Universal mobile keyboard

Abstract

A versatile and mobile keyboard and a highly energy efficient keyboard scanning method are provided. The keyboard may be used with a variety of mobile devices such as PDAs, cellular phones, and tablet PCs, through various interfaces such as an IR, USB, or Bluetooth™ interface. In particular, an IR head assembly is provided that includes an IR head, a movable arm on which the IR head is mounted, and a connector for attaching to a docking structure. The docking structure may be attached to a keypad, which is electrically coupled to the IR head for transmitting keystroke data through the IR head. When a mobile device is docked on the docking structure, the arm in the IR assembly may be moved to an optimal distance from the IR port of the mobile device to ensure high communication performance between the keyboard and the mobile device. An energy efficient keyboard scanning method utilizes higher-valued pull-up resistors for energy conservation. The keyboard scanning method includes a charging step to charge stray capacitance associated with the keys. The keyboard scanning method can also be operated at a variable scanning frequency.

Description

REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional of U.S. application Ser. No. 10 / 277,462 filed Oct. 21, 2002, the contents of which are incorporated herein by reference for all purposes.BACKGROUND OF THE INVENTION [0002] 1. Field of Invention [0003] The present invention generally relates to keyboards for mobile devices. More particularly, the present invention relates to a universal mobile keyboard including an infrared interface and an energy-efficient keyboard scanning method. [0004] 2. Discussion of the Related Art [0005] Personal digital assistants (PDAs) have become more popular and affordable with improved technology, allowing for enhanced display quality, color richness, contrast, processing speed, power efficiency, memory capacity, RF communication capability, and other desirable characteristics. Similar advances are also made in other mobile devices, such as cellular phones, smart phones (PDA plus cellular handset), industrial data terminals, and t...

AI Technical Summary

Benefits of technology

[0011] The present invention provides a universal keyboard that includes multiple interfaces for operability with a variety of mobile devices, such as PDAs, smart telephones, and cellular telephones. Furthermore, a highly energy-efficient method for scanning a keyboard is provided.

[0014] According to another embodiment of the present invention, a method for a low-power operation of a keyboard provides a micro-controller having output pins and input pins, wherein each key of the universal keyboard is coupled to both a designated output pin and a designated input pin, providing each input pin a pull-up resistor operably coupled to a voltage source. The pull-up resistor has a value between about 1 mega-ohm and about 100 mega-ohms to decrease power consumption. To operate this universal keyboard, a selected output pin is placed at a first voltage level, for example ground voltage level, and each input pin is then sensed to determine if a selected one of the keys associated with the selected output pin and one of the input pins is depressed. If the key is depressed, the output pin corresponding to the selected key is driven to a second voltage level, for example power source voltage level, to recharge the stray capacitance associated with the output pin and the selected input pin. After recharging, the output pin is put in high-impedance state and depends on the pull-up resister to maintain the voltage level.

[0015] The present invention allows for great flexibility in transmitting data to an IR port located at any of many positions on a mobile device while also providing a highly energy efficient keyboard scanning method.

[0016] According to another aspect of the present invention, a method is provided whereby the software driver for operating the keyboard is downloaded from a storage medium in the keyboard to a mobile device, according to the make and model of the program device, without having to place the mobile device in a cradle or a docking device attached to a desktop computer or a notebook computer.

Problems solved by technology

Some mobile devices offer touch-sensitive LCD screens with built-in recognition software for data input by handwriting or “graffiti.” However, data input using graffiti is not convenient or efficient unless the user is properly trained in the method.

Even then, data input using graffiti is not usually as fast as using a keyboard.

However, these input means are less efficient than small foldable keyboards that connect to the mobile device, such as a PDA, and offer the familiar desktop / notebook keyboard input style.

Such a connector often lacks stability.

However, these changeable connector heads achieve only limited flexibility, given the many connector types that are used among mobile devices.

However, typical infrared (IR)-based keyboards in the prior art suffer from several disadvantages.

Such a polished metal reflector is awkward to adjust and difficult to keep steady.

Thus, battery energy is inefficiently used, resulting in a shorter battery life or requiring a larger number of batteries (e.g., from 1 to 3 AAA batteries) or a higher battery capacity.

In addition, a stronger than required IR beam intensity may also in some instances overwhelm or “blind” the IR receiver circuitry in a mobile device IR port, causing data error or a sluggish response.

A reflector-based IR beam guidance scheme has limited flexibility in aligning to IR ports, as the IR port may be found in any of a variety of possible locations on a mobile device.

Images