#10. Doing Math

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.

You probably noticed that pins have different colors.

The pin’s color indicates the type of data that this pin is compatible with. Green pins can take and return numerical values. Blue pins work with pulses, a special data type that we will return to later.

Let’s try to do some math.

Patch

As you can guess, the multiply node transfers the result of the multiplication of the numbers from the input pins (IN1 and IN2) to the output pin.

In xod/core, you will find nodes for different mathematical and trigonometric calculations. Along with the multiply node, you will find add, subtract, and divide for very basic computations.

Test circuit

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

Circuit

↓ Download as a Fritzing project

How-to

  1. Add a new multiply or another math node to the patch.
  2. Link its left input to the first value provider.
  3. Set the right input value with the Inspector or link it to an output too.

Screencast

Turn the potentiometer knob. If you have followed the example. The LED on port 11 will reach the maximum brightness with a half-turn of the knob. This happens because the multiply node multiplied the input values and transferred them to the OUT pin. As IN2 was set to 2 in the Inspector, the value of the pot node doubles before reaching the LUM pin of LED2.

Next lesson →

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