NO338992B1 - Reading data source from mobile terminal - Google Patents

Description

[0001] The present invention relates to a system for reading a data source from a mobile terminal.

[0002] The use of RFID tags on goods, assets and animals is common, and the use of such tags increases as price and size decrease. Today, the RFID tags are read with their own readers, for example in baggage handling facilities or at a vet. In some cases, it would be an advantage to be able to read RFID tags with your own smartphone, for example if you want to determine whether a suitcase belongs to someone else or yourself, or if you come across an escaped pet and want to find the owner.

[0003] Automated sensors and meters are also becoming increasingly common, e.g. for home automation where they can e.g. measure room temperature, energy consumption, etc., and in training applications where they can measure pulse, body temperature or other parameters. Even such devices today require their own readers, and it would in many cases be advantageous to be able to read the sensor or meter with your own smartphone, for example to avoid having to buy and install separate readers.

[0004] Common to the aforementioned RFID and sensor applications is that a small amount of data must be read from an identity tag, sensor or meter, hereinafter called a data source. A smartphone is one example of a mobile terminal, here defined as a computer with the possibility of radio communication. Other examples are tablets and notebook PCs with radio transmitter(s) and radio receiver(s). As is known, it is possible to download software applications, so-called "apps", and install them on a mobile terminal as defined above. This makes it possible to retrofit functions on a mobile terminal people already have.

[0005] With these definitions, the outlined need can be expressed more precisely as a data source should be able to deliver a small amount of data, for example a unique ID or a measurement value, in response to a request from a mobile terminal. Mobile terminals are suitable for the purpose because one or more apps can be installed if needed, and used to read different sensors or chips, and possibly communicate over a mobile network to pass on data to a database, e.g. reading electricity or finding the owner of an escaped pet without to go to the vet. Because the amount of data sent from the data source to the mobile terminal is small, a high transmission capacity is not needed. Because data is only sent on demand, the data source does not need to be synchronized with a network at all times.

[0006] Published patent application US 2006293085 deals with a system comprising a mobile device which is able to simultaneously communicate over a mobile network and a system for reading a data source by using RFID communication technology. The Chinese publication CN 201733439 describes wireless mobile communication combined with an RFID transceiver. Data can be read from an RFID code via the communication unit's RFID transceiver and forwarded to a remote database using the mobile network. International patent application with publication number WO 2011041849 discloses an RFID transceiver and an RFID data source that can be implemented in a half-duplex or full-duplex transponder. A pulse-controlled switch can select a first or a second resonant frequency based on a quality factor.

[0007] In order to facilitate the understanding of the invention, some known radio-based techniques are first described superficially.

[0008] Systems for radio frequency identification (RFID) generally comprise a tag on an object to be identified and a reader to read a unique ID in the tag using radio signals. The read ID can then be used further, for example in a database lookup to find the owner of a suitcase or the telephone number of an animal owner.

[0009] So-called active RFID has a power source, e.g. a battery, in the tag, and range typically over 10 m. In some applications, e.g. in tags to be inserted into a glass ampoule under the skin of an animal or in adhesive tags used for theft protection of goods, there is too little space and/or too expensive to insert a battery.

[0010] Passive RFID has no power source in the tag, but collects energy from the radio signal from the reader, and uses the collected energy to return a signal with a unique ID and any other information stored in the tag. The range for passive RFID typically varies from a few centimeters to a few meters depending on the field strength of the signal from the transmitter. In some areas, the use of passive RFID is standardized.

[0011] For example, ISO 11784/11785, which defines the 134.2 kHz carrier frequency, are common animal tagging standards outside the United States. In the USA, corresponding standards and systems with a 125 kHz carrier frequency dominate today. The mentioned ISO standards define half duplex, which is common in ear tags for sheep, pigs, cattle and other large animals except horses, and full duplex, which is common in glass ampoules implanted under the skin of horses, dogs, cats and other pets. RFID readers to read the tags are found in relatively few places, e.g. at vets, the police etc.

