# Try This: Get Familiar Z-Axis Angle Measurements

The previous page Did You Know? This Way Up explained how to use arccos to calculate the angle between the micro:bit’s z sensing axis and gravity.

When the LED display is facing straight down, so is the z sensing axis.  So the angle between z and gravity is zero.

As the angle between the z-axis and gravity increases, so does the measurement.  When the LED display (and z-axis) is facing straight up, it’s angle is 180°.  Again, rotating past 180°, the angle decreases, like the last example where it’s back down to 135° again.

### Example script: z_axis_degree_of_tilt_try_this

• Enter and save z_axis_degree_of_tilt_try_this.
• Flash it into the micro:bit.
```# z_axis_degree_of_tilt_try_this

from microbit import *
import math

sleep(1000)

while True:
z = accelerometer.get_z()

if z > 1024:
z = 1024
elif z < -1024:
z = -1024

z_angle = round( math.degrees( math.acos( z/1024) ) )

print("z =", z, ", z_angle =", z_angle)
print()

sleep(750)```
• Open the terminal and experiment with various levels of tilt and rotation.

• Fill in the table with your measured z_angle values.
z z_angle Direction LEDs are facing
1024 0 Straight down
728 45 Half way between straight down and sideways
Sideways
-728 135 Half way between sideways and straight up
-1024 180 Straight up
Half way past straight up on way to sideways
Tilted toward you by 45°
Tilted away from you by 45°
GND corner tilted down by 45°
0 corner tilted down by 45°