Selecting A Projector For Classroom Use


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A non-technical overview of what to look for when selecting a projector for K-12 classrooms.

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Selecting A Projector For Classroom Use

  1. 1. Selecting a Projector for Classroom Use Video allows teachers to not only tell students what they need to learn from a specific lesson, but show them examples that helps develop understanding. SYNERGY BROADCAST SYSTEMS 16115 Dooley Road Addison, TX 75001 972-980-6991 or 800-601-6991
  2. 2. Analog TV is dead and quickly moving out of the classroom. The projector seems to be most popular replacement for several obvious reasons: The picture is much larger than the typical 19” TV most classrooms usually have installed and this is great because now the students in the middle and back of the room can actually see what’s on the screen. The picture seems much brighter in most of the projectors I’ve seen which is also great because the teacher can leave the lights on and still use the projector in many cases. The bad news is there appears to be more than 1,000 different projector models on the market and they range in price from a few hundred dollars to over $50,000.00. With that range of product offerings how is a school to decide on a particular model that will work best for all classrooms? In an effort to find the best value we began a search with Google and reluctantly determined that there was too much information and too many models and manufacturers to make a comparison simple. So, rather than make a brand or model recommendation it makes sense to try and identify the important features to look for when choosing a projector. Key Considerations The following are thoughts and ideas on what should be considered. There are many details, features and options but we decided to take a big picture view and focus on these areas: Lumens A lumen is a measurement of light output or brightness. The American National Standards Institute (ANSI) established a standardized testing procedure for projectors that involves averaging several brightness measurements taken from different locations. This number is called the ANSI lumen measure and because it is an industry standard you can use the number compare one projector to another to compare their relative brightness. The larger the number, the brighter. But how do you know what ANSI lumen number to look for? Does room size or audience size matter? What about room lighting? For classroom use it makes sense to use a projector that can function properly without having to turn off all the lights or darken the room to be able to see the picture. Teachers need eye contact to foster interaction and read student engagement to keep discussions active and moving. This also facilitates moving 2
  3. 3. back and forth between video and discussion mode to keep things interesting. In looking at the different types of projectors it appears that the very small portables (ultra portables) have between 1000 and 2500 lumens and the larger projectors for training rooms, conference rooms and classrooms have 2500 to 7000 lumens. The web site recommends the following guidelines for lumens and lighting. • 1000-1200 lumens for lights-off, low ambient light • 1500-2000 lumens with some ambient light • 2000-2500 lumens with bright ambient light Ambient light is considered room light or existing room light that originates from sources other than the projector. The brighter the ambient light the brighter the projector needs to be. Another consideration is audience size. The larger the audience the larger the picture needs to be so the more light necessary to overcome ambient light in a larger room. recommends the following guidelines for large audiences: • 2500 lumens for less than a hundred with ambient light • 3000 lumens for audiences of 100-200 with ambient light • 5000 lumens for audiences of 100 or more under bright lights Resolution Resolution is a way of relating to the sharpness of the picture. The higher the resolution the sharper the picture, or the more detail you can see. Resolution is typically displayed as 1024x768 where the first number represents the width in pixels and the second number is the relative height in pixels. Most projectors are available in several resolutions such as, • VGA (480x640) • SVGA (800x600) • XGA (1024x768) • SXGA (1280x 1024). One number is typically identified as the “native” resolution or default setting and is usually the optimum setting for that particular projector. Here are some things to think about. PowerPoint presentations, charts and most graphs will project just fine using a resolution of 3
  4. 4. 800x600. High resolution graphics, photos and small print on a web page or other fine detail will probably need 1280x1024. Your classroom computer or laptop resolution is important as well and should be the same as the projector so everything displays properly. Aspect Ratio The aspect ratio relates to the dimensions of your picture expressed in units as the number of units wide by number of units high. Old analog TV’s have a 4:3 aspect ratio, which means the picture is almost square in appearance. The new flat screen TV’s are 16:9 and are much wider than they are tall. The U. S. is currently transitioning from analog to digital TV where the older format is 4:3 and the newer format will be 16:9 so you will likely see and view both formats until all formats of video and other content transition to the new wider format. Check the specifications of any projector you are interested in to see what aspect ratio it supports. Some will only support 4:3 others will handle both. Types of Projectors Source: LCD was the most common projector type but DLP is newer and becoming more popular. DLP is typically the technology used in the smaller portable and lightweight models. LCD (liquid crystal display) projectors usually contain three separate LCD glass panels, one each for the red, green, and blue components of the image being fed into the projector. As light passes through the LCD panels, individual pixels can be opened to allow light to pass or closed to block the light. This modulates the light and produces the image that is projected onto the screen. DLP stands for Digital Light Processing and was developed by Texas Instruments. Instead of having glass panels through which light is passed, the DLP chip is a reflective surface made up of thousands of tiny mirrors. Each mirror represents a single pixel. In a DLP projector, light from the projector's lamp is directed onto the surface of the DLP chip. The mirrors wobble back and forth, directing light either into the lens to turn the pixel on, or away from the lens to turn it off. LCD Projectors: Strengths -Richer color (better in rooms with ambient light) -Draw less power -Produce less heat -Quieter -Sharper image on data 4