[0012] On a day-to-day basis, most people have relatively little need for reading ID tags on animals, so it is unlikely that large sections of the public will pay for or bring their own device for radio reading of animal identity in the event that they encounter on an escaped pet or a stray sheep. As mentioned, it would therefore be advantageous to be able to read the RFID tag with the smartphone you already have. Due to the relatively small need, however, it is also unlikely that manufacturers of mobile terminals will build RFID readers for 125 kHz and/or 134.2 kHz RFID tags into a smartphone or other mobile terminal.

[0013] Another example is near field communication (NFC - Near Field Communication) for use as contactless means of payment and key cards. In order to reduce problems with authentication in an environment with many users, for example when paying on a bus or subway, the range is intentionally limited to less than 20 cm. The term "near field" in the name is due to the fact that a receiving coil must be brought into a radio frequency near field from a transmitting coil so that the two coils form a transformer with an air core before signals can be transmitted between the coils, which are antennas in RF communication. An active NFC chip can read a passive tag in the same way as in passive RFID. NFC can also communicate with other active NFC chips. In both cases, the radio signals have a center frequency of 13.56 MHz, which lies in a so-called ISM band (Industrial, Scientific, Medical) available for short-range radio-based applications. NFC can be considered advanced RFID with options for authentication and encryption, and is described in more detail in e.g. ISO/IEC 18000-3 and ISO/IEC 18092:2013.

[0014] NFC chips are built into a number of smartphones, and in addition to contactless payment and authentication can also be used for other purposes. For example, passive NFC is used in so-called SmartTags for Samsung SUI, Sony Experia or Blackberry Z10, and active NFC in some cases to perform synchronization, so-called "handshaking", in a faster and more complicated protocol such as Bluetooth.

[0015] In connection with the present invention, the short range requires that the mobile terminal must be kept close to the data source for NFC to work. Even if support for NFC is built into an identity tag, it can therefore be difficult to read the tag with the NFC chips in a mobile device. For example, it can be difficult to read the tag on a suitcase on a roundabout a few meters away or to capture an escaped pet or a sheep to be collected from summer pasture. It would therefore be advantageous to be able to read a data source at a longer distance, for example 10-100 m, and then be able to contact the owner without the need to capture the animal or special equipment to read a tag.

[0016] A mobile terminal has a transmitter and receiver for communication with the mobile network. These radio units regularly exchange synchronization messages with base stations in the mobile network and, if necessary, transmit useful traffic between themselves and the mobile network over channels in reserved frequency ranges. By "mobile network" is generally understood here a network for transmitting voice and data to/from a mobile terminal using known technology, e.g. 2G, 3G and/or 4G technology, and by "base station" corresponding equipment in the network for direct radio communication with the mobile device regardless of what the component is called in the various techniques. In the context of the present invention, details of the mobile network are less important, but it should be understood that communication protocols for mobile networks generally require that the network elements are regularly synchronized with the mobile network. This requires energy, and will quickly drain a battery in, for example, a collar or a power meter. The protocols for mobile communication are therefore not very suitable for sensors that should only send a small amount of data on request and otherwise use the least possible energy to last as long as possible.

[0017] Bluetooth and/or Bluetooth Low Energy (BLE), including Apple's iBeacon, are other examples of radio techniques found in a typical smartphone. These communicate over an ISM band at 2.4GHz, typically have a range of up to 50-100m and are typically used for fast data transfer, for example between a PC and a smartphone connected to a mobile network or speech between a wireless microphone and a smartphone. Bluetooth and BLE require synchronization before data can be transferred, and as indicated are intended for the rapid transfer of large amounts of information, including synchronous data such as speech. In other words, these protocols also use a relatively large amount of energy to offer a performance that is not required in the present invention. In applications where little data is transferred asynchronously and the energy requirement should be as low as possible, these Bluetooth and BLE are therefore also less suitable.

[0018] There are a number of so-called PAN protocols (Personal Area Network), which are used for various purposes, for example home automation or reading biometric data such as pulse, body temperature, etc. from sensors in the home or on the body for use during training. Well-known examples include Zigbee and Z-wave. DASH7, according to ISO/IEC 18000-7, is particularly mentioned here as a technique that would be suitable for reading an electronic tag, because the protocol is adapted to the asynchronous transfer of small amounts of data, typically one packet of 256 B, only on request and which thus requires little energy. DASH7 uses an ISM band from 433 MHz, i.e. 25= 32 times 13.56 MHz which is used in NFC and corresponding RFID techniques. DASH7 and NFC can therefore relatively easily use the same antenna. However, neither Zigbee, Z-wave nor DASH7 are built into today's smartphones. Reading sensors or tags with these protocols therefore requires separate readers, which in turn can transfer data via WiFi, a mobile network or another network to a mobile terminal or another computer.

[0019] In summary, RFID as defined in ISO 11784/11785 for animal marking and corresponding protocols is simple and has a short range. NFC and compatible protocols with a 13.56 MHz center frequency are the next step up, with the possibility of authentication and encryption. NFC in smartphones still has a short range. Bluetooth and BLE are the next step up with faster data transfer and longer range than NFC. However, Bluetooth and BLE require more energy, and thus give a lower battery life, than lighter protocols such as DASH7, i.e. protocols compatible with ISO/IEC 18000-7. However, DASH7 is not built into today's mobile terminals.

[0020] The purpose of the present invention is to produce a system which solves at least one of the problems mentioned above, and which at the same time utilizes the advantages of known technology. More specifically, it is desirable to produce a system which makes it possible to read a small amount of data from a data source with a mobile terminal, for example a smartphone. Furthermore, the data source should be able to be read at distances over 20 cm both in the aforementioned applications where it is desirable to identify an animal, and in applications where it is desirable to be able to read, for example, a current meter or pulse sensor in a training application. The system should be able to be retrofitted to the greatest extent possible, and can be manufactured at a cost that can compete with existing systems with their own readers.

SUMMARY OF THE INVENTION

[0021] These objectives are achieved according to the invention with a system for reading a data source from a mobile terminal, where the mobile terminal is designed to be able to send a predefined pulse sequence towards a base station in a mobile network, and the data source comprises a first antenna designed to receive power in a first frequency range allocated to mobile traffic, a pulse-controlled switch, a control unit and transmitter circuits comprising a second antenna adapted to return useful data in a second frequency range, the pulse-controlled switch being designed to integrate a signal received over the first antenna and to close when it in the integrated signal detects reception of the predefined pulse sequence, and in the closed state to activate the control unit to extract useful data and deliver these to the transmitter circuits comprising the second antenna in order to return a data packet back to the mobile terminal by means of radio signals over a second frequency range different from the first frequency the area.

[0022] The system may comprise a resonant circuit connected to the first antenna and designed to only receive power in a relatively wide frequency range corresponding to the first frequency range allocated to mobile traffic.

[0023] The pulse sequence can, for example, be produced by the mobile terminal, e.g. a smartphone, alternately transmitting and not transmitting over a mobile channel in the first frequency range. The pulse width can be in the order of ms, i.e. significantly longer than the period of the mobile carrier in the first frequency range. The data source, e.g. a tag for radio identification or a sensor for simple telemetry, therefore does not need a receiver or logic for connection to or communication with the mobile network. It is similarly indifferent what the reader actually sends, as long as the transmission produces a pulse sequence that can be recognized by the pulse-controlled switch in the data source. Once the predefined pulse sequence is recognized, logic and transmitter circuitry in the data source is activated by applying electrical current and voltage. The transmitter circuits are adapted to return useful data, e.g. a unique ID or a measurement value, in a different frequency range, e.g. in the ISM band with frequency 13.56 MHz or 433 MHz and protocols that can be recognized by the mobile terminal.

[0024] Mobile terminals with NFC can receive signals with a center frequency of 13.56 MHz, but the invention is not limited to a specific return channel. For example, it is conceivable that the need for sensor applications for home automation, training applications or other conditions makes it commercially interesting to equip smartphones with, for example, DASH7 or equivalent PAN techniques with lower power consumption and lower transmission capacity than BLE. In that case, the invention can be used with such a PAN technique.

[0025] In a preferred embodiment, the system further comprises a software application for installation on the mobile terminal, where the software application is adapted to send the predefined pulse sequence over a mobile network, receive user data from the data source and further process the said user data.

[0026] With an installable software application, it is possible to download the application in a known manner and retrofit the system on existing and future mobile terminals, for example on a smartphone, a tablet or a laptop. The application can receive useful data from the data source via, for example, the NFC chip or a future DASH7 chip, and further process the received useful data. The further processing depends on which data is received. Sensor data from a heart rate monitor, temperature meter or the like can, for example, be produced graphically and/or logged in an application for training or an application for home automation.

[0027] In some embodiments, the further processing comprises sending the received useful data to a database. For example, data from an electricity or gas meter can be sent automatically to the energy supplier for settlement, or a unique ID from an RFID device in an ear tag, collar or a glass ampoule on or in an animal can be used for lookup in a database, for example for to find a telephone number for the animal's owner.

[0028] The pulse-controlled switch can be asynchronous, i.e. it works without a clock signal. This saves energy to drive the clock circuit, but makes it difficult to measure pulse width. Alternatively, the pulse-controlled switch can use a clock circuit. It is also possible to combine asynchronous and synchronous circuits, for example by starting the clock only after a wake-up sequence is received asynchronously.

[0029] In some embodiments, current induced in a receiving antenna charges a storage capacitor when the pulsed switch is in the open state. The storage capacitor can replace a battery in some embodiments, for example in a glass ampoule for injection under the skin of an animal.

[0030] Several features and advantages appear from the independent patent claims and the detailed description below.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in more detail in the following detailed description by means of examples and with reference to the attached drawings, where:

Fig. 1 is a schematic representation of a system according to the invention,

Fig. 2 schematically shows a data source with battery,

Fig. 3 schematically shows a data source with continuously charged storage capacitor,

Fig. 4 is a schematic representation of a pulse-controlled switch, and

Fig. 5 shows a known, basic memory cell in CMOS version.

DETAILED DESCRIPTION

[0031] Figure 1 is a schematic representation of a system according to the invention. The system comprises a data source 100 which, on request, sends a small amount of data 135, for example a measurement value or a unique ID, to a mobile terminal 200.

[0032] The mobile terminal 200, for example a smartphone, a tablet or a PC connected to a mobile network, communicates regularly with a base station 300 or equivalent. On a physical level, the mobile network includes radio signals 250 which are sent from the mobile terminal 200, the base station 300 and other transmitters in frequency ranges reserved for mobile voice and data communication. "First frequency range" means the amount of all bands reserved for mobile communication. The communication between the mobile terminal 200 and the base station 300 can jump from frequency to frequency, but it will always take place on one of the channels in the first frequency range.

[0033] In Figure 1, the mobile terminal sends a pulse sequence 210 towards the base station 300. The radio signal carrying the pulse is propagated in a spherical surface from the mobile terminal 200, so that the flux density decreases as l/n, where r is the radius of the spherical surface. Furthermore, the antenna 110 is significantly smaller than the antenna in the base station 300, and consequently receives a significantly smaller signal flux than the base station 300. However, it is possible to integrate the signal flux over time, for example for one or more milliseconds, and obtain readable values 0 or 1 at the antenna 110. In order to obtain practically readable values at the antenna 110, the distance between the mobile terminal 200 and the data source 100 must not be too large, e.g. below lOOm, and the power pulses sent out from the mobile terminal 200 must have a certain length, e.g. greater than or equal to 1 etc.

[0034] When the data source 100 recognizes a predetermined pulse sequence, it must send useful data 135 back to the mobile unit 200, illustrated by antenna 150 and return channel 151. This happens by keeping a pulse-controlled switch 120 open until a logic circuit recognizes the predefined pulse sequence 210 and closes the switch 120. When the switch 120 is closed, electrical power from an energy source 140 is passed through one or more circuits 130, which extract useful data 13 5 and send them over the antenna 15 0 and the data link 151 to the mobile terminal 200.

[0035] Fig. 2 shows the data source 100 in more detail. The antenna 110 is shown as a schematic coil, which may have one or more turns. The antenna coil 110 leads to a resonant circuit 112, which should only be able to receive power in a relatively wide frequency range reserved for mobile communication, and therefore need not take signal quality into account. Such circuits are well known. The resonant circuit 112 does not need to interpret the content of what is sent from the mobile terminal 200 in order to deliver a pulse sequence 210 on the signal line 113.

[0036] The pulse-controlled switch 120 recognizes the pulse sequence 210. When the pulse sequence 210 is recognized, the switch 120 is closed so that a connection is established from an energy source 140 through one or more sub-circuits, e.g. a control unit 130, a 13.56 MHz NFC tag 131 and a 134.2 kHz ISO circuit 132. Today's animal identities for 134.2 or 125 kHz can, if desired, be copied to an NFC chip, so that the same ID can be read both with an RFID reader at a veterinarian and with a mobile terminal, e.g. a smartphone, with suitable software.

[0037] Here, the energy source 140 holds a lower rail 141 at low potential and an upper rail 142 at high potential. Incoming signal 113 is measured in relation to the potential on rail 141, and the switch 120 opens for a current through a load represented by one or more sub-circuits 130. 131, 132. Transmitter circuits for the antenna 150 (see fig. 1) are not shown in fig. 2, but is included in a real embodiment.

[0038] In Figure 2, the energy source 140 is shown as a battery. A battery is appropriate if there is room for it and the battery is relatively easy to change, for example in a sensor in a house or in the collar of an animal. It is estimated that one of today's coin-sized Li+ cells will last for "months and years" in an application that delivers a small amount of data on demand. The duration obviously depends on how often the data source 100 is requested to send useful data 135. Developments in battery technology also make it reasonable to assume that the duration will increase and the physical size will decrease in the next few years. A device with a battery may have enough energy to power more sub-circuits than those mentioned above, such as a watch and/or a GPS receiver in a known manner.

[0039] Figure 3 shows an alternative embodiment where energy is collected in a storage capacitor 144. This variant makes use of the fact that mobile units and base stations in the vicinity of the data source 100 regularly send signals, so that the data source 100 is located in an RF field that can be tapped up to the switch 120 is closed by the predefined pulse sequence 210. The storage capacitor 144 then acts in the same way as the battery in Figure 2, i.e. it sends a current through the load 130 when the switch 120 is closed.

[0040] When the switch 120 is open, the storage capacitor 144 is charged. In this embodiment, the antenna coil 110 can be calculated for implantation in an animal, i.e. be of the order of 1 mm x 5 mm, so that the flux through the antenna coil 110 is relatively small. This means that the charging time will be correspondingly long. It is also important to implement the circuits with technology that has low current losses, for example CMOS or similar. Resistances, capacitances and diodes are shown in the drawings primarily for the purpose of illustration, and do not necessarily need to be part of a real implementation.

[0041] The energy source in Figure 3 is shown collectively as 140, and comprises a rectifier 143 with input from the signal from the resonant circuit 112 and output to respectively low potential 141 and high potential 142. The rectifier 143 is illustrated as a diode bridge, but can advantageously be implemented with field effect transistors in a known manner. The purpose of the rectifier 143 is only to charge the storage capacitor 144, which is advantageously a rolled-up electrolyte with the largest possible surface area. In the rolled-up state, the capacitor must fit in a glass ampoule for injection, but the voltage across the electrolyte need not be large. The capacitor 144 can thus be made of relatively thin layers without being too expensive. To avoid excessive voltage across the electrolyte, a surge protector is illustrated with a zener diode 145. Since the signal quality does not play a role in charging the capacitor 144, ripple reduction elements are unnecessary. The capacitance 144 and the zener diode 145 therefore do not need to be adapted to increase the signal quality on the rails 141 and 142.

[0042] Figure 4 schematically illustrates a switch circuit 120, where the signal line 113 has a voltage U(t) across lower rail 141 and zero point (reference voltage) defined by a voltage divider consisting of resistors RI and R2 between lower rail 141 and upper rail 142. A capacitance Cl is connected in parallel with R2 between the signal line 113 and lower rail 141 and forms a simple low-pass filter 121.

