# How to analyze skateboarding using PVDF film

A couple of months ago, I replayed the Tony Hawk Pro Skater and decided that I would also be as cool as the main character of the game. The plan looked like this:
2) I magically learn to do all the tricks;
3) Heifers, cars, money, sponsors, fame.

As you know, the path to heifers and money turned out to be a little longer than I imagined. One of the important problems that I encountered is the inability to analyze my own achievements. Even if I perform the trick, I can’t say how right. I can’t say for sure even to what height I jumped - what can be done to more subtle moments. Because of this, the learning speed drops.
I tried to shoot my attempts on camera, but it came out very badly. Firstly, there is only one angle, secondly, it takes a lot of time to view. If the skiing place is surrounded by cameras from all sides, then I will look very strange and the heifers will still bypass me.

In this article I will try to find a solution to this problem using quite a technical means. I ask you to perceive this as a question open for discussion rather than an answer, since the real solution, of course, requires a deeper study.

So, we need to remove two types of parameters:
1) The position of the legs on the board, as well as the force of pressing the board in different places.
2) Speed, revolutions in the air, lifting height.

##### Skateboarder foot position and push force

I see a solution to the problem of using a piezoelectric layer in a skateboard that would generate current using a direct piezoelectric effect. I recently worked with PVDF, and of course it seems to me to be a good candidate for the role of such a layer. PVDF is inert, has good strength, wear resistance, temperature conditions also suit us.

A similar layer should be under the skin (coating), directly on the deck. The skateboard diagram shows in which place. Putting the film on the deck is impossible due to serious physical exertion.
Unfortunately, to obtain the piezoelectric effect, it is necessary to deal with the polarization of PVDF, which is associated with very high voltages, and in industrial production it is not as fun as in the laboratory.
The main problem that I can’t overcome at the level of a mental experiment is the coordinate grid. Okay, PVDF generated a current, we were even able to understand the force with which the skater stepped on the board. But the position of the legs remains a mystery to us. The solution so far is seen only within the framework of matrix touch screens , but I do not like their structure, since it is completely not adapted for serious physical exertion.

##### Speed, RPM, Altitude, Data Transfer

Here everything has already been thought up to us. Gyros are riveted in tons at Chinese factories to take their place on the iPhone, and the accelerometer was still in my old LG player. The question is to design the circuit, since I originally intended to use the Rasberry Pi, but there are no such features.
Data transmission should be carried out via Bluetooth 4.0, the benefit of it is more than enough to transfer simple parameters. Synchronization happens with the phone.

##### And why?

We have in our pocket all the necessary parameters and here the fun begins. It was not for nothing that I mentioned a computer game at the beginning - it is transferred to reality. In addition to solving purely practical issues, such as comparing results and underlining errors during execution, this is gamification of a very real action. For all the jumps, you can earn points, you can take quests and complete them, you can use the data and compare them with friends - the scope for such actions is simply huge, and I will try to describe the specific application in the next article. It is important that we turn training into a game, and also add an element of sports to that activity, which is mostly individual.

In essence, I propose to discuss several issues: