xod/docs/tutorial/20-fade

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Smoother Changes

#20. Smoother Changes

Note This is a web-version of a tutorial chapter embedded right into the XOD IDE. To get a better learning experience we recommend to install the desktop IDE or start the browser-based IDE, and you’ll see the same tutorial there.

In the previous examples our servo turns to the set angle at its maximum speed. High speed is not always necessary and can damage the servo itself if the shaft hits an obstacle.

Let’s improve our patch by making the servo move more smoothly. To achieve that, we’ll need to set the VAL pin value along with a series of transitional values. There’s a node for that, and it's called fade.

The fade node is in xod/core. This node returns a smooth series of transitional values, so it will smoothen our servo motion.

• The TARG pin waits for a target value.
• The RATE pin is a number that defines amount of change for the transitional values per each second.

The output pin returns 0 at the start of the program. Then, it starts to move toward the TARG value by the RATE steps. The value of the output pin is saved, so if the TARG value changes, the output will start to move to this value from the last one returned.

Test circuit

Note The circuit is the same as for the previous lesson.

↓ Download as a Fritzing project

Now, the servo will turn at a speed of 18° per second (0.1 = 18°).

Next lesson →