact design of the sensor unit.

The solar cell is preferably designed as an SMD (surface-mounted device) solar module. In particular, the second circuit board comprises several SMD solar modules, in particular two to six, especially four. In one embodiment of the invention, two of the solar modules are connected in series.

The solar cell is preferably a monocrystalline solar cell. The solar cell's efficiency (at STC) is preferably above 20%, particularly 20-30%, and especially 22-28%. This ensures sufficient energy supply in a small installation space, even for indoor applications.

The first and second circuit boards are preferably directly connected to each other via an electrical connector. According to another embodiment, the circuit boards are connected to each other via an electrical cable.

The sensor is preferably designed as a level sensor.

Depending on the application, an ultrasonic sensor can be used as a level sensor.

According to a preferred embodiment, the sensor is a ToF sensor with a plurality of pixels.

The ToF sensor can comprise an emitter and a receiver, each of which is designed as an IR diode.

Such a sensor forms a grid with a large number of pixels so that the fill level can be determined in a large number of fields.

The receiver chip is preferably designed as a SPAD array (singlephoton avalanche diode).

The SPAD array can also be designed to measure the reflectance. This allows the type of filler material in the container to be determined. Furthermore, reflections caused by other objects, such as the container wall, can be masked out.

According to a further embodiment of the invention, the sensor can be a gas sensor. A gas sensor can be used, in particular, to monitor the air quality inside the container. Gas sensors are known that can be programmed in such a way that, for example, the gases produced by mold can be detected. In this way, the air quality can be monitored by the sensor module.

The gas sensor can be designed in particular to detect _CO2 and/or VOCs.

According to a preferred embodiment, the second circuit board comprises an antenna, in particular an NFC antenna.

The NFC antenna allows the sensor unit to be programmed or read using an NFC-enabled device, especially a tablet or smartphone. An NFC interface is provided for bidirectional communication. This is preferably located on the first circuit board.

The NFC antenna is preferably designed as a coil. The NFC antenna is preferably arranged in an inner layer of a multilayer circuit board. This allows for a compact design. In particular, the entire top side of the circuit board can be used for mounting solar modules.

The inductance of the NFC antenna is preferably between 10 and 30 µH at 100 kHz.

In a further development of the invention, the sensor unit comprises an energy harvesting module. The energy harvesting module comprises a voltage converter, via which the voltage generated by the at least one solar module, in particular in the millivolt range, can be increased such that a storage device used to supply energy to the sensor module can be charged.

The energy harvesting module can include a boost converter. This increases the voltage of the solar module, in particular by a factor of more than 10, preferably more than 100, in particular from 100 to 500. To increase the voltage, the boost circuit comprises transistors, in particular MOSFETs, connected via diodes, for example. These can gradually increase the input voltage, especially when connected in series in a chain.

In a further development of the invention, an energy harvesting module is connected to the antenna, in particular The NFC antenna can be used, for example, to charge the sensor unit's memory during configuration using an NFC-enabled device.

The energy harvesting module coupled with the NFC antenna can be integrated in particular in an NFC communication module.

For remote communication, in particular for transmitting the sensor data, the sensor unit preferably comprises a radio transmitter unit based on a low-power radio technology, for example LoRa, BAN, Sigfox or NBIoT.

The transmitting unit can be designed according to a low-power radio standard according to IEEE 802.15.4-2020 or IEEE 1451.5-2007.

The storage device is preferably designed as at least one capacitor, in particular a supercapacitor. Compared to a battery, a supercapacitor is particularly durable and resistant to extreme temperatures.

The capacitor is preferably an EDLC capacitor, i.e. a low-resistance double-layer capacitor.

The combined capacitance of the capacitor(s) is preferably 10 to 250 F.

Alternatively, a battery can be used.

The above-mentioned sensor serves as a primary measuring sensor in the sense of the invention.

In a further development of the invention, the sensor unit is designed with a secondary measurement sensor system. This allows for additional functionalities to be provided.

