Page 107 - Programming the Photon Getting Started With the Internet of Things

void loop() {
int val = analogRead(POT);

int ledval = map(val, 0, 4095, 0, 255);

analogWrite(led, ledval);

delay(200);
}

We can take a look at the code in the following stages to understand better what it is

doing:

Create an integer called val and assign it a value of 0.
Scale the analog read value, which runs from 0 to 4095, to the analog output value,

which ranges from 0 to 255.
Write the potentiometer value to the LED.

Pause for a few milliseconds and repeat the process.

analogRead

Just like the function digitalRead, which returned a value of either HIGH or LOW,
analogRead returns a value as well. In contrast to HIGH or LOW, analogRead returns an

integer value from 0 to 4095. That value represents a voltage from 0 to 3V3.

The return value can be stored in a variable for use later on in our code, or it can be
used right away using an if statement such as:

if (analogRead(POT) > 2000 {

analogWrite(led, 129);
}

In our sketch the analogRead value is stored in a variable called val.

The syntax for analogRead() is

analogRead(pin);

The parameter is

Pin, the analog pin that the sensor is connected to on the Photon.

analogRead() returns an integer value between 0 and 4095, which represents ground

and 3V3.