How Do I Choose the Best Electronic Whiteboard?
The basic composition of the audio-visual multimedia central control system is the central controller, projector, video booth, audio, computer, screen, and electronic whiteboard.
Audio-visual multimedia central control system
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The basic composition of the audio-visual multimedia control system is
With the rapid development of technologies such as projectors, video booths and interactive whiteboards, multimedia video classrooms have become an inevitable trend of modern teaching. At present, colleges and universities in China have basically realized multimedia teaching, and primary and secondary schools have also begun to implement them. Even rural primary and secondary schools have begun to implement multimedia video classrooms. The state has also invested a lot of money for the establishment and renovation of multimedia video classrooms. The success or failure of the construction of multimedia electronic classrooms will directly affect the teaching level.
According to the composition and characteristics of the multimedia system, full consideration should be given to the compatibility of the media equipment with the overall control system, the role of the media equipment in the system, the quality and cost-effectiveness of the equipment itself, and the impact of the installation environment when selecting multimedia classroom equipment. Multiple factors. The basic composition of the multimedia education central control system: central controller, projector, video booth, audio, computer, screen, electronic whiteboard.
All media devices in the entire multimedia classroom are centrally managed and controlled by a central control system. Its biggest feature is that it simplifies the complicated and tedious operation process, so that users can easily and calmly use various equipment. After several years of development and use, the concept of centralized control has been widely accepted. The centralized control system has become an indispensable device for multimedia classrooms.
The price of the intelligent central controller is generally around 20,000 yuan, and some are even more than 30,000 yuan. If the purchase is not made properly, it will bring great economic losses to the school. The following aspects should be noted when selecting a control system:
1. The system must be stable and reliable. The purpose of installing the control system is to simplify the operation, so that the teacher can easily and easily control various equipment to achieve the effect of doing more with less. If the system is not stable, the operation will not be simplified, but the teaching effect of the teacher will be affected. Therefore, the choice should be the quality first rather than the price.
2. Pay attention to the openness, compatibility and scalability of the system. The central controller should be simple to install, easy to upgrade, and easy to add and replace equipment; the control interface is simple and clear, the logic is clear, and the operation is convenient and fast.
3. Avoid blindly buying products that advertise high-tech. After more than ten years of development, the multimedia intelligent central control technology has become quite mature, and the market competition is very fierce. In order to break through and attract the attention of users, some manufacturers often advertise that they have adopted new technologies and added several functions. However, when the user bought the product and used it, they discovered that some of the functions might never be used, and it would become a factor of system instability. When buying, you must combine the actual situation of the classroom with the application as the main focus.
4. Attention should be paid to multiple control operation modes. Most control systems currently have touch screens, software, manual control panels and handheld remote controls. School teachers' computer operation levels are inconsistent. Some teachers are not familiar with computer operations and can use manual control panels. With the remote control, the teacher can also easily control various equipment after leaving the podium.
5. Pay attention to the manageability of the system when purchasing the intelligent central controller. With the development of multimedia teaching, there will be more and more multimedia classrooms in schools. If there are problems in several multimedia classrooms at the same time, audio-visual technicians will be exhausted. The intelligent central controllers designed by some manufacturers now have a built-in network management module that can manage and maintain the control equipment and controlled equipment of each multimedia classroom through the network. This intelligent central controller with manageable functions not only enables E-learning technicians are relieved from the heavy technical support work, and will also improve the teaching efficiency of multimedia classrooms.
With the extensive development of IT technology and optical technology, projector technology has also developed rapidly. LCD and DLP liquid crystal projectors are widely used in education, scientific research, commerce, and military fields due to their low cost, small size, and good projection effects. Due to the acceleration of the educational information process, multimedia teaching has been widely developed, and multimedia projectors have become more and more important in teaching. How to choose a suitable model from a wide range of products on the market to ensure that the equipment used in teaching has a good projection effect, stability and reliability, and functions that meet actual needs has become the top priority of campus procurement.
The projector is the most expensive device in a multimedia classroom. It is small in size, light in weight, and high in brightness (up to 4500 ANSI lumens). It can display text, graphics, images, data, etc. when connected to a computer; after inputting a video signal, it can play TV videos, VCD, DVD images, Multipurpose to one machine. The main technical indicators of the projector are parameters such as brightness, contrast, and resolution. There are table-type front-projection, ceiling-type front-projection, table-type rear-projection, and ceiling-type rear-projection on the installation methods. Generally, if the projector is used in a fixed manner, the ceiling method can be selected. If there is enough space, the overall effect of the rear projection method is the best. The effect of using the projector is closely related to environmental factors (room size, lighting conditions). Use in different environments will produce different effects. Therefore, when selecting a projector, the corresponding technical indicators of the projector should be determined according to the use environment. Such as determining the brightness of the projector according to the size of the classroom area. The following table is the corresponding table of the minimum configuration of the use environment and applicable brightness. If the funds are sufficient, you can choose a higher specification.