The secondary measurement sensor is preferably located on the second circuit board. This can be a temperature sensor, especially a precision temperature sensor.

An acceleration sensor, particularly a three-axis acceleration sensor, may also be present. This serves for fall and/or 3D or 6D orientation detection.

Furthermore, a hybrid filter multispectral sensor with integrated light sensor and a pressure sensor, in particular an absolute pressure sensor, may be present.

According to a further embodiment, the sensor unit comprises an RGB LED, particularly on the second circuit board. A light pulse can be emitted into the object to be measured, in particular the container, via the RGB LED. The multispectral sensor can thus determine the color of the illuminated object. The color of the light pulse can be changed, for example, via a software configuration of the sensor unit's controller, thus adapting it to the respective application.

The sensor unit according to the invention is preferably operated with software that can be divided into a data platform and a configuration software via the antenna interface.

• - Karte der eingesetzten Module mit Anzeige von Füllständen, Zeitstempel letzte Datenübermittlung, Kondensatorspannung, Funkqualität und/oder Filterfunktionen zum Eingliedern von relevanten Daten.
• - Liste der eingesetzten Module mit Anzeige von Füllständen, Zeitstempel letzte Datenübermittlung, Kondensatorspannung, Funkqualität und frei wählbarer Sekundärmess-Sensorik und/oder Filterfunktionen zum Eingliedern von relevanten Daten.
• - Detailansicht eines eingesetzten Moduls mit Anzeige von Füllständen, Zeitstempel letzte Datenübermittlung, Kondensatorspannung, Funkqualität und eingesetzte Sekundärmess-Sensorik und/oder Datenhistorie mit wählbarer Zeitspanne, Filterfunktionen zum Eingliedern von relevanten Daten und/oder 3D-Ansicht von zu messenden Objekte und deren Füllstand.
• - Aktionsbereich zum Senden von Daten-/Konfigurations-/Firmware-Updates an die montierten Module. Diese kann entweder als festgelegte Gruppe oder als Einzelbefehl erfolgen.
• - Karte der eingesetzten Gateways/Funkmasten mit Anzeige von Zeitstempel letzte Datenübermittlung, Funkqualität und/oder Filterfunktionen zum Eingliedern von relevanten Daten.
• - Objektbibliothek zum Anlegen neuer Objekte und deren 3D-Modelle und/oder Metadaten wie Länge, Breite, Höhe. So können Volumenberechnungen automatisiert vorgenommen werden.
• - Liste der eingesetzten Gateways/Funkmasten mit Anzeige von Zeitstempel, letzte Datenübermittlung, Funkqualität und/oder Filterfunktionen zum Eingliedern von relevanten Daten.
• - Detailansicht eines eingesetzten Gateways / Funkmast mit Anzeige von Zeitstempel letzte Datenübermittlung und/oder Funkqualität. Filterfunktionen zum Eingliedern von relevanten Daten.
• - Exportfunktionen für bspw. Excel mit den gesammelten Daten.
• - Schnittstellen-Management zum Konfigurieren zum Anbinden von Drittsystemen via REST-API.
• - Automatisierungs-Management zum Konfigurieren von Aktionen innerhalb der Datenplattform.
• - Benachrichtigungs-Management zum Konfigurieren von „Alarmen“ bei z.B. Erreichen von bestimmten Füllständen an bestimmten Sensoren, Temperaturen etc.
• - Nutzermanagement mit Berechtigungssystem.
• - Abrechnungsdaten.