[0043] The filter 121 works in that the incoming signal U(t) charges Cl at the same time that Cl is discharged through R2. If U(t) is a continuous high signal, Cl is charged faster than it is discharged through R2 until the voltage is large enough to set a gate S in logic circuit 122. When U(t) is small, the excess voltage on Cl is discharged through R2 and the input to port S goes low.

[0044] For the sake of clarity, note that U(t) is a voltage from the resonant circuit 112 in figures 2 and 3, and that the circuits 112 and 121 must be seen in context. The embodiment in Figure 4 assumes that U(t) is amplified in the resonant circuit 112 so that it has roughly the same value range regardless of the voltage induced in the antenna coil 110, i.e. that pulses are relayed regardless of the distance between transmitter 200 and antenna 110. Conversely, if U(t) was proportional to the voltage induced in the antenna coil 110, the circuit 121 would require a larger pulse width at a longer distance to the transmitter 200 to collect enough energy to set the gate S. Since the transmitter 200 does not know the distance to the antenna 110, it cannot adapt the pulse width. The circuit 121 thus assumes that the resonant circuit 112 amplifies the antenna signal to a suitable level regardless of the distance between the mobile terminal 200 and the antenna 110.

[0045] The logic circuit 122 is shown greatly simplified, and consists of an input S (set), an output Ql and a reset input R (reset). A real circuit 122 is connected to rails 141 and 142, but these connections are not shown in Figure 4. The output Q1 is high when an incoming pulse sequence corresponds to a predetermined pattern, eg 101010, and low when the pulse sequence is different from the predetermined pattern. The circuit 122 is preferably implemented with CMOS technology or equivalent for minimal power consumption, and can be implemented with known elements such as latches, logic gates, SR or D-type flip-flops and/or a shift register.

[0046] The logic circuit 122 can be asynchronous, ie lack its own clock input. An asynchronous circuit cannot measure pulse widths, but it is easy to connect an output line to lower rail 141 across a resistive network, for example R2, so that the desired bit pattern must be collected in a certain maximum time for the output Ql to give a high pulse . For example, suppose the predetermined pulse sequence is 10101010, where each value 1 and 0 lasts for 1 ms. The signal U(t) can be fed to the clock input of a shift register where each bit consists of two D flip-flops in master-slave connection. The first "clock cycle" 10 sets a value, say 1, in bit 1. The next incoming 10 combination copies bit 1 to bit 2 and sets bit 1 to 1, etc. After the sequence 10101010, the shift register in this example will contain 1111 after 8ms , so that the output Ql gives a high pulse. Then suppose that another random pulse sequence with two or more high pulses without a gap comes in. The capacitance Cl will then be kept charged, so that S remains high. Bit 1, and thus the shift register, does not change state until the next 0. In the case of several low pulses without gaps, the registration in the shift register is also delayed. For deviations from 10101010, it thus takes more than 8 ms to set all the bits in the shift register, and the first bit that was set in the shift register has had time to go low through the resistive network, so that the output Q2 becomes low.

[0047] Alternatively, the circuit 122 can be synchronous. By "synchronous circuit" is meant here a circuit which is supplied with a clock signal from the outside or has a built-in clock, for example an astable multivibrator. In an astable multivibrator, the width of the high signal can be equal to or different from the width of the low signal. For example, the clock signal can be applied to the shift register described above, and the incoming signal is applied to the data input of the master flip-flop in bit 1. A 4-bit shift register in this example can contain any combination of 0 and 1, and Ql is set high each time the shift register matches one of the 24 = 16 possible combinations.

[0048] The field-effect transistors Ml (N-type) and M2 (P-type) conduct when the gate is set high and low, respectively. A high pulse from Ql thus pulls latch 123 to a high potential. The latch 123 holds the gate of an N-type power transistor M3 high, so that M3 conducts current through the load 130 as described above.

