FIELD OF THE INVENTION

[001] The present invention relates, in general, to controlling electrical devices and, in particular, to a control device for controlling electrical devices.

BACKGROUND OF THE INVENTION

[002] Typically, to control an electrical device, a control device specific to the electrical device is utilized. For example, to control the speed of a ceiling fan, a regulator may be utilized. Similarly, to control the temperature setting of an air- conditioner (AC), a remote control device may be utilized. Since a separate control mechanism has to be used for each electrical device, the number of control devices in a location such as a room, having several electrical devices may be large, making it inconvenient to install and operate multiple electrical devices.

[003] In case a centralized control panel is used, for example, to control LED lights, fans, air conditioners, and smart sockets in a location, a bigger panel size mounted with multiple switches and regulators is required to be able to control the different electrical devices.

[004] In some conventional techniques, a smart panel having an LCD display and a touchscreen based input for selecting and controlling electrical devices is used to control the multiple electrical devices. Such a smart panel is quite expensive due to the LCD and touch components.

[005] Accordingly, there is need for a control device that can be used to control multiple electrical devices, which is economic, compact, and simple to operate. SUMMARY OF THE INVENTION

[006] Various aspects of the present invention relates in general to control devices and methods for controlling electrical devices. The control devices and methods of the present invention can be used for controlling a plurality of electrical devices in, for example, a house, an office, or any other establishment.

[007] A control device in accordance with various aspects of the present invention is economic, compact, and simple to operate. Also, with the same control device, it is possible to control powering on/off of different electrical devices and to regulate the levels of operating parameters of the corresponding electrical devices. The different electrical devices that can be controlled include, but are not limited to, light emitting diode (LED) lights, fans, and air conditioners. Accordingly, the operating parameters can be, for example, fan speed, lamp brightness, temperature settings, and the like.

[008] In an implementation, the control device includes a controller and two or more coaxial knobs operably connected with the controller. The two or more coaxial knobs include a first knob rotatable about an axis of the two or more coaxial knobs for providing a first input to the controller, and a second knob rotatable about the axis of the two or more coaxial knobs for providing a second input to the controller.

[009] In one implementation, the first input is obtained in response to rotating the first knob to a position selected from a plurality of predetermined positions. Here, each predetermined position of the plurality of predetermined positions is associated with a corresponding electrical device of the plurality of electrical devices. In accordance with the implementation, the second input is obtained in response to rotating the second knob in one of a clockwise and an anticlockwise direction. Here, rotating the second knob in the clockwise direction increases a magnitude of the corresponding operating parameter, and rotating the second knob in the anticlockwise direction decreases the magnitude of the corresponding operating parameter. [0010] The controller determines an electrical device to be controlled based on the first input, and modifies an operating parameter of the electrical device based on the second input. The control device can further include a memory for retaining a state of each electrical device and the controller can modify the operating parameter of the electrical device to be controlled based on the state of the electrical device retained in the memory.

[0011] In one implementation, the two or more coaxial knobs include a third knob with a push button that can provide a third input to the controller to toggle a state of the electrical device (between on and off) to be controlled. The control device may also have a display for rendering one or more of the electrical device to be controlled, the operating parameter of the electrical device to be modified and a present level of the operating parameter.

BRIEF DESCRIPTION OF DRAWINGS

[0012] Various features, aspects, and advantages of the present invention will be explained in more detail in the following description, with reference to exemplary embodiments that are illustrated in the accompanying figures in which:

[0013] Fig. 1 illustrates a control device for controlling a plurality of electrical devices, in accordance with an implementation of the present invention;

[0014] Fig. 2(a) illustrates a front view of the control device, in accordance with an implementation of the present invention;

[0015] Fig. 2(b) illustrates a side view of the control device, in accordance with an implementation of the present invention; [0016] Fig. 3 is a simplified diagram of generating and providing inputs to a controller of the control device, in accordance with an implementation of the present invention;

[0017] Fig. 4 is a simplified diagram of control of a plurality of electrical devices by the controller of the control device, in accordance with an implementation of the present invention; and

[0018] Fig. 5 is a schematic of a control module for controlling an electrical device, in accordance with an implementation of the present invention.

