How to make a stylus for a capacitive touchscreen

Good day to you, dear habro-readers.

I want to offer you a material which I hope will be of interest to the handy enthusiasts. And it may even be useful to someone.
')
Some time after I became the owner of a mobile device with a capacitive touchscreen, I had the obsessive idea that it was more convenient to perform some actions with the help of a strange magic wand.

First of all, my research brought me to the store where you can traditionally find such things. But to my disappointment, the blunt specimens that were there in the assortment caused skepticism.



The shape and accuracy of the hit was not far from the fingers, and the screen's reaction was worse. The sensor picked up the touch only after a little pressure. The usefulness left doubts. I had to abandon the purchase.

In my opinion, ideally, the form should have been pointed. It is like a drawing pencil, which can produce precise movements. But as far as I managed to find out, this form is not suitable for a capacitive screen. Apparently it is focused on contact with a larger area of ​​contact, comparable to the touch of a finger.

We managed to find a couple of interesting articles and videos on this topic - use the negative pole of the battery and twist an antistatic film into a tube . Alas, both options did not suit me. The battery thickness is the same finger. And twisting the tube every time can be convenient for someone, but this is clearly not for me.

There are doubts about the feasibility of the idea. Due to the wide spot, it will not be possible to accurately direct the touch. Yes, and conductive material, usually metal, will scratch the surface of the screen.

As a result, the output was found.


It turns out that the ring-shaped form is quite perceived by the sensor and, moreover, the center is visible. Balagodarya what you can see where you direct and fall.

The secret of the miracle wand is simple: a steel washer (any other conductive material will do), an aluminum rod (the same should be a conductor) and a skein of thread.



Thanks to a cryptographic analyzer which, by the way, this time was used for peaceful purposes. Thanks to improvised means from home tools, we get something similar to a dentist's tool.



The handle must be soldered at an angle that will be as compatible as possible with the natural position of the hand and the full adherence of the ring plane to the screen surface.



Of course, it would be possible to stop at this, but such a design would scratch the screen and has no chance of getting high marks from habra readers :)

This problem was successfully solved with the help of ... thread.

Ring-shaped edge is good not only because it allows you to more accurately aim through the center, but also because it allows you to wrap yourself with a thread. Some doubters seem that an additional layer of thread will degrade the sensitivity of the screen. But it is not. As you know, to determine the touch sensor does not need absolute contact. It is enough to bring the finger very close. In this case, the touch may not be.



In conclusion, I will say that I was pleased with the result.
- The reaction is the same as on the finger. No need to press.
- Does not leave marks, does not scratch and even wipes the screen.
- Accurate sight.

We work with the Android shell


There are disadvantages
- Since the principle of operation is based on the passage of current through the metal stylus to the human body. That is, it will not work in parchatki.
- On my model of the communicator, the lower touch buttons (“back”, “menu”, “house”, “search”) do not work as well as we would like.

Typing text


PS Believe it or not, but after all this was written and prepared all the accompanying pictures / video, I learned that one Canadian manufacturer already produces styluses of a similar design. I found out about this when I uploaded the first video to YouTube and it issued similar videos. The idea was not new, and I began to doubt whether to send this article to the broad masses, as it is possible to undergo attacks related to accusations of plagiarism. Then he decided, since such a decision was launched into mass production, it means that the construction was successful and it was all invented for good reason. Despite the fact that there was a coincidence of a good idea, it’s still worth telling :)

PS v 2. Some readers were interested in the suitability of the structure in the winter conditions of our harsh regions. It turned out that in this case, this device may be useful, although the sensitivity certainly deteriorates. I tried the thickest gloves that I had. If the handle is squeezed harder, the reaction gets a little better.



And one more example of sketching notes by hand: