3. cad input devices assoc.prof.dr. ahmet zafer Şenalp mechanical engineering department gebze...
DESCRIPTION
Input Devices Keyboard CD-ROM DVD-ROM Tablet/digitizer Scanner Mouse Trackball Light pen Touchpad Touchscreen Kontrol dials or knobs Function switches Joystick Voice input 3D Data Acquisition Systems Dr. Ahmet Zafer Şenalp ME 521 3Mechanical Engineering Department, GTU 3. CAD Input DevicesTRANSCRIPT
3. CAD Input Devices
Assoc.Prof.Dr. Ahmet Zafer Şenalpe-mail: [email protected]
Mechanical Engineering DepartmentGebze Technical University
ME 521Computer Aided Design
Hardware of a CAD System
Input/Output Devices
Graphical Input
Alpha Numeric Input
Graphical Output
Alpha Numeric Output
Computer(CAD Workstation,
Computer Terminal,Micro computer)
Dr. Ahmet Zafer Şenalp ME 521 2Mechanical Engineering Department, GTU
3. CAD Input Devices
Input Devices
KeyboardCD-ROMDVD-ROMTablet/digitizerScannerMouseTrackballLight penTouchpadTouchscreenKontrol dials or knobsFunction switchesJoystickVoice input3D Data Acquisition Systems
Dr. Ahmet Zafer Şenalp ME 521 3Mechanical Engineering Department, GTU
3. CAD Input Devices
Conventional keyboards are text only devices. Keyboards are the essential and basic input devices for all computer applications. They are typically employed to create & edit programs or to perform word processing functions. A typical keyboard is shown in the above figure. It is divided into four different areas
• The first area " (A) " is for normal typewriting when entering text strings. • The second one " (B) " is the function key area for simplified handling of common operations. • The third area " (C) " is composed by seperate cursor and control keys. This area presents several different
configurations depending on the supplier of the keyboard, including arrows, thumbwheels etc • The fourth area " (D) " is the numeric keyboard for fast numerical digit input.
Working principals of keyboards are simple. A keyboard has typically two registers whose contents can be read by the computer, one to set a status bit when a key has been struck the other to identify the key by its character code.The value of the status bit is monitored in a continuous repetitive manner. When the user hits a key, the status bit is set and application program is consequently interrupted to clear the status bit, followed by reading the corresponding code of the key character. The loop is repeated every time the user strikes a key.
Keyboard
Dr. Ahmet Zafer Şenalp ME 521 4Mechanical Engineering Department, GTU
3. CAD Input Devices
is a pre-pressed optical compact disc which contains data. The name stands for "Compact Disc Read-Only Memory". Computers can read CD-ROMs, but cannot write to CD-ROMs which are not writable or erasable.
A CD-ROM drive reads digital data (whether computer data or audio) from a spinning disk by focusing a laser on the disk’s surface. Data is storage in the form of lands, which are flat areas on the metal surface, and pits, which are depressions or hollows.
A standard compact disk can store 650 MB of data or about 70 minutes of audio.
CD-ROM
Dr. Ahmet Zafer Şenalp ME 521 5Mechanical Engineering Department, GTU
3. CAD Input Devices
Many of today’s new PCs feature a built-in Digital Versatile Disc-read-only memory (DVD-ROM) drive rather than a standard CD-ROM drive. DVD-ROM is a high- density medium capable of storing a full-length movie on a single disk the size of a CD.
Pre-recorded DVDs are mass-produced using molding machines that physically stamp data onto the DVD. Such discs are known as DVD-ROM, because data can only be read and not written or erased.
Blank recordable DVD discs (DVD-R and DVD+R) can be recorded once using a DVD recorder and then function as a DVD-ROM. Rewritable DVDs (DVD-RW, DVD+RW, and DVD-RAM) can be recorded and erased many times.