DETAILED DESCRIPTION

[0019] Various features, aspects, and advantages of the invention will be better explained with regard to the following description, appended claims, and accompanying figures. It should be noted that the description and figures merely illustrate the principles of the present invention along with examples described herein and, should not be construed as a limitation to the present invention. It is thus understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and examples thereof, are intended to encompass equivalents thereof. Further, for the sake of simplicity, and without limitation, the same numbers are used throughout the drawings to reference like features and components.

[0020] Fig. 1 illustrates a control device 102 for controlling a plurality of electrical devices, in accordance with an implementation of the present invention. The control device 102 may be implemented in an environment 100, for example, a room, a house, an office, or any other building having a plurality of electrical devices. The plurality of electrical devices include, for example, a ceiling fan 104, an electric lamp 106, and an air-conditioner (AC) 108. Although the environment 100 is shown to have three electrical devices, the environment 100 may include any number of electrical devices.

[0021] The control device 102 includes two or more coaxial knobs, which can be utilized by a user 110 for controlling the plurality of electrical devices. The two or more coaxial knobs includes a first knob 112 rotatable about an axis (113) of the two or more coaxial knobs and a second knob 114 rotatable about the axis of the two or more coaxial knobs. In an example, as illustrated in Fig. 1, the second knob 114 may be mounted over the first knob 112. In another example, the first knob 112 may be mounted over the second knob 114.

[0022] The first knob 112 and the second knob 114 are operably connected to a controller 116 of the control device 102. The controller 116 can receive inputs generated upon rotation of the first and second knobs and can generate corresponding signals for controlling an electrical device. In an example, the controller 116 is a PIC 16F 1827 controller. However, it will be understood that the controller 116 can be any microcontroller, microprocessor, or the like.

[0023] In operation, a first input is provided to the controller 116 on rotation of the first knob 112 and a second input is provided to the controller 116 on rotation of the second knob 114. Based on the first input and the second input, the controller 116 determines an electrical device to be controlled and modifies an operating parameter of the electrical device to be controlled.

[0024] In an implementation, the electrical device to be controlled is determined based on the first input and the modification of the operating parameter is performed based on the second input. For this, the first knob 112 can be rotated to a position selected from a plurality of predetermined positions, each predetermined position being associated with a corresponding electrical device. As a result of the rotation of the first knob 112 to the selected position, the first input is generated indicating the selected electrical device. Further, the second knob 114 can be rotated in one of a clockwise and an anticlockwise direction to generate the second input. In one example, rotation of the second knob 114 in the clockwise direction may be used to increase a magnitude of the corresponding operating parameter, and rotation of the second knob 114 in the anticlockwise direction may be used to decrease the magnitude of the corresponding operating parameter.

[0025] The operating parameter of an electrical device refers to a parameter related to a function of the electrical device. For example, in the case of the ceiling fan 104, the operating parameter includes speed of the ceiling fan 104. In the case of the electric lamp 106, the operating parameter includes brightness of the electric lamp 106. Further, in the case of the AC 108, the operating parameter includes temperature of the AC, operating mode and/or fan speed of the AC 108.

[0026] The modification of the operating parameter refers to adjusting a level of the operating parameter of the electrical device. As mentioned above, the adjustment of the level of the operating parameter includes both increase and decrease in the level of the operating parameter. The level of the operating parameter may be expressed in different ways. For example, the level of the operating parameter includes magnitude of the operating parameter in absolute unit terms, such as 200 revolutions per minute (rpm) and 25° C. The level of the operating parameter may also refer to a percentage value of the operating parameter relative to another value of the operating parameter, such as 80% of the maximum brightness, and ratio value, such as 2/3rd of the rated speed.

[0027] In one example, to modify the speed of the fan 104, the user 110 can rotate the first knob 112 to select the fan 104 and then rotate the second knob 114 to modify the speed. Subsequently, to modify the brightness of the lamp 106, the user 110 can again rotate the first knob 112 to select the lamp 106 and then rotate the second knob 114 to modify the brightness. Therefore, the control of several electrical devices can be performed with ease by the user 110 using the control device 102. Example mechanisms for generation of inputs, determination of the electrical device to be controlled, and modification of the operating parameter are explained in greater detail hereinafter.

