Official reseller of Sensu Brush in Russia. How Capacitive Screen Styluses Work

A stylus is a pen-like instrument designed for tablets and computers with touch screens. Stylus can be used to select menu items, draw, write notes, sign documents, and more. This document describes various ways to use the stylus, how to solve various stylus-related problems, and how to solve touch-screen problems before and after using the stylus.

Understanding stylus technology

Active stylus(also known as a digital stylus) uses a digitizer built into the screen to communicate between the touch screen and the stylus. The active stylus can support many or all of the functions performed by a mouse, such as right-clicking, hovering, and more. Many models of active stylus can block accidental touching of the screen with the hand lying on the screen or palm movements while writing, and the screen will register only touch of the stylus.

Passive stylus(also known as a capacitive stylus) acts just like a finger. Passive styluses do not require batteries and will work on any touchscreen device.

Differences between active and passive stylus

This section describes some of the differences between active and passive stylus.

Note.

Components marked with an asterisk (*) may not be available on all active styluses.

Passive stylus problems

The stylus does not work

If you are trying to use a passive stylus, but the touchscreen does not respond to touch, use your finger to test the screen for functionality. To resolve this issue, see HP PCs - Troubleshooting Touch Screens (Windows 10, 8).

The stylus is skipping, inaccurate, or erratic

If the stylus is skipping, the tip may be too small to be recognized by the screen. Small tip precision styluses are only available on computer models that support active (digital) stylus.

Problems with active styluses

Short battery life

Most active styluses will automatically turn off if left unused for a while to save energy. Improper storage of an unused stylus can drain the battery. Place the stylus flat and make sure there is no pressure on the tip or buttons.

Stylus accuracy issues

If the stylus is unstable when your hand touches the screen, make sure the tip of the stylus is at least 5 mm from where your hand touches the screen.

The touch screen stops responding to finger touches during and after using the stylus

If your system supports accidental touch lock, the touch screen will not respond to touch when using the active stylus. The screen will begin to recognize your finger 1.5 seconds after using the stylus.

If the touchscreen responds slowly to manual input after using the stylus, you may need to update the firmware for the touchscreen.

Enter your model number in the box Enter your HP product name, product number, or serial number, For example: HP Specter 15-bl000 x360 Convertible PC, then click Find.

If a list of model numbers is displayed, select the model number from that list.

The software and drivers page for your model is displayed.

Make sure in the box Detected operating system the correct value is specified. If necessary, click Change, select your operating system and version, and then click Change.

Click Firmware.

If a touchscreen firmware update is available, click Download next to the update.

Follow the instructions on the screen to install the firmware update.

How the Galaxy Note stylus works.
From the first day of use, I was very interested in the question - how, on an ordinary capacitive screen, which perceives only a certain area of ​​touch, it was possible to achieve the work of a thin stylus, and even with a button and several degrees of pressing?

In this article I will try to answer this question by talking a little about the interesting technical solutions used in this phone.

First, let's remember the theory.

The capacitive screen determines the point of contact by the leakage current when the capacitor is charged, in the role of one plate of which is the phone screen and the other - the human body. The back of the glass in your smartphone has thin lines of transparent conductive material (you can see them when you look at the screen from a certain angle in good lighting).

Capacitive sensor: mini-capacitors (in the form of the letter H) and conductors between them.

The touchscreen controller charges and discharges these capacitors with limited current many times per second, each time measuring the capacitance of each and comparing it to the standard capacitance stored in memory. As soon as you touch the glass with your finger, you become such a large capacitor plate that you can charge.
Naturally, this will require energy, which is closely watched by the controller. As soon as he discovers that any cell begins to consume a lot of energy (a lot is compared to normal consumption, but even for a conventional LED it is crumbs), which, with a limited current, turns into an increase in the charge time - he realizes that there is something to the glass. then touched.

Based on information from several capacitors, it is possible to calculate the place and area of ​​contact using rather complex formulas. Or a few touches, the number of simultaneously detected touches is limited only by the controller and the screen size (it is very difficult to fit 20 fingers on a 3 "screen).

This technology has several limitations. For several reasons, such as the inability to arrange the elements tightly enough (transparency decreases), limited conductivity of the glass, and the need to cut off interference from accidental touches, interference, dirt on the screen, etc. had to be content with a minimum contact area of ​​5x5 mm.
In addition, the object that touches the screen must have a sufficient intrinsic capacity, comparable to that of the human body. What do we get as a result? The inability to use gloves (most of them have a sufficiently large resistance to reduce the leakage current to a minimum that is not detected by the controller), the need for large stylus, which must be galvanically connected to the user's body (therefore, most of them have a metal case).

What input systems work with stylus, can sense pressure, and have excellent accuracy? These are the electromagnetic antenna systems that are used in the vast majority of graphic tablets.

Wacom pen tablet with stylus:

The principle of their operation is also not prohibitively complicated - the stylus transmits at a certain frequency, and the antenna inside the tablet receives it. The controller can find out the exact position thanks to the clever shape of the antenna, and information about the pressure on the stylus is transmitted by frequency or code messages.

