The “Magic” of SMART Boards: How Touch Technology Works
Classroom Tools on March 20 2014
Many of us use touch technology everyday, whether it be on our smartphones or SMART Boards. Some of us have gotten so used to screens responding to our commands that we instinctively touch all screens expecting to get a reaction. Although touch screens are an extremely widely used part of technology, much like coding, few of us know how they actually work.
It may not surprise you that there are different types of touch technology. If you’ve ever used a 600 series SMART Board and an iPhone, you’ve noticed that they aren’t made up of the same materials yet both respond to your touch. The 600 series board uses what is called resistive technology. Resistive touch technology is pressure sensitive, which is why you may have encountered “issues” with your board not responding to you the way you thought it would when dragging things across a large area. This is usually due to a lack of consistent pressure that interrupts the signal to the board. Resistive technology uses two surfaces coated with conductive materials that are separated by an air pocket. When the two surfaces are touched, they make contact with each other and that send signals to the computers to react to the touch. Because the surfaces are so large, it can be difficult for the computer to take two signals at a time accurately.
Smartphones use a different type of technology called capacitive touch. There are several different kinds of capacitive touch technologies but what they all have in common is that they create a small electrostatic field that can be interrupted by other conductive materials, like your finger. If you’ve ever wondered why your phone doesn’t work when you have gloves on it’s because the gloves insulate your electrostatic charge. Gloves that are meant to be used with smartphones sometimes use thin metal threads at the fingertips through which the charge can be passed. There are some capacitive technologies which allow the use of a stylus or gloves.
Another type of touch technology uses cameras and infrared sensors to sense the points of contact on the board. The 800 series SMART Boards use this type of technology. This is why the 800 series is capable of sensing the difference between a finger, pen and fist. The cameras are able to gather information such as shadow size or number of objects in the area in order to send signals to the computers that tell it that we want to erase when we use a fist or that two people are at the board.
The optical touch technology is relatively new, and when you compare it to resistive technology you can see why its limitations would lead some to want to develop a more versatile technology. Of course, unless you understand how the first technology works, you can’t develop a different or new technology.