# Use of the system

## What does eFly measure The figure shows the rod under the load of the cast forward. The correctly positioned eFly sensor is represented in red and the rod deflection in green. As you can see, the position of eFly is such that it is hardly affected by the inflection of the rod. Therefore all the inertial values ​​measured describe what happens at the level of the handle of the rod. What happens to the tip of the rod can only be hypothesized but not measured. However, this does not constitute a limitation as the actions and reactions are transmitted and received by the sensor in the vicinity of the angler that generates the movement. In short, eFly is the recorder of the actions generated by the fisherman and not of the effect that these actions produce on the line. With eFly it is therefore possible to know what are the kinematic characteristics of the movement of the rod which in turn are the result of the player's action and the inertial reactions of the rod and line.

Now let's see what are the quantities that eFly is able to measure, their units of measurement and their meaning.

### Angles

Angles are measured in degrees and are defined as we have already seen above.

Through the three angles it is possible to express the position of the rod at any moment of the cast. The most important of the three (primary or frontal angle) is the one that expresses the orientation of the rod with respect to the horizontal position with the tip towards the target. The zero angle corresponds to the horizontal position of the rod, 90 degrees correspond to the vertical and so on. The time convention is also used for angles.

#### Front Angle  The horizontal direction (zero degrees) is conventionally made to coincide with 9 o'clock. The vertical position (ninety degrees) with 12 o'clock.

Degree Hour
0 9
30 10
60 11
90 12
120 1
150 2
180 3

#### Side Angle  The target direction (zero degrees) is conventionally made to coincide with 12 o'clock. The right direction (minus ninety degrees) with 3 o'clock.

Degree Hour
-90 9
-60 10
-30 11
0 12
30 1
60 2
90 3

#### Pole Angle  The reel vertical direction (zero degrees) is conventionally made to coincide with 6 o'clock. The left position of the reel (ninety degrees) with 9 o'clock.

Degree Hour
90 9
60 8
30 7
0 6
-30 5
-60 4
-90 3

### Angles Rate

Angle eate or angular velocity is measured in degrees per second and expresses the rate of change of the angle. The value of the angular velocity is directly related to the peripheral velocity of the rod pole. As you go up towards the tip, the peripheral speed undergoes a delay which is greater the greater the flexibility of the rod. With any rod, the instant of maximum speed of rotation does not coincide with the instant of maximum speed of the tip. The latter is always delayed by a few degrees (and moments).

The difference is quite small for properly balanced rod-line systems. For considerations we can, with a good approximation, say that the point of maximum frontal speed in the back must be close to 1 o'clock, in the down close to 11 o'clock.

### Accelerations The linear acceleration measured by eFly is referred to the reference system of the sensor shown in the figure. The trend of the accelerations is directly linked to the forces that the angler exerts on the rod and to the inertial reactions of the rod itself. During the casting action the directions of the frontal and vertical accelerations change continuously and it is interesting at what moments the force is exerted. When reading the acceleration graphs it is important to remember that the measurement reference system is integral with the rod, as shown in the figure.