Field of the technology

The present invention relates to a sensor device, and in particular but not exclusively a sensor device having a PIR (Passive infra red) motion sensor device.

Background of the technology

With the growing shortage of energy, as well as the increasing of people's awareness of the need to protect the environment, saving energy such as electricity is becoming more important.

In order to save electricity, people often install PIR (Passive Infra Red) motion sensors to lighting fixtures. PIR motion sensors can detect the movement of people, and the sensor is activated when movement is detected and often there is a control that automatically switches the sensor off after a certain period of time, which can effectively save electricity. However, existing PIR motion sensors are generally only used with particular types of individual lighting fixtures, for example, a single LED (light-emitting diode) lighting fixture, or a single compact fluorescent lamp lighting fixture. Furthermore, the efficiency of a common PIR motion sensor is poor, and the installation process is very complicated, and also customization is often required for particular light fittings. As result of the difficulties of installing PIR sensors, their use is not extensively adopted.

Summary of the invention

The device of the current invention seeks to overcome the problems with known sensors by providing a new structure of PIR motion sensor device which is suitable for LED lamps.

According to the present invention there is provided a PIR motion sensor device, including a PIR motion sensor and a main circuit board, of which the main circuit board is connected with the PIR motion sensor, a power output device and a ballast transformer, of which the power output device and the ballast transformer are connected with the main circuit board.

Advantageously, said sensor device also includes a timer, of which the timer is connected with the main circuit board.

Advantageously, it also includes a light sensor or image sensor, of which the light sensor or image sensor is connected with the main circuit board via a photonic circuit board.

Advantageously, the power output device includes a DC power output device and an AC power output device.

In a preferred arrangement the sensor includes a common power supply for the PIR and the driver for the PIR. By having a common supply rather than an individual power supply for the PIR and a separate power supply for the driver there is a reduction in the number of components which reduces the cost of production of a sensor.

Preferably the sensor includes a heat barrier between the PIR and the electronic driver. This barrier allows the PIR to operate without hindrance from the heat generated by the electronic driver.

Preferably the sensor device includes a casing in which the PIR motor sensor, the main circuit board, the power output device and the ballast transformer are located inside the casing.

The present invention may have a combined PIR with integral driver in the same housing but allows the unit to be used separately from the area or space used by the light source such as one or more LEDs. Also the combined PIR/driver can easily be connected to the LED unit/product.

The above-mentioned technical solution has the following beneficial effects in that as the PIR motion sensor device is connected with both the power output device and ballast transformer at the same time, the PIR motion sensor can be made applicable to different lighting fixtures. It can be connected with various types of power interface, so the PIR motion sensor device has better efficiency. Further, it can be easily installed and so can be extensively used.

Description of the drawings

An embodiment of the invention will now by described by way of example only as illustrated in the accompanying drawings in which:

Figure 1 shows an sensor according to an embodiment of the invention;

Figure 2 shows a sensor in connection with an LED lighting fixture; and

Figure 3 shows a sensor in connection with a compact fluorescent lamp lighting fixture.

Detailed description of the embodiments

As shown in Figure 1 , the PIR motion sensor device includes a PIR motion sensor 1 , a main circuit board 2 and a light sensor or image sensor 5, wherein the PIR motion sensor 1 , a timer 4, a power output device and a ballast transformer 3 are connected with the main circuit board 2. The light sensor or image sensor 5 is connected with the main circuit board 2 via a photonic circuit board 6. The power output device and the ballast transformer 3 are connected with the lighting fixture 7.

The PIR motion sensor 1 is used to detect movement of an object and to give a signal to the main circuit board 2 to determine whether there is movement of people. The image sensor or light sensor 5 is used to detect light and to give a signal to the main circuit board 2 via the photonic circuit board 6 and based on this signal the main circuit board 2 determines whether light illumination is required. The timer 4 is used to calculate the duration of the light illumination. The power output device includes a DC power output device and an AC power output device such that the PIR motion sensor device 8 can be used in DC power lighting fixtures such as LED lighting (as shown in Figure 2) and AC power lighting fixtures. Compact fluorescent lamp lighting fixtures are controlled by the ballast transformer (as shown in Figure 3).

The device also includes a casing, with the PIR motion sensor 1 , the main circuit board 2, the light sensor or image sensor 5, the timer 4, the power output device and ballast transformer 3 and the photonic circuit board 6 all located inside the casing. By placing both the PIR motion sensor and the power output device inside the casing they are located away from the operating area of the actual light fixture. This significantly reduces likelihood of false activation of the PIR motion sensor caused by the heat (IR) emissions of the fixture. Furthermore, in the event of the light fixture being an LED fixture, which are also known to generate significant local heat, the DC power output device of the power output device, which in this case would comprise an LED driver circuit, is similarly located away from the heat source formed by the LED light fixture which otherwise may cause problems to the PIR or the LED/LEDs.

Another consideration and technical problem in achieving a combined LED driver with integral PIR are the problems caused during the manufacturing of the complete product effectively with the three elements. It is disadvantageous to have three units interconnected with each other from a components cost point of view, from a manufacturing process point of view and from an aesthetic point of view. Embodiments of the present invention include the combination of a combined PIR with an integral driver in the same housing but which allows the unit to be used separately from the area or space used by the LED/LEDs, whilst still allowing the combined PIR/driver to be easily be connected to the LED unit/product.

A further consideration is the heat relationship between the components of the PIR driver and the components used within the PIR motion sensor itself. In some embodiments, an additional heat barrier is provided between the PIR and the electronic driver. This barrier allows the PIR to operate without hindrance from the heat generated by the electronic driver.

In the embodiments of the present invention a common power supply powers both the PIR motion sensor and the PIR driver, as opposed to an individual power supply for the PIR and a separate power supply for the driver, thus reducing components numbers and cost and production complexity.

The PIR motion sensor is used so that when there is movement of an object or person the sensor can detect movement within a range and give a signal that is used to switch on the power output device or ballast transformer. Regardless of whether the sensor is installed in LED lighting fixtures or compact fluorescent lamp lighting fixtures, the lighting fixtures can provide light illumination for a variable or set period of time. The device does not require complicated processes to be installed in the light fixtures and it gives convenience for consumers in respect of purchase and installation.

It should be noted that the above mentioned embodiments illustrates rather than limits the invention and that alterations or modifications are possible without departing from the scope of the invention as described. Furthermore, the invention not only covers individual embodiments but also combinations of embodiments described.