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Userspace Arduino:AnalogReadSerial

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Introduction

Just like an Arduino, a potentiometer can be hooked up to the Beaglebone Black and its analog value can be printed to the console using "Serial". There are a few differences, however.

  • Firstly, the analog voltages on the Beaglebone Black are scaled from 0 to 1.8 V. Any voltage higher than this can damage the bone.
  • Also, the Beaglebone Black has a dedicated reference voltage level for analog operations. The pin P9_32 needs to be used as AVcc and P9_34 needs to be used as AGND.
Connecting a potentiometer to the Beaglebone Black


Hardware

You need:

  • Potentiometer, a 10kΩ will do fine
  • Wire to join the stuff

Wire the potentiometer with the two extreme pins to P9_32 and P9_34. The middle pin of the potentiometer goes to AIN5, i.e., P9_36.

You can also use the Bacon Cape which has a nice sliding potentiometer already hooked up to AIN5.

Sketch

Derived from AnalogReadSerial

/*
  AnalogReadSerial
  Reads an analog input on AIN5 (P9_36) or pin 20 in the current variant, prints the result to the console.
 
 This example code is in the public domain.
 */
#define Pot 20
// the setup routine runs once when you press reset:
void setup() {
}

// the loop routine runs over and over again forever:
void loop() {
  // read the input on analog pin 0:
  int sensorValue = analogRead(Pot);
  // print out the value you read:
  Serial.println(sensorValue);
  delay(1);        // delay in between reads for stability
}