2.7 KiB
Acceleration
Get the acceleration value (milli g-force) in one of three dimensions, or the combined force in all directions (x, y, and z).
Find the acceleration of the @boardname@ (how fast it is speeding up or slowing down).
input.acceleration(Dimension.X);
~hint
You measure acceleration with the milli-g, which is 1/1000 of a g. A g is as much acceleration as you get from Earth's gravity.
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Watch this video to learn how the accelerometer on the @boardname@ works:
https://www.youtube.com/watch?v=byngcwjO51U
Parameters
- dimension: the direction you are checking for acceleration, or the total strength of force.
x: acceleration in the left and right direction.
y: acceleration in the forward and backward direction.
z: acceleration in the up and down direction.
strength: the resulting strength of acceleration from all three dimensions (directions).
~hint
Forces in space
Since we don't live on a flat world, forces happen in three dimensional space. If the movement of an object isn't exactly in the direction of one axis, we need a way to calculate its acceleration from the values measured for all the axes together.
If you put your @boardname@ on a level table and push it diagonally, you have an acceleration in two dimensions. You can find the acceleration in that direction just like how you calculate the long side of a triangle using the two shorter sides (X and Y):
strength2D = Math.sqrt((accelX * accelX) + (accelY * accelY))
If you decide to lift your @boardname@ off the table, then you've just added another dimension, so insert the acceleration value for the Z axis into the equation:
strength3D = Math.sqrt((accelX * accelX) + (accelY * accelY) + (accelZ * accelZ))
This calculation is called the Euclidean norm of acceleration.
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Returns
- a number that means the amount of acceleration. When the @boardname@ is lying flat on a surface with the screen pointing up,
xis0,yis0,zis-1023, andstrengthis1023.
Example: bar chart
This example shows the acceleration of the @boardname@ with a bar graph.
basic.forever(() => {
led.plotBarGraph(input.acceleration(Dimension.X), 1023)
})
Example: quake meter
Every 5 seconds, with the @boardname@ facing upward on a flat surface, show how much the earth is shaking (if at all).
basic.forever(() => {
basic.showNumber(input.acceleration(Dimension.Strength))
basic.pause(5000)
})