Good afternoon friends!
Today we will talk about one very convenient device, to which we are so accustomed and without which we can no longer imagine working on a computer.
What is a "mouse"?
A “mouse” is a push-button manipulator designed together with a keyboard for entering information into a computer.
Indeed, he looks like a mouse with a tail. A modern computer is already unthinkable without this thing.
The “mouse” is much more convenient to use than, for example, the built-in manipulator of a laptop.
Therefore, users often disconnect this laptop “mat” and connect the “mouse”.
How does this convenient thing work?
The first designs of manipulators
The first manipulators included a ball that touched two disc rollers.
The outer rim of each disc had perforation. The shafts were located perpendicular to each other.
One shaft was responsible for the X coordinate (horizontal movement), the other for the Y coordinate (vertical movement).
When the manipulator moved along the table, the ball rotated, transmitting torque to the shafts.
If the manipulator was moved in the “right-left” direction, then the shaft responsible for the X coordinate rotated predominantly. The cursor on the monitor screen also moved right-left. If the mouse moved in the “toward or away” direction, the shaft responsible for the Y coordinate primarily rotated. The cursor on the monitor screen moved up and down.
If the manipulator moved in an arbitrary direction, both shafts rotated, and the cursor moved accordingly.
Optical sensors in old mice
Such devices contained two optical sensors - optocouplers. The optocoupler includes an emitter (LED emitting in the IR range) and a receiver (photodiode or phototransistor). The emitter and receiver are located at a close distance from each other.
When the manipulator moves, shafts with disks rigidly attached to them rotate. The perforated edge of the disk periodically crosses the radiation flow from the emitter to the receiver. As a result, the output of the receiver produces a series of pulses, which goes to the controller chip. The faster the mouse moves, the faster the shafts will rotate. The pulse frequency will be higher, and the cursor will move faster across the monitor screen.
Buttons and scroll wheel
Any manipulator has at least two buttons.
Double “clicking” (pressing) on one of them (usually the left one) starts execution of a program or file, clicking on the other one launches a context menu for the corresponding situation.
Devices designed for computer games may have 5-8 buttons.
By clicking on one of them you can fire a grenade launcher at the monster, on the other you can launch a rocket, on the third you can unload a good old hard drive at it.
Modern mice also have a scroll wheel, which is very convenient when viewing a large document. You can view such a document only by rotating the wheel and without using buttons. Some models have two wheels scrolling, while you can view text or graphics by moving both up and down and left and right.
Below the scroll wheel there is usually another button. If you view a document by rotating the wheel and simultaneously pressing it, the manipulator driver activates such a mode that the document itself begins to move up the screen. The speed of movement depends on how fast the user rotated the wheel before pressing it.
In this mode, the cursor changes its shape. This makes it even more convenient... In short, get it, cook it, chew it, all that's left to do is swallow it. Pressing the wheel again switches from “auto view” to normal mode.
Optical mice
Subsequently, the manipulator was improved.
The so-called optical “mice” appeared.
Such devices contain emitting Light-emitting diode(usually red), a transparent reflective plastic prism, a light sensor and a control controller.
The LED emits rays that, reflected from the surface, are captured by the sensor.
When the manipulator moves, the flow of received radiation changes, which is captured by the sensor and transmitted to the controller, which generates standard signals for a specific interface. Optical mouse more sensitive to movement and does not require a mat for itself, like the old ball manipulator.
An optical mouse has no rubbing parts (with the exception of the potentiometer, the rotation of which is transmitted from the scroll wheel) that wear out or become dirty. This is also an advantage.
Possible problems with manipulators
The mouse, like any equipment, has a limited service life. It's no secret that the bulk of computer equipment is made in China. The goal of any business is profit, so the Chinese comrades even save on cables for mice, making them as thin as possible.
Therefore, the first weak point of manipulators is the cable.
More often internal break one or more cores occurs at the point where the cable enters the mouse.
The cable has 4 wires, two of them are power, the third is clock frequency, and the fourth is information.
If the mouse is not visible to the computer, the first thing you need to do is “ring” the cable.
If a break is detected, you should cut off part of the cable with the connector (behind the point where the cable enters the mouse body, closer to the connector) and the remaining piece to the printed circuit board of the manipulator, naturally observing the color.
PS/2 Mice Can't switch on the fly .
Otherwise, her controller (her tiny “brain”) may fail. And it’s good if the matter is limited to just this. The PS/2 interface controller on the motherboard may also fail, which is much worse.
If the cable is intact, but the mouse is not recognized by the controller, then most likely its controller has failed and it must be replaced. A cable break in optical mice can also be suspected by the lack of light from the LED (which is located near the surface that moves on the table). In other cases, there may be no light due to a faulty LED or controller, but this is rare.
Manipulators with COM or USB interface Can switch on the fly. However, currently devices with a COM interface are practically not found.
You have to “click” the mouse many thousands of times, and the buttons may fail after prolonged use. To replace the button, you need to disassemble the manipulator and solder another one. It is not necessary to use the same one as it was. The main thing here is to maintain the height in order to maintain the length of the key stroke. However, manipulators have long been quite affordable, and most users do not bother with their repair.
