CN102780418B - A kind of self-powered remote control unit - Google Patents

Abstract

The invention provides a self-powered remote control device. The user shakes the remote control device to generate power for the device to operate. The remote control has a movable body, such as a steel ball, which can move freely within a larger housing. When the user shakes the remote control device, the steel ball collides with the side of the casing and hits the piezoelectric sensor installed in the casing. The generated electricity then goes through a step-down transformer, is rectified by diodes, and is then used to charge a dielectric storage medium such as a capacitor. The capacitor uses this electric energy to power the encoder and the wireless signal transmitter. When the user presses the button on the remote control device, the encoder performs an encoding operation according to the pressed button, transmits the encoded signal to the wireless signal transmitter, and the wireless signal transmitter transmits the encoded signal to the wireless signal transmitter. An encoded signal is transmitted from the remote control.

Description

A self-powered remote control device

technical field

The invention relates to a hand-held remote control device using a power generating unit. In particular, the invention relates to the construction and architecture of the remote control device and the construction and architecture of the power generating unit.

Background technique

Remote controls are widely used in a variety of applications. Currently, hand-held remote controls are used to control various appliances in the home. They are also used with vehicles, industrial equipment and other devices where wiring may be inconvenient or aesthetically inappropriate. Common handheld remote controls have traditionally been battery powered, but inherent in battery powered systems is the problem of inoperability when the battery has been depleted. Battery-powered devices can also be damaged by leaking battery fluid. Furthermore, a large number of used batteries are disposed of in the environment, and the disposal of these batteries with hazardous components raises real health and environmental concerns.

To alleviate the above-mentioned problems, manufacturers of handheld remote controls have recently experimented with mechanically powered remote controls. Specifically, the mechanical energy comes from the user pressing a button, and this mechanical energy is converted into electrical energy by using a piezoelectric energy generator. However, several problems limit the usefulness of such remote controls.

(1) The energy generated by the user pressing the button is rather limited and often not sufficient to power the remote control over an extended period of use. Repeatedly pressing the buttons is also tedious and uncomfortable for the user.

(2) Constructing the push button mechanism requires a complicated mechanical structure, thus increasing manufacturing costs.

(3) Because the impedance of the piezoelectric energy sensor is high, it is difficult to obtain an impedance matching the load of the circuit, so the generated electric energy cannot be effectively transmitted to the load. In this case, the load is an encoding device and a wireless transmitter.

(4) The material for manufacturing the piezoelectric unit is currently made of a toxic lead-containing ceramic material which itself contains environmental pollutants when the piezoelectric unit or the remote controller is finally disposed of.

The amount of electrical power required to transmit a radio frequency signal depends on factors such as, among others, the length of the digital signal, the frequency of the radio frequency signal, the required range, the topography of the transmission medium, and the sensitivity of the receiver. Based on currently available RF transmitter ICs and encoder ICs, the energy required for a typical transmission at a range of 50 meters is about 100 μJ. Likewise, the amount of electrical power required to transmit an infrared signal depends on many factors. Based on current technology, the energy required for infrared emission within a range of about 5 meters is 350 μJ. Therefore, there is a need for a piezo-powered remote control that fulfills these needs without requiring strenuous user effort.

Continuing improvements in the design and fabrication of piezoelectric powered devices are increasing the efficiency and practical use of these devices, but there is still significant room for further improvement in the design and architecture of these devices.

Contents of the invention

The present invention aims to provide a new and useful remote control device.

In summary, the present invention provides a handheld remote control device powered by energy from a user shaking the device. The movable body is located in the remote control device, and as the remote control device is shaken, when the movable body hits the piezoelectric energy sensor, electric energy is generated. Unlike today's piezoelectric powered devices where the user must repeatedly press a button to charge the device, the rocking operation of the present invention allows the user to exert greater force on the remote control device in an ergonomic and comfortable manner. In addition, the present invention can have fewer moving parts than conventional piezoelectric power supplies, so this simplified structure reduces manufacturing costs.

A second aspect of the invention aims at increasing the efficiency of piezoelectric sensors by using multiple piezoelectric layers in a single sensor, wherein the individual layers are mechanically laminated in series and electrically connected in parallel. This structure allows for better matching to typical load impedances. This configuration also reduces the output voltage of the sensor such that a step-down transformer is generally not required when connecting to a tank circuit.

