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Topic: Sharp IR distance sensor as a "button" (Read 1 time) previous topic - next topic


Apr 28, 2011, 11:22 am Last Edit: Apr 29, 2011, 08:10 am by dingenot Reason: 1
Hey, I'm currently working on a project to make a Sharp IR 2Y0A02 sensor to work as a keyboard button in a game. http://www.acroname.com/robotics/parts/R144-GP2Y0A02YK.html

To do this I first wanted to test it with a led and see if I could turn on the led by activating my IR sensor.

I've been looking at these homepages:

So far I've thought of doing it like this. I haven't tested it yet, because I'm not sure that it is correct.

Code: [Select]
int IRpin = 1;                       // analog pin for reading the IR sensor

int ledPin = 10; // Setup LedPin on Digital Pin 10

void setup() {

pinMode(ledPin, OUTPUT); // Initialize the LED pin as an output:

Serial.begin(9600);                    // start the serial port

void loop()  

 if (sensors[0] < 750)
   // Turn on the LED if we get a High Reflectance.    
   digitalWrite(ledPin, HIGH);
 // Turn off the LED if we have a Low Reflectance.
 else digitalWrite(ledPin, LOW);  

What do you think of this?
At the moment, I'm not sure what I should name the sensors[0] or what distance it should be set at.
Also, do I need to program it to show me the distance time?

Hope you will be able to help me  :)


Welcome in the wonderful world called Arduino ,

First use the # button if you want to publish code  (you can modify your 1st post, select the code and press the #button)

The reading of the sensor will fail, so I rewrote your code a bit so it should work

Code: [Select]

#define THRESHOLD 750

int ledPin = 10; // Setup LedPin on Digital Pin 10

void setup()
  pinMode(ledPin, OUTPUT);

void loop()
  int sensorValue = analogRead(A0);


  if (sensorValue < THRESHOLD )
    digitalWrite(ledPin, HIGH); //High Reflectance. 
    digitalWrite(ledPin, LOW); // Low Reflectance.

To improve the stability of the readings, you can repeat them in a loop like in the function below.
Code: [Select]

unsigned int sharpRawAvg()
  unsigned long raw = 0;
  for (byte i=0; i<32; i++)
    raw += analogRead(A0);
  return raw/32;

You can add this function to your code and call it from your sketch
int sensorValue = analogRead(A0);
int sensorValue = sharpRawAvg()

Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)


Apr 29, 2011, 08:40 am Last Edit: Apr 29, 2011, 09:07 am by dingenot Reason: 1
Thanks a lot, I'm going to try it today :)

I dont know yet what my threshold is, but I'm going to test it today. And I guess I should just use the number I get from that test.

So if this works, should I just replace the
Code: [Select]
int ledPin = 10 and the other ledPin with the keyboard output I'm going to use? I opened a keyboard and took the keyboardchip out.

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