Anyone have a problem using this type of sensor and getting a lot of noise or spikes in the output signal? I tried using an electrolytic capacitor to help mitigate the noise but it keeps showing spikes in output.

I tried a filter, but the noise spikes are there and I need a consistent and steady output value. I read in a blog that when using arduino if you are plugged into a computer there may be ambient noise from the PC itself through the USB cable.

here is the code I have.

#include <Filters.h>

const int output = 6;
const int input = 0;

const long referenceMv = 5000;


float windowLength = 1;     // how long to average the signal, for statistist



void setup() {

}
void loop() {
  // filters out changes faster that 5 Hz.
float filterFrequency = 50.0;  

// create a one pole (RC) lowpass filter
FilterOnePole lowpassFilter( LOWPASS, filterFrequency );   
RunningStatistics lowpassFilterStats;                    // create running statistics to smooth these values
lowpassFilterStats.setWindowSecs( windowLength );

while( true ) {

  lowpassFilter.input( analogRead(input) );
  lowpassFilterStats.input(analogRead(input));
  // do something else
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(output, OUTPUT);
  // put your main code here, to run repeatedly:
  //int val = lowpassFilter.output();
  int val = lowpassFilterStats.mean();
  int mV = (val * referenceMv) / 1023;
  int percent;
  percent = map(val,0,1023,0,10000);
  Serial.print(mV);
  Serial.print(",");
  Serial.println(percent);
  analogWrite(output, val);
  delay(10);
 }
}

I have posted a project using this sensor as well as taken high-resolution tear-down photos of the sensor and put it on my blog here

Searchable datasheet => http://sharp-world.com/products/device/lineup/data/pdf/datasheet/gp2y0a41sk_e.pdf.

The last diagram in the datasheet is essentially a linear correlation between the sensor's output voltage (on the y axis) and 1/L + .42 (on the x axis), where L is the length in cm. In the form y = mx + b it has an m of about 12.7. Solving for the length gives L = 12.7/V - .42, in cm. On a 5V Arduino with 10-bit ADC conversion, V = 5 x (analogReading/1023). So you can substitute V and crunch a few numbers to get a nice little conversion formula:

int reading = analogRead(sensorPin);
reading = max(1, reading);  // avoid dividing by zero!
float cm = (2598.42/reading) - .42;

I found that this gave very good results, and the calculation is simple and fast. Hope this helps others using this sensor!

We're trying to develop a smart bin which will read the fill-level of the bin and notify us by email when the bin is full and ready for collection. Can we get help on this? I'm thinking this sensor could be used to read the distance from the top of the bin to the material inside and notify when the distance is say xcm. The bin wil approximately 1m in height. Rjio rijo.ealias@gmail.com

Does anyone know the field of view for this type of sensor? I can't find it in the datasheet

Would this sensor be able to detect the distance to a water level if placed at the top of a tank?

I did a dumb calibration / "best fit" power curve in Excel after some measurements of the voltage reading in an Arduino to inches, here's my function:

int sensorValue = analogRead(A0);
float inches = pow(sensorValue,-0.867) * 539.98;

This is using 5V USB powering the board and the Vcc going to a 5V pin on the arduino.

Hope this helps anyone using this

Anybody know what the refresh rate for receiving new reading is on this device. I realize that it's outputting a continuous analog signal, but what is the effective response time in terms of that signal responding to changes in distance.

somebody know which is pigtail that recommended?