User manual

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It takes about 100 microseconds (0.0001 s) to read an analog input, so the maximum reading

rate is about 10,000 times a second.

 Syntax

analogRead(pin)

 Parameters

pin: the number of the analog input pin to read from (0 to 5 on most boards, 0 to 7 on the Mini

and Nano, 0 to 15 on the Mega)

 Returns

int (0 to 1023)

What’s Potentiometer?

A potentiometer is a simple knob that provides a variable resistance, which we can read into the

Arduino board as an analog value. In this example, that value controls the rate at which an LED

blinks.

We connect three wires to the Arduino board. The first goes to ground from one of the outer

pins of the potentiometer. The second goes from 5 volts to the other outer pin of the

potentiometer. The third goes from analog input 2 to the middle pin of the potentiometer.

By turning the shaft of the potentiometer, we change the amount of resistence on either side of

the wiper which is connected to the center pin of the potentiometer. This changes the relative

"closeness" of that pin to 5 volts and ground, giving us a different analog input. When the shaft is

turned all the way in one direction, there are 0 volts going to the pin, and we read 0. When the

shaft is turned all the way in the other direction, there are 5 volts going to the pin and we read

1023. In between, analogRead() returns a number between 0 and 1023 that is proportional to

the amount of voltage being applied to the pin.

Example code: