xod/docs/tutorial/14-map-adjust/README.md

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Adjusting Map Range

#14. Adjusting Map Range

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.

After the previous lesson, the map node linearly maps the 20–50°C range to the 0–90° servo rotation. Let’s raise the sensitivity. Say, we want to map 15–30°C to 0–90° rotation.

However, what will happen if the X pin of the map receives data that is outside the input range (10 or 42, for example)? The output value which is a servo angle will fall outside the desired range too.

For such cases there is a sibling node called map-clip. It works the same way, but any input that is out of range will be rounded to Smin or Smax. Thus, if X receives a value of 10, the map-clip node will accept it as 15, and 42 will be accepted as 30.

Test circuit

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

↓ Download as a Fritzing project

How-to

Just use the map-clip instead of the map if you want the output range to be guaranteed.

If you prefer °F, you can easily translate the data from the thermometer with the c-to-f node from xod/units. The range will be 59–95°F.

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