GB2588198A

GB2588198A - A bicycle light

Info

Publication number: GB2588198A
Application number: GB1914890.7A
Authority: GB
Inventors: Andrews Luke; Ray Ben; Dhome-Casanova Thomas; Vairon Jonah
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-10-15
Filing date: 2019-10-15
Publication date: 2021-04-21
Also published as: GB201914890D0

Abstract

A bicycle light 10 comprises one or more light emitters, sensors adapted to detect a number of conditions and adapted to provide a signal to a controller, the bicycle light further comprising a controller adapted to receive signals from the sensors and adapted to control an output of the said one or more light emitters in dependence on the conditions detected by the sensors. The sensors comprise at least an accelerometer and a proximity sensor, so that the light emitters convey. The lamp may use flashing and/or high brightness modes to indicate deceleration (braking) and vary the response depending on speed and distance to a vehicle approaching from the rear.

Description

A Bicycle Light Fieid of the invention The present inventive concept relates to bicycle lights, methods of controlling bicycle lights, and kits for bicycle Light assemblies.

The present inventive concept is envisaged to be a development in the field of road safety for cyciists.

Background to the invention

According to The Royal Society for the Prevention of Accidents, a quarter of annual fatal cycling accidents in the UK involve a car hitting the rear wheel of a bicycle (RoSPA, 2017). There is a need to reduce the number of such accidents by improving the visibility of cyclists on the roads.

Known devices, which aim to improve cycling safety, include bicycle lights which emit a Light signal to indicate when a bicycle is braking.

There is a need to provide more effective Lighting devices to further improve the safety of road users, cyclists in particular. -2 -

Summary of invention

The present inventive concept is directed to a bicycle Light comprising one or more light emitters, sensors adapted to detect a number of conditions and adapted to provide a signal to a controller, the bicycle light further comprising a controller adapted to receive signals from the sensors and adapted to control an output of the said one or more light emitters in dependence on the conditions detected by the sensors, wherein the sensors comprise at least an accelerometer and a proximity sensor, so that the light emitters convey information about the conditions by way of their output.

The bicycle light is thus adapted to emit different light signals in dependence on the conditions detected.

The bicycle Light may thus be adapted to have at least a first mode of operation, a second mode of operation and a third mode of operation, the mode of operation being activated in dependence on conditions detected by the sensors and the mode being indicated by signals of the light emitters.

The conditions may be intrinsic to the bicycle itself, such as the acceleration of the bicycle, or extrinsic, such as proximity to the sensor of an independent object such as another road vehicle. The sensors may be provided as a discrete unit capable of detecting more than one condition, or may be provided as separate sensors each capable of detecting a single condition. The skilled reader will appreciate that while the term acceleration is used throughout this specification, the main focus is on warning of a deceleration of the bicycle to which the bicycle light is attached, as well as proximity thereto by a following vehicle -for example under braking conditions.

Thus, information about an acceleration of the bicycle light can be conveyed to an observer, such as the driver of another road vehicle. Furthermore, information about the proximity of another body, such as an following vehicle, can be conveyed to an observer.

Safety to the cyclist and other road users is thus improved because drivers of vehicles travelling behind the bicycle can be warned effectively when the bicycle decelerates, and an additional degree of warning can be provided if the proximity of a following vehicle -3 -is deemed unsafe. Furthermore, the controller may be adapted to provide a warning if the combination of acceleration and proximity is such that said combination is deemed unsafe.

Other road users will be somewhat familiar with the use of light signals to provide a warning or information. For example, the use of brake Lights and hazard warning Lights by power-propelled vehicles is well established. The driver of a vehicle thus does not need special training to understand what a solid red light might mean, for example. An important feature is drawing the attention of another road user to a change in conditions by varying the output of the light emitters when conditions change. The chance of a collision is thus decreased.

Under a first set of conditions, the bicycle Light may have a first mode of operation. In the first mode one or more Light emitters may provide a light signal of a first colour. For example, a continuous light signal of a selected colour may be provided, or alternatively, a flashing Light signal of a selected colour. In the first mode the bicycle Light functions similarly to a conventional rear bicycle light. The first set of conditions may include acceleration within certain pre-determined bounds, and with no object being detected as being nearby. The first mode may optionally provide no light signal. This may be appropriate if, for example, the bicycle light is used during daylight conditions.

