My project reads the A0 input generated by a number of buttons wired in series with stepped resistors. That part works fine as, depending on which button is pressed, I get varied inputs. The issue I'm presently trying to deal with is why the A0 reading doesn't revert back to (or close to) zero after the button is released.
I tested the functionality using this sketch:
int buttonInput = 0;
void setup(){
pinMode(A0, INPUT);
Serial.begin(9600);
}
void loop(){
buttonInput=analogRead(A0);
Serial.print("A0 reading:");
Serial.println(buttonInput);
delay(2000);
}
With this result:
When the button is pressed the reading jumps to 272 and then immediately drops back to 3 or 4 when it's released. This is the behaviour I expect to see.
However, when I insert the same A0 read functionality into this sketch:
#include <SD.h> // SD library
#define SD_ChipSelectPin 10 //pin connected to CS pin on SD card.
/* Other SD card pin connections:
* CS - 10
* SCK - 13
* Miso - 12
* MOSi - 11https://support.arduino.cc/hc/en-us/sections/360003198300
*/
#include <TMRpcm.h> // also need to include this library...
#include <SPI.h>
TMRpcm tmrpcm; // create an object for use in this sketch
const int greenLEDPin = 2; // LED connected to digital pin 2
const int redLEDPin = 3; // LED connected to digital pin 3
int buttonInput = 0; // current analog value read from pin A0
int buttonNumber = 0; // which one of the 7 selector buttons activated bnased on buttonInput value
int tuneSelection = 0; // which set of songs/tunes selected based on reading of pin A1
int tuneInput = 0; // analog read from pin A1
void setup(){
/* Set the volume and check that the SD card is installed and operational.
* Set red LED flashing if not, else turn on green LED.
*
*/
// set the analog pin as input
pinMode (A0, INPUT);
//set the digital pins as outputs
pinMode(greenLEDPin, OUTPUT);
pinMode(redLEDPin, OUTPUT);
tmrpcm.setVolume (6);
tmrpcm.speakerPin = 9; // speaker output pin
Serial.begin(9600);
while (!SD.begin(SD_ChipSelectPin)) { // see if the card is present and can be initialized:
// If card not ready, flash red pin
Serial.println("SD fail");
digitalWrite(redLEDPin, HIGH); // turn the LED on (HIGH is the voltage level)
delay (1000); // wait for a second
digitalWrite(redLEDPin, LOW); // turn the LED off by making the voltage LOW
// wait for a second
}
Serial.println("SD read OK");
digitalWrite(redLEDPin, LOW);
digitalWrite(greenLEDPin, HIGH);
delay(500);
}
void loop(){
/*tuneSelection = analogRead (A1); // determine which selection of tunes/sounds based on pot position
if (tuneInput >= 0 && tuneInput <= 200)
{tuneSelection = 1;
}
if (tuneInput >= 201 && tuneInput <= 400)
{tuneSelection = 2;
}
*/
tuneSelection = 1;
buttonInput = analogRead(A0); //Check if a button has been pressed
Serial.print("A0 reading: ");
Serial.println(buttonInput);
if (tuneSelection = 1)
{
if (buttonInput >= 30 && buttonInput <= 110)
{
tmrpcm.play ("Raffi1.wav");
while (tmrpcm.isPlaying ())
{
digitalWrite(redLEDPin, HIGH);
digitalWrite(greenLEDPin, LOW);
delay (5000);}
}
if (buttonInput >= 111 && buttonInput <= 175)
{
tmrpcm.play ("Raffi2.wav");
while (tmrpcm.isPlaying ())
{
digitalWrite(redLEDPin, HIGH);
digitalWrite(greenLEDPin, LOW);
delay (5000);}
}
}
digitalWrite(redLEDPin, LOW);
digitalWrite(greenLEDPin, HIGH);
while (buttonInput>=30)
{
buttonInput=analogRead(A0);
Serial.print("A0 reading: ");
Serial.println(buttonInput);
delay(3000);
}
}
I get this result:
A button press generates a reading of 352 but, when released, the A0 reading only drops to the 120 range, which creates a problem in my code.
Can anyone explain what's happening here and/or what I've done wrong?
Thanks.