The data platform may include at least some of the following information:

• - Map of the modules used with display of fill levels, timestamp of last data transmission, capacitor voltage, radio quality and/or filter functions for integrating relevant data.
• - List of the modules used with display of fill levels, timestamp of last data transmission, capacitor voltage, radio quality and freely selectable secondary measuring sensors and/or filter functions for integrating relevant data.
• - Detailed view of a module used with display of fill levels, timestamp of last data transmission, capacitor voltage, radio quality and secondary measurement sensors used and/or data history with selectable time period, filter functions for incorporating relevant data and/or 3D view of objects to be measured and their fill level.
• - Action area for sending data/configuration/firmware updates to the mounted modules. This can be done either as a defined group or as an individual command.
• - Map of the gateways/radio masts used with display of timestamp of last data transmission, radio quality and/or filter functions for incorporating relevant data.
• - Object library for creating new objects and their 3D models and/or metadata such as length, width, and height. This allows volume calculations to be performed automatically.
• - List of the gateways/radio masts used with display of timestamp, last data transmission, radio quality and/or filter functions for incorporating relevant data.
• - Detailed view of a deployed gateway / radio mast with display of timestamp last Data transmission and/or radio quality. Filter functions for incorporating relevant data.
• - Export functions for e.g. Excel with the collected data.
• - Interface management for configuring the connection to third-party systems via REST API.
• - Automation management to configure actions within the data platform.
• - Notification management to configure “alarms” when, for example, certain fill levels are reached at certain sensors, temperatures, etc.
• - User management with authorization system.
• - Billing data.

Furthermore, the data platform can be used to make predictions about maintenance, fill levels, etc. using machine learning algorithms.

Furthermore, it is possible to determine the position of modules mounted on dynamically positioned objects even without GNSS electronics integrated into the hardware. This is possible through signal triangulation at the permanently installed gateways.

• - Auslesen eines Moduls vor Ort mit den relevanten Parametern zum Einbinden in das Funknetzwerk.
• - Konfigurieren aller relevanten Parametern zum Einbinden in das Funknetzwerk, falls Werkseinstellungen abgeändert werden müssen.
• - Triggern einer Testnachricht zum Senden an die Datenplattform.
• - Überspielen von Firmware-Updates.

The configuration software preferably includes the following functionalities:

• - Reading out a module on site with the relevant parameters for integration into the wireless network.
• - Configure all relevant parameters for integration into the wireless network if factory settings need to be changed.
• - Trigger a test message to send to the data platform.
• - Transferring firmware updates.

According to a further aspect, the invention relates to a sensor unit.

This may in particular include the features described above.

The sensor unit comprises a housing which can preferably be inserted into the through hole of a wall.

On its upper side, the sensor unit comprises at least one solar cell for power supply. The terms "top" and "bottom" serve only to define the different sides within the meaning of the invention. For example, the sensor module can also be installed in the side wall of a container.

A sensor, in particular a fill level sensor, is provided on the underside. The sensor unit also includes a storage device, in particular a capacitor.

The sensor unit further comprises an antenna, in particular an NFC antenna, as well as an energy harvesting module, via which the storage device can be charged with the energy generated by the solar cell.

As described above, the energy harvesting module or another energy harvesting module can also draw its energy from the antenna.

The sensor unit is preferably also installed in a container, in particular a storage container, waste container, the false floor of a room, in particular a server room, or a distribution cabinet.

The container includes a wall with a through hole into which the sensor is inserted.

The sensor unit can in particular be designed as a cover with a circumferential collar on the housing.

The invention further relates to a method for monitoring the fill level of a container, in particular a container as described above.

The fill level in the container is detected by means of a sensor unit inserted into a container wall, wherein the sensor unit is supplied with energy by means of at least one solar cell arranged on the sensor unit via an energy harvesting module, wherein the fill level is transmitted via a radio transmitter unit designed according to a low-power radio technology.

This enables maintenance-free monitoring of fill levels, particularly in municipal waste disposal.

Brief description of the drawings

• 1 und 2 sind perspektivische Darstellungen eines Ausführungsbeispiels eines erfindungsgemäßen Sensormoduls.
• 3 ist eine Draufsicht auf die Oberseite der zweiten Platine, die mit Solarzellen bestückt ist.
• 4 ist eine Draufsicht auf die Unterseite der zweiten Platine.
• 5 ist eine Draufsicht auf die Oberseite der ersten Platine.
• 6 ist eine Draufsicht auf die Unterseite der ersten Platine.

