If the quality of the spin measurement is too low, the app may display the speed result but no spin value. There may be several reasons for this and possible solutions.
Too much spin
If you put too much spin on the ball, it can’t be measured. The measurement range goes up to 150 rps (revolutions per second). Values above 150 rps are reached by very few players (mostly pros) on powerful topspin shots. With the Team Pro version, you get access to experimental features that let you increase the measurement range.
Wrong ball type
The spin measurement requires SPINSIGHT balls. It does not work with normal balls or balls for the Elite system. Sometimes the balls get mixed up. Check that you are using a SPINSIGHT ball.
Camera focus not good enough
If the camera focus is not good enough, the dots on the ball are too blurry to detect the spin. Run the measurement again to correct the focus.
On iPhones, the camera focus can change after a few minutes, especially if you performed the calibration with a cold phone. If you notice that more and more balls are not displaying the spin value, perform the calibration again. After that, it should remain stable.
A player is moving in the camera image
If a player is in the camera image, this can interfere with ball detection. This occurs mainly with short balls played over the table. Or when ball buckets are played over the table near the net. The closer the player is to the net, the greater the risk that ball detection will not work.
Increase the distance to the net to reduce the problem. You can also change sides of the table, as the camera cannot see the corners of the table on the side facing the camera.
Unstable image background
If the background of the measurement is not smooth and dark, measurement problems may occur. Try placing a dark border behind the table to give the measuring camera a better background.
Light reflection on the table
If light from lamps or windows is reflected on the table, measurement problems may occur in some areas. Try placing the measuring mobile phone on the other side of the table, moving the table or using a different table.
Not enough light
In dark rooms, measuring serves may work well, but fast topspin balls may cause problems. If possible, turn on more lights.
Too much light
In very bright rooms and direct sunlight, measuring serves may work well, but fast topspin balls may cause problems. Avoid direct sunlight if possible.
Uneven light
If you use additional light sources that only illuminate parts of the table, or light sources that have an uneven pattern, measuring fast balls may be problematic. If possible, try to achieve uniform lighting.
Flickering light
If the room is lit with flickering fluorescent tubes or flickering LEDs, measurement problems may occur.