EP3740770A1

EP3740770A1 - Device for reading the status of electronic electricity meters, method of reading electronic electricity meters, procedure for reading the status of electronic electricity meters and use of the device

Info

Publication number: EP3740770A1
Application number: EP19710586.9A
Authority: EP
Inventors: Zdenek HALBICH; Jirí MERZ
Original assignee: VisionqCz SRO
Current assignee: VisionqCz SRO
Priority date: 2018-01-19
Filing date: 2019-01-15
Publication date: 2020-11-25
Also published as: CZ201829A3; WO2019141299A1

Abstract

Device for continuous status reading of electronic electrometers consists of a battery (1), source (2) supply voltage (3), wireless communication module (4), monitor (5) battery voltage, optical communication interface (6), antenna (7) and protection circuit (8), where these blocks or elements in aggregate serve to collect and transfer data obtained from regular electronic electrometers, where low-power wide-area network (LPWAN) is used for the data transfer, which requires extremely low costs for construction and operation, while this compact device has a fixture removable using a magnet, using an optical port for obtaining data from the electrometer.

Description

Device for reading the status of electronic electricity meters, method of reading electronic electricity meters, procedure for reading the status of electronic electricity meters and use of the device.

Technical field

The invention involves a device and its mechanical structure and its mechanical connection for reading status information from electronic electricity meters (particularly measured consumption of power and related information) via an optical communication interface and remote transfer of this information by low-power wide-area network LPWAN to a cloud data storage.

Background Art

Optical (IR) ports of modern electronic electricity meters are currently used for single readings (typically once per year) of power consumption by suppliers for the purposes of preparing consumption statements or for diagnostic and maintenance purposes. Continuous measuring of consumption and provision of relevant information to clients online are either overlooked by suppliers or are handled by special, technologically complex and expensive electricity meters equipped with some“standard” communication technologies (GSM/GPRS, Wi-Fi, MBus wireless) - e.g. Landis+Gyr ZMF100 electricity meter. Solutions currently available, which allow online monitoring of power consumption by reading the information form electricity meters, use optical impulse output for collection of consumption information. The disadvantage of this option is in the necessity of initial“manual” setup of software counters, the calculation coefficient and subsequent continuous synchronization (loss of a mere impulse = loss of synchronization and total corruption of all other measurements). They require complicated infrastructure based on Wi-Fi communication for transfer of information, 230V network supply and a data concentrator - see e.g. the Energomonitor project.

Description of the Invention

The basic idea comprises the state-of-the-art technologies of Internet of Things (loT) to construct and operate a very cheap, price accessible device serving to collect, transfer, present and process data obtained from regular electronic electricity meters. Data transfer uses the low-power wide-area network (LPWAN), characteristic for its extremely low cost of construction and operation. In the invention this involves:

miniature, compact device

fed by AA battery or power accumulator

communicating data for low-power, cheap LPWAN to LoRaWAN network to cloud storage

detachable magnetic fixture

using an optical port compliant with the IEC 62056-21 norm to obtain the data from the electricity meter. Description of device connection according to the invention

The device based on this invention serves to provide automatic, contactless collection of data from electricity meters and its wireless transfer via low-power radio network to a central server. The data then may be freely processed both for personal use as well as for power distributors. Emphasis is placed on maximum ease of installation and network registration, as well as user account creation and displaying of measured values.

The whole device is supplied by a battery, preferably a lithium battery with nominal voltage of 3.6V, which has an advantage in it long life and with average consumption of 20uA permits years of usage. Should there be a power source with similar or better parameters than a lithium battery, then such an alternative power source may also be used. Supply voltage is brought from the battery to the protection circuit. This part contains a semi-conductor diode, which serves as protection against polarity reversal (e.g. when the user changes the batteries). The semiconductor diode lets the current through, but in one direction only, i.e. from the anode to the cathode. Should there be different polarity at the semiconductor diode, i.e. when switching of positive and negative supply voltage clamp the diode is polarized in the so- called leeward direction and allows through minimum current amounting to single units ^LA, which is called reverse current. This reverse current, due to its size, will not pose danger to other parts of the device.

Since the battery described above could deliver at short circuit up to dozens of amperes and passage of this extreme current could lead to e.g. ignition, there is a resettable fuse connected in the protection circuit behind the semiconductor diode. This fuse will disconnect the battery from the device when the current rises above the given level and will protect both the battery and other parts of the device during any defect on the device. The resettable fuse has an auto- regenerative ability and after disconnection it will bring itself back to conductible condition, therefore, it is not necessary to replace the fuse.

The protection circuit is followed by a supply voltage source. This part of the device contains mainly a linear voltage stabilizer with very low own consumption and a very low voltage drop on this circuit. Other elements include blocking capacitors, which prevent feedback oscillation of the linear stabilizer during an abrupt change of supply voltage, and since the device is supplied by a battery in this solution abrupt change in supply voltage cannot occur in front of the stabilizer, or during an abrupt change of consumed power from the linear stabilizer. Since one of the device targets is an extremely long lifespan, the processor unit and the communication module are mostly in a very low power mode and the consumption of the device is in mere microamperes. However, during communication with the electricity meter and during data sending via radio connection, momentary growth in current consumption occurs, amounting to dozens of milliamperes. Here, the blocking capacitators that prevent oscillation of linear stabilizer feedback and the loss of stabilization characteristics pay off. Output voltage from the linear stabilizer, which feeds all other parts of the device, where the stabilizer is part of the power source, is 2.5 V. Due to that and due to the characteristics of the stabilizer described above, i.e. very low own consumption and very low voltage decline, the device is operable already with voltage of 2.7 V.

The battery voltage monitoring device is connected behind the protection circuit and consists of a voltage divider and an operative amplifier. The voltage divider made of two resistors with high resistance amounting to megaohms MQ, ensures the decrease of the value of the measured battery voltage to a value given by the ratio of resistance value of resistors in voltage divider, which is then suitable for further processing by the processing unit. Due to the high resistance value of the resistors in the divider the current flowing through these elements is very low, i.e. less than one microampere ^LA, and therefore does not burden the battery and does not decrease its lifespan. The high resistance value, however, causes that the voltage divider has a high exit resistance and thus cannot be connected directly to an analog-digital converter contained in the processor unit, because its entry resistance is in tens of kiloohms (kQ) and the measured value will be greatly distorted and unusable. This problem is solved by an operative amplifier used as an impedance divider. This connection then has an extremely high entry resistance of tens of MQ, so it does not place voltage burden on the voltage divider and can be connected to the entry of analog-digital converter of the processor unit without producing errors in battery voltage measuring.

The processor unit contains a microprocessor, which runs the whole device, most suitably a 16 bit microprocessor with extremely low input of approximately 50 in sleep mode, in which the microprocessor is 95% of the time. It controls the communication module for access to low-power wireless network, controls the communication process with the electricity meter via optical communication interface and also controls the battery voltage through integrated analog-digital converter. It is basically a final status automat. After starting or restarting the microprocessor, all used peripheries are set up first, particularly the timer, which is part of the processor unit and which as the only one remains in running mode even in the most economical mode of the microprocessor, where almost all of its part are switched off and the consumption is in single MAs.

First of all, a communication test with the electricity meter is attempted in the loop. If this test is successful, the data is sent to the server via a wireless low-power network (see below). Subsequently, the entire microprocessor is switched to a very low input mode, when only the special timer is running. After passing of the defined period, usually 10 minutes, this timer brings the processor back to active mode again. The entire process constantly repeats itself. Battery status is also checked and the status is sent in a data package together with the electricity meter data.

Optical communication interface serves to transfer the information between the device and the electricity meter. It is directly connected to the processor unit, which ensures its control. It consists of a phototransistor and a LED diode. Both elements work in the specter of a close infrared field, approx. 880 nm. The IR (infrared) LED diode, when passing of the electric current, emits infrared radiation and serves as a transmitting element. The size of the actuating current is set via resistors to approx. 10 mA, which is a suitable compromise between power consumption and emitted output. The IR LED diode is not connected directly to the processor unit, but is switched by a bipolar PNP type transistor. The exit microprocessor port has a limited maximum exit current and the PNP transistor allows to use the low current from exit microprocessor pin to switch the bigger current flowing through the IR LED diode. When exposed to infrared radiation, the current starts flowing through the sensor element, e.g. an IR phototransistor, at which point opening happens. The phototransistor is connected between the zero potential GND (ground) and the pull up resistor, which is fed by supply feed of 2.5 V. If the sensitive area of the semi-conductor is exposed to infrared radiation, the phototransistor starts leading the current and a logical value“L” marking 0 V voltage is displayed on the exit of the circuit connected to the microprocessor. If the semiconductor is not exposed, the phototransistor is closed and logical value Ή” indicating 2.5 V voltage is displayed on the exit. Serial communication between the device and the electricity meter takes place in this manner. In this type of transfer the communication starts by emitting the start bit with logical value“L” and then individual bits follow from transferred byte and the transfer is stopped by a stop bit with logical value Ή”. The infrared signal is not modulated in any way.

The wireless communication module ensures the transfer of measured data via an antenna to a low-power wireless network of the LPWAN type to a cloud storage. It contains circuits of modulator, demodulator and generator of base frequency. Modulator circuits serve to create a high-frequency signal with modulated data package intended to be emitted from the device. Exit from the modulator circuits is led to the exit amplifier, which ensures the required emitting output and is connected to the antenna. The antenna is at the same time connected to the entry low-interference amplifier, the so-called Low Noise Amplifier LNA, which strengthens the signal received by the device. It is connected to a demodulator, which demodulates the high-frequency signal and transfers it to a data package, which is processed by the processor unit. Part of the wireless communication module is besides the modulator and demodulator circuits also the base frequency generator consisting of a crystal oscillator, voltage controlled oscillator and phase locked loop. The crystal oscillator together with the voltage controlled oscillator (Voltage Controlled Oscillator VCO) and phase locked loop (Phase Locked Loop PLL) generates an exact frequency for the modulator and demodulator circuits. The crystal oscillator functions on the principle of oscillation of an element made of piezoelectric material, when voltage is brought to two opposing electrodes. The size and shape of this crystal determines the resonance frequency, which the crystal oscillator then generates.

The phase locked loop of the crystal oscillator, which is part of the wireless communication module, is a feedback circuit, the task of which is to maintain the exit signal phase with entry signal. Its exit is brought to the voltage controlled oscillator via a bottom filter (this filter allows through only signals up to a certain frequency). Its exit signal of frequency corresponding to control voltage is brought to the first entry of the phase detector via a divider (N) and to the second entry the signal is brought from the crystal oscillator. This connection ensures at the entry of the voltage controlled oscillator such voltage that the output frequency is equal to the frequency of the crystal oscillator multiplied by the constant N, which corresponds to the dividing ration of the divider. Thus, the signal is synthetized with accurate frequency for the modulator. The same frequency is used also in the demodulator for received signal.

The wireless communication module in basic configuration consists of one integrated circuit. In a different configuration it may be represented by more integrated circuits, which together make up this module.

In the basic configuration the antenna is connected directly to the printed circuit board by a screw connector and with the outer jacket of the device e.g. box (housing) it comprises a compact set. It may happen that the antenna must be taken out of the box in which the electricity meter is located. In such a case, the antenna may be connected to the device via a cable.

The device is attached to the electricity meter by a magnetic element located near the optical communication interface exit. Any other way of attaching the device that allows connection of the optical communication interface with the electricity meter is nor excluded by this invention, nevertheless the magnetic attachment appears to be the most suitable connection.

If needed, the device may be fitted with an optical or metallic cable for remote connection of the device with the electricity meter. The metallic cable in such solution contains circuits that transfers the optical signal to electric signal in both directions. Such solution is generally unfavourable and more complicated, expensive and demanding and is thus suitable only in situations where there is no free space available in front of the electricity meter, thus making installation of this device impossible. The device is, however, so small that it fits almost in any electricity meter box, whereby we can say that if the probe fits in than the device according to this invention will fit in too.

Advantages in comparison to the existing status:

Modern remote access to information about power consumption: The device allows continuous readings from regular electronic electricity meters equipped with optical interface (e.g. invention prepared in line with the Standard IEC 62056- 21 ) and sending of this information in preset time intervals to cloud storage for further processing. The data is then available continuously in numeric and graphic form in physical units (kWh) and also in financial expression (CZK) via web browsers of PCs, tablets and smartphones.

Economic efficiency: the majority of regularly used electricity meters may be very quickly equipped with the device using a magnet - in order to obtain online information on consumption it is thus not necessary to replace the existing device with a new and expensive device with a communication interface. Price accessibility: the device is completely maintenance-free (with the exception of battery replacement approx once every 2-3 years in the case of the invention), simple and accessible to the broad public, (expected final price of the invention is up to CZK 1 ,000.00). Network operation is also cheap - network for Internet of things of the LPWAN type (so-called Low Power WAN) is inexpensive to construct and the regular price for transfer of information from one device will not exceed 1 Euro per month in this invention.

High-tech nature: the device is based on state-of-the-art technologies both in electronics (low-power parts, battery feed) and in architecture of the follow-up infrastructure (loT network, cloud storage, web access), which allows the development of solution, which does not require any specific specialized user knowledge during installation.

High value in use: at minimum costs the user gains permanent overview of power consumption on his premises. After entering few values (approx. 4 according to supplier in this invention example) it is possible to transfer information on consumption for a selected time frame from physical units directly to currency units (CZK, EUR). Comparison with paid deposits allows more efficient steering of balance available in regards to the supplier. Consumption limits may be set for a selected period and upon crossing this limit, e-mail or SMS notifications will be automatically generated. Notifications are also generated at negative balance, where there is the danger of high arrears at the end of the settlement period. Naturally, notifications can be bound to values entered by the user.

Summary of advantages:

The device based on this invention deals with the following issues:

accurate, continuous measuring of power consumption by data reading directly from the electricity meter; transfer of information on consumption via a modern radio network LPWAN to cloud storage;

presentation of collected data online in real time via a web browser on regular PCs and also on mobile smartphone devices (telephones, tablets).

The device based on this invention that is performing continuous reading of electricity meter counters (or other quantities that the relevant electricity meter provides) has the following product capabilities:

in line with the REGULATION OF THE EUROPEAN PARLIAMENT AND COUNCIL 2009/72/EC from 13 July 2009, on common rules for the internal market in electricity, it provides the consumers with proper information on power consumption and its costs and that with sufficient frequency that allows them to efficiently regulate their consumption.

It is at the same time an innovative solution, which:

is very simple in structure, cheap - very affordable;

requires no tools, equipment or technical knowledge for its installation; allows easy attachment and removal from the optical port using a magnet;

uses a communication standard (in invention example DLMS standard is used), which allows consistency of data even during temporary removal of the device (e.g. by power supplier during single power consumption reading).

For transfer of data it uses modern, cheap, low power radio network (Low Power WAN) with high range (LoRaWAN, SigFox or NB loT), which allows supply from a battery with lifespan of at least 2 years (depending on adjustable frequency of readings and transfers). This invention example uses the LoRaWAN network.

Description of Drawings

Fig. 1 depicts the device based on the invention with electricity meter;

Fig. 2 depicts the general wiring diagram of main elements;

Fig. 3 depicts detailed wiring diagram of all elements.

Examples of Embodiments

Example 1

Device for continuous reading of electronic electricity meters according to Image 1 consists of these parts and/or elements:

battery 1 or power accumulator;

supply voltage source 2;

processor units 3;

wireless of communication module 4;

battery voltage, or power accumulator monitor 5;

optical communication interface 6;

antenna 7 and

protection circuit 8;

Example 2

The device according to Image 2 and according to Example 1 , where the battery 1 is lithium battery with nominal voltage of 3.6 V, where the source 2 contains a linear stabilizer 2a of voltage and blocking capacitors 2b, where the processor unit 3 consists of a microprocessor 3a, an analog and a digital converter 3b and atimer 3c, where the wireless communication module 4 consists of a crystal oscillator 4a, a phase locked loop 4b, a voltage controlled oscillator 4c, a demodulator 4d, a low-noise amplifier 4e and a modulator 4f, where the battery voltage monitor 5 consists of a resistor divider 5a and an operative amplifier 5b, where optical communication interface 6 consist of a phototransistor 6a and a led diode 6b, a resistor for adjusting the IR radiation intensity 6c, a bipolar transistor 6d and where the protection circuit 8 is made up of a semiconductor diode 8a and a resettable fuse 8b. Example 3

Device according to example 2, where source 2 has output voltage of 2.5 V. The microprocessor 3a is a 16 bit microprocessor with extremely low input. The communication module 4 serves for access of the low-power wireless network LPWAN, particularly type LoRaWAN, SigFox or NB loT and allows continuous reading of regular electronic electricity meters equipped with optical interface e.g. according to the Standard IEC 62056-21 and sending of this information in predetermined time intervals to cloud storage for further processing. The phototransistor 6a and the LED diode 6b work within the IR specter on a wavelength of 880 nm. The size of the actuating current is set by resistors 6c to approximately to10 mA.

Example 4

Device according to image 1 is favorably attached to the electricity meter by a magnetic element created by the output of the optical communication interface 6.

Example 5

Device according to any of the examples above, where the wireless communication module 4 contains at least one integrated circuit.

Example 6

Device according to any of the examples above, where antenna 7 is connected to the printed circuit board via a screw connector and comprises a compact set with the outer jacket or is connected to the printed circuit board via an external cable.

Example 7

Device according to any of the examples above, where the devices is fitted with optical or metallic cable for remote connection of the device with electricity meter.

Example 8

Manner of reading of electronic electricity meters via optical interface includes these steps explained in points:

emission of infrared radiation via a led diode 6b of optical communication interface 6 during passing of current, while the led diode 6b is switched by a bipolar PNP type transistor 6d connected to the output of the processor unit 3, which ensures that the exit current if approx. 1 mA from the exit pin of the processor unit 3 switches current flowing through IR LED diode 6b of approx. 10 mA, necessary for generating such intensity of infrared radiation, which is sufficient for phototransistor actuation on the side of the receiver of optical communication interface 6 in the electricity meter, while the size of the actuating current is set via a resistor 6c to approx. 10 mA; reception of the signal via reception element of optical communication interface 6, which is the IR phototransistor 6a, through which, when exposed to radiation from the opposite side of the optical communication interface in the electricity meter, the current starts flowing and it then opens, while the phototransistor 6a is connected between the zero potential GND (ground) and pull up resistor, to which supply voltage of 2.5 V is brought and if the sensitive area of the semiconductor is exposed to infrared radiation, the phototransistor 6a starts passing electric and logical value“L" with nominal voltage of 0 V is displayed on the output of the circuit connected to the microprocessor 3a and if the semiconductor is not exposed, then the phototransistor is closed and logical value“H" corresponding to 2.5 V is displayed;

the processing of logical values “L” and Ή” in the control program of the processor unit 3 is done by commencing communication by sending a start bit with logical value“L” then followed by individual bits from the transferred byte ad the transfer is completed by a stop bit with logical value“H", whereby the data from the electricity meter is read to the processor unit 3;

selection of required data on consumption from the electricity meter by control program of the processor unit 3; transfer of data via exit port to wireless communication module 4 to be sent to the cloud storage.

Example 9

Procedure of electricity meter status reading is controlled by an end status automat, which is implemented in the software in the control unit and performed in the following steps:

at first, an attempt to start communication with the electricity meter is made in the main loop;

if this attempt is successful, data is sent to server via wireless low power network;

subsequently, the entire microprocessor 3a is switched to a very low power mode, in which only the special timer 3c is running;

after the defined period of 10 minutes passes, this timer 3c will again bring the processor 3a to active condition; battery 1 voltage is then checked and status is sent in a data package together with data from the electricity meter;

the entire process is continuously repeated.

Example 10

Device is used as in examples 1 to 7 to monitor the status of electronic electricity meters via an optical interface and ensuring of transfer of these status information via a LPWAN type radio network to cloud storage.

Industrial utilization

The method of data monitoring and the device are suitable to monitor the status of electronic electricity meters via an optical interface and ensuring of transfer of these status information via a LPWAN type radio network to cloud storage.

Claims

PATENT CLAIMS

1. A device for continuous monitoring of status of electronic electricity meters consists of the following parts and/or elements:

battery (1);

supply voltage source (2);

processor units (3);

wireless communication module (4);

battery voltage monitor (5);

optical communication interface (6);

antenna (7) and

protection circuit (8).

2. Device according to claim 1 characterized by having a lithium battery (1) with nominal voltage of 3,6 V.

3. Device according to claim 1 characterized by having a source (2) that contains a linear voltage stabilizer (2a) and blocking capacitors (2b).

4. Device according to claim 1 characterized by having a processor unit (3) consisting of a microprocessor (3a), an analog-digital converter (3b) and a timer (3c).

5. Device according to claim 1 characterized by having a wireless communication module (4) consisting of a crystal oscillator (4a), a phase locked loop (4b), a voltage controlled oscillator (4c), a demodulator (4d), a low noise amplifier (4e) and a modulator (4f).

6. Device according to claim 1 characterized by having a battery voltage monitor (5) consisting of a resistor divider (5a) and an operating amplifier (5b).

7. Device according to claim 1 characterized by having an optical communication interface (6) consisting of a phototransistor (6a), a led diode (6b), resistor (6c) and a bipolar transistor PNP (6d).

8. Device according to claim 1 characterized by having a protection circuit (8) consisting of a semiconductor diode (8a) and resettable fuse (8b).

9. Device according to claim 1 or 3 characterized by having a source (2) with output voltage of 2.5 V.

10. Device according to claim 4 characterized by having a 16 bit microprocessor (3a) with extremely low power of approx. 50 uW in sleep mode.

11. Device according to claim 1 or 5 characterized by having a communication module (4) connected via low power wireless network LPWAN, particularly type LoRaWAN, SigFox or NB loT, to remote data storage, particularly cloud storage.

12. Device according to claim 7 characterized by having a phototransistor (6a) and LED diode (6b) accustomed for picking and emitting radiation in infrared specter at the wavelength of 870 to 950 nm.

13. Device according to claim 1 to 12 characterized by having the device connected to an electricity meter via a magnetic element created near the output of the optical communication interface (6).

14. Device according to claim 1 , 5 or 11 characterized by having a wireless communication module (4) consisting of at least one integrated circuit.

15. Device according to any claim 1 to 12 characterized by having an antenna (7) connected to a printed circuit board via screw connection and comprising a single set with the outer jacket or is connected to the printed circuit board via an external cable.

16. Device according to any claim 1 to 13 characterized by having the device fitted with optical and metallic cable for remote connection of the device with the electricity meter.

17. Method of reading status of the electronic electricity meters via the optical interface contains following steps expressed in points:

emission of infrared radiation via led diode (6b) of optical communication interface (6) during passing of current, while the led diode (6b) is switched by bipolar PNP type transistor (6d) connected to the output of the processor unit (3), which ensures that the exit current if approx. 1 mA from the exit pin of the processor unit (3) switches current flowing through IR LED diode (6b) of approx. 10 mA, necessary for generating such intensity of infrared radiation, which is sufficient for phototransistor actuation on the side of the receiver of optical communication interface (6) in the electricity meter, while the size of the actuating current is set via a resistor (6c) to approx. 10 mA;

reception of the signal via the reception element of the optical communication interface (6), which is the IR phototransistor (6a), through which, when exposed to radiation from the opposite side of the optical communication interface in the electricity meter, the current starts flowing and it then opens, while the phototransistor (6a) is connected between the zero potential GND (ground) and pull up resistor, to which supply voltage of 2.5 V is brought and if the sensitive area of the semiconductor is exposed to infrared radiation, the phototransistor (6a) starts passing electric and logical value“L” with nominal voltage of 0 V is displayed on the output of the circuit connected to the microprocessor (3a) and if the semiconductor is not exposed, then the phototransistor is closed and logical value Ή” corresponding to 2.5 V is displayed;

the processing of logical values “L” and Ή” in the control program of the processor unit (3) is done by commencing communication by sending a start bit with logical value“L” then followed by individual bits from the transferred byte ad the transfer is completed by a stop bit with logical value Ή”, whereby the data from the electricity meter is read to the processor unit (3);

selection of required data on consumption from the electricity meter by control program of the processor unit 3

transfer of data via exit port to wireless communication module 4 to be sent to the cloud storage.

18. The procedure for reading electricity meter status is characterized by being controlled by a status automat, which is implemented in the software in the control unit and is performed in the following steps:

subsequently the entire microprocessor (3a) is switched to very low power mode, in which only the special timer (3c) is running;

after passing of the defined period of 10 minutes this timer (3c) will again bring the processor (3a) to active condition;

battery (1) voltage is then checked and status is sent in a data package together with data from the electricity meter;

the entire process is continuously repeated

19. Use of the device according to any of the claims 1 to 14 to read the status of electronic electricity meters via an optical interface and ensuring of transfer of these status information via a radio network type LPWAN, particularly type LoRaWAN, SigFox or NB loT, to remote data storage, particularly cloud storage.

List of reference marks:

1 - battery or power accumulator

2 - source

2a - linear voltage stabilizer

2b - blocking capacitors

3 - processing unit

3a - processor

3b - analog-digital converter

3c - timer

4 - wireless communication module

4a - crystal oscillator

4b - phase locked loop

4c - voltage controlled oscillator

4d - demodulator

4e - low noise amplifier

4f - modulator

5 - battery voltage monitor

5a - resistor divider

5b - operating amplifier

6 - optical communication interface

6a - phototransistor

6b - LED diode

6c - resistor

6d - bipolar transistor PNP

7 - antenna

8 - protection circuit 8a - semiconductor diode

8b - resettable fuse