The subject matter of the invention will be explained below with reference to an embodiment based on the drawings 1 until 6 be explained in more detail.

• 1 and 2 are perspective views of an embodiment of a sensor module according to the invention.
• 3 is a top view of the second circuit board, which is equipped with solar cells.
• 4 is a top view of the bottom of the second board.
• 5 is a top view of the first board.
• 6 is a top view of the bottom of the first board.

Detailed description of the drawings

1 shows a sensor unit 1 in a perspective view.

The sensor unit 1 is designed as a lid that can be inserted into the through-hole of a container, for example, into an opening in the lid of a waste container. The housing 10 of the sensor unit 1 comprises an upper part 11 designed as a collar. When mounted, the collar rests against the wall of the container adjacent to the through-hole.

The lower part 12 of the preferably circular-cylindrical sensor unit 1 is provided with an external thread 13.

To mount the sensor unit 1, a through hole designed as an internal thread is made in the wall of the container.

The sensor unit 1 is then screwed in until the collar of the upper housing part 11 comes into contact with the wall.

In this embodiment, the upper part 11 and the lower part 12 are connected by means of screws 14.

Two opposing flats 15 of the lower part 12 serve for clamping during its manufacture.

In this illustration, the second circuit board 100 can be seen at the top, which comprises a plurality of solar cells 101. In this exemplary embodiment, four solar cells 101 designed as SMD solar modules are present, which are distributed in a substantially rectangular arrangement on the top side of the circuit board 100.

The second board 100 forms a measuring and transmitting module.

2 is a perspective view in which the underside of the sensor module 1 can now be seen.

On the underside, the first board 200 is aligned inwards into the container when assembled.

On the underside, the first circuit board 200 comprises at least one sensor, which in this embodiment is designed as a ToF sensor module 210.

The second board 200 contains the measuring and transmitting electronics.

The ToF sensor module 210 comprises a receiver matrix designed as a SPAD array and can thus detect the fill level of a container at a large number of measuring points.

3 is a top view of the second circuit board 100 with the solar cells 101. In addition to the solar cells 101, an NFC antenna 103 is integrated into the circuit board 100, which is connected to an NFC interface, preferably located on the first circuit board. The NFC antenna 103 is thus positioned closest to the user, ensuring the best possible reception and transmission quality.

The NFC antenna 103 is designed as a coil and arranged in an intermediate layer of the circuit board 100.

Optionally, additional layers of the circuit boards can include additional antennas, for example for BLE (Bluetooth Low-Energy).

4 is a top view of the underside of the second board 100.

On the bottom there is a plug contact 102.

In this embodiment, the circuit boards (100, 200) are plugged together via an electrical connector.

In this embodiment, the plug contact 102 is arranged centrally on the circular circuit board 100.

5 is a top view of the first circuit board with the ToF sensor 210. The ToF sensor 210, which provides a primary sensor, is preferably located approximately centrally on the circuit board 200.

In addition to the ToF sensor 210, another sensor is planned to provide additional functionality.

In this embodiment, an RGB LED 201 is located on the circuit board 200, via which light pulses can be emitted into the container interior. A temperature sensor 202 is also located on the circuit board 200.

A hybrid spectral sensor 206, which is preferably arranged in a central region of the circuit board 100, serves to detect the light color of reflected light, in particular light that is emitted and reflected by the RGB LED.

There is also a pressure sensor 203 for measuring the absolute pressure.

For fall and orientation detection, a 3D acceleration sensor 204 is also located on the circuit board 200.

A transmitter module 230, preferably designed according to the LoRa standard, is used for remote communication.

The transmitter module 230 is equipped with low-power radio technology.

The transmitter module 230 includes a microcontroller that is used to control and program the sensor unit.

In this embodiment, the transmitter module 230 is connected to an antenna connector 205, which is also located on the circuit board 200. A connecting cable for the antenna for the transmitter module (not shown) can be inserted into the antenna connector 205. The antenna for the transmitter module can be attached, for example, to the inner wall of the housing, e.g., by gluing.