DVD-ROM
Dr. Ahmet Zafer Şenalp ME 521 6Mechanical Engineering Department, GTU
3. CAD Input Devices
Tablet is a computer input device that allows one to hand-draw images and graphics, similar to the way one draws images with a pencil and paper. These tablets may also be used to capture data or handwritten signatures. It can also be used to trace an image from a piece of paper which is taped or otherwise secured to the surface. Capturing data in this way, either by tracing or entering the corners of linear poly-lines or shapes is called digitizing.
A graphics tablet (also called pen pad or digitizer) consists of a flat surface upon which the user may "draw" or trace an image using an attached stylus, a pen-like drawing apparatus. The image generally does not appear on the tablet itself but, rather, is displayed on the computer monitor. Some tablets however, come as a functioning secondary computer screen that you can interact with directly using the stylus.
Some tablets are intended as a general replacement for a mouse as the primary pointing and navigation device for desktop computers.
Tablet/digitizer
Dr. Ahmet Zafer Şenalp ME 521 7Mechanical Engineering Department, GTU
3. CAD Input Devices
Tablet/digitizer
Dr. Ahmet Zafer Şenalp ME 521 8Mechanical Engineering Department, GTU
3. CAD Input Devices
Tablet types:Some of them use magnetic field to determine x,y coordinates.Some of them use strain wave.Acoustic tablets use acoustic methods. Microphones are placed in x,y,z axis. Pointer will point to the end of a certain frequency ranges. Microphones recieve this sound and x,y,z coordinates are determined according to recieving and formation time of sound. 2 and 3 D applications are avalibale.
Tablet/digitizer
Acoustic 3D tablet
Dr. Ahmet Zafer Şenalp ME 521 9Mechanical Engineering Department, GTU
3. CAD Input Devices
With hardware a scanner or optical scanner is a hardware input device. Scanners allow a user to take an image or text and convert it into a digital file, so that a computer can read or display the file. A scanner can be connected to a computer using USB, Firewire, Parallel, or a SCSI port.
Other types of computer scannersSheetfed scanner - scanner that scans paper by feeding paper into the scanner.Handheld scanner - scanner that scans information by holding the scanner and dragging it over a page you want to scan.Card scanner - scanner designed to scan business cards.
Scanner
Dr. Ahmet Zafer Şenalp ME 521 10Mechanical Engineering Department, GTU
3. CAD Input Devices
In computing, a mouse is a pointing device that functions by detecting two-dimensional motion relative to its supporting surface. Physically, a mouse consists of an object held under one of the user's hands, with one or more buttons. It sometimes features other elements, such as "wheels", which allow the user to perform various system-dependent operations, or extra buttons or features that can add more control or dimensional input. The mouse's motion typically translates into the motion of a cursor on a display, which allows for fine control of a graphical user interface.
Mouse
First mouse of the world (1952)
The first computer mouse, Douglas Engelbart, (1963)
Dr. Ahmet Zafer Şenalp ME 521 11Mechanical Engineering Department, GTU
3. CAD Input Devices
Operating an opto-mechanical mouse:1. moving the mouse turns the ball.2. X and Y rollers grip the ball and transfer movement3. Optical encoding disks include light holes.4. Infrared LEDs shine through the disks.5. Sensors gather light pulses to convert to X and Y vectors.
Mouse
Dr. Ahmet Zafer Şenalp ME 521 12Mechanical Engineering Department, GTU
3. CAD Input Devices
Cable Mouse In early times of computers mouse work by connecting to serial port. Recently this connection
is adopted to PS/2 port. Today, most cable mouse connects to the USB port of a computer mouse. In addition, by means of various adapters, USB ports can be converted to PS / 2 or vice versa.
Cordless Mouse Infrared mouse: This mouse uses an infrared communication with the computer. System is
connected to computer’s serial, PS/2 or USB port, and mouse connects to the system by means of infrared rays. If an object is present between the mouse and the system mouse movements won’t be detected. Today this type of mouse is no longer available in the market.
Radio wave mouse: Different from infrared mouse this mouse use radio wave signals for communication. Coverage areas is generally measured in tens of meters.
Bluetooth mouse: This mouse use Bluetooth cordless technology for communication. Has advantages compared to above two types: Can be used with every device as uses a standard protocol (PC, Apple and even Pocket PC)
Mouse
Dr. Ahmet Zafer Şenalp ME 521 13Mechanical Engineering Department, GTU
3. CAD Input Devices
Types according to motion detection methods: Mechanical mice Mechanical mice detects motion by means of a ball which can rotate by the mouse
movement. This ball is coated by rubber and inside core is metal. As dust can cover the movement ball by passing time maintenance should be performed.
Mouse
Dr. Ahmet Zafer Şenalp ME 521 14Mechanical Engineering Department, GTU
3. CAD Input Devices
LEDed Optical Mice These types of mice enable motion by reflection of the LED emitted. Top version
models has 1000-2000 dpi resolution.
Mouse
Dr. Ahmet Zafer Şenalp ME 521 15Mechanical Engineering Department, GTU
3. CAD Input Devices
Laser Optical Mice These types of mice enable motion by light emitted by laser light source.
Appropriate choice for those desire high resolution. Resolution can be 3000 dpi and more. If mice are categorized according to motion detection, most expensive is the laser optical mouse.
Mouse
Dr. Ahmet Zafer Şenalp ME 521 16Mechanical Engineering Department, GTU
3. CAD Input Devices
A trackball is a device which is very similar to a mouse. It consists of an “upside-down” mouse, in which the ball on the bottom of the mouse has been turned up to the top. As the ball is rolled by the hand of user it moves and the cursor on the screen. It controls the position of the cursor on the screen with the direction of rotation controlling the direction of cursor movement and the distance the cursor travels controlled by the number of revolutions of the ball. Also some functional buttons can be added to the trackball similar to mouse.
In CAD applications large balled models are preferred for better precision. Before the invention of touchpad the usage of trackball was common in laptop computers.
With the end of 1990’s with the invention of scroll wheel that is used in mice the usage of trackball is decreased.
Still used in cartography and similar applications.
Trackball
The world's first trackballinvented by Tom Cranston,(1952)
Logitech trackmanDr. Ahmet Zafer Şenalp ME 521 17Mechanical Engineering Department, GTU
3. CAD Input Devices
A Lightpen is an input device which allows interaction with a display from a computer screen.
The lightpens can be used to input data as well as to draw as shown in the figure. The idea behind the lightpen is the familiarity of an ordinary writing. It is a direct and natural form of input. A light pen can work with any CRT-based display, but not
with LCD screens. A light pen is fairly simple to implement. A light pen
works by sensing the sudden small change in brightness of a point on the screen when the electron gun refreshes that spot. By noting exactly where the scanning has reached at that moment, the X,Y position of the pen can be resolved.
Light pen
Dr. Ahmet Zafer Şenalp ME 521 18Mechanical Engineering Department, GTU
3. CAD Input Devices
Even invented in 1952 became popular in 1980’s.
First Light pen
Light pen
Dr. Ahmet Zafer Şenalp ME 521 19Mechanical Engineering Department, GTU
3. CAD Input Devices
A touchpad (also trackpad) is a pointing device consisting of specialized surface that can translate the motion and position of a user's fingers to a relative position on screen. They are a common feature of laptop computers and also used as a substitute for a computer mouse where desk space is scarce. Touchpads vary in size but are rarely made larger than 40 square centimeters
Touchpad
Touch pads consist of single plastic mylar membrane silkscreened with a silver conductive grid and two resistive strips and works in a similar way with touch screens except the fact that it works on a flat pad. When a key is pressed, two electrical resistances are reflected between a common line and the x and y output lines.
Dr. Ahmet Zafer Şenalp ME 521 20Mechanical Engineering Department, GTU
3. CAD Input Devices
The touch screen, namely touch-sensitive-screen, works by direct user-interaction with the CRT. A screen overlay is capable of sensing the physical contact of the operator's fingers or any other stylus on the screen. The screen overlay consists of transparent plates that fit over the screen and can convert the touch of the user, by optical, electrical or acoustical methods, into digital information consisting of several screen coordinates. The touch sensitive screen is utilized mainly to choose one out of a set of options presented in the panel. Just like on ATM machines, in industrial process control applications. It can also be used for drawing some shapes on the screen but since its accuracy is not great compared to other input devices not used for this purpose much. Disadvantages: Extended use causes tired arms, Smudges on screen, Insufficient accuracy for CAD applications based on pixel by pixel drawing.
Touchscreen
Dr. Ahmet Zafer Şenalp ME 521 21Mechanical Engineering Department, GTU
3. CAD Input Devices
Touchscreen
Dr. Ahmet Zafer Şenalp ME 521 22Mechanical Engineering Department, GTU
3. CAD Input Devices
Control dials or knobs
The dials, which are used as valuators, are graphical devices adequate to input scalar values to application programs. They are rotary potentiometers grouped in special assemblies most commonly used to control rotation or linear movements of objects displayed on a screen. When the user moves the dial, the voltage being output is changed. The translation from voltage to digital information is made by analog-to-digital converters. The dials can be programmed to input values into the graphics program. Beside this some dials have a user-programmable label. The label can indicate the function of the dial. As the functions of the dials change in the program the labels can be changed interactively so the functions of the dials are always clear.
Dr. Ahmet Zafer Şenalp ME 521 23Mechanical Engineering Department, GTU
3. CAD Input Devices
Function switches
Buttons and function switches are either toggle or push-button switches. They may be either continuously closed, continuously open, or momentary-contact switches. The most common convenient type of function switch incorporates both capabilities. Software controlled lights indicating which switches or buttons are active are usually provided. Buttons and switches are frequently incorporated into other devices. Switches make the on/off settings for input or mode of operations.
Dr. Ahmet Zafer Şenalp ME 521 24Mechanical Engineering Department, GTU
3. CAD Input Devices
Clasical Joystick: Literally only 1 or 2 button + direction, functions as a control tool
Joystick
Dr. Ahmet Zafer Şenalp ME 521 25Mechanical Engineering Department, GTU
3. CAD Input Devices
Input output functions: In old times control devices only reflect the choice of the player to the game but by improving technology joysticks are changed and joysticks that response to sense are developed. These respond according to the movement they sense and generally vibration property is presented by game devices such as PlayStation (dual shock) Example: A crash in a car race is responded by the vibration of the joystick.
Joystick
Second Generation JoystickSecond generation joysticks have more than two buttons and have perfect ergonomic structure, the routing function is analog and detects all kinds of precise orientation and most important is that it is a control device with input output function.
analog controlled nintendo; first 64 then game cube applied
Dr. Ahmet Zafer Şenalp ME 521 26Mechanical Engineering Department, GTU
3. CAD Input Devices
The best example to the last generation joysticks: Nintendo wii control device
Cordless control Input output function Sensing function: Sensing function enables the player’s the movements to be sensed
and converted to the game. Example: In a tennis play the movement of player’s hand is simulated as a movement of tennis racket
Joystick
Dr. Ahmet Zafer Şenalp ME 521 27Mechanical Engineering Department, GTU
3. CAD Input Devices
A voice entry system (VDE) consists of a microphone attached to a speech recognition device, which in turn transmits voice command information to a computer. As it can be understood from its name VDE working principal is data entry through voice commands. When user sounds a command, the command is interpreted according to a preprogrammed definition of its meaning.
Voice input
Dr. Ahmet Zafer Şenalp ME 521 28Mechanical Engineering Department, GTU
3. CAD Input Devices
3D Data Acquisition Systems
2D Image: (for each pixel: X and Y coordinates and light intensity). The intensity could be gray (8 bits: 0 – 255) or color RGB (24 bits).