[0028] Fig. 2(a) illustrates the front view of the control device 102, in accordance with an implementation of the present invention. As illustrated in Fig. 2(a), in addition to the first knob 112 and the second knob 114, the two or more knobs can include a third knob 202. In one example, the third knob 202 can be mounted on the second knob 114 so that the second knob 114 is arranged between the first knob 112 and the third knob 202. The third knob 202 can have a push button for providing a third input to the controller 116 in response to a press and release of the push button. Based on the third input, the controller 116 can determine one of powering on and powering off of the electrical device to be controlled. Thus, the controller 116 can toggle a state of the electrical device to be controlled based on the third input. For example, in operation, the user 110 can rotate the first knob 112 to select the fan 104 and can then actuate the third knob 202 by pressing and releasing the push button. Accordingly, the controller 116 can toggle the fan 104 to an OFF state if it was previously ON or to an ON state if it was previously OFF.

[0029] In an implementation, a pin 204 may be attached to the first knob 112. The pin 204 indicates which electrical device has been selected to be controlled. In one implementation, the control device 102 may also include a display 206, which can be used to render one or more of the selected electrical device, the operating parameter of the electrical device to be controlled, and a present level of the operating parameter of the electrical device to be controlled. The display 206 may be, for example, a digital display, an LED display, or the like. In one example, the display 206 may be mounted on top of the two or more knobs. In other examples, the display 206 may be mounted in other locations, such as on the first knob 112 or on a panel to which the control device 102 may be fixed. In the example illustrated in Fig. 2(a), by looking at the display 206, the user 110 can discern that the electrical device selected to be controlled is the electric lamp 106 and its current brightness level is 80 percentage of its maximum brightness.

[0030] Fig. 2(b) illustrates the side view of the control device 102, in accordance with an implementation of the present invention. It can be understood from the side view that the first knob 112 and second knob 114 may be mounted coaxially. Therefore, the first knob 112 and the second knob can be rotated about the same axis. Further, if the third knob 202 is present in the control device 102, the third knob 202 can optionally be mounted coaxially to the first knob 112 and the second knob 114. In an implementation, the two or more knobs are mounted coaxially on a base plate (not shown). Each of the two or more knobs may be connected to the base plate by, for example, fasteners. Other connecting means can also be used to connect the two or more knobs to the base plate. The mounting of the two or more knobs on the base plate helps in coupling the two or more knobs as a single entity. Further, it makes the control device 102 compact and provides for easy handling of the two or more knobs by the user 110.

[0031] Fig. 3 is a simplified diagram of generating and providing inputs to the controller 116 of the control device 102, in accordance with an implementation of the present invention. As mentioned earlier, the first knob 112 can be rotated to a position selected from a plurality of positions for generation of the first input. In an example, the first knob 112 may have a smooth / continuous rotation, i.e., the first knob 112 is arranged to rotate continuously in response to a corresponding input from the user, and the first knob can be stopped at any position during its rotation to provide the corresponding input. In another example, the first knob 112 may have a latched rotation, i.e., the first knob 112 is arranged to be rotated in a stepped / staged manner between several positions. In other words, the first knob 112 in latched rotation, can be rotated by the user from one position to another (separated at least by a few angles), and the first knob stops only at the predetermined positions. The first input generated corresponding to each position of the first knob 112 can have a different value. In an implementation, the first input is a first voltage that is generated corresponding to a selected position (e.g. various positions of the first knob 112 can be mapped with various voltage levels, and different voltage levels / ranges can correspond to different devices).

[0032] In an implementation, to generate the first voltage corresponding to the rotation of the first knob 112, the control device 102 includes a first potentiometer 302. The first voltage may be obtained across the fixed contact and the sliding contact of the first potentiometer 302. In an example, when the first knob 112 is rotated clockwise to a first position, the sliding contact moves so that the resistance between the fixed contact and the sliding contact is Rl and the voltage drop between the fixed contact and the sliding contact is VI. In other words, when the first knob 112 is rotated to the first position, a first voltage of VI is generated. When the first knob 112 is rotated further clockwise, the resistance between the fixed contact and the sliding contact becomes R2, which can be greater than Rl, and the voltage drop across the resistance R2 becomes V2, which can be greater than VI. Thus, as the first knob 112 is rotated further in the clockwise direction, the value of the first voltage can increase and if the first knob 112 is rotated back in the anti -clockwise direction, the value of the first voltage can decrease. Based on the magnitude of the first voltage that is provided as the first input, the controller 116 can determine which electrical device has been selected to be controlled. Although the generation of the first voltage is explained with respect to a potentiometer circuit, it is to be understood that any mechanism that outputs a voltage corresponding to rotation of a knob can be utilized for generation of the first voltage. [0033] After rotation of the first knob 112 to a position corresponding to that electrical device, the user 110 can modify an operating parameter of that electrical device by rotating the second knob 114, which results in the generation of the second input. Alternately, the first knob 112 may already be at the desired position and only the second knob 114 is required to be operated. Based on the second input, the controller 116 can adjust the level of the operating parameter of the electrical device to be controlled. For this, in an example, the second knob 114 may be implemented as a suspension switch, which can be rotated in two directions - one in the clockwise direction and another in the anticlockwise direction. When the force exerted for rotating the second knob 114 is released, the second knob 114 snaps back to its rest or neutral position, which can be a center point.