Let’s say “thank you” to the good old “mice” with a ball in their bellies - they served us well...
Concluding the article, we note that there are varieties of manipulators with laser emitter instead of LEDs, which provide more accurate and faster cursor positioning. This speed and accuracy are especially in demand in games.
There are also wireless (radio) “mice” in which the exchange of information with the computer is carried out not over a wire, but over a radio channel. Therefore, they contain their own power source - a pair of finger-type galvanic cells of AA or AAA size. Let us remind you once again that the manipulator connector is inserted into one of the ports.
That's all for today.
Victor Geronda was with you.
See you on the blog!
Have you ever wondered how things work, what path they take from idea to implementation, how simple simple things are? How easy is it to make a comb? What about a computer mouse? And a wooden computer mouse made from a single block of mahogany with an LCD screen, with its own electronic filling and a cable made and braided especially for it? I think you will be interested in my journey, which I went through during the 2.5 years of creating my mouse.
Design, construction, modeling
Since I was a complete zero in design, I approached the matter as a complete layman. I bought plasticine and started sculpting the mouse of my dreams.
First, I built a mouse that is ideal for me to use on a desktop. She is big and dark gray in the photo. Then I made a mouse that would suit me as a mobile mouse (small dark gray). And then I took the piece of plasticine I had stolen from the children to work, and my colleagues sculpted a mouse that claimed to be the “folk mouse.” It fit perfectly into the hands of the majority of the male population of our team (multi-colored in the photo). And what? The result is banal and dull forms that we twitch with our hands in every possible way day and night. Apparently, among the three standard mice, any user will find a comfortable one. The triumph of the ideal?
As a result, a mouse was modeled behind the computer, which, from my point of view, pretended to be elegant and beautiful.
At that moment I really liked her. And without thinking twice, I divided the computer model into parts. Elements of fastening and interfacing with electronic filling were thought out. It sounds simple, but in reality hundreds of hours of painstaking work were spent.
After this, the resulting parts were grown on a 3D machine to test assembly.
Material - polyamide. It fits well in the hand, like a glove. All parts fit together, technological assembly also went without problems
The next stage is milling in wood. I probably purchased a dozen different species of mahogany trees, but I started with the sapele tree, the rest of the species are waiting in the wings.
I didn't like the design in real life. The vertical gaps between the buttons and the case looked bad and untidy. Technological “sores” when working with wood are visible - chipping and removal of wood. Well, and most importantly, the keys did not bend, there was no click.
I thought about the design for a long time. Something was confusing, and there was no feeling of satisfaction. Then I realized that the mouse lacks solidity. I decided to return to the original version of the mouse, which I sculpted at the very beginning, only at a professional level and using sculptural plasticine. There are two design options in one mouse. Convenient for comparison and decision making.
After receiving the final version, 3D scanning was done and the surfaces were transferred to SolidWorks.
The second model turned out not much more successful than the first. The buttons were not being pressed and there was no way to fix this in the current model. The model's marriage was laid down at the DNA level. We need a more comprehensive approach with simultaneous control of both design and technology. Otherwise nothing will work. There will be either technological excellence or good design, but not all at once. These characteristics sit on opposite sides of the seesaw. So I throw everything in the trash and start over. Sketch-design-sculpting-testing-growing and so on, but with technological control of critical parameters on the one hand, and design on the other. We are looking for a middle ground.
The third model was made within the framework of the classic product design cycle. I started with a sketch.
Contours are drawn.
And finally, the approved design.
Plasticine model.
3D scanner, surface acquisition.
Computer model.
Then the process of finishing the body began. The body was cut out on a CNC machine, tested, modified, and then cut out again. As a result, only the tenth version of the case turned out to be functional. The biggest problem was making the keys comfortable to press. As a result, in some places the thickness of the wood decreased to 0.7 mm! It took me a year to refine the body.
The wheel and connector were also made of wood.
I laser engraved the wheel with the Clickwood brand.
The eleventh version of the case is coming, to which I will make minor changes. I also started developing a wireless version of the mouse. The wireless module is based on Bluetooth technology, the optosensor is laser. AAA size batteries, 2 pieces, replaceable. When recharging, the mouse will continue to work. All the elements are arranged very tightly, and I had to rack my brains quite a bit when assembling them. A cavity specially cut into the wooden body of the mouse serves as a container for batteries.
Wooden parts
Working with wood begins with the selection of wood. The boards must have the correct geometry, have a minimum of knots and defects, and have the necessary moisture content.
First, the boards are dried at home. At least six months.
After this, the board is sawn into small bars, which are dried for several weeks at the site of their further processing. At all stages, humidity is controlled by a special device. If the drying process is neglected, the wood loses geometric stability, and the manufacture and operation of the mouse becomes impossible.
The prepared bars are processed on a CNC machine using a specially created program.
From the very beginning of creating a part until the final assembly of the mouse, the parts are rigidly fixed to metal equipment so that at no stage does the part change its shape and geometric dimensions.
The processing of the upper part of the mouse has to be done with pinpoint precision, since its profile is designed for a soft click and is very thin in some places. I control the pressing force with a grammeter. In normal mice it ranges from 50 to 75 GS. I'm trying to achieve 50 GS.
Wood is the biggest challenge in my project. Not only is this the most significant part of the cost, but the percentage of defects here is very high. Wood is an anisotropic material. It may fail, there may be defects, chips may occur, and simply an error in the finishing technology can lead to the mouse body being thrown into the trash. I admit that I am still improving the processing technology, and I am not completely sure that I have found the right one. For statistics: in the first batch of ten cases, only three reached the finished product. Therefore, the part of the technological chain associated with wood is critically important for the cost and quality of the finished product. It is constantly being worked on.
In the future I plan to work with bone. In particular, I am already creating a wheel from bone.
Electronic part
I developed the first mouse design myself. The sensor was a top-end optical sensor ADNS-3090 from Avago, the brains were an Atmel controller, and the rest were components from brand companies like Murata, Yageo, Geyer, Omron and Molex.
I paid special attention to the high-quality nutrition of the mouse, here, in my opinion, I reached the absolute level with my perfectionism
The first working breadboard.
In black version, final.
There were also experiments with different buttons. I always tried to choose a quiet mouse among others. Well, since I’m making it myself, I decided to conduct an experiment and make such a mouse and try it out. To do this, I replaced the clicking left and right “micrics” with soft and quiet ones used for the central button (have you noticed that the central button always clicks quieter?). A special version of the board was created, on which all three identical “micrics” were mounted.
I selected and bought a batch of gold-plated connectors for the mouse. As usual, in China. I don’t know about “better contact”, but they harmonize perfectly with the wood.
Screen, firmware
Fascinated by the idea of placing a display in a mouse, I began searching for it among hundreds of suppliers. The requirements were simple: strict dimensional restrictions and the ability to at least symbolically display at least eight familiar places. While I was selecting it, I learned almost everything about displays. They differ by type: symbolic and graphic, by technology: TAB, COG, TFT, OLED, LCD, E-Paper and others. Each type or technology has a lot of varieties, sizes, colors, lighting, etc. In general, there was a lot to dig into.
After surfing half the internet, I found out that the size I needed was made by only one company in the whole wide world. All other options are definitely larger in size. And even the display I found barely fit inside the mouse. As an option, a custom display was considered, which could be made for me according to my requirements, but this is a very expensive option for me (about one hundred thousand rubles). For the first model, a graphic display with a resolution of 128 by 64 pixels is quite suitable, which is what I chose.
In order to figure out how the display actually looks and fits with my mouse, I had to order all varieties of this display from the manufacturers. What do these varieties mean? The model name consists of unpronounceable alphanumeric combinations like FP12P629AU12. All of them are composed of various blocks and are clearly deciphered in the specification. For example, the example given can be assembled from blocks FP.12.P.629A.U12, where the type, size, voltage, controller, operating temperature range and other information about the model are encrypted. And the last block is the trickiest. It can have several dozen values, each of which means one or another combination of such characteristics as the presence and color of the backlight, background color, symbol color, and the range of degrees from which information can be clearly read. These are the parameters that were interesting to me.
As a result, “for testing” I ordered 18 different modifications. The manufacturer agreed, but said that the minimum order was 5 displays for each modification. There was nowhere to go, and I had to agree, knowing that 90% would go into the trash can. And then, one cloudy day, the express delivery service brought me home a huge box in which a homeless person of average build could live. The box contained 18 smaller boxes, each of which comfortably accommodated 5 displays, securely secured for a long trip to cold Russia. There was so much accompanying packaging that it was enough for my mother-in-law to cover several beds for the winter.
As a result, after thorough tests on a specially assembled stand, two displays turned out to be suitable for the series. They differ only in background: gray and yellow-green. These are the ones I will offer to complete the mouse. By default I plan to set it to yellow-green, but two more options will be available: a display with a gray background and a mouse without a display at all.
But the main intrigue was what information can be shown on the screen? I was offered different ideas: ambient temperature, indication of the arrival of letters, something else that was not very original.
My train of thought followed a different path. Let's start with the fact that there are two significant restrictions on displaying operational information: the presence in front of the user of a huge and high-quality source of any information (monitor) and the need to turn the mouse over to obtain information. In addition, the screen is small, the resolution is low, and the LED interferes with normal reading. Therefore, I came to only one conclusion: the information should be of an entertaining nature only, the practical value of which tends to zero, but at the same time the WOW! effect should be killer.
What kind of information can have such properties in a device of mediocre complexity? There is not much of it: mileage, time of use, speed of movement, number of clicks and scrolling of the wheel. I decided to abandon the last parameter, since it seemed uninteresting to me. All other parameters are tied to the session (the last time the mouse was used from the moment power was supplied to it, i.e. connecting to the computer or turning on the computer itself) and to the entire lifetime of the mouse. For example, the user can find out at any moment how many times he pressed the left mouse button or how many meters his mouse has traveled today or since the time of its purchase. The information is absolutely useless, but it will help those who are especially curious to understand how much he torments the mouse. If other interesting ideas appear, they can be implemented with new firmware.
I also added general information about the mouse (model, mouse and firmware number, month of manufacture) and a settings screen. You can choose the language and system of measures (English or metric). To store all this information, we had to add permanent storage flash memory to the circuit.
To fit this amount of information, I had to break everything down into screens. Each screen displays one type of information and shows session and all-time parameter values. There are six screens in total, which can be changed using the mouse wheel.
The first option was implemented in a purely textual manner, for which several font options were even developed.
I made a firmware to evaluate how the text looks using the created font on the mouse screen. It looks terrible, what can I say.
Now it has become obvious that the screen needs graphics, and not a set of symbolic information. Therefore, I brought a designer into the work, and together we prepared three graphic options; in the end, the second option was recognized as the most successful.
Of course, this design required higher resolution, so it had to be adapted.
But that's not the end of the story. After I selected the mouse screen, I ordered a trial batch for breadboards. As a result, screens arrived, but for some reason the number of pins differed from what was indicated in the specification (datasheet). In response to the request, the manufacturer received an answer that everything was fine, this was a minor modification, and it would not affect the performance in any way. Meanwhile, the missing two wires were responsible for the brightness of the displayed graphics.
It was all very suspicious. And just like he was looking into the water. We remade the board for a modified screen, soldered it, and then it turned out that the screen was completely dim. It's as if the device's batteries are dead. And this became clear after a long and painstaking work of searching and selecting screens, purchasing a trial batch of all modifications and testing them. Time, money, and so on.
But the story turned out to have a good ending. After correspondence with the Chinese, it turned out that the screen can now adjust its contrast directly from the firmware. We repaired the firmware, and everything started to show just fine!
Everything is shown as planned: mileage, speed, number of clicks, etc.
Subsequently, the firmware also changed several times: a setting for changing the language appeared. Two languages on one screen are bad - readability deteriorates, Cyrillic abracadabra will only irritate an English-speaking user, and support for other languages may be needed in the future. The difficulties began when I tried to adjust the mouse travel. It seems that there is something complicated: the optical sensor transmits the increment in two coordinates, which must be converted to a system of measures and added modulo to the current value. That's the whole mileage.
But, as it turned out, not everything is so simple. Two people with mice with the same sensor installed can get radically different results! The thing is that the resolution of the sensor (sensitivity) very much depends on the surface on which the mouse is rolling. The best results are obtained when the mouse rolls on white paper. Slightly worse on wood and fabric. It's really bad for laminate and film. The declared sensitivity is achieved only on ideal, from the point of view of the sensor, surfaces.
This makes no difference to the end user. He connects the mouse and, through trial and error, sets the operating system to a comfortable cursor speed. The system remembers this coefficient and uses it to increase or decrease the movement coordinate increment values.
But it’s a completely different matter if you plan to read these parameters directly from the mouse. The mouse on one surface will show the result of running one meter, on the other - one and a half. Speed will also lie. And something needs to be done about this.
To solve this problem, we had to introduce the “Sensitivity” parameter, which allows you to individually select the coefficient for each surface. By default it is equal to one, which corresponds to the surface of white paper. It can be increased or decreased in the settings. You don’t have to touch it at all, everything will work just fine as is. But for true perfectionists, the leaflet included with the mouse will contain a table from which you can select a coefficient for the existing surface and instructions on how you can independently configure the mouse to show the exact mileage.
During the development of the firmware, another side effect of the sensor was discovered. If you take the mouse and simply wave it in the air, the mileage readings will also change. This is due to the fact that the sensor detects the surrounding space as a certain surface and also tries to obtain mouse offset values. Therefore, you can observe the following effect: you turn the mouse over, look at the mileage parameters and are surprised that they change upward right before your eyes. Of course, you can install a tilt angle sensor in the mouse that turns off the sensor while it is turned over, but doing this only for the situation described is unreasonable. Perhaps it will appear in the next version, but not now. After all, the mouse is raised only to look at the indicators, and 99.9% of the time it is on the surface and receives the correct information.
Cable
I decided to make the cable as flexible as possible so that it would not interfere with the movement of the mouse and would be “invisible” for kinematics. Well, I personally don’t like the “spring” cable.
Sometimes it seems that when creating a product, the cable is the most insignificant part of the product. What's easier is to buy the required amount of cable in the store and unsolder it. No big deal. But, alas, not here in Russia. Sometimes it seems that our industry is no longer capable of making anything more complex than cast iron irons. Attempts to find a cable resulted in a three-week search and shaking up the assortment of absolutely all manufacturers of Russian cable products. It turned out that our standards do not describe a cable suitable for modern electronic devices. For example, a four-core microphone cable with a KMM 4x0.12 mm2 braid has an outer diameter of 5 mm. That's a lot. Older mice and keyboards have a seemingly thick cable that is only 3.5mm in outer diameter. The closest analogue on sale was a cable from the German company Lapp Kabel, but its outer diameter was just 3.5 mm. Now imagine the braid on such a cable. Introduced? I'll tell you that I saw a similar cable on power cords for irons
So, it turned out: you can’t buy such a cable in Russia. Dot. Well, we are not used to retreating. I go to production and try to order, fortunately they still make cables in Russia. And to do this, let’s define my requirements. So what do I need:
The cores are copper, made of braided wires (for flexibility).
Number of cores - 4.
Screen - yes.
Flexibility - maximum.
The outer diameter of the cable is strictly no more than 3 mm.
Color - Pantone 4625 C.
Bottom line: I tried to contact probably a dozen possible manufacturers of cable products; no one is interested in messing with my order. They didn’t even ask what mileage I needed. Bottom line: such a cable cannot be purchased or produced in Russia. Sad. But we are not used to retreating.
I go to Alibaba.com. I find the first Chinese manufacturer I come across, write a letter and literally within a few hours I receive an answer: we will make any cable for you! I'm shocked. I send him the specification, money for delivery, and a week later I receive a sample. Wow! And I lost almost three months, trying to patriotically place an order in Russia. It turned out that the Chinese could easily make me a cable with an outer diameter of 2.5 mm.
As a result: I ordered 4 different samples from China. At first I was not satisfied with the scratchability and dullness of the outer shell, then I was not satisfied with the flexibility of the cable, then again I was not satisfied with the flexibility, and in the end I settled on the last sample sent, which I was ready to order. They couldn't be more flexible. The cable has memory. As a result, I accidentally received a cable with memory, although I wanted one that was as flexible as a rope
I ordered a kilometer, two weeks later I had the cable. Total time spent: six months.
Braided my kilometer of cable. There were two options.
Approximately 10% of the cable was rejected. This is the beginning of the bays, where the braid is unraveling and the machine has not yet entered operating mode. And some places where, for some reason, loops and knots of braided threads formed.
If the end of the cable is not sealed with heat shrink, it will fluff up immediately, the threads are synthetic! Therefore, the installation of the cable assembly is complicated by the preventive attachment of heat shrink.
The outer diameter of the braided cable was 3.2 mm, i.e. The braid added 0.7 mm to the cable diameter. It doesn’t seem like much, but a regular mouse usually has a cable with a diameter of 3.5 mm, and in the era of wireless mice it seems thick and heavy. Recently, non-budget mice have begun to be equipped with cables with a diameter of 3 mm, and they no longer interfere so much during work; they are almost invisible. But the keyboard cable can have an outer diameter of 4 mm. And even more. But this doesn't matter for the keyboard.
Plastic parts
No matter how much I would like to make the body parts of the mouse entirely from wood, I cannot do without plastic. You need legs, an axle for the wheel, a support for the axle and a piece of glass for the display.
Therefore, I had to order a mold from the Chinese.
After each test casting, the Chinese sent me a dozen samples, which I tested on my mouse.
As a result, I modified the mold three times until the quality began to satisfy me. The problems were different. For example, after assembly I got a problem with dust that formed between the display and the protective glass. It looks untidy. Moreover, the mouse will scratch on the surface, and dust will gradually accumulate there. I had to convert the glass into a container with sides where the display would be placed, after which the contour would be sealed.
The result is something like this.
Refining a mold is not an easy task at all, and changes can only be made in the direction of making the part larger. Therefore, any inaccuracy or error can ruin the entire work. For reference: each revision means a month and a half of waiting for new samples. And the change itself could be microscopic, but necessary.
I won’t dwell on plastic parts; this technology is now leading, and I can’t tell you anything new or interesting here. I’ll just say about the legs, for which I spent a long time selecting a material with reduced friction, after which I conducted tests and “races” of mice in order to determine the winner with minimal friction.
Processing and coating
First, careful work is carried out, removing lint, sanding and polishing the surface.
I had a difficult task ahead of me. It was necessary to stabilize the wood so that the geometry of the mouse did not change depending on humidity, and to protect the wood from working in an aggressive environment (sweat and grease from the hand).
From the very beginning I refused varnish. Varnish is a surface film that eventually cracks and breaks down, leaving the wood bare. Sweat and fat penetrate the pores, the wood darkens, and the irreversible process of its degradation begins. Therefore, it was decided to use oil as impregnation and protection, and wax to give a commercial look.
To make it clear: the tree is completely saturated with pores, which contain either air or the oil of the tree itself (if the tree is a rubber tree). Our task is to fill the pores as much as possible with our oil, which should then polymerize and protect the wood.
In order not to prolong the story, I will say that I tried a lot of oils: linseed, teak, tung, Vaseline, Danish. Each oil has its own character. For example, wax is very difficult to apply to teak oil, while linseed oil takes a very long time to polymerize. Therefore, it is necessary to introduce a catalyst into it - a drier.
I ended up developing two technologies. The first is the technology of vacuum impregnation of wood. It works like this: I create a vacuum in an environment with oil and wood. Air begins to escape from the pores. After removing the vacuum, the pores are filled with oil. As a plus, the tree is well stabilized. The downside is that it gets very dark. Looks good, but not for everyone.
The second technology is surface coating with oil. The oil is applied 1-2 or more times with a non-woven cloth.
Apply carnauba wax.
And rub with a muslin circle.
Then, using a hair dryer, I “dissolve” the dry wax residues in narrow and difficult places. In the case of “insoluble” debris, I pick up a toothbrush with stiff bristles, remove the debris, and then repeat the waxing procedure locally again.
If we evaluate the labor costs of processing, then manual labor for one mouse is about four hours.