3D Range Image/Data from Range Sensing Devices and 3D Camera –data points defined by their x, y, z coordinates (cloud point data).• Mechanical probe (measurement and scanning)• Laser scanning
Triangulation-based range sensing devices Time-of-flight based range sensing devices
Machine vision based CAD model generation for: • reverse engineering• machine vision and intelligent robot• vehicle size measurement and traffic monitoring• scanning of 3D object, human body, and art work
Dr. Ahmet Zafer Şenalp ME 521 29Mechanical Engineering Department, GTU
3. CAD Input Devices
Automotive Design and CAD Model Generation
Scanning of Clay Model toObtain Surface Data
Design Details Using CAD System
Dr. Ahmet Zafer Şenalp ME 521 30Mechanical Engineering Department, GTU
3. CAD Input Devices
Full Size Foam Model Machined Using a 5-Axis CNC Mill from 3D CAD Model
Dr. Ahmet Zafer Şenalp ME 521 31Mechanical Engineering Department, GTU
3. CAD Input Devices
Scanners withMechanical Probe
Dr. Ahmet Zafer Şenalp ME 521 32Mechanical Engineering Department, GTU
3. CAD Input Devices
CAD Modeling Based on a 3-D Vision System
• 3D Range Sensors (3D Cameras): 3D Cloud Data Points– Triangulation-based: visible laser light,short range, accurate– Time-of-flight-based: laser light & micro wave, long range, less accurate
• Processing of 3D Range Data– 3D Cloud Data Points Cross-section-based CAD Model– Generation of a Complete Description for Objects and Workspace –
Sensor Fusion
• Forming a Surface Model and Carrying out Reverse Engineering– Cross-section -based CAD Model Surface Model CNC Machining; RP; etc.
Dr. Ahmet Zafer Şenalp ME 521 33Mechanical Engineering Department, GTU
3. CAD Input Devices
Global Model Generation with Multiple View Fusion
Dr. Ahmet Zafer Şenalp ME 521 34Mechanical Engineering Department, GTU
3. CAD Input Devices
Automated Vehicle DimensionMeasurement System for Commercial andOversize Vehicles
Implemented at BC Ferries Terminal• Real-time Vehicle Dimension Measurement• Complex Vehicle Shapes• Dimensions Measured at Speeds up to 120 km/hr• Adverse Weather Conditions• Height and Width Accuracy: 15 cm• Length Accuracy: 30 cm
Dr. Ahmet Zafer Şenalp ME 521 35Mechanical Engineering Department, GTU
3. CAD Input Devices
Automated Real-time Dimension Measurement of Moving Vehicles Using Infrared LaserRangefinders
Dr. Ahmet Zafer Şenalp ME 521 36Mechanical Engineering Department, GTU
3. CAD Input Devices
Automated Real-time Dimension Measurement of Moving Vehicles Using Infrared LaserRangefinders
Dr. Ahmet Zafer Şenalp ME 521 37Mechanical Engineering Department, GTU
3. CAD Input Devices
Reverse Engineering and Automated CNC ToolPath Generation for Efficient and High QualitySculptured Part Machining
Geometric Modeling Based on 3D Scanning• Challenges:
– Accuracy/Lighting/Range (Selecting Right 3D Sensing Tech)– Occlusion (Obstruction)/Multiple View Fusion– Multiple Level Modeling: Cloud Data Points/Crosssections/
Surfaces/Solid• Applications:
– Reverse Engineering (e.g. Face Mask)– Size Measurement (e.g. Moving Vehicle)– Object Recognition (e.g. Moving Vehicle)– 3D Log CAD Model Generation– 3D Sculpture Documentation– Shoe Making– Character Modeling in Movies/Computer Games
Dr. Ahmet Zafer Şenalp ME 521 38Mechanical Engineering Department, GTU
3. CAD Input Devices