[0034] In accordance with the abovementioned example, the rotation of the second knob 114 in the clockwise direction may correspond to an increase in the level of the operating parameter, and the rotation of the second knob 114 in the anti -clockwise direction may correspond to a decrease in the level of the operating parameter. The level of adjustment of the operating parameter may also be affected based on a duration for which the second knob 114 is held at a position. For example, when the second knob 114 is rotated from its rest position in a clockwise direction and held there for two seconds, the controller 116 may determine that the level of the operating parameter is to be increased by x units. Similarly, when the second knob 114 is rotated from its rest position to its clockwise position and held there for three seconds, the controller 116 may determine that the level of the operating parameter is to be increased by y units, where y is greater than x.

[0035] In an implementation, the second input is a second voltage generated upon rotation of the second knob 114. In order to generate the second voltage, the control device 102 may include a second potentiometer 304. Therefore, based on the second voltage and the time period for which it is received, the controller 116 can determine whether to increase or decrease the operating parameter and the level of increase or decrease of the operating parameter. Although the generation of the second voltage is explained with respect to a potentiometer, it is to be understood that any other type of voltage generation means may be used for generating the second voltage. Further, while the second knob 114 has been described as being implemented as a suspension switch, it can be implemented using other techniques also as will be easily understood in the art.

[0036] In addition to modifying the operating parameters, the control device 102 can be used to toggle the state of the electrical device by providing the third input from the third knob 202 to the controller 116 using, for example, a push button mechanism as discussed earlier. In another implementation, the second knob 114 itself can be used to switch the electrical device ON or OFF. For example, if the user 110 holds the second knob 114 in the active position in the anti-clockwise direction after the operating parameter has reached a zero level, the controller 116 may switch OFF the electrical device. Subsequently, when the user 110 moves the second knob 114 to the active position in the clockwise direction, the controller 116 may first switch ON the device and then modify the level of the operating parameter.

[0037] The arrangement of the two or more coaxial knobs as described above can also be used in a scenario where the electrical device to be controlled may have more than one operating parameter that can be modified by the user 110. For example, the AC 108 can have two operating parameters: temperature and fan speed. In this scenario, the various predetermined positions of the first knob 112 may correspond to a combination of the operating parameter and the electrical device to be controlled. For example, a first position of the first knob 112 may correspond to temperature of the AC 108, a the second position of the first knob 112 may correspond to the fan speed of the AC 108, while a third position may correspond to the brightness of the lamp 106. Therefore, the first knob 112 can be rotated to a position that corresponds to a selected operating parameter and electrical device to be controlled and the selected operating parameter can be then modified using the second knob 114.

[0038] Fig. 4 illustrates a block diagram for control of a plurality of electrical devices by the controller 116, in accordance with an implementation of the present invention. The plurality of electrical devices can include electrical device- 1, electrical device-2 ... electrical device-n. The controller 116 can receive the first input, the second input, and the third input, if the third knob 202 is present, and can determine control actions, such as modification of operating parameter and toggling of the state, to be performed.

[0039] The controller 116 determines an electrical device to be controlled based on the first input. For this, the controller 116 utilizes a memory (or storage component 402). The storage component 402 can be, for example, a non-volatile memory or the like. The storage component 402 stores a first table 404 having a mapping of first input values and electrical devices corresponding to the first input values. In an example, the information of the electrical devices may be stored in the first table 404 in the form of device identifiers (IDs), each of which corresponds to an electrical device. For example, the electrical device having the device ID 1 is the first electrical device, the electrical device having the device ID 2 is the first electrical device, and so on. When the first input, such as the first voltage, is received, the controller 116 compares the value of the first input against the mapping in the first table 404 to determine which electrical device is to be controlled. For example, when the controller 116 receives a first input of value 2.0, the controller 116 compares this value with the first table 404 to determine that the electrical device having device identifier (ID) 4 is to be controlled. It is to be understood that the values provided in the first table 404 are for illustrative purposes alone, and any other set of first input values may be used for determining the electrical device to be controlled. [0040] The first input values, in the first table 404, are shown to be stored in the form of single values. However, the first table 404 may store the first input in the form of a range of values as well. For example, a range of 0.4-0.6 can correspond to the device ID 1, a range of 0.9-1.1 can correspond to device ID 2, and so on. Hence, even in cases where the first input, generated corresponding to a position of the first knob 112, has some inaccuracies, the controller 116 can be used effectively.