[0049] It should be understood that the transmit and antenna circuit 150 in Figure 1 can be activated similarly to the latch circuit 123 and the reset circuit 124 in Figure 4. The power transistor M3 in Figure 4 is intended as an example, and it is therefore not assumed that the load 130 must be supplied with energy through a power transistor 130.

[0050] Low Q2 causes M2 to conduct, so that the input to a reset circuit 124 is set high. The reset circuit 124 resets the circuit 122 through the R input, and can also reset other elements, e.g. the latch 123. For the record, it is specified that the circuit 122 contains logic which ensures that Ql is set high for a short period if and only if an incoming pulse sequence coincides with a predetermined pattern, and that the output Q2 is set low if and only if the pattern is violated. Circuit 122 is shown with separate outputs Ql and Q2 to illustrate that a near-permanently low output Ql should not set R near-permanent, thus keeping circuit 122 near-permanently zeroed, for example during periods when it should have been comparing pulse sequences to a predefined pattern . Active values high, respectively low, on the outputs Ql and Q2 are only intended to illustrate that active high and active low produce the same effect through the different transistors Ml and M2.

[0051] Figure 5 shows a latch 123, more specifically a so-called SRAM cell or basic memory cell in CMOS version. The circuit consists of two inverters "back to back", i.e. where the output of one inverter is connected to an input of the other and vice versa. It is well known that any pair of inverting elements, e.g. NOR gates or NAND gates, connected back to back provide corresponding latches, and can be connected to progressively more complex elements, e.g. SR or D-type flip-flops, registers etc. The circuit 123 of Figure 5 and CMOS versions of more complex elements can easily be found in textbooks and on the Internet. They can therefore be used to implement the present invention without further inventive effort.

[0052] The examples above can be easily modified. For example, it is trivial to produce a shift register with fewer or more than 4 bits, the circuits can be constructed differently than described, and active high/active low can be chosen according to what is most practical. The scope of the invention is therefore not defined by the examples above, but by the following patent claims.

Claims (12)

1. System for reading a data source (100) from a mobile terminal (200), characterized in that the mobile terminal (200) is designed to be able to send a predefined pulse sequence (210) towards a base station (300) in a mobile network; and that the data source (100) comprises a first antenna (110) designed to receive power in a first frequency range (250) allocated to mobile traffic, a pulse-controlled switch (120), a control unit (130) and transmitter circuits comprising a second antenna (150) adapted to return useful data in a second frequency range, the pulse-controlled switch (120) being designed to integrate a signal received over the first antenna (110) and to close when, in the integrated signal, it detects reception of the predefined pulse sequence (210) , and in the closed state to activate the control unit (130) to extract useful data and deliver these to the transmitter circuits comprising the second antenna (150) in order to return a data packet (135) back to the mobile terminal (200) by means of radio signals over a second frequency range different from the first frequency range. 2. System according to claim 1, further comprising a resonant circuit (112) connected to the first antenna (110) and designed to only receive power in a relatively wide frequency range corresponding to said first frequency range (250) allocated to mobile traffic. 3. System according to claim 1 or 2, where the second frequency range is an ISM band at 13.56 MHz. 4. System according to claim 1 or 2, where the second frequency range is an ISM band at 433 MHz. 5. System according to one of the preceding claims, further comprising a software application for installation on the mobile terminal, where the software application is adapted to cause the sending of the predefined pulse sequence over a mobile network, receive useful data from the data source and further process said useful data. 6. System according to claim 5, where the further processing includes sending the received useful data to a database. 7. System according to one of the preceding claims, where the pulse-controlled switch (120) is asynchronous. 8. System according to one of the preceding claims, where the pulse-controlled switch (120) is synchronous. 9. System according to one of the preceding claims, where the data source (100) comprises a battery (140). 10. System according to one of claims 1-8, where the pulse-controlled switch in the open state causes current induced in a receiver antenna (110) to charge a storage capacitor (140). 11. System according to one of the preceding claims, where the data source (100) is placed on or in an animal. 12. System according to claim 10, where the data source (100) is encapsulated in a glass ampoule for injection under the skin of an animal.