Small meeting rooms and conference rooms up to 50 square meters | 1000 1500 ANSI lumens |
50 to 300 square meters of medium-sized classrooms and conference rooms | 1500 3000 ANSI lumens |
Large conference rooms and classrooms of more than 300 square meters | Above 3000 ANSI lumens |
The following points must be noted in the installation of the projector:
1. Calculate the distance between the projector and the screen (determined by the screen size). The height of the screen hoisting and the distance from the first row of seats should be calculated according to ergonomic principles, to prevent students from looking up at the screen too much, so that the screen falls into the relaxed field of vision of the students, and let students watch the screen and the screen in a more comfortable posture. Copy notes to reduce students' visual fatigue and improve learning effectiveness and efficiency.
2. The top edge of the screen hanging on the wall should be on the same horizontal line as the ceiling projector lens, and the center point of the projector lens and the center point of the projection screen should be on the same vertical line.
3. Select a suitable mounting bracket, install the fixing screws, and tighten the bolts in place.
4. Adjust the keystone, focus, etc. of the projection screen.
Video booth, also called physical display, is one of the indispensable teaching equipment in multimedia classrooms. It is a new type of image acquisition equipment. The video booth is connected to the projector. Teachers can use it to display various slides, models, transparencies, manuscripts, and other physical objects on the projection screen clearly and realistically through the video camera, so as to optimize the teaching process, increase classroom capacity, Improve classroom teaching efficiency and teaching effect.
For the purchase of video booths, you can start from the following three aspects:
1.Select the video booth that suits you
The product performance requirements are determined according to the user's own use environment and purchase budget. If you want to pursue high-quality projection demonstration effects, the double-sided desktop video display stand should be the ideal choice. If you want to make the video booth work position not fixed, you can Choosing a bottom-mounted video display stand. This type of product can enhance the portability of the video display stand due to the bottom-plate separation. It is very suitable for small-scale movement. If users want to use the video display stand on a business trip, they should choose a portable product. Of course, this product is very expensive.
2.Determine key technical indicators
When buying a video booth, in addition to the CCD resolution, we should also refer to some other functions and indicators, such as positive and negative film inversion, black and white color inversion, the quantity and quality of auxiliary light sources, input and output. The number of ports, whether it has an RS-232C serial port, whether it has an infrared remote control function, etc., and with reference to the opinions of other users, select a few products for the actual comparison test of the next stage of product performance.
3.Comprehensive comparison
The work at this stage is particularly important, which can effectively compare the actual performance of the product, so as to determine the final product selection. In this phase of comparison, try to use professional test cards to focus on the true reproduction of product colors, the uniformity of lens focus (the center and edges are consistent), the accuracy of autofocus, the contour correction of the lens, and pincushion distortion. For detailed comparative evaluation, etc., for the reliability and stability of product quality, we should refer to the opinions of other users and the opinions of experienced engineering and technical personnel as well as product quality and other factors as much as possible.
The audio response in the multimedia classroom selects a system with wide frequency response and high fidelity, suitable for multimedia teaching, and has a microphone reverberation function, enabling teachers to comment and explain while playing media content.
The configuration of audio equipment in a multimedia system can comply with the following three principles:
The principle of simplicity
The audio configuration of a multimedia classroom should not be as complicated as the configuration of professional stage sound reinforcement equipment. This is because of two reasons: First, there are more users in the multimedia classroom. These people have different levels of operating skills. It is also relatively simple; the second is that multimedia classrooms with less than 300 seats do not need to choose professional stage sound reinforcement equipment. Therefore, I suggest that the audio system of the multimedia classroom does not need to be equipped with a mixer and various peripheral equipment (such as professional reverberators, equalizers, exciters, etc.).
High power principle
Although the sound effects of multimedia classrooms are not as irritating as those of movie theaters or dance halls, I still think that a sufficiently powerful amplifier and main speaker are crucial to the listening quality of multimedia classrooms, because a too low power amplifier or speaker is in order to provide Sufficient sound pressure to work in the non-linear region will cause at least two problems: one is that the signal-to-noise ratio of the sound system is greatly reduced; the other is that the sound system is likely to cause howling when the sound is amplified, and it will seriously damage the amplifier. Or speakers. It is generally believed that the effective output power of the main speaker is measured at about 1W / person / channel, and the rated power of the main channel of the AV amplifier is taken to be about 1.2 times the power of the main speaker to provide sufficient headroom. For example, in a classroom with a capacity of 100 people, the effective output power of the main speaker is 100W, and the rated power of the main channel of the amplifier is 120W. However, in reality, the rated power of the main channel of the amplifier in the multimedia classroom is far from sufficient. Sometimes it feels that the sound system can get enough sound pressure level and sound effect when playing music, but the effect occurs after connecting the microphone. Great changes. In fact, you can use the following method to test: connect the microphone when the audio system is not inputting the audio signal, then turn the microphone volume of the amplifier to the maximum, and listen to the amount of AC noise emitted from the speaker. This is the best test of the quality of the audio system. Method.
Versatility
In the current situation of school education investment is still relatively tight, the multi-functional classroom has practical significance. The key to achieving multi-functionality in a multimedia classroom is to choose a suitable AV amplifier.
In short, the audio system of a multimedia classroom is an indispensable part of a multimedia system. Only with reasonable configuration of audio equipment can a suitable and uniform sound field be obtained in the classroom, and the effectiveness of the multimedia classroom in teaching can be brought into full play.
Multimedia computer A computer that can comprehensively process multimedia information such as sound, images, and videos. The multimedia computer generally refers to a multimedia personal computer. Its main function is to integrate audio and video, graphic images, and computer interactive control for comprehensive processing.
The multimedia computer occupies the main position in the classroom equipment. In the system, it is not only a computer teaching medium, but also a network connection device. It may also be the operating platform of the central control system. Because it is in a multi-tasking working state most of the time, try to choose a multimedia computer that runs fast, has large memory, is equipped with a sound card, network card, and optical drive with strong error correction capabilities, and works stably and reliably.
Because the computer in the multimedia classroom should be suitable for the teaching of different courses, the configuration of the software must take into account the needs of different courses. For computers that do not have a recovery protection card installed, system protection recovery software should be installed to prevent malfunctions caused by misoperation, etc.
The best projection effect can only be obtained by selecting the correct screen according to the actual usage. In order to enable users to make the right choice, some guidance is given here from the type of screen and technical indicators. Although these instructions will apply in most cases, there are no strict rules for each description, depending on your actual use environment.
Four main steps to choosing the right screen:
Select the screen type: The type you choose should be best suited to your specific usage needs. For example, if you need a front projection screen, you can choose a wall-mounted or ceiling-mounted type, and there are manual and electric specifications; if you need a rear projection screen, you can choose a hard screen or a soft screen. In general, if you need a fixed-position projection site, a wall-mounted, ceiling-mounted or tripod-mounted screen is your best choice. If you need to move the screen to different orientations, the portable screen is your best choice.
Choosing the best screen size: Choosing the best screen size mainly depends on the area of the space used to plan the number of seats and the arrangement of the audience. The first rule is to choose a screen that is suitable for the audience-not a screen that is suitable for the projector, which means that the audience's visual experience is the first. We provide the following formula for selecting the screen size for your reference: * The screen height is approximately equal to 1/6 of the distance from the screen to the last row of seats in the auditorium, so that the audience of each row can clearly see the projection screen content. * The distance between the screen and the first row of seats should be greater than 2 times the height of the screen. * The bottom of the screen should be at least about 122 cm from the seat of the auditorium.
Choose the format (screen ratio) that suits the needs of the projection equipment you are using. A list of common formats is as follows:
Image format | Screen ratio (high) |
NTSC system | 4: 3 |
PAL system | 4: 3 |
HDTV (High Definition Television) | 16: 9 |
Widescreen | 1.85 |
Selection of screen fabric: The screen fabric you choose should be suitable for the needs of your projector and audience. However, if a screen needs to be used by multiple projectors, the screen fabric should be selected to suit the needs of the projector with the higher screen requirements. For example, when you have both a slide projector (or a shadow projector) and an image projector, because the light output of the projector is lower than that of the slide projector (or a shadow projector), you should choose the reflectivity (gain) parameter that is suitable for the projector. Fabric. However, since the brightness of most projectors is now relatively high, a white plastic screen with a lower reflectance (gain) than a glass bead screen can achieve better projection results (for example, a wider viewing angle range).
Before buying a specific screen, you also need to understand the main technical indicators of the screen
Gain: The ability of the screen to incident light. When the incident light angle is constant and the incident light flux is constant, the ratio of the brightness in a certain direction of the screen to the brightness in an ideal state is called the brightness coefficient in that direction, and the maximum value is called the gain of the screen. Generally, the gain of the matte white wall is set to 1, if the screen gain is less than 1, the incident light will be weakened; if the screen gain is greater than 1, more incident light will be reflected or refracted.
