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 IDE, launch it, and you’ll see the same tutorial there.

Now, let's learn how to work with conditionals in XOD.

We will measure a lightness level, and if the values exceed or are below the threshold, we will turn an LED on or off.

XOD has greater-than and less-than nodes to do simple mathematical comparisons. They are in xod/core.

The LHS and RHS pins receive numbers to compare, and output pins return the comparison result expressed as a boolean value (true or false).

Test circuit

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

↓ Download as a Fritzing project

How-to

Place a xod/core/less (or greater) node to trigger an action when a measured parameter goes under (or over) a threshold value.
Use the LHS pin to link the value measured.
Set the threshold as the RHS pin value.
In cases where figuring out the proper threshold is tricky use a value from a potentiometer to adjust it dynamically.

In the example shown, if the analog-input node (our photoresistor) returns a value greater than the threshold, the greater node will set the GT pin to true, and the LED will turn on.

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#18. Comparing Numbers

Test circuit

How-to

README.md