Projection keyboard
Encyclopedia
Input device
In computing, an input device is any peripheral used to provide data and control signals to an information processing system such as a computer or other information appliance...
whereby the image of a virtual keyboard
Virtual keyboard
A virtual keyboard is a software component that allows a user to enter characters. A virtual keyboard can usually be operated with multiple input devices, which may include a touchscreen, an actual keyboard and a computer mouse.- Types :...
is projected onto surface: when a user's fingers are placed on the projected "keys", the device translates them into keystrokes.
History
An optical virtual keyboard was invented and patented by IBMIBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
engineers in 1992. It optically detects and analyses human hand and finger motions and interprets them as operations on a physically non-existent input device like a surface having painted or projected keys. In that way it allows to emulate unlimited types of manually operated input devices (such as a mouse, keyboard, and other devices). All mechanical input units can be replaced by such virtual devices, optimized for the current application and for the user's physiology maintaining speed, simplicity and unambiguity of manual data input.
In 2002, the start-up company Canesta developed a projection keyboard using their proprietary "electronic perception technology". The company subsequently licensed the technology to Celluon of Korea.
A proposed system called the P-ISM will combine the technology with a small video projector
Video projector
A video projector is an image projector that receives a video signal and projects the corresponding image on a projection screen using a lens system. All video projectors use a very bright light to project the image, and most modern ones can correct any curves, blurriness, and other...
to create a portable computer the size of a fountain pen
Fountain pen
A fountain pen is a nib pen that, unlike its predecessor the dip pen, contains an internal reservoir of water-based liquid ink. The pen draws ink from the reservoir through a feed to the nib and deposits it on paper via a combination of gravity and capillary action...
.
Design
A projection keyboard generally works by:- A laserLaser video projectorA laser video projector is a video projector that modulates a laser beam in order to project a raster-based image. The systems work either by scanning the entire picture a dot at a time and modulating the laser directly at high frequency, much like the electron beams in a CRT, or by optically...
or beamerVideo projectorA video projector is an image projector that receives a video signal and projects the corresponding image on a projection screen using a lens system. All video projectors use a very bright light to project the image, and most modern ones can correct any curves, blurriness, and other...
projects visible virtual keyboard onto level surface - A sensor or camera in the projector picks up finger movements
- detected co-ordinates determine actions or characters to be generated
Some devices use a second (invisible infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
) beam:
- An invisible infraredInfraredInfrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
beam is projected above the virtual keyboard - Finger makes keystroke on virtual keyboard. This breaks infrared beam and infrared light is reflected back to projector
- Reflected infrared beam passes through infrared filter to camera
- Camera photographs angle of incoming infrared light
- Sensor chip determines where infrared beam was broken
- detected coordinates determine actions or characters to be generated
The laser keyboards use laser and infra-red technology to create the virtual keyboard and to project the hologram of a keyboard on a flat surface.
The projection is realized in four main steps and via three modules: projection module, sensor
Sensor
A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. For example, a mercury-in-glass thermometer converts the measured temperature into expansion and contraction of a liquid which can be read on a calibrated...
module and illumination module. The main devices and technologies used to project the hologram are a diffractive optical element, red laser diode
Diode
In electronics, a diode is a type of two-terminal electronic component with a nonlinear current–voltage characteristic. A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material connected to two electrical terminals...
, CMOS camera and sensor chip and an infrared (IR) laser diode.
Template projection (Projection module): A template produced by a specially designed and highly efficient holographic element with a red diode laser is projected onto the adjacent interface surface. The template is not however involved in the detection process and it is only used as a reference for the user. In a fixed environment, the template can just as easily be printed onto the interface surface.
Reference plane illumination (Micro-illumination ModuleTM): An infra-red plane of light is generated on the interface surface. The plane is however situated just above and parallel to the surface. The light is invisible to the user and hovers a few millimeters above the surface. When a key position is touched on the surface interface, the light is reflected from the infra-red plane in the vicinity of the key and directed towards the sensor module.
Map reflection coordinates (Sensor Module): The reflected light user interactions with the interface surface is passed through an infra-red filter and imaged on to a CMOS
CMOS
Complementary metal–oxide–semiconductor is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits...
image sensor in the sensor module. The sensor chip has a custom hardware embedded such as the Virtual Interface Processing CoreTM and it is capable of making a real-time determination of the location from where the light was reflected. The processing core may track not only one, but multiple light reflections at the same time and it can support multiple keystrokes and overlapping cursor control inputs.
Interpretation and communication (Sensor module): The micro-controller in the sensor module receives the positional information corresponding to the light flashes from the sensor processing core, interprets the events and then communicates them through the appropriate interface to external devices. By events it is understood any key stroke, mouse or touchpad
Touchpad
A touchpad is a pointing device featuring a tactile sensor, a specialized surface that can translate the motion and position of a user's fingers to a relative position on screen. Touch pads are a common feature of laptop computers, and they are also used as a substitute for a mouse where desk...
control.
Most projection keyboards use a red diode laser as a light source and may project a full size QWERTY
QWERTY
QWERTY is the most common modern-day keyboard layout. The name comes from the first six letters appearing in the topleft letter row of the keyboard, read left to right: Q-W-E-R-T-Y. The QWERTY design is based on a layout created for the Sholes and Glidden typewriter and sold to Remington in the...
layout keyboard. The project keyboard size is usually 295 mm x 95 mm and it is projected at a distance of 60 mm from the virtual keyboard unit. The projection keyboard may detect up to 400 characters per minute and it may be connected by using either USB ports or Bluetooth.
The projection keyboard unit works on lithium-ion batteries and it has a capacity of at least 120 minutes of continuous typing. The projection unit sizes vary on the manufacturer but normally it is not bigger than 35 mm x 92 mm x 25 mm.
Connectivity
Projection keyboards connect to the devices they are used for either through BluetoothBluetooth
Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances from fixed and mobile devices, creating personal area networks with high levels of security...
or USB.
The Bluetooth projection keyboard is a wireless
Wireless
Wireless telecommunications is the transfer of information between two or more points that are not physically connected. Distances can be short, such as a few meters for television remote control, or as far as thousands or even millions of kilometers for deep-space radio communications...
virtual keyboard, a pocket-size device that projects a full-size keyboard through infrared technology onto any flat surface.
Bluetooth dongle technology enables the projection keyboard for point to multi-point friendly connectivity with other Bluetooth devices, such as PCs, PDA
PDA
A PDA is most commonly a Personal digital assistant, also known as a Personal data assistant, a mobile electronic device.PDA may also refer to:In science, medicine and technology:...
s and mobile phone
Mobile phone
A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...
. Bluetooth is an open specification for wireless data transmission which operates on the globally available 2.4GHz radio frequency.
The way the Bluetooth projection keyboard is connected to a device varies depending on the specific laptop, phone or computer that the user intends to use it for. All the connectivity instructions normally come with the product and they basically consist in turning on the Bluetooth connection on one's device and then turning on the keyboard.
The USB projection keyboard works like a regular USB keyboard. The connection between the virtual keyboard and the device is made through a USB port
Computer port (hardware)
In computer hardware, a port serves as an interface between the computer and other computers or peripheral devices. Physically, a port is a specialized outlet on a piece of equipment to which a plug or cable connects...
, which is available on every computer, laptop and other devices that are compatible with the projection keyboard. Connection instructions come as well with the product and with the manufacturer's specifications but it mainly consists in Plug and Play the devices.