Tricky antenna inside a graphics tablet:

The exact same system is implemented inside the Galaxy Note (both I and II). Above there is a glass, on the back of which there is a capacitive sensor, under it is a screen, and under it is a receiving and transmitting antenna for the stylus.
Here, to make it clearer - I drew a picture.

And here is the Wacom touchscreen controller (blue) that manages all this cunning economy, and the cable to the antenna (green):

However, an approximate description of the technology is not at all sufficient to satisfy my curiosity. Just a little more, and I would have dared to disassemble the stylus, but I found the site of fellow microsin, who had already done this. Photos of the disassembled stylus belong to him.
This is how it looks from the side:

Part of the body is removed with sandpaper. There are no batteries, so the pen is powered by the screen. The transmit-receive coil is closer:


And now without the case:


And the fee:


The scheme is very simple, to some extent even "clumsy". But beautiful and without unnecessary complications.


The simplest oscillatory circuit with a variable resonant frequency. The frequency can be changed either by changing the capacitance (an additional capacitor is connected through a button, and, accordingly, responds to its pressing), or by changing the inductance - by changing the distance between the two parts of the core on which the coil is wound.

And the distance changed due to pressure on the tip of the stylus - it was transferred to the soft silicone pad, and led to a change in its shape. and hence the gap.
What am I telling you, I have a photo:


It is the same, 1 - a ring-gasket, 2 - the second part of the core, 3 - a tip.
The tip also consists of two parts - a plastic support and a fluoroplastic tip:

Interestingly, a stylus with such a design does not need a screen as such; to detect a touch, you just need to bring it to the screen and press the tip with your finger, and the controller will register the press anyway.
If you fix the tip of the stylus with tape, you can draw with strokes without touching the screen.

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Nowadays, capacitive touch screens are replacing resistive screens more and more actively. This type has obvious advantages: this type of sensor is more robust and durable due to the fact that the flexible resistive membrane in it is replaced by a grid of electrodes. The capacitive screen supports more touches than its sibling, it is more transparent, and only for it the multitouch technology, which is popular today, is now implemented.

Need for a stylus

The difficulty lies in the fact that using your fingers to work with the interface is not always convenient, and in this case there are no other options. This is quite noticeable when drawing or entering handwritten text on the tablet screen, as well as in winter, when you don't want to take off your gloves on the street, but certain manipulations need to be made. At such moments, many would use a stylus for a capacitive screen. Many may remember the convenience of using such a manipulator if they once owned smartphones with resistive screens. It allows for more precise manipulations. But the capacitive screen does not respond to the touch of an ordinary stylus, since it requires a certain capacitance to work with it, which accepts and conducts an electric current with a low voltage. Mobile phone manufacturers are also ready to offer a stylus for a capacitive screen. It can be different in appearance, but it is made from special conductive materials. The stylus for a capacitive screen has a fairly simple device that allows you to make it yourself.

Varieties

The mobile gadgets market offers four types of stylus models:

In the form of a brush;

On a sponge;

Rubber;

Plastic.

Available options

The stylus model SPMP 1019, designed for iPhone, iPad, HTC and Samsung screens, belongs to the second category. This model is considered inexpensive, and high quality is ensured through the use of a metal case. The presence of a hook, similar to that on a ballpoint pen, allows you to conveniently fix it. Its disadvantage is fragility. This gadget will not lose its tactile properties at low temperatures. At the moment, the most convenient stylus for a capacitive screen is made of conductive rubber. It has design features that provide a seamless touch experience with your fingers on the screen. The tactile response of such devices is considered to be the highest. The degree of depression is easily adjustable.

From what was written earlier, it should be clear to you that the market is ready to provide a huge variety of options for this device. However, the question of how to make a stylus for a capacitive screen can be of concern to many. Here you can recommend the following set of tools: an embossed pushpin, nail file, metal pen, tin, soldering iron, glue, copper wire, self-adhesive, battery. The wire should be soldered to the button, after which the workpiece should be pushed into the handle body, and glued at the end. Stick the self-adhesive on the button, and cut off the remains. The other end of the wire should be fixed to the battery, close the handle body. The stylus for the capacitive screen is ready!

The market of modern gadgets has decided to remind us again of the already forgotten stylus. Branded "sticks" were recently presented by Apple; Samsung is releasing a line of S Pen styluses for its Galaxy Note product. Such a device is also convenient for those who like to draw on the screen of their smartphone or tablet. It is quite possible to make a stylus with your own hands quickly and without the use of expensive materials.

Resistive, capacitive and heat shield

If you are eager to make your own stylus, then first of all find out the type of touch screen of your device - this will directly affect the materials for your craft:

• Resistive screen... This type reacts to absolutely any touch - with a finger, a sushi stick, a pencil, etc. Choose what you like best and your stylus is ready!
• Capacitive screen... This touchscreen only reacts to the touch of conductive objects. A person also refers to them to some extent - our fingers, like ourselves, conduct current. This quality is possessed by all organic substances and creatures, as well as most metals.
• Heat shield... As the name suggests, the display will only respond to the touch of an object that emits heat. That is why it is difficult for us to work with such screens in the conditions of Russian frosts.

Do-it-yourself capacitive stylus assembly

First, stock up on:

• ballpoint pen;
• aluminum foil;
• cotton swab;
• scotch tape;
• scissors.

The assembly of a capacitive stylus looks like this:

1. Remove the refill from the ballpoint pen.
2. Cut off half of the cotton swab at a sharp angle. Insert it into the place of the rod in the handle with the cotton head outward.
3. Tape the cotton swab into the handle.
4. Take a piece of foil and wrap it tightly around the handle, 1 cm away from the cotton head.
5. Secure the foil wrap with a piece of tape. Your DIY stylus is ready!

To use this device, you need to have a glass of water on hand - for optimal performance, the cotton swab will need to be moistened from time to time. The capacitive screen will not deteriorate from the moisture in the stylus. Also remember to keep your fingers on the foil all the time - this is necessary in order for static electricity to act on the display.

Additional ways

You can make a stylus for a capacitive screen with your own hands in a slightly different way. For instance:

1. Take an aluminum tube and attach a piece of anti-static sponge to one of its ends, which can be found in chip boxes.
2. You can build a stylus with your own hands from the same pen without a rod, replacing the cotton wool with paper, and the foil with metal packaging for chocolate, coffee, tea, etc.
3. Some users prefer to use a thin battery as a stylus, bringing its negative pole to the screen.
4. You can use one anti-static film rolled into a tube, securing its shape with pieces of tape.
5. A lightweight aluminum stick that does not scratch the screen is also a good stylus. Only its head should not be too small, otherwise the screen simply will not "see" this object.

DIY thermal stylus assembly

You will need:

• feather pen;
• gel pen with an elastic band for fingers;
• a piece of foil;
• a piece of a dish sponge or washcloth;
• a piece of cellophane.

It's easy to assemble such a stylus:

1. Leave only the body of the helium pen, and the rubber band from the nib.
2. Dampen a sponge with water.
3. To avoid streaking on the screen, wrap the sponge in cellophane.
4. Now insert the cellophane-covered sponge into the handle. You can push it with the same helium rod, slowly - so as not to harm the bundle. As a result, only the sponge ball wrapped in a bag should be visible from the handle.
5. Remove the finger elastic from the handle.
6. Fold the sheet of foil twice and twist a thin flagellum out of it.
7. Place this foil rod so that one end touches the sponge and the other wraps around the body of the pen.
8. Make several turns of the flagellum, put the elastic in place. The part of the foil that will stick out over the elastic can be cut off. The stylus is done!

As you have seen, making a stylus with your own hands is a rather "cheap and angry" easy way, both for a thermal screen and for a capacitive screen. For a resistive display, any convenient handy item can be used as a stylus.

Touchscreens are all the rage these days, and it seems that stylus has become a relic of the past, thanks to new technologies and better finger response on the smartphone screen. But when it comes to phablets like the Samsung Galaxy, adjusting the S-Pen is certainly useful for more precise and sharper actions (and the fat minus of the screen).

Of course, there are drawbacks to using a stylus, and there are questions. Unlike a finger, the S-Pen can malfunction and become a huge problem, preventing you from exactly how to use it and getting used to it quickly. So if you're having trouble and excitement with light touches, or worse, you have to push hard on your pen to register, here's what you can do.

I firmly believe “ if you guessed right then this will work”Theory of the mid-80s. If you press on any device malfunction with just the right strength and without anger at it, as a rule, this will fix the problem. And that goes for the S-Pen Application as well. Take your stylus, and slam it decently hard on a flat surface. It is so simple. Now, if it doesn't work, you can take more technical and less energetic routes to help tune your Samsung S Pen.

Install potentiometer

A potentiometer is an electro-mechanical transducer that converts the movement of your pen into electrical resistance (or something similar). This is basically what makes your stylus work on the screen.

And guess what?

You can open your Silus and adjust it to suit you, no matter what TSilus you have. This will work for Samsung Galaxy Note's, Galaxy Note II and Galaxy Note 10.1 that have an S Pen, or just about any other stylus with button. This won't work on any regular Stylus without buttons.

You need to remove the button on the S Pen. You can simply cut it off with a razor. And don't worry, it can be put back in place, no problem.

When this button is disabled, you will have access to the potentiometer.

The potentiometer on the LEFT in the picture above and below is what you will need - Setting.

With a razor or small screwdriver, you can turn the potentiometer clockwise to decrease the sensitivity and counterclockwise to increase it. Try it out and see if it works to your liking, then set the knob again.

This tip might work with a bunch of other pushbutton styluses as well, not just the Samsung branded version, but won't work on regular conductive styluses as all they do is simulate fingers.

P.P.S. If you have any problems or need further help, feel free to ask. We have a special, dedicated stream set up on our site to deal with any questions you may have.

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