When acceleration is detected outside a selected acceleration range, a second mode of operation may be initiated. In the second mode, the one or more light emitters provide a different light signal from that of the first mode. For example, if the first mode provides a continuous Light signal of a selected colour then in the second mode the light signal may be flashing; if the first mode provides a flashing light signal of a selected colour then in the second mode the light signal may be continuous. The second mode may provide a different colour of Light signal than that of the first mode. The second mode may differ from the first mode in brightness.

Thus, there is an improved possibility that the attention of a driver of a following vehicle will be drawn so that the driver can take appropriate action to avoid a collision.

The selected acceleration range may be pre-determined or may be variable in dependence on other factors -such as proximity of an object to the bicycle light -4 -When proximity of an object is detected outside a selected proximity range, a third mode of operation may be initiated. In the third mode, the one or more light emitters provide a different light signal from that of the first mode or the second mode. For example, the third mode may provide illumination of light emitters in addition to the or each illuminated in the first mode or the second mode; the or each light emitter of the first or second mode may provide a different colour of Light signal.

The selected proximity range may be pre-determined or may be variable in dependence on other factors -such as the acceleration of the bicycle Light.

The controller may be adapted to initiate the first mode, the second mode or the third mode. The controller may be adapted to vary the acceleration range and/or the proximity range in dependence on other factors. For example, if an object is detected within a Lower pre-determined threshold proximity then the acceleration range may be reduced or if the acceleration is detected at or above a higher pre-determined threshold then the proximity range may be increased. This provides for an "earlier" initiation of the third mode; for example if the bicycle is decelerating very rapidly then the third mode may be initiated when a vehicle is further away than the proximity threshold or if a vehicle is very close then a smaller deceleration than the acceleration threshold can initiate the third mode.

The controller may be arranged to initiate at least three emitting modes: i. a first mode, active unless another mode is initiated; ii. a second mode, initiated when an acceleration range is met; for example when the bicycle decelerates significantly; and iii. a third mode, when a proximity range is met; for example when an object is detected close to the bicycle light.

As described above, the proximity threshold may be changeable dependent on the acceleration of the bicycle Light. For example, if the bicycle is braking more heavily, the distance at which the proximity of a following vehicle is judged to be unsafe may increase. The controller may therefore be adapted to assess the acceleration of the bicycle light when determining the proximity range. -5 -

Thus, at Least three different Light signals can be emitted to a following vehicle depending on the acceleration of the bicycle and the proximity of the said following vehicle. A distinction can therefore be drawn between the scenario where no significant braking or proximity event is occurring, the scenario where a bicycle is braking and the proximity of a following vehicle is safe (or there is no following vehicle present), and the scenario where a bicycle is braking and a following vehicle is at an unsafe proximity.

The second and third emitting modes may not be mutually exclusive, i.e. they may be active together or separately.

In the first mode, one or more Light emitters of the bicycle light may emit a solid or flashing light signal of a first colour.

In the second mode, one or more Light emitters of the bicycle light may emit the other of a solid or flashing Light signal at the first wavelength. In other words, the converse of the first mode. The second mode light signal may be emitted at a greater brightness than the first mode light signal. The second mode light signal may be the same (i.e. solid or flashing) as the first mode, but brighter than the first mode.

In the third mode, one or more Light emitters of the bicycle light may emit a further solid or flashing Eight signal. The third mode may thus be brighter than the first or second mode, and/or provide a signal of a second colour. The third mode light signal may be at the same or a greater brightness than the first and second light signals.

Thus, the colour of the third light signal may be different to the colour of the first mode and second mode Light signals, so that a distinct warning is clearly made when the proximity of a following vehicle becomes relevant.

The colour, frequency, duration of signal or brightness, and other characteristics of each light signal may otherwise differ between emitting modes. Thus, for example, in a first mode the signal may flash at a first rate and in the second mode the signal may flash at a second rate.

The bicycle light may comprise a first set of light emitters for emitting a first or second mode light signal, and a second set of light emitters for emitting a third mode light signal. A set may comprise a single light emitter or more than one light emitter. -6 -

The bicycle light may comprise a set of one or more light emitters for emitting the first and second mode light signals, and a set of one or more light emitters for emitting the third mode light signal.

Each mode light signal may be emitted by a distinct set of Eight emitters.

Thus, the bicycle light provides a multi-stage warning device for improving the efficacy with which a warning signaE is propagated towards a vehicle travelling behind a bicycle. The modes are arranged to gradually increase the severity of the warning signal to a following vehicle so that the seriousness of a potential collision is communicated more effectively.

A Eight emitter may comprise a light emitting diode (LED).

The bicycle light may comprise a set of one or more LEDs each arranged as a set to emit the first and second mode Eight signals, and a set of one or more LEDs each arranged to emit the third mode light signals. The set of LEDs arranged to emit the first, second and/or third mode Eight signals may comprise LED bars or strips.

Separate signals, which represent the different modes of operation, are therefore more clearly distinguished. If LED bars form the first and second Eight emitters, they can be larger and take up more space within the bicycle light than the third light emitters, so that the first and second modes result in a more intense signal than that of the third mode as such. Clearly, if the second and third mode are active substantially simultaneously then the total output will be Earger than that of the first and second modes.

The first set of Light emitters may be red coloured LEDs. The second set of light emitters may be amber coloured LEDs.

The controller may be adapted to provide a cease mode if the condition(s) for that mode cease. The controlEer may be adapted to delay ceasing a mode for a predetermined cease time after the condition(s) for that mode cease.

The controller may adapted to cease a mode after a predetermined timeout time has elapsed, after the initiation of said mode. Therefore, a mode can be stopped after a 7 -predetermined time so that a following vehicle does not receive an incorrect warning from the bicycle light when a deceleration or proximity event has ceased.

The controller may be adapted to comprise a digital signal processor. The digital signal processor may be adapted to generate a rolling average of signal data received thereby.

Thus, "raw" data provided by a sensor may be more usefully interpreted by the controller. For example, a single discrete measurement may not automatically initiate a change of mode by the controller.

The bicycle light may comprise means for effecting an automated power-on/power-off function. The means may comprise a hall effect sensor. A hall effect sensor avoids the need for a manually operated power switch. Removing the need for a manually operated power switch reduces the risk of water ingress which might damage the bicycle light Thus, the durability and reliability of the bicycle Light is improved.

One or more of the light emitters, controller and sensors may be arranged on a mainboard housed within a chassis.

The bicycle light may further comprise a cover arranged to fit onto the chassis. The Light emitters, controller and sensors may be thus contained within the chassis and protected from dirt or water ingress by the cover. The cover may be formed at least partly of acrylic glass, otherwise known as plexiglass or PMMA.

Preferably, substantially the whole bicycle Light is enclosed within a fully sealed chassis..

This configuration provides the advantage of sealing the bicycle light against potential water ingress. The durability and Lifespan of the bicycle Light is thus improved.

The chassis may be formed at least partially of metal. Metal further improves the durability of the bicycle light, particularly when the bicycle Light might be dropped or knocked against during everyday use.

The bicycle Light may be at least partially formed of plastic. The bicycle light chassis and/or cover may be formed by injection moulding or by additive manufacturing (sometimes referred to as 3D printing). The bicycle light may be formed from polylactic acid (PLA), acrylonitrile butadiene styrene (ABS) and/or polyurethane resin. -8 -

The bicycle light may comprise a waterproof charging socket. The charging socket may be a micro-USB socket having IP68 waterproof rating.

The accelerometer may be a LIS3DH sensor. The proximity sensor may be a VL53L1X sensor.

The bicycle light may comprise one or more magnets for attaching the bicycle light to a corresponding mount.

The present inventive concept is also directed to a kit for a bicycle Light assembly, the kit comprising a bicycle Light as described, and a mount arranged to be connectable to the bicycle light and to part of a bicycle.

The bicycle Light and mount may comprise corresponding parts of a magnetic connection.

This configuration is particularly advantageous because the bicycle Light can be straightforwardly connected and disconnected to the mount without the need for additional fixings or tightening/loosening of mechanical connectors.

The bicycle light may have a top end and a bottom end and the bicycle Eight may comprise magnets positioned towards both the top and bottom ends; and wherein the mount incorporates corresponding magnets arranged to align with the magnets of the bicycle light.

The mount may comprise a bracket arranged to reversibly attach the mount to part of a bicycle such as the seat post of a bicycle frame.

The mount may comprise a backing plate, wherein the shape of the backing plate corresponds to the shape of the rear surface of the bicycle light. Thus, the bicycle Light can be more securely connected to the mount.

The present inventive concept is also directed to a method for controlling a bicycle Eight having one or more light emitters, sensors adapted to detect a number of conditions and a controller, the method comprising the steps of: -9 -a) monitoring the values of acceleration of the bicycle light and proximity of another body to the bicycle light; b) initiating or maintaining a first mode of operation; c) initiating a second mode of operation if the acceleration of the bicycle light is outside a selected acceleration range; d) initiating a third mode of operation if an object is detected outside a selected proximity range; and wherein a light signal emitted by the bicycle light differs between modes of operation.

The second and third modes of operation may not be mutually exclusive and may occur together.

The method may further comprise an initialisation step before step a). The initialisation step may comprise a step of configuring each sensor. The initialisation step may comprise a step of calibrating each sensor.

The steps of the method may be implemented by the said controller.

The monitoring step may comprise a step of recording several samples from each sensor and processing the samples to provide a rolling average.

The monitoring step may comprise a step of implementing a dynamic average adjustment The monitoring step may comprise a step of implementing a numerical differentiation with respect to time of acceleration (jerk).

The monitoring step may be implemented by a digital signal processor. Such a digital signal processor may be integral with the controller, or may be a discrete component.

The selected acceleration range may be pre-determined or may be variable in dependence on other factors -such as proximity of an object to the bicycle light.

-10 -The method measures intrinsic and extrinsic conditions and the result of the method is physical and technical in that a light signal is output and/or varied. The intended result includes a potential change in behaviour of a driver of a following vehicle thus avoiding or reducing the risk of collision. While the method may be implemented by a data processing device it is inherently technical because it receives physical "stimuli" and has a physical output and result.

Detailed description of the invention

Exemplary embodiments of the present inventive concept will now be described with reference to the accompanying drawings in which: Figure 1 shows an exploded view in perspective of a bicycle Light assembly; Figure 2 shows a view of the bicycle light of Figure 1, from a rearward point of view, with the cover of the bicycle light removed; Figure 3 shows a cross section through the bicycle light of Figures 1 and 2 in the direction shown by the arrows in Figure 2; Figure 4 shows a view of a mount for a bicycle light assembly; Figure 5 shows a side view of a bicycle light assembly, comprising a bicycle light and a mount; Figure 6 shows a flow diagram for an exemplary embodiment of a method of controlling a bicycle light; and Figure 7 shows a flow diagram for an exemplary embodiment of a further more detailed sub-method of acceleration processing.

Figure 1 shows a bicycle Light assembly 10 comprising a bicycle Light 11 and a mount 30. A bicycle light 11 has a chassis 12, a mainboard 14 and a filter 16. The mainboard 14 incorporates an array of light emitters 18, 20, a controller, an accelerometer, a proximity sensor (not shown) and means for connecting the sensors, the controller and the light emitters 18, 20 to one another.

The accelerometer and proximity sensor are arranged to detect speed changes of the bicycle Eight 11 -and thereby the bicyde to which it is attached in use -and the proximity of a vehicle travelling behind the bicycle light 11. The controller is arranged to process the data obtained by each of the sensors and control the light signals of the light emitters 18, 20 depending on the data obtained. The controller has several pre-set emitting modes and in each emitting mode different Light signals are programmed to be emitted from one or more of the light emitters. Thus, different signals can be emitted from the bicycle light depending on the data obtained by the accelerometer and the proximity sensor.

The chassis 12 has a rear surface 22, a front surface 24 and side surfaces 26. The front surface 24 incorporates a recess 28 for bounding the mainboard 14. The filter 16 is attachabEe to the front surface 24 of the chassis 12 to contain the mainboard 14 inside the chassis 12.

The inside of rear surface 22 of the chassis 12 incorporates a number of magnets for attaching the bicycle light 10 to a corresponding mount 30. The mount 30 incorporates a corresponding number of magnets 40 for attaching to the magnets on the rear surface 22 of the bicycle Light 11. The mount 30 further comprises a bracket 32 for mounting the mount (and bicycle light 11 when it is attached to the mount 30) to a part of a bicycle such as a seat post (not shown).

The bicycle Light 11 has three emitting modes which are dictated by the controller depending on data obtained from the accelerometer and the proximity sensor. The emitting modes are: i. a first mode, active unless another mode is initiated; ii. a second mode, initiated when an acceleration range is met; for exampEe when the bicycle decelerates significantly; and iii. a third mode, when a proximity range is met; for example when an object is detected close to the bicycle light.

-12 -The accelerometer is a LIS3DH sensor and the proximity sensor is a VL53L1X sensor. The bicycle light also includes power and control systems, high speed charging, and the proprietary sensor and LED driver electronics that allows for the functionality of the device.

The mainboard 14 is shown in greater detail in Figure 2. The mainboard 14 comprises -as light emitters -an array of two LED bars 18 and two further LEDs 20. The LED bars 18 are arranged to emit a light signal during the first, second and third modes. The further LEDs 20 are arranged to emit a light signal during the third mode. The mainboard 14 also comprises other electronic components not explicitly shown in Figure 2.

The LED bars 18 and further LEDs 20 are active simultaneously when the third mode is triggered.

The LED bars 18 are larger than the further LEDs to maximise visibility of the bicycle light 11 during the first mode.

The bicycle Light 10 also comprises a rechargeable battery (not shown) and a port 34 for receiving means for charging the battery. The port 34 is a micro-USB port arranged to receive a micro-USB charging cable. Briefly turning back to Figure 1, it can be seen that the filter 16 incorporates a corresponding aperture 36 for allowing the charging cable to be inserted into the port 34.

Figure 3 shows a portion of the bicycle Light 11 housing the battery 38, which is a cross-section of the bicycle light 10 of Figure 2. The battery 38 and port 34 are housed within the chassis 12. A magnet 40 is located underneath the battery 38. The chassis 12 is comprised of aluminium. In the region of each magnet 40 the chassis 12 is sufficiently thin to allow the magnet 40 to interact with a corresponding magnet of the mount 30. The bicycle light 11 has two magnets.

Figure 4 shows a front view of the mount 30. The mount 30 incorporates two magnets 40 for interacting with corresponding magnets of the bicycle light 11. Thus, the bicycle light 11 may be reversibly attached to the mount 30 using cooperating magnets positioned on the rear surface 22 of the bicycle light 11 and on the mount 30.

-13 -The mount further comprises a bracket 42 arranged to reversibly attach the mount 30 and thereby the bicycle light 11 (when it is mounted) to a part of a bicycle (not shown), such as a seat post The bracket 42 comprises a collar which may be opened to allow part of a bicycle to be located within the collar and closed to fix the mount 30 to the bicycle part. The collar has a screw and threaded socket 44 so that the collar can be tightened against a bicycle part The mount 30 also has a backing plate for abutting against the rear surface of the bicycle light (not shown in Figure 4).

Figure 5 shows the bicycle assembly 10 from the side, with the bicycle light 11 detached from the mount 30. The mount 30 further comprises locating pins 46 for aligning and joining the bicycle Eight 11 and the mount 30. The backing plate 48 is smaller than the rear surface 22 of the bicycle Light 11. The collar 42 projects horizontally from the backing plate 48 so that the bicycle light assembly may be attached to a vertical tube of a bicycle, such as a seat post, such that the bicycle Light 11 is parallel to the vertical tube.

Figure 6 shows a flow diagram for an exemplary embodiment of a method of controlling a bicycle light On boot (for example when the device is powered up), the bicycle Eight is initialised, which includes configuration and calibrating the accelerometer and the proximity sensor. The controller has a clock which, together with the inputs (sensors) and outputs (light emitters) are enabled. The sensors are activated and configured. The proximity sensor undergoes cross-talk calibration and is tested for correct operation. The accelerometer is tested for correct operation and initial calibration metrics are taken.

The main sensor Loop begins. The controller begins the acceleration and proximity digital signal processing (DSP), which provide data about the current acceleration (braking) status and distance to any objects in the line-of-sight of the proximity sensor. The acceleration status is constantly monitored.

The bicycle light is initially in a first mode as described. A second mode, labelled in Figure 6 as "Stage 1", is initiated if a braking flag is set, for example if the bicycle decelerates outside a selected acceleration range. A timeout routine disables the "Stage 1", i.e. second mode after a pre-determined time and the controller then re-initiates the first -14 -mode until a further braking or proximity event occurs (for example when a subsequent flag is set).

The proximity of any nearby objects in the line-of-sight of the proximity sensor is also monitored. If a proximity flag is set, for example if an object is detected outside a selected proximity range, then a third mode is initiated. A timeout routine disables the third mode after a pre-determined time and the controller then re-initiates the first mode until a further proximity or braking event occurs (for example when a subsequent flag is set).

In the event that a proximity flag is triggered at the same time as or during a braking flag a "Stage 2" mode is initiated, in which the second and third modes are in operation simultaneously.

Figure 7 shows a flow diagram for an exemplary embodiment of a further more detailed sub-method of acceleration processing. Continuously, live inertial acceleration data in ms-1 is polled from the accelerometer, and that raw information is put through several rolling averages of high, medium and low frequencies.

Concurrently, the rolling averages, are processed to determine whether the cyclist is decelerating. The Low F filter is used as a baseline (to remove constant offsets e.g. acceleration due to gravity and orientation) and the High F filter as a live smoothed acceleration reading, hence their difference (A-B) can be taken as the "True Acceleration Data". This is compared with calibration threshold values and a Medium F filter (to prevent false positives due to recent offsets that haven't reached the Low F filter, e.g. hill climbing) to produce the yes/no braking status. The positive flag then disables live updates of the Low F filter to prevent spurious on-off switching as the offset slowly climbs.

The Med F point is fed back into a "Dynamic Averaging Adjuster" which modifies the averaging point depths, in relation to the peak variability of the jerk data (during times of frequent increase/decrease the Low F depth is extended to reduce variability). The skilled reader will appreciate that jerk is a measure of a rate of change of acceleration.

Claims

-15 -Claims 1. A bicycle light comprising one or more light emitters, sensors adapted to detect a number of conditions and adapted to provide a signal to a controller, the bicycle light further comprising a controller adapted to receive signals from the sensors and adapted to control an output of the said one or more light emitters in dependence on the conditions detected by the sensors, wherein the sensors comprise at Least an accelerometer and a proximity sensor, so that the light emitters convey information about the conditions by way of their output 2. A bicycle light according to claim 1, wherein the bicycle Light is adapted to have at [east a first mode of operation, a second mode of operation and a third mode of operation, the mode of operation being activated in dependence on conditions detected by the sensors and the mode being indicated by signals of the light emitters.3. A bicycle Eight according claim 2, wherein the second mode of operation is activated if the accelerometer detects acceleration outside a selected acceleration range.4. A bicycle light according to claim 2 or claim 3, wherein the third mode of operation is activated if the proximity sensor detects an object outside a selected proximity range.5. A bicycle light according to 3 or claim 4, wherein the selected acceleration range and/or selected proximity range can vary in dependence of one another.6. A bicycle Light according to any of claims 2 to 5, wherein the light emitters indicate a different Light signal in each of the first mode, second mode and third mode.7. A bicycle Light according to any preceding claim, wherein the bicycle light comprises more than one discrete set of Eight emitters.8. A bicycle light according to any preceding claim, wherein the controller is adapted to provide a cease mode.-16 - 9. A bicycle light according to any preceding claim, wherein the controller further comprises a digital signal processor.10. A bicycle light according to claim 9, wherein the digital signal processor is adapted to generate a rolling average of signal data.11. A bicycle light according to any preceding claim, further comprising means for effecting an automated power-on/power-off.12. A bicycle Eight according to claim 11, wherein the said means comprises a hall effect sensor.13. A bicycle light according to any preceding claim, wherein at Least the Light emitters, controller and sensors are arranged on a mainboard housed within a chassis.14. A bicycle light according to any preceding claim, wherein substantially the whole bicycle light is enclosed within a fully sealed chassis.15. A kit for a bicycle light assembly, the kit comprising a bicycle Eight according to any preceding claim, and a mount arranged to be connectable to the bicycle light and to part of a bicycle.16. A kit for a bicycle light assembly, wherein bicycle Light and mount comprise corresponding parts of a magnetic connection. 25 17. A method for controlling a bicycle Light having one or more Light emitters, sensors adapted to detect a number of conditions and a controller, the method comprising the steps of: a) monitoring the values of acceleration of the bicycle light and proximity of another body to the bicycle light; b) initiating or maintaining a first mode of operation; c) initiating a second mode of operation if the acceleration of the bicycle light is outside a selected acceleration range; -17 -initiating a third mode of operation if an object is detected outside a selected proximity range; and wherein a light signal emitted by the bicycle light differs between modes of operation.18.A method according to claim 171 further comprising an initialisation step before step a).19. A method according to claim 17 or claim 18, wherein the monitoring step comprises a step of recording several samples from each sensor and processing the samples to provide a rolling average.20. A method according to claim 19, wherein the monitoring step comprises a step of implementing a dynamic average adjustment.21. A method according to claim 19 or 20, wherein the monitoring step comprises a step of implementing a numerical differentiation with respect to time of acceleration (jerk).