Viewing angle: The reflection of the screen in all directions is different. The further away from the center of the screen in the horizontal direction, the lower the brightness; the viewing angle when the brightness drops to 50% is defined as the viewing angle. Viewing an image from an angle of view has satisfactory brightness; viewing an image from an angle of view has insufficient brightness. Generally speaking, the larger the screen gain, the smaller the viewing angle (metal screen); the smaller the gain, the larger the viewing angle (white plastic screen, because of the care of students, education screens mostly use white plastic screen). Glass bead curtains are more popular.
The screen is divided into two types: reflective and transmissive. The reflective type is used for front projection, and the transmissive type is used for rear projection. The front projection screen is divided into flat screen and curved screen. The flat screen has a small gain and a large viewing angle, and the ambient light must be weak; the arc screen has a large gain and a small viewing angle, and the ambient light can be strong, but the incident light reflected by the screen is different in all directions. In terms of texture, it is divided into glass curtain, metal curtain, embossed plastic curtain, etc., which are generally applicable.
The size of the screen is defined by the size of its diagonal. The aspect ratio of general video images is 4: 3, and the education curtain is square. For example, a 1.83m (72-inch) screen, according to the Pythagorean theorem, it can quickly be concluded that the width of the screen is 1.5m and the height is 1.1m.
At present, electronic whiteboards are mainly divided into interactive and photocopying. Interactive whiteboards (also known as interactive whiteboards and interactive whiteboards) need to be used in conjunction with a projector to realize the integration of projection display, screen marking, whiteboard writing, and operating a computer. The written content is saved directly to the computer. The copy-type electronic whiteboard can only be used as a separate whiteboard, and the written content can be output through a printer.
Before buying an electronic whiteboard, you must first consider the use of the electronic whiteboard. The following provides some suggestions for the selection of interactive electronic whiteboards in multimedia electronic classrooms, mainly from the four aspects of brand, product, price and service.
Brand
First of all, look at the interactive electronic whiteboard brand. The brand is a long-term accumulation of the company and a reflection of the company's comprehensive strength. So you need to look at the company, whether there is a research and development team to continuously improve product quality; whether to establish a customer-centric Service team to provide customers with comprehensive support; whether they have their own production lines to ensure timely delivery.
product
Then to examine the interactive whiteboard product itself, it needs to be inspected from five aspects: practicality, ease of use, stability, sensitivity and aesthetics.
Practicality
Practicality refers to whether the function of the product is suitable for you. From a functional perspective, it is not that the more functions, the more complicated the better. It only suffices to meet the actual needs of the enterprise. At present, the functions of various manufacturers' products are similar. Judge.
Ease of use
Ease of use refers to whether the product is simple and convenient to use, whether the screen provides corresponding shortcut keys, whether the connection between the products is a universal connection, whether to use a dedicated writing pen, whether the pen feels comfortable, and whether the weight is appropriate. Whether the user can use it without training, the ease of use of the product is easy to judge.
stability
The stability mainly includes the stability of the hardware and the life of the entire product, whether the hardware's electronic components are greatly affected by temperature, whether it will be affected by the surrounding magnetic field, whether the product has undergone strict testing, and the current electromagnetic induction interactive whiteboard is stable. Better performance than pressure-sensitive and infrared electronic whiteboard. The life of the electronic whiteboard is mainly determined by the selection of the panel. The softer material generally has a relatively short life. The flatness of the panel will also greatly affect the life. The processing technology of the whiteboard will also affect the life. Whether the four corners of the whiteboard are reinforced Whether the bracket is stable. The stability of the product is generally difficult to judge at once, and some investigations on the use of old users are needed.
Sensitivity
Sensitivity is an important indicator. The products provided by some manufacturers are not sensitive enough, and there is a phenomenon that the line cannot be drawn, the line is not continuous, and the line is not flat. In terms of sensitivity, the interactive whiteboard of electromagnetic induction type is sensitive to pressure. . This is easy to detect. Just draw a line on the whiteboard and you can judge. If there is no line drawing or the line is not continuous, it means that the sensitivity is insufficient.
Aesthetics
Aesthetics mainly refers to whether the appearance of the product is beautiful, whether the surface of the board is flat, whether it is reflective, whether the frame is flat, whether the size of the whiteboard is suitable for the place, and whether the panel is flat has a great impact on the projection effect and the life of the whiteboard.
price
Then you need to examine the price. The current price of whiteboards ranges from thousands to tens of thousands, and some are even prohibitively expensive. You don't have to find the cheapest or most expensive one. Users can combine other aspects to find the right price.
service
Service is also an important factor, because the interactive electronic whiteboard has been in use for 5-10 years, whether the manufacturer has provided service commitments for core components of the whiteboard, whether it has provided service commitments for accessories, whether it provides software upgrade services, and whether it provides installation training. Etc. are the focus of investigation.