[0041] Upon determination of the electrical device to be controlled, the controller 116 can determine a level of adjustment of the operating parameter of that electrical device or toggle the state of the electrical device depending on whether the second or the third input is received.

[0042] Considering the scenario where the controller 116 receives the second input, the determination of the level of adjustment of the operating parameter by the controller 116 will now be described, by way of example and not as limitation, in accordance with an implementation in which the second knob 114 is a suspension switch.

[0043] In one example, when the second knob 114 is rotated to the active position in the clockwise direction, the second voltage is generated as the second input. Based on the second voltage and the time period for which the second voltage is received, the controller 116 determines that the level of the operating parameter is to be increased and the extent of increase. Thereafter, the controller 116 generates a signal, hereinafter referred to as a first signal, based on the second input, indicating the extent to which the level of the operating parameter is to be adjusted. In an example, the first signal includes a plurality of bits. Each value of the first signal may correspond to a level of adjustment of the operating parameter.

[0044] The first signal is received by a control module or a communication module that corresponds to the electrical device to be controlled. For example, if the electrical device to be controlled is device 1 , then the first signal is received by the control module of device 1. Whereas, if the electrical device to be controlled is device 2, then the first signal is received by the communication module of device 2.

[0045] Whether an electrical device is controlled using a control module or a communication module depends on the type / connection of the electrical device. For example, if the operating parameter of the electrical device to be controlled can be controlled by adjusting the voltage supplied to it, such as the ceiling fan 104 and electric lamp 106, the first signal may be received by a control module that corresponds to that electrical device. However, if the electrical device to be controlled is to be controlled by communicating a control signal to the electrical device, such as the AC 108, the first signal is received by a communication module. In such a case, the control signal may be sent wirelessly from the communication module to the electrical device. The electrical device that can be controlled by communicating a control signal to the electrical device can be referred to as a smart electrical device.

[0046] Thus, the control device 102 can include a control module corresponding to each electrical device that can be controlled by adjusting its input voltage supply. For example, as illustrated in Fig. 4, the control device 102 includes a control module- Device 1 corresponding to the first electrical device and a control module-Device 3 corresponding to the third electrical device. The control module includes an electrical circuit that can adjust the voltage supplied to the electrical device to be controlled in response to the first signal. When the first signal indicates that the level of the operating parameter is to be increased, the control module increases the voltage supplied to that electrical device. The electrical circuit of the control module and the adjustment of the voltage by the electrical circuit based on the first signal is explained in detail later with respect to Fig. 5. [0047] As discussed above, the control device 102 also includes a respective communication module for controlling smart electrical devices. The communication module includes a transmitter that can transmit the first signal to the electrical device to be controlled. In an example, the communication module is a Bluetooth™ module, which can communicate the first signal to that electrical device through the Bluetooth™ standard. In other examples, the communication module can be a Wireless-Fidelity (Wi-Fi) module, which can communicate the first signal over a Wi- Fi network, or a power line communication (PLC) module, which can communicate the first signal over a power line. Other modes of communication that can communicate the first signal to the electrical device to be controlled can also be utilized by the communication module.

[0048] Since different smart electrical devices may communicate through different modes of communication, the control device 102 may include a plurality of communication modules, such as the communication module-device 2 and the communication module-device 6, which can communicate through various modes of communication. However, if all the smart electrical devices to be controlled by the control device 102 communicate through the same mode of communication, the control device 102 may include a single communication module corresponding to that mode of communication. The operation of the smart electrical device to control its operating parameter based on the signal received by it is well known in the art, and is not explained herein for the sake of brevity. In an implementation, the mode of communication for each smart electrical device is stored in the storage component 402. The controller 116 can utilize the mode of communication information for sending the first signal to the electrical device to be controlled.

