CH713721B1 - A method of transmitting data from an electronic device to an electronic device. - Google Patents

Abstract

The invention relates to a method (Pcd) for transmitting data from an electronic device to an electronic device, comprising the following steps: transmitting (Pcd_Em1) a sequence of light signals by a light source of the electronic device, each signal having a light intensity level belonging to a set of at least four light intensity levels, said sequence corresponding to a coding of the data to be transmitted, detecting (Pcd_Det1) successive light intensity levels by an optical sensor of the electronic device , so as to reconstitute the sequence, decode (Pcd_Dec) the sequence in order to reconstitute the data. The electronic device can be, for example, a smartphone or a tablet and the electronic device a watch, for example.

Description

TECHNICAL AREA

The present invention relates to a method of transmitting data from an electronic device to an electronic device, in particular an electronic watch.

PRIOR ART

[0002] So-called “connected” watches, capable of communicating with an electronic device such as a smartphone, have established themselves in recent years in the watch industry. The setting of such a watch can be carried out manually, in particular by activating push buttons, crowns and / or touch keys, which is relatively restrictive for the user or the after-sales service responsible for the setting.

[0003] To avoid these drawbacks, it is now possible to adjust an electronic watch automatically, by equipping it with devices supporting Bluetooth Low Energy technology or near-field communication technology. However, these devices are quite complex to set up and require the incorporation of specific means of communication both on the electronic device and on the watch, in particular antennas. They must also be certified, which causes an additional cost.

[0004] In patent application EP3211491, a new way of transferring adjustment data to an electronic watch from an electronic device, typically a smartphone, has been proposed, which is simpler and less expensive than the solutions cited above. For this, the watch includes a phototransistor intended to detect light signals coming from a light source of the electronic device. These light signals encode data through a modulation with two states: presence or absence of light. However, this type of bipolar optical modulation has the drawback of allowing only relatively low transmission rates. On the other hand, the transmission can only be asynchronous, and the operating systems of electronic devices cannot guarantee perfect stability of the transmission frequency. The transmission periods therefore risk not being of identical lengths, which can be the cause of errors in reception and decoding.

SUMMARY OF THE INVENTION

The object of the present invention is to remedy the drawbacks presented in the preceding part, by proposing an improved optical transmission method.

To this end, the invention relates to a method of transmitting data from an electronic device to an electronic device, comprising the following steps: emit a sequence of light signals by a light source of the electronic device, each signal having a level of light intensity belonging to a set of at least four light intensity levels, said sequence corresponding to a coding of the data to be transmitted , detect successive levels of light intensity by an optical sensor of the watch, so as to reconstitute the sequence, decode the sequence in order to reconstruct the data.

Advantageously, the electronic device is an electronic watch, but it will be understood that the method could very well be adapted to other types of electronic devices and that no step of the method requires limiting the receiving device to a electronic watch.

[0008] The data encoding being carried out in the form of light signals with at least four states, it will be said that the signals encode these data by means of an optical modulation at at least four levels, more simply called multilevel optical modulation . By multi, we will therefore mean at least four.

This method has the advantage of being able to be implemented in a predominantly automatic manner. In particular, in the case where the electronic device is an electronic watch, this method can be implemented without the user having to perform any complex adjustment via crowns, push buttons or touch keys for example. Naturally, the process must be initiated, which can be carried out either manually by pressing a push button, or automatically, for example via a system on standby by default which wakes up on reception of a certain light sequence. The automated transmission of data between the electronic device and the electronic watch greatly facilitates the programming of the watch. It also helps prevent errors or inaccuracies resulting from manual configuration. It offers the user the possibility of using the more user-friendly interface of the electronic device, typically a smartphone application, to select and configure the data to be transferred to the watch. All kinds of data can be transmitted by this medium, including short messages, subject to the display capabilities of the watch. This will allow you to easily set the time, change the time, set an alarm, set the date, or transmit other information such as moon phases, times and tide coefficients, sunset and sunrise times, etc.

[0010] In addition, this method has the advantage of not requiring the incorporation of communication antennas (expensive, bulky and sometimes incompatible with metal casings) on the watch (or more generally, the electronic device) or the electronic device, the optical communication system between the watch and the electronic device consisting only of a point light source of the light-emitting diode type and of an optical sensor, for example a phototransistor or a photodiode.

Finally, the method according to the invention is particularly advantageous in that it allows either an asynchronous transmission at a higher rate than in the case of a bipolar optical modulation, or a synchronous transmission, as explained below. after.

In the case of an asynchronous transmission, the emission of light signals on at least four levels of light intensity makes it possible to accelerate the transmission. Indeed, instead of detecting whether the light source is on or off as is the case in application EP3211491, that is to say detecting levels of intensity among two possibilities, the level of intensity is detected. light from said source among at least four possibilities. The output is therefore at least doubled (in particular, it is doubled if the light source can take four and only four different levels of light intensity).

[0013] In the case of synchronous transmission, the emission of light signals on at least four levels of light intensity makes it possible to transmit a clock signal in addition to the data. On each clock period, part of the data (for example one or more bits) is transmitted with the phase (high or low state) of the clock. In particular, when the clock is high, the data part is encoded on certain light intensity levels, while when the clock is low, said data part is encoded on d ' other levels of light intensity. Using threshold levels, it is therefore possible for the electronic device to reconstruct the data taking into account the clock signal also transmitted.

Thus, in one embodiment, the set of at least four intensity levels is divided into a first part and a second part, one light signal out of two of the sequence having a light intensity level belonging to in the first part, the other signals having a level of light intensity belonging to the second part.

The method according to the invention can comprise one or a technically possible combination of the following characteristics.

In a nonlimiting embodiment, the detection step further comprises a resynchronization sub-step consisting in reinitializing a sampling period counter of the electronic device upon detection of a change in brightness by the optical sensor and provided that the sampling periods counted by the counter are between two threshold values.

[0017] In a non-limiting embodiment, the light intensity levels of the assembly are distributed regularly on a brightness scale.

In a non-limiting embodiment, the method comprises a step of transmitting a sequence of light signals at two intensity levels corresponding to clock phases, simultaneously with the step of transmitting the sequence of light signals corresponding to the data to be transmitted, by a second light source of the electronic device, and a step of detecting a succession of the two levels of light intensity by a second optical sensor of the electronic device, so as to reconstitute the clock, the two sequences of light signals being emitted on two distinct wavelengths.

[0019] In a non-limiting embodiment, the method comprises an additional step of generating a transmission report.

In a nonlimiting embodiment, the step of generating a transmission report comprises an emission of a light signal by a light emitting diode of the electronic device.

In a non-limiting embodiment, the step of generating a transmission report comprises a positioning of display means of the electronic device. If the electronic device is a watch, these display means are for example hands, and / or display disks (for example disks for displaying the day, month, moon phase, etc., a portion of which is in front of a counter to display information).

[0022] In a non-limiting embodiment in which the electronic device is an electronic watch, the method comprises an additional step of analyzing an image of the dial of the watch taken by a camera of the electronic device, following the positioning of the display means of the watch.

In a nonlimiting embodiment, the electronic device is portable, in particular of the smartphone or electronic tablet type.

By "portable electronic device" is meant an electronic device, also called a user terminal, capable of being worn and transported by a user, and of being functional during transport. This is the case for example with a smartphone. Of course, devices requiring mains power, such as desktop computers, are excluded from this definition. Sets of devices, such as a laptop computer to which a peripheral is connected by wireless or wired link are also excluded from this definition.

This method has the advantage of requiring very little equipment: a portable device of the smartphone type with an appropriate mobile application is sufficient to implement it. The method does not require the use of dedicated equipment such as a sensor to be connected to a computer, nor of bulky equipment. Anyone (for example a watchmaker) with a smartphone having the appropriate application could implement the method.

In a nonlimiting embodiment, the light source is an area of a display screen of the electronic device.

In a non-limiting embodiment, the light source is a light-emitting diode also serving as a flash for the electronic device.