A third aspect of the invention aims to further increase the efficiency of the piezoelectric sensor by using a curved ceramic disk. This allows the bending-mode deformation of the ceramic to generate additional electrical energy.

A fourth aspect of the present invention aims at increasing the durability of the piezoelectric sensor by subjecting the sensor to compressive stress in a plane perpendicular to the impact direction.

A fifth aspect of the present invention proposes the use of non-toxic piezoelectric materials in the construction of the piezoelectric sensor, thus mitigating the environmental concerns associated with current commercial piezoelectric units made from toxic lead-containing ceramic materials.

Description of drawings

The advantages of the present invention can be more easily ascertained when the following description of the embodiments of the present invention is read in conjunction with the accompanying drawings, wherein:

1(a) and 1(b) are diagrams showing a remote control device having a power generating unit according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a step-down transformer connected to an output terminal of a power generation unit.

FIG. 3 is a diagram showing a second embodiment of the present invention having a power generating unit including an additional second piezoelectric energy sensor.

FIG. 4 is a circuit diagram of a second step-down transformer circuit, which can be used to replace the step-down transformer in FIG. 2 in an embodiment of the present invention.

FIG. 5 is a diagram of a third embodiment of the invention having a power generating unit with a curved piezoelectric sensor.

FIG. 6 is a diagram of a fourth embodiment of the invention having a power generating unit with a multilayer piezoelectric sensor.

Figure 7 is a circuit diagram schematically showing a configuration that may be used in some embodiments of the invention, including a piezoelectric sensor with multiple layers connected directly to a storage capacitor without a step-down transformer.

Fig. 8 is a photograph showing two power generating units manufactured in the second embodiment of the present invention, one in an assembled state and the other in an unassembled state.

FIG. 9 is a graph showing accumulation of energy stored in a storage capacitor when a user shakes a remote control device in the first embodiment of the present invention.

FIG. 10 is a graph showing the accumulation of energy stored in a storage capacitor in the configuration shown in FIG. 4 .

FIG. 11 is a graph showing electric power generated by a flat piezoelectric sensor and a curved piezoelectric sensor in the first and third embodiments of the present invention.

Fig. 12 is a diagram showing electric power generated by a single-layer piezoelectric sensor and a multi-layer piezoelectric sensor in the first and fourth embodiments of the present invention.

detailed description

Example 1:

Embodiments of the present invention will now be described with reference to FIGS. 1( a ) and 1 ( b ). Here, the remote control device 1 includes a power generation unit 2, an electric energy storage device 3, a voltage regulation unit 4, a control unit 6 (a digital encoder in this embodiment) and a wireless signal transmitter 7, and the control unit 6 is connected to the At least one input device 5 (button in this embodiment) on the front panel of the remote control housing.

The generating unit includes a movable body 8 confined in a cavity in a housing 10 and a piezoelectric energy sensor 9 attached to the housing 10, the movable body 8 having a weight of at least 3 grams. In this embodiment, the movable body 8 is connected to one end of the housing with a body of elastic material 11, preferably a spring. The movable body 8 may be a stainless steel ball. At static state, as shown in Fig. 1(a), the movable body squeezes the piezoelectric sensor due to the compressive stress from the spring.

The piezoelectric sensor 9 is made of lead-free piezoelectric material and is in the form of a ceramic disk with two electrode layers coated on opposite surfaces. The piezoelectric sensor is bonded to one end of the housing with an adhesive 12 such as epoxy. Preferably, the piezoelectric sensor is surrounded by epoxy such that compressive stress is exerted on the piezoelectric ceramic disk due to shrinkage of the epoxy during curing. Furthermore, a protective layer 13 such as a metal plate may be bonded on the surface of the piezoelectric sensor 9 which is struck by the movable body 8 .

When the user shakes the remote control device 1 along its longitudinal axis, ie the length of the housing of the device, the movable body 8 oscillates with the assistance of the spring. When the movable body 8 moves toward the spring, the kinetic energy from the movable body 8 is converted into elastic potential energy and stored in the compressed spring, as shown in FIG. 1( b ). When the spring pushes away from the movable body 8, the elastic potential energy stored in the compressed spring is converted back into kinetic energy again. Furthermore, since the user is now also shaking the device 1 in the opposite direction, the user is accelerating the device 1 in the opposite direction of the movement of the movable body 8 . Thus, the movable body 8 is accelerated relative to the device 1 under the compressive stress of the spring and the acceleration of the device 1 by the user in the opposite direction.

The movable body 8 , which is a ball in this embodiment, now returns at high speed and hits the piezoelectric sensor 9 . The momentum of the ball causes tension on the piezoelectric material, and this generates electrical energy through the piezoelectric effect. The generated electric energy is stored in the electric energy storage device 3 , which in turn supplies power to the control unit 6 and the wireless signal transmitter 7 .

In this embodiment, there is also a voltage regulation unit 4 , as shown in FIGS. 1( a ) and 1 ( b ), the voltage regulation unit 4 includes a voltage monitor 14 , a switch 15 and a voltage regulator 16 . The voltage regulation unit 4 is connected to the output of the electrical energy storage device 3 and performs two functions: first, it ensures that the storage capacitor 22 stored in the electrical energy storage device 3 is The electric energy in has sufficient voltage, secondly, the voltage regulator 16 component itself provides a constant supply voltage so that the control unit 6 (digital encoder) and the wireless signal transmitter 7 can operate normally.

Next, when the user initiates a manual input, such as pressing a button on the input device 5 of the remote control device 1 , the control unit 6 , which is a digital encoder in this embodiment, will perform an encoding operation and generate an output to the wireless signal transmitter 7 . Then, the wireless signal transmitter 7 emits a wireless signal according to the transmission received from the control unit 6.

The wireless signal transmitter 7 may include, but is not limited to, a radio frequency ('RF') transmitter or an infrared transmitter. Radio frequency transmission of signals for remote control applications is well known in the art. The advantages of radio frequency transmission over infrared transmission include low power consumption, relatively long transmission distance, and non-line-of-sight signal propagation. A wireless signal transmitter 7 using a radio frequency transmitter can be implemented using a suitable encoder and antenna. The encoder generates digital signals according to the state of the buttons on the remote control device 1 . The digital signal from the encoder modulates the RF output signal of the RF transmitter. The output of the RF transmitter is typically connected to an antenna (not shown) for efficient radiation of the RF output signal. The RF output signal is then received by a corresponding RF receiver located nearby.

Optionally, the use of an infrared transmitter may be considered more appropriate in applications where cost plays a decisive role, shorter transmission distances are feasible, or wireless signals need to be confined in space. Circuits for transmitting wireless signals are well known in the art. For example, infrared signal transmission can be achieved by controlling the on-off blinking of an infrared light emitting diode ('LED') using a suitable encoder integrated circuit ('IC') and transistor. The information attempted to be sent is encoded in the form of a blink of an infrared diode, which is then received by a corresponding infrared detector and decoder integrated circuit located nearby.

A method of fabricating a piezoelectric disk will now be described. Here, the piezoelectric ceramic disk has a lead-free composition: (1-x)K _0.5 Na _0.5 NbO ₃ -xLiNbO ₃ ('KNN-LN'). x is a value in the range 0 to 0.1. KNN-LN ceramic discs are prepared from raw materials K ₂ CO ₃ , Na ₂ CO ₃ , Nb ₂ O ₅ and Li ₂ CO ₃ through a solid-state reaction process. Since carbonate powders are sensitive to moisture, they were first dried before use, and then weighed according to the formula (1-x)K _0.5 Na _0.5 NbO ₃ -xLiNbO ₃ (x=0 to 0.1), and then under ultrasonic irradiation Scattered in ethanol to form slurry. After the slurry was dried and milled, the mixed powder was calcined at 850 °C to form the perovskite phase of KNN-LN. After ball milling and mixing with polyvinyl butyral ('PVB') as a binder, the calcined powder was uniaxially pressed into disks and sintered at 1050°C in air. The ceramic disk samples obtained after sintering had a diameter of 8.6 mm and a thickness of 0.8 mm. The two main surfaces of the ceramic disc were then polished and coated with silver paste at 550° C. to form two electrodes. The samples with electrodes were polarized at 40 kV/cm for 30 minutes at 120°C. For a disc of (1-x)K _0.5 Na _0.5 NbO ₃ -xLiNbO ₃ , where x=0.06, the obtainable piezoelectric coefficient d ₃₃ is 184 pC/N.

Optionally, piezo discs are available in lead-free composition: Ba _0.85 Ca _0.15 Zr _0.1 Ti _0.9 O ₃ (BCZT). The ceramic discs of BCZT were prepared from raw powders BaCO ₃ BaZrO ₃ , CaCO ₃ and TiO ₂ through a solid-state reaction process similar to that described above. The calcination temperature of BCZT is 1350°C, and the final sintering temperature is 1450°C. After electrode coating and electrode polarization, the piezoelectric coefficient d33 of 323 _p C/N can be obtained for the _BCZT ceramic disc.

It should be noted that lead-free piezo discs typically have very high electrical impedance. Therefore, once hit by the movable body 8, the ceramic disc generally produces a high voltage but low current power output. Fig. 2 shows the configuration of the electrical energy storage device. In order to reduce the voltage and improve the utilization efficiency of the electric energy generated in the piezoelectric sensor 9 , the electric energy storage device 3 may include a step-down transformer 20 . As shown in FIG. 2 , the output of the piezoelectric sensor 9 is connected to the input of a transformer 20 which then outputs a reduced voltage to a pair of diodes 21 and a storage capacitor 22 . The step-down transformer 20 circuit improves the impedance matching between the power generation unit 2 and the electrical energy storage device 3 . The alternating current ('AC') from the output of the step-down transformer 20 circuit is then rectified by a pair of diodes 21 . A storage capacitor 22 connected to a diode allows charge accumulation, wherein one of the capacitors accumulates charge in the positive direction of alternating current and the other capacitor accumulates charge in the negative direction. The two storage capacitors 22 are connected in series, and the output voltage across the two storage capacitors 22 is the sum of the accumulated voltages of each storage capacitor.

The embodiment shown in Fig. 2 has the advantage over the prior embodiments known in the prior art of four diode full-wave bridge rectification power storage circuits connected to a single capacitor: The energy accumulated by the storage capacitor is doubled, reducing the number of diodes needed for the 2 energy storage circuits (from 4 to 2), and reducing energy loss due to the forward voltage drop of the diodes.

Example 2:

Another embodiment of the invention is shown in Figure 3, where the movable body 8 is not attached to any elastic material and has two piezoelectric energy sensors 9 instead of one. When the user shakes the remote control device 1 , the movable body 8 located in the cavity in the housing 10 of the power generating unit 2 is accelerated relative to the housing 10 . When the moving body 8 hits either of the two piezoelectric sensors 9 attached to both ends of the housing 10, electric energy is generated. Then, the electrical energy is stored in the electrical energy storage device 3 and supplied to the control unit 6 and the wireless signal transmitter 7 as required.

FIG. 4 shows a possible circuit diagram of the electrical energy storage device 3 when using two piezoelectric sensors 41 . Each piezoelectric sensor 41 is connected to a respective step-down transformer 42 , and each step-down transformer 42 is connected to a pair of diodes 43 . Both pairs of diodes are connected to the same pair of storage capacitors 44 . In the same way, the pair of storage capacitors can be connected to multiple step-down transformers when more piezoelectric transducers are to be added.

Example 3:

This embodiment is similar to Embodiment 2 except that a piezoelectric ceramic disk having a convex top surface 51 and a concave bottom surface 52 is used, as shown in FIG. 5 . The piezoelectric sensor 9 is placed such that the movable body 8 hits the convex top surface 51 of the ceramic disc. The curved surface provides a bending deformation mode on the piezoelectric ceramic disc for generating additional electrical energy. The concave bottom surface 52 of the piezoceramic disk can be bonded to the solid bottom with an adhesive layer such as epoxy. To protect the ceramic disc, each end of the ceramic disc is covered with epoxy resin 12 . As the volume of the epoxy shrinks during curing, this causes protective compressive stress to be applied to the ceramic disc.

Example 4:

In this embodiment, the remote control device 1 has two piezoelectric sensors 9, as shown in Fig. 6, each piezoelectric sensor 9 comprises a plurality of thin layers of piezoelectric material 62, which are laminated together But connected in series. Preferably, the piezoelectric sensor comprises multiple layers of thin piezoelectric lead-free ceramics. The multiple layers of piezoelectric material 62 are referred to as piezoelectric multilayers. The purpose of using the piezoelectric multilayer is to reduce the impedance of the piezoelectric sensor 9 and to increase the energy generation efficiency. Since the lower impedance improves the impedance matching between the power generation unit 2 and the electrical energy storage device 3 , the generated energy will also be more efficiently transmitted to the electrical energy storage device 3 . In order to significantly reduce the impedance of the piezoelectric multilayer sensor, the thin piezoelectric layer needs to have a thickness preferably below 100 μm, and the multilayer should consist of at least 5 layers, preferably more than 10 layers, of the layered piezoelectric material 62 . Piezoelectric ceramic multilayers can be formed by co-firing of ceramic metals (as electrode layers) well known in the art. The ceramic-metal multilayer can be formed by a ceramic tape-casting process before co-firing at high temperature, followed by alternate lamination of ceramic tapes with printed electrodes. Then, the electrodes are crossed and the odd layers are connected to a common, while all the even layers are connected to a second common. Accordingly, the respective piezoelectric layers are mechanically laminated in series while being electrically connected in parallel. Due to this construction, the impedance of the piezoelectric energy sensor can be reduced.

In general, the smaller the thickness of the piezoelectric material and the greater the number of piezoelectric layers, the more the sensor's impedance and voltage output are reduced. When the thickness of the piezoelectric ceramic layer is in the millimeter or submillimeter range, the voltage generated by one collision can be about 100V. But by using multiple piezoelectric layers, each with a layer thickness in the range of 10 μm, the output voltage can be reduced to only a few volts, but the voltage and current characteristics are significantly improved. Therefore, when multiple piezoelectric layers are used, a step-down transformer as shown in Fig. 2 and Fig. 4 is not necessary. As shown in FIG. 7 , the multilayer piezoelectric ceramic sensor can be directly connected to the electric energy storage capacitor 71 through a pair of rectifying diodes 72 .

Other embodiments:

It should be noted that in other embodiments the movable body 8 can be a ball, a cylinder, or a cylinder with two spherical convex surfaces 61 , as shown in FIG. 6 . Those skilled in the art will appreciate that the shape and mass of the movable body may be configured to maximize energy production efficiency within the physical constraints of the power generation unit 2 .

Experimental results:

Figure 8 shows two fabricated prototypes of the power generation unit of the invention. The fabrication unit is derived from Example 2. One of the generating units is presented assembled and the other unassembled. Also shown are two types of movable bodies, a stainless steel ball and a copper shot. In a test experiment, the energy harvested by the storage capacitor in an embodiment with only one piezoelectric sensor (as shown in FIG. 2 ) is shown in FIG. 9 . Each capacitor in the electrical energy storage device has a capacitance of 10 μF. A total of 400 μJ of energy is obtained in the storage capacitor. The energy harvested by the storage capacitor in an embodiment with two piezoelectric sensors (as shown in FIG. 4 ) is shown in FIG. 10 during various tests. In this example, a total of over 530 μJ of energy was obtained.

FIG. 11 is a graph of the results of numerical simulations showing the difference in energy generated by both flat and slightly curved KNN piezoelectric disks after a movable body collides. The results show that when using a curved KNN disk with a convex top surface 51 and a concave bottom surface 52 (as shown in FIG. 5 ), a KNN disk such as the piezoelectric sensor 9 shown in FIG. There are substantial improvements. This is because additional bending deformation modes are excited when bending piezoceramics are used.

Figure 12 shows the results of a numerical simulation comparing the energy generated by a piezoelectric sensor with a single KNN thick disk of 0.8mm thickness and a KNN multilayer piezoelectric sensor with 10 thin layers but the same total thickness. A load resistor of 300Ω was used in this test. Both multilayer piezoelectric sensors and single layer piezoelectric sensors generate the same energy at infinite resistance (open circuit). However, as shown in Figure 12, the efficiency of the multilayer piezoelectric sensor is significantly better when the finite load impedance is factored in. The simulation also shows that the spike voltage is reduced from ~200V for the single layer piezoelectric sensor to ~20V for the multilayer piezoelectric sensor. As discussed above, multilayer piezoelectric sensors have reduced impedance, which provides a better impedance match to the load. Additionally, the lower output voltage of the multilayer piezoelectric sensor eliminates the need for a step-down transformer.

Claims (22)

1. A self-powered remote control device, comprising: a power generating unit, wherein the power generating unit includes a housing and a movable body confined within the housing, the movable body being configured to move relative to the housing when the housing is driven by user action, the first The piezoelectric energy sensor includes a piezoelectric material attached to the housing and configured to be struck by the movable body, by collision between the movable body and the first piezoelectric energy sensor, from the The kinetic energy of the movable body produces electrical energy; an electrical energy storage device for receiving energy from said generating unit; an input device, configured to receive a manual input of a user operation; a control unit for performing an encoding operation to generate an output based on said manual input; and a wireless signal transmitter powered by the electrical energy storage device and configured to transmit a signal based on the output; Wherein, the relative movement between the movable body and the housing is generated by the user shaking the remote control device. 2. The device according to claim 1, wherein the movable body is connected to one end of the housing by an elastic material for urging the movable body toward the first piezoelectric energy sensor; When the movable body starts to squeeze the first piezoelectric energy sensor, shaking the remote control device causes the elastic material to deform and store elastic energy, and when the movable body moves toward the first piezoelectric energy sensor The elastic energy is converted into the kinetic energy of the movable body to generate electrical energy when it hits the first piezoelectric energy sensor. 3. The device of claim 2, wherein the resilient material is a spring. 4. The device of claim 1, wherein a second piezoelectric energy sensor is attached to the housing, the second piezoelectric energy sensor configured to be struck by the movable body, by means of the movable body The impact between the movable body and the second piezoelectric energy sensor generates electrical energy from the kinetic energy of the movable body. 5. The device of any preceding claim, wherein the first piezoelectric energy sensor has a convex top surface and a concave bottom surface, wherein the convex top surface is adapted to be struck by the movable body. 6. The device of claim 5, wherein the concave bottom surface of the first piezoelectric energy sensor is bonded to the housing with an adhesive layer. 7. The device of claim 1, wherein the first piezoelectric energy sensor comprises multiple layers of the piezoelectric material. 8. The device of claim 7, wherein the first piezoelectric energy sensor comprises a plurality of piezoelectric ceramic layers. 9. The device of claim 7, wherein the first piezoelectric energy sensor comprises a plurality of piezoelectric polymer layers. 10. The device of claim 7, wherein each layer of piezoelectric material has a thickness below 100 μm. 11. The device of claim 1, wherein the first piezoelectric energy sensor is subjected to compressive stress in a plane perpendicular to the direction in which the movable body strikes the first piezoelectric energy sensor. 12. The device of claim 11, wherein the compressive stress on the first piezoelectric energy sensor is created by an adhesive material surrounding the first piezoelectric energy sensor. 13. The device of claim 1, further comprising a protective layer disposed on a surface of the first piezoelectric energy sensor. 14. The apparatus of claim 1, further comprising a step-down transformer connected to the output of the power generating unit. 15. The device of claim 1, wherein the electrical energy storage device comprises a plurality of diodes and a plurality of capacitors, at least one capacitor of the plurality of capacitors is configured to accumulate charge during the forward direction of the charging current while the At least one capacitor of the plurality of capacitors accumulates charge during a negative phase of the charging current, and the plurality of capacitors is configured to continuously discharge the charge. 16. The device of claim 1, further comprising a voltage regulation unit connected to the electrical energy storage device. 17. The apparatus of claim 16, wherein the voltage regulation unit comprises a voltage monitor component, a switch component, and a voltage regulator component. 18. The device of claim 1, wherein the wireless signal transmitter is a radio frequency transmitter. 19. The device of claim 1, wherein the wireless signal transmitter is an infrared transmitter. 20. The device of claim 1, wherein the piezoelectric material is a lead-free piezoelectric ceramic. 21. The device according to claim 20, wherein the lead-free piezoelectric ceramic has a composition of (1-x) K _0.5 Na _0.5 NbO ₃ -x LiNbO ₃ , where x=0 to 0.1. 22. The device of claim 20, wherein the lead-free piezoelectric ceramic has a composition of Ba _0.85 Ca _0.15 Zr _0.1 Ti _0.9 O ₃ (BCZT).