[0049] In an implementation, the adjustment of the level of the operating parameter is rendered on the display 206. Therefore, the user 110, when rotating the second knob 114, can get a visual feedback of the adjustment of the level of the operating parameter, and can stop rotating the second knob 114 when the display 206 indicates the level to which the user 110 desires to adjust the operating parameter. The display 206 can also display the electrical device to be controlled on rotation of the first knob 112. For example, when the user 110 rotates the first knob 112 to its first position, the display 206 may display T, indicating the device ID of the first electrical device, the name of the electrical device, such as 'fan', 'lamp', or 'AC, or a symbol indicating the electrical device, such as a lamp symbol shown in Fig. 2(a).

[0050] In an implementation, to generate the first signal corresponding to the second input for adjusting the level of the operating parameter, the controller 116 can store a state and present level of operating parameter of each electrical device in the storage component 402. For example, the controller 116 utilizes a second table 406, for storing present levels of the operating parameters of each electrical device and a third table 408 for storing a state of each electrical device. The controller 116 can determine a target value of the level of the operating parameter based on the state, the present level of the operating parameter, and the second input, which indicates the level by which the operating parameter is to be adjusted (increased or decreased). The controller 116 can then update the level of the operating parameter in the second table 406 to the target value. The controller 116 may generate the first signal based on the updated value of the level of the operating parameter retrieved from the second table 406, to adjust the present level of the operating parameter to the target value.

[0051] The above explanation describes the determination of the target level of the operating parameter when the second knob 114 is a suspension switch. As explained earlier, the second knob 114 can be a knob that can be rotated to a plurality of positions from its rest position, and the value of the second input generated corresponds to the position to which the knob is rotated. If the second knob 114 can be rotated to a plurality of positions, in an example, the controller 116 can adjust the present level of the operating parameter of the electrical device to be controlled based on the value of the second input generated. For example, if the second knob 114 is rotated from its rest position to its first clockwise position, based on the corresponding value of the second input generated, the controller 116 may determine that the value of the operating parameter is to be incremented by 2 units, and if the second knob 114 is rotated from its rest position to its first anti-clockwise position, based on the corresponding value of the second input generated, the controller 116 may determine that the value of the operating parameter is to be decremented by 4 units. Accordingly, the controller 116 can update the second table 406 and generate the first signal, for communicating to the control module corresponding to the electrical device or to the communication module.

[0052] Further, if the controller 116 receives the third input to toggle the state of the electrical device to be controlled, the controller 116 can determine the present state of the electrical device, i.e., whether the electrical device is presently on or off utilizing the third table 408. Similar to the first table 404 and the second table 406, the third table 408 may be stored in the storage component 402, as illustrated in Fig. 4.

[0053] Upon determination of the present state of the electrical device to be controlled, the controller 116 can toggle the state of that electrical device. For this, the controller 116 can utilize the control module or communication module corresponding to the electrical device. In one example, the controller 116 communicates a second signal to the control module corresponding to the electrical device, for toggling the state of the electrical device. The toggling of the state of the electrical device by the control module based on the second signal is explained in detail later with reference to Fig. 5. If the electrical device to be controlled is a smart device, the controller 116 can communicate the second signal to the smart device through the communication module. For example, if the present state of the electrical device is off, the second signal may be a power on signal to the electrical device. The toggled state of the electrical device to be controlled may be updated in the third table 408, so that the updated values of states of the electrical devices are stored in the third table 408. In an implementation, the second signal is generated based on the updated value of the state stored in the third table 408.

[0054] Fig. 5 is a schematic of a control module for controlling an electrical device, in accordance with an implementation of the present invention. The control module 500 includes a regulator 502, which receives the first signal from the controller 116. The regulator 502 can include a relay and a TRIAC based control circuit.

[0055] In operation, the controller 116 may communicate the first signal to the regulator 502 over an inter-IC (I2C) bus. The first signal is received by a digital potentiometer 504 of the regulator 502. The regulator 502 receives an input voltage supply as its input and adjusts the voltage supplied to the electrical device based on the first signal. As will be understood, the input voltage supply can be an alternating current voltage supply. The digital potentiometer 504 can be, for example, a DS1868 digital potentiometer. The digital potentiometer 504 includes a plurality of resistances and a tap point between each consecutive pair of resistances. The tap points are accessible to a wiper of the digital potentiometer 504. Based on the first signal received, the position of the wiper changes, thereby varying the resistance offered by the digital potentiometer 504. The wiper may move, for example, forward-backward, up-down, left-right, or any other direction based on the first signal for increasing or decreasing the resistance offered by the digital potentiometer 504. The extent to which the wiper may move in a direction depends on the first signal. Therefore, depending on the first signal, which indicates the extent to which the level of the operating parameter is to be adjusted, the resistance offered by the digital potentiometer 504 is adjusted.