BRIEF DESCRIPTION OF THE FIGURES

The details of the invention will emerge more clearly on reading the description which follows, made with reference to the accompanying drawings in which: FIG. 1 represents a watch, seen from the dial side, receiving, via an optical sensor, a light signal emitted by a light emitting diode of a smartphone also used as a flash of said smartphone, said smartphone being seen on the back side FIG. 2 represents a watch, bottom side view, receiving, via an optical sensor, a light signal emitted by a portion of a smartphone screen, the optical sensor being positioned opposite said portion, the smartphone being viewed from the screen side FIG. 3 represents levels of light intensity as a function of phases of a clock, in the case of a synchronous optical modulation with four levels of light intensity FIG. 4 represents levels of light intensity emitted by a light source of a portable electronic device, before and after a step of calibrating the method according to one embodiment of the invention FIG. 5 represents steps of the method according to one embodiment of the invention.

DETAILED DESCRIPTION

Figures 1 and 2 show an electronic device MT, in the present case an electronic watch although this is not limiting, and an electronic device AE capable of implementing the data transfer method according to the invention. More particularly, the MT watch is equipped with an optical sensor PR, in the present case a phototransistor although this is not limiting, connected to a microcontroller (not shown) of the MT watch. The transmission method consists in emitting a sequence of light signals by a light source SL of the electronic device AE on at least four distinct levels of light intensity, in receiving the sequence of light signals by the optical sensor PR of the electronic device MT , and converting the received sequence into a usable signal.

In a first configuration shown in Figure 1, the PR phototransistor is located under the CD dial of the MT watch, facing an opening allowing light to pass. In another configuration, the PR phototransistor is located on the side of the back of the MT watch which is at least partially transparent to allow light to pass or which has a removable hatch. Of course, many other configurations can be envisioned. Note that the optical sensor is not necessarily a phototransistor, it may alternatively be a photodiode or a photovoltaic cell.

The transfer of data from the electronic device AE is effected by means of the light source SL, for example a flash or a screen EC of said device AE. In the configuration shown in FIG. 1, the electronic device AE is a smartphone and the emission of light signals is carried out via the flash of the smartphone which constitutes the light source. The flash being located on the back of the camera, it is possible to use the EC screen of the AE camera to manage the transfer application using the EC screen of the smartphone during data transfers while visually controlling changes to the MT watch display.

In the configuration shown in Figure 2, the electronic device AE is a smartphone and the emission of light signals is performed via the screen EC of the smartphone. More precisely, the screen EC comprises a disk-shaped zone, the level of light of which is homogeneous, said zone constituting the light source SL. The MT watch is placed directly against or in front of the EC screen of the smartphone, opposite the luminous disc. In this case, the application must be configured before performing the transfer and, if the CD dial of the MT watch is not visible, a data transfer check step must be performed after the operation. This configuration has the advantage of being less sensitive to external light disturbances than the configuration of FIG. 1.

In an alternative embodiment of the previous configuration, the screen EC can be separated into two zones in order to circumscribe the light source to one of the zones of the screen EC. The remaining area of the EC screen is reserved for the user interface of the application controlling the data transfer. Data transmission and control of its execution are thus facilitated.

It is noted that the electronic device AE shown is of the portable type, but it could alternatively be a peripheral connected to a desktop computer, for example by USB link, this peripheral comprising a light source as described in the preceding paragraphs (a light emitting diode or a portion of a device screen). This variant has the advantage of being able to increase the modulation speed which could be limited by the performance of portable electronic devices of the smartphone type.

The data transfer can be performed using different types of optical modulation. As mentioned above, a bipolar modulation of NRZ type is easy to implement but has limited performance. It is therefore advantageous to take advantage of the possibilities of screens or flashes of smartphones (or more generally of screens or flashes of portable electronic devices) to achieve multilevel optical modulation. Recent screens and flashes can in fact generally emit on at least 4 distinct light intensity levels (one level of which can for example correspond to the state “no light emission”).

The synchronous multilevel modulation according to the invention makes it possible to transmit at each clock period part of the data (for example a bit) but also the phase (low state or high state) of the clock, all this thanks to a single sequence of light signals. FIG. 3 represents an example of synchronous modulation at four levels, which allows each clock phase to transmit one bit and said phase. In this example, phases n and n + 2 correspond to a low state of the clock, and phases n + 1 and n + 3 corresponding to a high state of the clock. On a low state of the clock, the bit to be transmitted is coded on the 2 lowest light intensity levels. On a high state of the clock, the bit to be transmitted is coded on the 2 highest levels of light intensity.

Furthermore, in the case of an asynchronous multilevel modulation, it is advantageous to choose a sampling frequency of the MT watch which is much greater than the theoretical transmission frequency of the electronic device AE, of so as to be free from possible variations in the emission period. Typically, the sampling frequency is chosen 16 times greater than the transmission frequency.

In addition, the method according to the invention in the case of asynchronous optical transmission advantageously comprises a resynchronization step implementing a counter of sampling periods of the watch MT. In the case of a sampling frequency 16 times greater than the transmit frequency, no transition (from 0 to 1, or vice versa) should be detected during the first 8 sampling periods counted by the counter. If such a transition exists, it is interpreted as an error. This kind of error results for example from a flickering of the light source which would be interpreted, wrongly, as a change in level. On the other hand, a transition is sought in the 12 sampling periods following the first 8 sampling periods. If such a transition is detected, then the previous bit is recorded and the counter is reset to its initial value.

In addition, when no transition is detected during a large number of sampling periods, there is a risk of phase shift between the electronic transmitter AE device and the receiver MT watch due to the instability of the frequency of transmission of the coded signal. It is interesting in this case to use the technique of "bit stuffing" which consists in adding fictitious transitions allowing to regularly resynchronize the receiver with the transmitter. For example, in a transmission of a long series of bits of zero value, a bit of value one is introduced after a series of five zeros. On the receiver side, the reverse procedure is carried out: after detection of five successive bits of value zero, a hit of value one is expected. If not, it is determined that an error has occurred. If this is the case, the value bit one is not taken into account for decoding and the counter is reset.

According to an embodiment of the method according to the invention, the transmission method comprises a step of calibrating the levels of light intensity emitted by the light source of the MT watch. These levels are calibrated so that they are distributed regularly with respect to a luminosity scale, that is to say such that the difference in luminosity between two closest levels is constant. This step makes it possible to optimize the distinction of the different brightness levels in order to avoid level reading errors on the receiver side. An example is shown in figure 4. This figure shows the brightness levels as a function of the data to be coded, before calibration (“original” curve) and after calibration (“corrected” curve).

In one embodiment in which the data transmission is asynchronous, the MT watch is equipped with two optical sensors capable of receiving distinct wavelengths, for example the one corresponding to blue for the first optical sensor and the corresponding one to red for the second optical sensor. Likewise, the electronic device AE is equipped with two light sources capable of emitting on these two wavelengths. In this case, one of the sources transmits the data asynchronously, while the other light source transmits a clock signal, so that the receiver can synchronize with the transmitter.

In one embodiment, the method comprises a step of generating a transmission report, the report being produced by the watch MT for the user or the electronic device AE. For example, at the end of a transmission operation, display means of the AF watch (for example the hour, minute and second hands) of the watch may be positioned so as to signify success or failure. transmission failure. This particular position of the display means AF can be read by the user who is thus informed of the progress of the transmission. Alternatively, the electronic device AE can, thanks to its camera CM and to image analysis means, analyze the position of the display means AF of the watch MT and deduce therefrom whether the transmission has been carried out correctly or not. . It is also possible to add to the watch MT a light-emitting diode capable of emitting, at the end of a transmission, a short sequence intended to be received by an optical sensor of the electronic device AE. Depending on the sequence, the electronic device AE can determine whether the transmission was successful.

In conclusion, the multilevel optical transmission between an electronic device and an electronic device makes it possible, depending on the asynchronous or synchronous mode chosen, to increase the transmission rate or to reduce the risks of errors. Naturally, those skilled in the art will know how to make multiple variations from the embodiments presented without departing from the scope of the claims. For example, as has already been mentioned, there is no reason to limit the electronic device to an electronic watch since the invention relates to a method of transmitting data for which the nature of the receiving device does not. does not come into play, except of course in the particular case where the method comprises a step of generating a report via watch hands.

Claims (17)

1. Method (Pcd) for transmitting data from an electronic device (AE) to an electronic device (MT), comprising the following steps: - emit (Pcd_Em1) a sequence of light signals by a light source (SL) of the electronic device (AE), each signal having a level of light intensity belonging to a set of at least four levels of light intensity, said sequence corresponding to a coding of the data to be transmitted, - detect (Pcd_Det1) successive light intensity levels by an optical sensor (PR) of the device (MT), so as to reconstitute the sequence, - decode (Pcd_Dec) the sequence in order to reconstitute the data. 2. Method (Pcd) of transmission according to the preceding claim, the set of at least four intensity levels being divided into a first part and a second part, one light signal out of two of the sequence having an intensity level. light belonging to the first part, the other signals having a level of light intensity belonging to the second part. 3. Transmission method (Pcd) according to one of the preceding claims, the detection step (Pcd_Det) further comprising a resynchronization sub-step (Det1_Rsc) consisting in reinitializing a device sampling period counter (MT ) upon detection of a change in brightness by the optical sensor (PR) and provided that the sampling periods counted by the counter are between two threshold values. 4. Method (Pcd) of transmission according to one of the preceding claims, the light intensity levels of the assembly being distributed regularly on a brightness scale. 5. Method (Pcd) of transmission according to one of the preceding claims, comprising a step of transmitting (Pcd_Em2) of a sequence of light signals at two intensity levels corresponding to clock phases, simultaneously with the step of emission (Pcd_Em1) of the sequence of light signals corresponding to the data to be transmitted, by a second light source (SL) of the electronic device (AE), and a step of detection (Pcd_Det2) of a succession of the two levels of light intensity by a second optical sensor of the device (MT), so as to reconstitute the clock, the two sequences of light signals being emitted on two distinct wavelengths. 6. Method (Pcd) of transmission according to the preceding claim, characterized in that the second optical sensor is a phototransistor or a photodiode. 7. Method (Pcd) of transmission according to one of the preceding claims, characterized in that it comprises an additional step of generation (Pcd_Crd) of a transmission report. 8. Method (Pcd) of transmission according to the preceding claim, the step of generating (Pcd_Crd) a transmission report comprising an emission (Crd_Em3) of a light signal by a light emitting diode of the device (MT). 9. The transmission method (Pcd) according to claim 7, the step of generating (Pcd_Crd) a transmission report comprising a positioning (Crd_Pos) of display means (AF) of the device (MT). 10. The transmission method (Pcd) according to the preceding claim, wherein the device (MT) is an electronic watch, and the display means (AF) are hands and / or display disks of said watch. 11. Method (Pcd) of transmission according to claim 10, comprising an additional step of analysis (Crd_Aly) of an image of the dial (CD) of the watch (MT) taken by a camera (CM) of the electronic device. (AE), following the positioning of the display means (AF) of the watch (MT). 12. Method (Pcd) of transmission according to one of the preceding claims, characterized in that the electronic device (AE) is portable, in particular of the smartphone or electronic tablet type. 13. Method (Pcd) of transmission according to one of the preceding claims, characterized in that the light source (SL) is an area of a display screen (EC) of the electronic device (AE). 14. Method (Pcd) of transmission according to one of claims 1 to 12 characterized in that the light source (SL) is a light-emitting diode also serving as a flash for the electronic device (AE). 15. Method (Pcd) of transmission according to one of the preceding claims, characterized in that the optical sensor (PR) is a phototransistor. 16. Transmission method (Pcd) according to one of claims 1 to 14, characterized in that the optical sensor (PR) is a photodiode. 17. Method (Pcd) of transmission according to one of claims 1 to 16, wherein the electronic device (MT) is an electronic watch.