Assembly
Next comes the installation operation, but before it you still need to remove traces of processing from the technological holes. Then, using a special 3M tape, I adjust and glue the legs (the body can move by a fraction of a millimeter, and this will be immediately noticeable: it will wobble like a lame stool). Then I lay the cable, mount the board, support, install the wheel and also, if necessary, adjust the buttons (there should be no chatter) and pressing force. This operation can also take up to four hours.
Design and principle of operation of an optical mouse
Today you won’t surprise anyone with an optical mouse. But ten years ago, when the first generation of optical “rodents” had just appeared, not many could boast of such an outlandish manipulator. Meanwhile, the ability to move the cursor using a “rodent” with a red LED in its “abdomen” was another step forward in computer technology.
Actually, the first optical mice had two LEDs, and one of them emitted light in the red range, and the other in infrared. Accordingly, there were two photodiodes that worked “paired” with the above-mentioned LEDs. For such a mouse, a special mat was needed with a surface made of a special reflective material, onto which a fine grid of blue and black lines perpendicular to them was applied. The blue lines absorbed the light from the red LED, and the black lines absorbed the infrared.
Thus, one photodiode “noticed” the passage over the blue lines of the mat, and the other - over the black ones. At the moment of passage over the line, the photodiode generated a corresponding electrical pulse. The mouse controller, by counting impulses, determined the direction and magnitude of movement.
We can say that the pad performed a function similar to that performed by the entire mechanical part in an optical-mechanical mouse (an ordinary mouse with a ball, which many have probably disassembled more than once).
The advantages of such mice include the absence of moving and inertial parts, operational reliability, and positioning accuracy. And the disadvantages are the rug, which required constant care and cleaning, and, as always (where without money), the high cost. In addition, if the mousepad was lost or damaged, the mouse would lose its functionality. But in 1999, Agilent Technologies developed its own optical navigation technology, for which a mat was not required at all. And since today Agilent has produced more than 75 million sensors of various modifications for optical mice, we can assume that this technology has come to the yard of both manufacturers and users. In addition, the above-mentioned company produces not only optical sensors, but also almost all the necessary components for assembling an optical mouse (a kind of do-it-yourself kit (see Fig. 1)), which makes the production of optical mice affordable even for small ones (such as and I would like to add “Chinese”) companies. Figure 1 shows two options for the lens and clamp. But no matter which one the manufacturer prefers, it does not fundamentally affect the operation of the optical system.
The essence of this technology is as follows: an optical sensor sequentially reads surface images (frames), and then mathematically determines the direction and amount of movement.
red
Light-emitting diode
LED clamp
A complete optical system consists of four components: optical sensor, lens, red LED and LED clamp. You can see how it looks when assembled in Fig. 2.
Optic
The optical sensor includes three functional blocks: image acquisition system (IAS); digital signal processor (DPS); serial data interface.
Structurally, the optical sensor is a microcircuit with sixteen legs (although there is an option with eight), on the lower part of which (on the side of the legs) there is a lens.
Behind the lens is a monochrome CMOS camera, which photographs a small area of the surface with an area of about a square millimeter. The surface frame is divided into small areas (squares). For each such area, the average brightness value is calculated. The range of assigned values is from 0 to 63, where 0 is assigned to the black area and 63
White. Thus, a mosaic image is obtained, consisting of squares of varying brightness. Here is one such square, i.e. element of the image is the anchor point, or rather, one reference (see Fig. 3). And the resolution of an optical mouse is determined in counts per inch, i.e. cpi, not dpi, like regular mice. Agilent produces both 400 and 800 cpi sensors, and 800 cpi models can be programmed to operate at 400 cpi. By the way, some companies in the technical characteristics of their optical mice claim a resolution of 420 or 500 cpi. But looking through the technical documentation for various sensors, I have not seen such characteristics. And it’s very hard to believe that some small Chinese company produces sensors of its own design, when such a recognized authority in this field of “mouse building” as Logitech buys them from Agilent. And if I already mentioned Logitech, I would like to add that most of its models, with the exception of the cheapest ones, are equipped with sensors with a resolution of 800 cpi.
But let's go back to technology. Keeping in mind that the sensor photographs a very small area of the surface, and the cursor on the screen must move smoothly and without lag, and for this to happen, sequentially read frames of the surface must overlap each other with a slight offset, the surface is photographed at a very high speed - 1500 pictures per second . This allows you to move the mouse at speeds of up to 12 inches (30 centimeters) per second. There are also sensor options that photograph the surface at 2000 or 2300 images per second and allow you to move the mouse at a speed of 14 inches (35 cm) per second. Moreover, Microsoft claims that its latest developments include sensors with a shooting speed of 6000 frames per second. Again, technical description at
I have not seen such a sensor, but I think that in this case it is quite possible. All of the above applies to the image reading system. Next, the captured frames are processed by a digital signal processor using a special, naturally patented, algorithm. By comparing the received frames, the processor determines the amount and direction of mouse movement (see Fig. 3), and then converts this data into coordinates.
Since the sensors are mostly quartzed by an oscillator with a frequency of 18 MHz (there are options at 24 MHz), we can assume that the power of the digital processor is 18 million operations per second. The calculated coordinates are then transmitted to the computer using a serial interface. The first models of sensors were able to “communicate” with a computer via the PS/2 interface, and to work via the USB interface an additional controller was required. By the way, the default frequency of sending coordinates when using the USB interface is 125 times per second, PS/2 - 100 times. But some parameters of the sensor itself can be set via the serial port - in particular, the resolution and frequency of sending coordinates.
Now let's look at the purpose of other components of the optical system. Since it is dark under the arm even during the day, the surface that the sensor photographs must be illuminated. The sensor camera is configured to perceive light in the red emission spectrum (l= 639 nm). That's why a red LED is used, the main task of which is to ensure the operation of the sensor on the entire working surface, even with a minimal amount of emitted light. The higher the brightness of the light, the more surfaces the sensor will work on.
To ensure uniform illumination of the surface, light from the LED passes through the light guide and is scattered by the lens. Through another lens, the sensor reads an image of the surface. Structurally, two lenses and a light guide are made as one part and are called the same word “lens”.
In addition to the function of scattering and focusing light, the lens performs another important function - protecting the sensor from electrostatic voltage discharge. It is clear that the lens must be located at a strictly defined distance from the working surface and from the sensor. Therefore, the printed circuit board (PCB) and the support surface (base plate), on which the elements of the optical system are installed, must have strictly defined parameters, including thickness. Well, the last element of the optical system is the latch. It serves to fix the elements of the optical system relative to each other.
At this point, we can leave the optical system alone and talk about the surface on which this system should work. Since the sensor uses microscopic features of the surface, the more such features, the better. These include surfaces with good texture (which any fabric has) and patterned features. And even on regular white paper, optical mice work quite well. But the sensor does not work well with any reflective surface, be it a mirror, glass, or just the plastic surface of a rug. Other “bad” surfaces include half-tone surfaces and rugs with a three-dimensional image.
But be that as it may, positive aspects such as the absence of moving parts, precise positioning, smooth and easy movements make an optical mouse a rather attractive purchase.
And if you take mice in the price category up to $20, then most likely they will have the same type of sensor and, accordingly, identical characteristics. In this case, you should pay attention to the ergonomics of the product, the presence
additional buttons, quality of materials and manufacturer's name. In addition, an important point for optical mice is the build quality. And if you hear the name of the company for the first time, then you should think about whether to buy such a mouse or not. In any case, before purchasing, it doesn’t hurt to read reviews on specific models.
That's probably all. Best wishes.
Igor Maslovsky, [email protected]
The light guide is raised above the chip
Lens and diffuser
View of the objective part of the optical mouse
Bottom view of the objective part in assembled condition
The mouse signal wire is sometimes seen as a nuisance and limiting factor. Wireless mice lack this factor. However, wireless mice have a serious problem - along with the signal cable, they lose stationary power and are forced to have an autonomous one, from batteries or batteries, which require recharging or replacement, and also increase the weight of the device.
Wireless mouse batteries can be recharged both outside the mouse and inside it (just like batteries in mobile phones). In the latter case, the mouse must be periodically connected to stationary power via a cable, docking station or induction power pad.
v Optical connection.
The first attempts were to introduce infrared communication between the mouse and a special receiving device, which, in turn, was connected to the computer port.
Optical communication showed a major drawback in practice: any obstacle between the mouse and the sensor interfered with work.
v Radio communication.
Apple Wireless Mighty Mouse
Radio communication between the mouse and the receiving device connected to the computer eliminated the shortcomings of infrared communication and replaced it.
There are three generations of wireless mice. The first generation used frequency bands intended for radio-controlled toys (27 MHz). They had a low sampling frequency (typically 20-50 Hz), unstable communication, and mutual influence when located close together. Such mice had a curious problem: since the range of action of these mice was several meters, and organizations, as a rule, purchased the same type of equipment in batches, there were cases when the cursor on the computer screen was controlled by a mouse located even on the next floor. Such mice, as a rule, have a switch that allows you to select one of two RF channels; in most cases, switching to another channel solved the problem. Currently, first generation mice are no longer produced.
Wireless mouse with dongle
Gigabyte Force M9 ICE Black wireless mouse with laser sensor
The second generation of radio mice used the free frequency range of 2.45 GHz and was built on the basis of highly integrated high-speed radio channels. In such solutions, it was possible to completely get rid of the “childhood diseases” of the first generation. The main disadvantage is the need for a special USB dongle, which contains the mouse receiver. This dongle occupies a USB slot on your computer. Losing the dongle makes the mouse a dead piece of hardware due to the incompatibility of radio communication methods from different manufacturers. The second generation mice are the most popular currently.
The third generation of radio mice uses standard radio interfaces. Typically this is Bluetooth or (much less frequently) other standard personal area network radio interfaces. Mice with Bluetooth do not need a special dongle, since modern computers are equipped with this interface. Another advantage of Bluetooth mice is that no special drivers are required. The disadvantage of Bluetooth is its high price and higher power consumption.
Induction mice.
Induction mice most often have induction power from a special working platform (“mat”) or graphics tablet. But such mice are only partly wireless - the tablet or pad is still connected with a cable. Thus, the cable does not interfere with moving the mouse, but also does not allow you to work at a distance from the computer, as with a regular wireless mouse.
Since the end of the 20th century, the production of accessories specifically for computer game lovers has been gaining increasing momentum. This trend has not spared computer mice either. This subtype differs from its regular office counterparts in its greater sensitivity (up to 8200 dpi for the Razer Taipan), the presence of additional, individually customizable buttons, a non-slip outer surface, and design. In high-end gaming mice, the weight distribution is adjusted - this is necessary to ensure that all the legs of the mouse are evenly loaded (so the mouse glides more smoothly).
Like any computer element, the mouse has become an object for modding.
Some mouse manufacturers add functions to alert the mouse about any events occurring on the computer. In particular, Genius and Logitech produce models that notify you of the presence of unread emails in your mailbox by lighting an LED or playing music through the speaker built into the mouse.
There are known cases of placing a fan inside the mouse case to cool the user's hand while the user is working with an air flow through special holes. Some mouse models designed for computer gamers have small eccentrics built into the mouse body, which provide a vibration sensation when shooting in computer games. Examples of such models are the Logitech iFeel Mouse line of mice.
In addition, there are mini mice designed for laptop owners that are small in size and weight.
Some wireless mice have the ability to work as a remote control (for example, Logitech MediaPlay). They have a slightly modified shape to work not only on the table, but also when held in the hand.
v Advantages and disadvantages
The mouse has become the main point-and-point input device due to the following features:
· Very low price (compared to other devices like touch screens);
· The mouse is suitable for long-term use. In the early days of multimedia, filmmakers liked to show computers of the “future” with a touch interface, but in reality this method of input is quite tedious, since you have to hold your hands in the air;
· High accuracy of cursor positioning. With the mouse (with the exception of some “unsuccessful” models) it is easy to hit the desired pixel on the screen;
The mouse allows many different manipulations - double and triple clicks, dragging, gestures, pressing one button while dragging another, etc. Therefore, you can concentrate a large number of controls in one hand - multi-button mice allow you to control, for example, a browser without using the keyboard at all .
The disadvantages of the mouse are:
· Danger of carpal tunnel syndrome (not confirmed by clinical studies); [source not specified 365 days]
· For work, a flat, smooth surface of sufficient size is required (with the possible exception of gyroscopic mice);
· Instability to vibrations. For this reason, the mouse is practically not used in military devices. The trackball requires less space to operate and does not require moving your hand, cannot get lost, has greater resistance to external influences, and is more reliable.
Computer mouse is a very useful and convenient graphical information input device.
Currently, almost every personal computer is equipped with this device. The Windows operating system and all programs designed to work in its environment are entirely focused on using the mouse. Virtually all actions in Windows, except typing, can be done without using a keyboard, using only one mouse. Moreover, without a mouse, working with Windows becomes significantly more difficult and slower.
Structurally, the mouse is a streamlined plastic box containing:
a massive rubberized ball that rotates when you move the mouse over a smooth surface;
two or three buttons;
mechanism for converting ball rotation into electrical signals;
electronic circuit for receiving and processing data about the state of the mouse (mouse coordinates and button positions).
The mouse is connected to the computer system unit with a flexible cable. Sometimes, instead of a cable, infrared rays are used to connect the computer to the mouse. In this case, there is no mouse wire and does not interfere with work.
The figure shows the internal structure of a mouse. The figure shows the following required mouse components:
1. Photo emitter
2. Photodetector
3. Ball (usually it is covered with rubber for better grip on the table surface.)
4.Rotating roller
5.Press wheel
6.Button
7.Cable
8.Controller (special chip)
Currently the most common optomechanical mice . Their popularity is primarily due to their low cost. The rotation of the rubberized metal ball when moving such a mouse is transmitted to two rollers. One of them is located along the mouse, and the second - across. This is what “mechanics” consists of. The rotation of the rollers is converted into an electrical signal using optoelectronic sensors consisting of an LED and a receiver, between which there is a disk with slot-like slots mounted on the roller. As the disk rotates, the LED beam either passes through the slits or is interrupted, and pulses are formed at the output of the receiver. The built-in microprocessor counts them and generates a digital code that is sent through an interface to the PC, where it is processed by the driver. The optomechanical mouse has two unreliable elements. First, there is a mechanism that turns the movement of the ball into rotation of the sensor disks. Secondly, the connecting cable, which is constantly subject to bending during operation.
To eliminate the first drawback, instead of a ball, a number of modern mouse models use optical motion sensor . These mice have no moving parts, so they have high positioning accuracy. The first models of such devices were supplied with a special “lined” mat. When moving, the sensor worked like a primitive scanner, converting alternating dark and light areas on the rug into electrical impulses. Modern optical mice can work on almost any surface - the sensor responds to the natural uneven reflectivity of the material. Instead of a ball, a sensitive optical sensor is placed in it, capable of tracking the movement of relatively small textures on the sliding surface (mat, sheet of paper, etc.), invisible to the eye, not to mention scratches and other mechanical and color inhomogeneities. Their movement in the field of view of the sensor is converted by a specialized processor into an increment of linear coordinates corresponding to the movement of the user’s hand. The surface under the mouse is digitized at a frequency of 1500 times per second.