[0056] The variation in the resistance offered by the digital potentiometer 504 causes a variation in the voltage drop across the digital potentiometer 504. For example, when the resistance offered by the digital potentiometer 504 is higher, the voltage drop across the digital potentiometer 504 is higher, and vice versa. [0057] In one implementation, the digital potentiometer 504 is connected to gate terminal of a triac 506 through a diac 508. A capacitor 510 is connected across the gate terminal of the triac 506. The rate at which the voltage across the capacitor 510 builds up determines when the voltage across the triac 506 exceeds its threshold value and, therefore, when the triac 506 switches on. When the voltage across the capacitor 510 builds up rapidly, the triac 506 switches on at an earlier instance during a half cycle of the input voltage supply. Therefore, a greater amount of the input voltage is provided to the electrical device. In contrast, when the voltage across the capacitor 510 builds up slowly, the triac 506 switches on at a later instance during the half cycle of the input voltage supply. Therefore, a lesser amount of the input voltage is provided to the electrical device.

[0058] The variation of the resistance of the digital potentiometer 504 adjusts the rate of building up of voltage across the capacitor 510; higher the value of the resistance offered by the digital potentiometer 504, slower is the rate of building up of voltage across the capacitor 510, and vice versa. Therefore, the adjustment of the resistance offered by the digital potentiometer 504 controls when the triac 506 is turned on and off and, in turn, the amount of the input voltage supply provided to the electrical device.

[0059] In order to decrease the level of the operating parameter of the electrical device to be controlled, the controller 116 generates the first input signal that will cause the wiper of the digital potentiometer 504 to move to adjust the resistance of the digital potentiometer 504. If the extent to which the operating parameter is to be adjusted is greater, the first signal causes greater displacement of the wiper from its original position, thereby adjusting the resistance offered by the digital potentiometer 504 to a greater extent. In an example, for the duration the second knob 114 is held at a position, initially, the first signal may vary slowly, but later, the first signal may vary rapidly. Therefore, the adjustment of the resistance of the digital potentiometer 504 is slow initially, and rapid later. This enables achievement of the target level of the operating parameter in a lesser time. For example, the temperature setting of the AC 108 may increase from its present value, say, 18° C to 20° C slowly, from 20° C to 24° C a little faster, and from 24° C to 28° C even faster.

[0060] The control module 500 may also include a control relay 512, if the third knob 202 is present, for toggling the state of the electrical device to be controlled. The control relay 512 receives the second signal from the controller 116. Based on the second signal, the control relay 512 switches on or off. If the control relay 512 switches off, the input voltage supply is disconnected from the electrical device to be controlled, thereby switching off that electrical device. If the control relay 512 switches on, the input voltage supply is connected to the electrical device to be controlled, thereby switching on that electrical device.

[0061] It should be apparent that the control device and / or components thereof, need not be limited to the examples illustrated / described using the abovementioned figures. For example, the control device may have varying number of knobs than those shown in the figures - four, five etc. With such a configuration, desired functionality may be enabled for different knobs. Also, different knobs may be utilized differently. For instance, in Fig. 1 and in various examples provided above, it is depicted that the first knob 112 is the positioned as the initial knob and used to select an electrical device / operating parameter, the first knob may be used for other function (e.g. level selection). Such variations in functions of the knobs will be readily apparent to those skilled in the art. Also, the input from each knob may be detected in different ways. For instance, a mechanical movement / position may be sensed in response to user input for determining corresponding knob inputs.

[0062] Thus, as has been discussed above, the control device can be implemented in a cost effective manner using simple mechanical, electromechanical and electronic components for controlling a plurality of electrical devices. With the control device and methods of the present invention, the requirement of several control devices, one for each electrical device, is eliminated. Since the control device has simple construction with minimal components, the control device is compact, cost effective, easy to install and configure, and user friendly. Further, the control device can also be retrofitted in a location having multiple electrical devices.

[0063] Although the present invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternate embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention.