History of displacement sensors
Hi Habrahabr!
I suggest you recall the history of the development of displacement sensors, consider how they work, and assess the prospects for the future.
In 1963, at the Stanford Research Institute, the design of the mouse movement sensor was first developed. It consisted of two perpendicular wheels protruding from the body of the device. When moving the mouse wheel spinning each in its dimension.
Later, this design was replaced by a ball drive, in which the movement of the mouse is transmitted to a rubberized steel ball protruding from the housing. Two rollers pressed to the ball remove its movements in each of the measurements and transmit them to the sensors that convert these movements into electrical signals. This mouse had two types of sensors: contact and optocoupler.
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The contact sensor is a textolite disk with radial metal tracks and three contacts pressed against it.
The optocoupler consists of a double optocoupler - an LED and two photodiodes with a disk in which there are holes or radial slots that block the light flux as it rotates. When you move the mouse, the disk rotates and a signal is taken from the photodiodes at a frequency corresponding to the speed at which the mouse moves.
The second photodiode, which is offset at some angle or has an offset system of holes on the sensor disk, is used to determine the direction of rotation of the disk.
After some time, optical sensors of the first generation were developed, which were represented by various optocoupler sensors with indirect optical coupling — light-emitting and light-sensitive diodes that receive reflections from the working surface. Such sensors had one common feature - they required a special hatching on the working surface.
The second generation of optical mice already had a more complex device. At the bottom of the mouse, a special LED was installed, which illuminated the surface on which the mouse moves. The miniature camera "photographs" the surface more than a thousand times per second, transferring this data to the processor, which draws conclusions about the change of coordinates.
Currently, sensors are widely used that use a semiconductor laser for illumination. Such sensors are widely used in all possible ways: from the classic design of a mouse to a five-finger manipulator .
Since the main purpose of the sensors is to determine the coordinates, it is also worth mentioning as touchpads and touch screens of smartphones.
The principle of the touchpad, based on measuring the capacity of a finger or measuring the capacity between the sensors. Capacitive sensors are located along the vertical and horizontal axes of the touchpad, which allows to determine the position of the finger with the desired accuracy.
The most popular types of smartphone screens are resistive and capacitive.
The resistive touch screen consists of a glass panel and a flexible plastic membrane. Both the panel and the membrane are coated with a resistive coating. The space between the glass and the membrane is filled with micro insulators, which are evenly distributed over the active area of the screen and reliably isolate the conductive surfaces. When the screen is pressed, the panel and the membrane are closed, and the controller, using an analog-to-digital converter, registers the change in resistance and converts it to touch coordinates.
The capacitive touchscreen is a glass panel covered with a transparent resistive material. The electrodes, located at the corners of the screen, supply a small alternating voltage to the conductive layer. When you touch the screen with your finger or other conductive object, a current leakage appears. In this case, the closer the finger to the electrode, the less the resistance of the screen, which means that the current strength is greater. The current in all four corners is recorded by the sensors and transmitted to the controller, which calculates the coordinates of the touch point.
Gradually, the masses include the methods of determining the coordinates using position sensors in three dimensions in space. For example, sensors of this type include: gyroscope, accelerometer, GPS.
Not to mention the wide dissemination of the method using cameras, both one and several. The most famous example is the Kinect controller.
My personal opinion is that the future is in 3D technology.
Already there is an experience of using programmable gestures in front of a computer, set-top boxes and other interactive devices.
Perhaps soon, having come to the store for another industry novelty, we will see a controller on the counter that allows you to interact with the computer simultaneously using voice, camera images, air movement in space, or moreover, fixing electrical impulses in your head. Who knows.
In this review, far from all sensors in the world that move in space were considered, but only the most common ones in everyday life.
Source of technical details: Wikipedia
I suggest you recall the history of the development of displacement sensors, consider how they work, and assess the prospects for the future.
Past
In 1963, at the Stanford Research Institute, the design of the mouse movement sensor was first developed. It consisted of two perpendicular wheels protruding from the body of the device. When moving the mouse wheel spinning each in its dimension.
Later, this design was replaced by a ball drive, in which the movement of the mouse is transmitted to a rubberized steel ball protruding from the housing. Two rollers pressed to the ball remove its movements in each of the measurements and transmit them to the sensors that convert these movements into electrical signals. This mouse had two types of sensors: contact and optocoupler.
')
The contact sensor is a textolite disk with radial metal tracks and three contacts pressed against it.
The optocoupler consists of a double optocoupler - an LED and two photodiodes with a disk in which there are holes or radial slots that block the light flux as it rotates. When you move the mouse, the disk rotates and a signal is taken from the photodiodes at a frequency corresponding to the speed at which the mouse moves.
The second photodiode, which is offset at some angle or has an offset system of holes on the sensor disk, is used to determine the direction of rotation of the disk.
After some time, optical sensors of the first generation were developed, which were represented by various optocoupler sensors with indirect optical coupling — light-emitting and light-sensitive diodes that receive reflections from the working surface. Such sensors had one common feature - they required a special hatching on the working surface.
The second generation of optical mice already had a more complex device. At the bottom of the mouse, a special LED was installed, which illuminated the surface on which the mouse moves. The miniature camera "photographs" the surface more than a thousand times per second, transferring this data to the processor, which draws conclusions about the change of coordinates.
The present
Currently, sensors are widely used that use a semiconductor laser for illumination. Such sensors are widely used in all possible ways: from the classic design of a mouse to a five-finger manipulator .
Since the main purpose of the sensors is to determine the coordinates, it is also worth mentioning as touchpads and touch screens of smartphones.
The principle of the touchpad, based on measuring the capacity of a finger or measuring the capacity between the sensors. Capacitive sensors are located along the vertical and horizontal axes of the touchpad, which allows to determine the position of the finger with the desired accuracy.
The most popular types of smartphone screens are resistive and capacitive.
The resistive touch screen consists of a glass panel and a flexible plastic membrane. Both the panel and the membrane are coated with a resistive coating. The space between the glass and the membrane is filled with micro insulators, which are evenly distributed over the active area of the screen and reliably isolate the conductive surfaces. When the screen is pressed, the panel and the membrane are closed, and the controller, using an analog-to-digital converter, registers the change in resistance and converts it to touch coordinates.
The capacitive touchscreen is a glass panel covered with a transparent resistive material. The electrodes, located at the corners of the screen, supply a small alternating voltage to the conductive layer. When you touch the screen with your finger or other conductive object, a current leakage appears. In this case, the closer the finger to the electrode, the less the resistance of the screen, which means that the current strength is greater. The current in all four corners is recorded by the sensors and transmitted to the controller, which calculates the coordinates of the touch point.
Future
Gradually, the masses include the methods of determining the coordinates using position sensors in three dimensions in space. For example, sensors of this type include: gyroscope, accelerometer, GPS.
Not to mention the wide dissemination of the method using cameras, both one and several. The most famous example is the Kinect controller.
My personal opinion is that the future is in 3D technology.
Already there is an experience of using programmable gestures in front of a computer, set-top boxes and other interactive devices.
Perhaps soon, having come to the store for another industry novelty, we will see a controller on the counter that allows you to interact with the computer simultaneously using voice, camera images, air movement in space, or moreover, fixing electrical impulses in your head. Who knows.
In this review, far from all sensors in the world that move in space were considered, but only the most common ones in everyday life.
Source of technical details: Wikipedia
Source: https://habr.com/ru/post/144893/
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