An NFC module 240 is connected to the NFC antenna (103) of the second board.

Furthermore, at least one energy harvesting module 220 is located on the circuit board 200, which is designed in such a way that even the voltage of the solar cells in the minivolt range can be increased in such a way that an energy storage device can be charged.

The energy harvesting electronics 220 includes a device that can provide feedback to the integrated microcontroller radio transmitter unit on the current energy and charge status of the storage device. This ensures that measurement and transmission cycles are only initiated when sufficient energy is available, thus preventing undefined states and process interruptions.

The NFC module 240 is also equipped with an energy harvesting section and can thus extract energy from the NFC radio waves and also load it into the memory.

This allows the storage to be charged particularly effectively and quickly.

6 shows the underside of board 200.

On the underside 200 there is a connector 207 for an electrical connection to the second circuit board.

Furthermore, in this embodiment, there are two supercapacitors 208 on the underside, which are charged via the at least one energy harvesting module.

The circuit boards shown here are encapsulated in the housing with a potting compound so that the housing is hermetically sealed.

The invention made it possible to provide a largely maintenance-free sensor unit, particularly for detecting fill levels in containers.

List of reference symbols

1

Sensor unit

10

Housing

11

Upper case

12

Lower housing part

13

external thread

14

screw

15

flattening

100

second board (solar/NFC antenna module)

101

solar cell

102

plug contact

103

NFC antenna

200

Circuit board (measurement and transmission electronics)

201

RGB LED

202

Temperature sensor

203

pressure sensor

204

Accelerometer

205

Antenna connection

206

Hybrid spectral sensor

207

Plug connection

208

Supercapacitor

210

ToF sensor module

220

Energy harvesting module

230

Transmitter module

240

NFC module

QUOTES CONTAINED IN THE DESCRIPTION

This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10 2022 116 041 A1 [0002]

Claims (10)

Sensor unit, comprising a housing insertable into the through-opening of a wall, in particular the wall of a container, wherein a first circuit board with at least one sensor and at least one second circuit board with at least one solar cell are arranged in the housing. Sensor unit according to the preceding claim, characterized in that the at least one sensor is designed as a fill level sensor, in particular as a ToF or ultrasonic sensor, or as a gas sensor. Sensor unit according to one of the preceding claims, characterized in that the second circuit board comprises an antenna, in particular an NFC antenna. Sensor unit according to one of the preceding claims, characterized in that the sensor unit, in particular on the first circuit board, comprises an energy harvesting module. Sensor unit according to the preceding claim, characterized in that the energy harvesting module delivers energy obtained from the at least one solar cell and/or the antenna to a storage device. Sensor unit according to one of the preceding claims, characterized in that the sensor unit comprises at least one capacitor, in particular a supercapacitor, as a memory. Sensor unit according to one of the preceding claims, characterized in that the sensor unit comprises an RGB LED, a temperature sensor, an acceleration sensor and/or a pressure sensor, and/or that the antenna is coupled to an NFC interface on the first circuit board, and/or that the housing of the sensor unit is hermetically sealed, in particular by means of a potting compound, and/or that the housing comprises an external thread for screwing into the through-hole, and/or that the at least one solar cell is designed as an SMD solar cell. Sensor unit, in particular according to one of the preceding claims, comprising a housing, wherein the sensor unit comprises at least one solar cell for energy supply on an upper side and at least one sensor on an underside, and wherein the sensor unit comprises a memory, at least one antenna and an energy harvesting module. Container, in particular storage container, waste container, false floor of a room, in particular server room, or distribution cabinet, comprising a wall with a through hole into which a sensor according to one of the preceding claims is inserted. Method for monitoring the fill level of a container, in particular a container according to the preceding claim, wherein the fill level in the container is detected by means of a sensor unit inserted into a container wall, wherein the sensor unit is supplied with energy by means of at least one solar cell arranged on the sensor unit via an energy harvesting module, wherein the fill level is transmitted via a radio transmission unit designed according to a low-power radio technology.