  5. 5. LCD Projectors: Disadvantages -More visible pixels -Some screen door effect on certain video images -Physically larger -Poorer contrast -Blacks come out lighter gray versus DLP projectors DLP Projectors: Strengths -Smoother video -Smaller -Pixels less visible -"Blacker" blacks -Higher contrast DLP Projectors: Disadvantages -Color filter wheel often produces soft but audible whine -Poorer reds and yellows at full power -Color saturation -Need more lumens than LCD, for rich colors (Source: Weight Weight can be a concern if you plan to move your projector from classroom to classroom or if you mount it on the wall or the ceiling. Obviously, if you are going to be moving your projector around without the benefit of a cart the smaller the better and there are many portable models from which to choose. Expect the portable models to weigh between 1.5 and 4 pounds. Larger models will weigh 7 – 15 pounds and heavier. The heavier the projector the more expensive to mount on the wall or ceiling. Connectivity With all the new devices available today some care should be taken to make sure the projector you select has all the connectors you will need. Examples include a VGA connector for your computer, USB for a document camera, S-video, composite video, left and right audio, audio connectors for external speakers, and HDMI for high def devices. User Controls Take a test drive on the user controls. How easy is it to actually use the projector’s controls? Is navigation easy or difficult? Is it intuitive or will you need to keep the manual tethered to the machine? Opt for simple controls whenever possible to reduce support calls. 5
  6. 6. Remote controls are usually included with each projector and third party control panels can be used to control not only the projector but other devices in the classroom as well. Lamp Life and Energy Conservation Projector lamps are expensive so look for projectors that have a lamp life of 2,000 hours or greater. Also look for projectors that have sleep modes or power conservation controls. These prolong lamp life and also save on the school’s power bill. Zoom Choose a projector with a zoom lens for more picture flexibility. The zoom feature can be automatic or manual and should be a feature on the remote control. Keystone Keystoning is a distortion of the projected image and is caused by either the projector or display surface being on an angle. As an example, if the projector is on a table and displays on the wall the top of the picture is likely to be wider than the bottom. Some projectors can adjust keystoning within the projector. It’s a good feature to have. Throw Throw is the distance between the projector and the display. A short-throw projector can be very close to the screen where as a long-throw projector must be farther back. Make your decision based on where you plan to install the projector. What’s the distance between the projector and the screen? To avoid having students step on wires when using a table or cart, select a short- throw projector so it can be positioned closer to the screen and away from student desks Some projectors have interchangeable lenses for short or long throw situations. Most manufacturers provide calculators on their web sites to help you determine the throw and screen size for each model as well as the right size for a particular classroom dimension. Lens Shift Lens shift is a great feature to have that enables the lens to shift up, down, left or right to provide greater installation flexibility. By shifting the lens one direction or the other you avoid the need to physically move the projector or the mount to true-up the angle of the picture to the screen or display surface. In a brief search of several brands this feature appears on mostly high-end models but it does not hurt to ask about it in your quest. 6
  7. 7. Network Management Choose a projector with a network connection if you will deploy large numbers. Having this connectivity available usually means the projector has administrative software that allows monitoring of usage, lamp life and other measurable areas. A key consideration here is the ability to remotely turn the power off to all units to save on the electric bill and preserve the lamp. Summary In the end, it’s about setting priorities when in search of the perfect projector. If you want some feedback I would encourage you to talk with other schools that have purchased projectors and have some experience. They can probably explain the mistakes they made the first time they purchased a projector and you can learn from their experience. If their projectors are a year old or older don’t expect to find the same model available. This market appears to change and update models on a very frequent basis. You can also attend trade shows to visit all of the manufacturers. Some of these shows will even hold a projector “shoot out” and show them side by side so you can compare models. Be careful when making replacement purchases as well. Minor changes in the throw or angle of the lens from one projector to the next might mean having to move all of your mounting brackets, which can be an expensive undertaking so it makes sense to try a replacement model on an existing bracket before you make the purchase. Resources and search projectors to find resellers and manufacturers. Please refer to the manufacturer’s web site for specific information. provides a screen and throw calculator 7
  8. 8. This document is designed to provide recommendations to be used as guidance when considering your projector needs. This is not designed to recommend one manufacturer over another or one model over another but to provide you with some general guidelines to think about as you decide what features make sense for your particular situation. Synergy Broadcast Systems does not sell or endorse any projector brand or model. About Synergy Broadcast Systems Synergy Broadcast Systems is located in Addison, TX (Dallas). Founded in 1987 to serve the education, cable, broadcast, government and healthcare markets the company’s solutions help facilities manage and utilize video content in the most efficient and effective manner to capture, catalog, organize, archive, report and deliver video for broadcast, video on demand, streaming and digital signage. The company’s systems are modular, economically scalable and forward-focused to provide solutions that solve video organization and delivery problems and provide migration options for future growth and expansion. For additional information call 800-601-6991 or visit VideoCourier VideoCourier is a suite of solutions designed for education to make video delivery to the classroom, desktop, mobile device or meeting rooms easy. VideoCourier modules include content acquisition, cataloging and search, multiple delivery methods, storage, archiving and reporting. For more information on VideoCourier visit our web site at or call us at 800-601-6991. 8