Peripheral+Devices

Classroom teachers, instructional assistants, and students often will be required to use peripheral devices in connection with teaching, learning, and classroom management. A basic knowledge of the available devices and their functionalities can help teachers effectively integrate technology into the curricula. In addition, this information may be useful when designing and maintaining an instructional technology system at the classroom level. ** Printers ** The printer choice largely is dependent on the purpose or job, as different technologies are capable of different levels of image/text quality and print speed; some technologies are inappropriate for certain types of physical media, such as photo paper or transparencies. Classroom printers can be attached directly to computers. Computer labs generally share one or more printers accessed via a network; networked printers optimally have a higher print speed than classroom printers. The Electronic Test Delivery System demands a high-speed printer for test tickets. Special projects requiring a high degree of color resolution may need specialty printers. Typically, ink jet printers are appropriate for printing color-intensive graphics, and laser printers are best for printing text documents due to their fast print speeds. However, some color ink jet printers can print fast without tearing paper or using excessive amounts of ink.

There are several specifications to consider when assessing the image/text quality of printers. Resolution is a widely used specification that refers to the number of dots per inch (dpi) that can be printed horizontally and vertically. A high-resolution printer is capable of printing more detailed images and text than a printer with a lower resolution. Print speed measures the number of pages generated per minute (ppm); however, printer manufacturers often determine these speeds by printing basic text documents at the lowest-quality settings (draft mode) on plain paper. Users should expect to experience half the print speed that manufacturers report.

Before making a purchase, you should also examine printed text and images. Different text fonts should be legible, fully formed with no fuzzy edges, and crisp. The tops and bottoms of characters should be correctly aligned from one row to the next. The letter openings (counters) should be well rounded; if not, the printer may be using too much ink. When assessing image quality, three characteristics should be considered: color accuracy, sharpness, and dynamic range. In assessing color accuracy, the inside areas of images should be dense and evenly shaded. Transitions from dark to light colors (gradient) should have smooth transitions instead of distinct bands (color banding). Images should show balanced color saturation as opposed to overly saturated colors or washed-out areas. Image sharpness can be judged by looking for crisp outer edges with smooth corners. For the dynamic range, there should be clear details in highlighted and shadow areas.

The cost of consumables such as ink and paper should also be considered. Typically, ink jet printers cost less than laser printers, but ink jets contain smaller cartridges that have to be replaced more often. Therefore, the total cost of ownership may be lower with a laser printer. The printing cost per page should be calculated in determining the total cost of ownership. This is determined by dividing the cost of a cartridge by the number of pages it can print; for example, if a $40 cartridge can print 800 pages, the cost per page is five cents ($40/800=.05). A multifunctional device that provides copying, printing, scanning, and faxing capabilities may provide the lowest overall cost of ownership by eliminating the expenses of purchasing and maintaining multiple pieces of equipment. For more information, review the state procurement contracts for printers on the VITA Supply Chain Management Web page at http://www.vita.virginia.gov/procurement/contractSearch.cfm?mode=keyword. Monitor specifications are described in terms of screen size and quality. The screen size refers to the diagonal length from one corner of the monitor box to the other. A stated screen size of 17” normally results in a viewable area of only 15.1”. 3-D displays, such as virtual reality environments, can be generated by using a 3-D display device with a computer. There are several devices for generating 3-D displays, but the most common are LC (liquid crystal) shutter glasses and HMD (head-mount displays). 3-D displays offer an alternative environment for students to experience and learn a variety of subject matter via interactive simulations, models, etc. ** CD and DVD Drives ** CD drives—standard on PCs—read or write data on a compact disc. It is defined by its speed (e.g., 16x, 48x). DVD drives can read both CDs and DVDs. A DVD can hold more than 25 times more data than a CD in higher-density multilayer storage format. Educational software is available in DVD and CD formats. Most computers come with either built-in or external speakers. External speakers can enhance the sound levels of a computer or classroom projection device. For computers that lack built-in microphones, external microphones or USB headsets may be used for audio input. In a computer lab setting, headsets can control sound from multiple computers simultaneously. Inexpensive //headphone splitters// can allow two sets of headphones to be accessed on one computer. Projection devices enhance teacher and student presentations in classrooms and computer labs. While classroom projection devices can be as simple as an overhead projector or a computer-based LCD (liquid crystal display) or DLP (digital light processing) projector, wall-mounted flat-panel screens can enhance an auditorium or lab setting. When choosing a projection device, consider its ANSI lumens, resolution, and lamp life. For projecting detailed data and graphics onto a 60-inch diagonal screen, a projector with 300-400 ANSI lumens and a resolution of at least 1024 x 768 is preferred (Projector Central, 2007).  An interactive whiteboard is a peripheral device that requires a computer to generate the display either directly or via a projector. Operating directly as a large room display, the end user might use built-in software to capture notes written on the whiteboard-like surface and/or control the computer (click and drag), markup (annotate a program), or use optical character recognition (OCR) on the computer-generated image displayed from the whiteboard and/or touch-screen surface.
 * Monitors **
 * Average entry-level PCs usually come with a 17” monitor, which is adequate for most general-purpose applications.
 * Larger 19” or 21” monitors may be appropriate for video editing or advanced graphics work (e.g., multipage layout).
 * Teachers of students with special needs may want to consider larger monitors.
 * Speakers, Microphones, and Headsets **
 * Projection Devices **
 * Electronic Whiteboard **

The interactive whiteboard is connected to a computer through a wired medium (e.g., USB, a serial port cable) or a wireless connection such as Bluetooth. There are different types of interactive whiteboards including electromagnetic, infrared optical, laser, ultrasonic, and camera based. These are available with three forms of imagery: · Front-projection whiteboards have a video projector in front of the whiteboard. · Rear-projection whiteboards have a projector located behind the whiteboard; some are self-contained, with the projector and the whiteboard in a single cabinet. · Add-on systems attach to an existing monitor, such as a large flat-screen monitor.

Considerations for an interactive whiteboard include room design, room size, controllable lighting, and the desired interactive features. Approved state contracts for interactive whiteboards and other peripheral devices can be invaluable resources during the selection process. These state contracts can be reviewed on the VITA Supply Chain Management Web page at http://www.vita.virginia.gov/procurement/contractDetail.cfm?contract_id=2804 http://www.vita.virginia.gov/procurement/contractDetail.cfm?contract_id=2806.

At the time of publication, Smart Inc., which produces a full line of interactive whiteboards, had a grant program for K-12 entities located at http://smarterkids.org/k12/index.asp. Inexpensive flatbed scanners often can meet basic classroom scanning needs, such as generating student handouts. A low-resolution scanner works well for scanning text or data; however, for accurate OCR (optical character recognition), a high-resolution scanner and OCR software are necessary. Photographs or other detailed graphics may require a 600 x 600 dpi (dots per inch) scanner. The higher the dpi resolution, the better the resulting image will be. Combination flatbed/automatic document-feeder scanners with a fairly high page-per-minute feed rate may be more appropriate for administrative use. Digital cameras can enhance the teaching and learning process. Two resources for guidance on the purchase of digital cameras are Kathy Schrock’s //Teacher Helpers Guide to Digital Gadgets—// // Digital Cameras and Camcorders in the Classroom //  ( http://school.discovery.com/schrockguide/gadgets.html ) and  Keith Lightbody’s  // Digital Cameras Enhance Education // ( http://www.zardec.net.au/keith/digcam.htm ). In general, the purpose of the digital camera will determine its necessary features. Professional-quality images for art or graphics classes may require cameras that have the following: exposure controls such as aperture and shutter priority, choice of metering modes, bracketing, and lens attachments. A camera with a resolution of seven megapixels or higher should be used to take images that will be printed or require retouching. Always consider factors like focus control, flash modes, ease of use, file-download format, file-storage capabilities, and compatibility with USB ports.
 * Scanners **
 * Cameras **
 * Personal Response System **

=  = = A personal response system is also called a classroom response system or an audience response system. The system comprises hardware and software that collect and display student input to teachers’ questions. The system can use an infrared or radio-frequency signal sent to a receiver attached to a teacher’s computer; the necessary components are a student keypad, receiver, computer, and software.   = ** Voice Amplification Systems ** Voice amplification systems have been used as assistive technologies for students with hearing impairments for years. This technology can facilitate all facets of teaching and learning by lessening the strain on a teacher’s voice and helping students remain attentive and engaged. The system’s setting will determine its necessary features. The room dimensions, the presence or lack of acoustical tiles, flooring type, the presence of large fixtures, and other factors must be considered when choosing a voice amplification system. Computer-based microscopes electronically collect data for analysis during inquiry-based learning. Several models are available; the microscope’s purpose will determine its type and features. Table 6 includes some guidelines. **Table 6. Guidelines for Selecting Computer-Based Microscopes**
 * Computer-Based Microscopes **
 * || **Microscopes** ||
 * Good || Digital, 20X-50X zoom ||
 * Better || Digital, 20X-100X zoom, USB plug-n-play, digital image capture ||
 * Best || Digital, 20X-500X zoom, USB plug-n-play, digital image and video capture, LED illumination, Save file format: BMP, JPG, AVI ||

**Sensors (Probes)** Sensors and p robes electronically collect data as a part of inquiry-based hands-on activities in such curricula as science, mathematics, and technology. Probes are components of //probeware//, which is equipment and software that gathers and analyzes data in real time. Probeware systems interface with a computer, graphing calculator, or self-contained measuring system. The data can be displayed as graphs, tables, meters, or values. **Table 10. Guidelines for Selecting Probes** -35° to +135°C; displays degrees in C, K, and F ||
 * || ** Probes ** ||
 * Good || Temperature sensor with range of
 * Better || Multimeasure sensor with temperature range of -10° to +50°C; sound level range of 40-90 dBA; light range of 0-5000 lux ||
 * Best || Multimeasure sensor including probeware system with temperature range of -35°to +135°C; selectable light ranges of 0-100, 0-10,000, and 0-150,000 lux; sound level of 50-100 dbA, voltage ±24 V, and sound maximum sample rate of 200 Hz ||