xod/docs/tutorial/15-buttons

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Buttons

#15. Buttons

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.

So, buttons! They could be read with a button node from xod/common hardware. The node makes all the work related to signal debouncing so that you have not to bother about it.

The button node has a purple output pin called the PRS. This pin returns a new type of data: boolean.

Boolean data can have either of two values: true or false. In our case, the button node returns a value of false when idle and true while the button is being pressed.

Good news, in XOD boolean and number data types are compatible. Here are two rules of datacasting:

• Boolean-to-number: if you send a boolean false to a numeric (green) input, it will be interpreted as a numeric 0; if you send a boolean true, it will be interpreted as a numeric 1.
• Number-to-boolean: if you send any numeric value except 0 to a boolean (purple) input; it will be interpreted as true, and if you send 0, it will be interpreted as false.

Test circuit

↓ Download as a Fritzing project

How-to

Let’s bind a button with the LED.

1. Add a xod/common-hardware/button node.
2. Set the PORT value.
3. Link the PRS button output to the destination pin (LUM of the led in our example).

Now, when you press the button the button node sets the PRS pin to true, the led node (LUM pin) interprets it as 1, and the LED turns on at full brightness.

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