IR.Reflect.Array

Rick Waldron edited this page Jan 28, 2016 · 13 revisions

The IR.Reflect.Array class constructs an array of analog (digital arrays are not currently supported) reflectance sensors like the QTR-8A from Pololu.

Parameters

  • pins An array Numbers or Strings for the analog sensor pins.

  • emitter The pin where the emitter LED is attached. For these arrays, there is one pin that controls all of the emitters.

    var eyes = new five.IR.Reflect.Array({
      emitter: 13,
      pins: ["A0", "A1", "A2", "A3", "A4", "A5"]
    });
  • options An object of property parameters.

    Property Type Value/Description Default Required
    pins Array of Numbers, Strings ["A*", ...]. The pins that the sensors are connected to yes
    emitter Number, String Digital Pin. The pin that the light emitter is connected to yes
    freq Number Milliseconds. The frequency in ms of data events. 25ms no

Shape

Property Name Description Read Only
id A user definable id value. Defaults to a generated uid No
pins The pin addresses that the sensors are attached to No
isOn Are the emitters on? Yes
isCalibrated Does the array have calibration data? Yes
isOnLine Is the array currently tracking a line? isCalibrated===true Yes
sensors An array of sensor objects that represent each sensor in the array. Yes
calibration The current calibration data. Yes
raw An array of raw values from all the sensors. Yes
values If calibrated, an array of calibrated values (between 0 and 1000). If not calibrated, raw data (between 0 and 1023). Yes
line If calibrated, a value between 0 and (n-1)*1000+1. For example, 6 sensors will have a line between 0 and 5001. Yes

Component Initialization

Analog

new five.IR.Reflect.Array({
  emitter: 13,
  pins: ["A0", "A1", "A2"], // any number of pins
  freq: 25
});

Usage

var five = require("johnny-five"),
    board = new five.Board();

board.on("ready", function() {

  // Create a new `reflectance` hardware instance.
  var eyes = new five.IR.Reflect.Array({
    emitter: 13,
    pins: ["A0", "A1", "A2"], // any number of pins
    freq: 25
  });

  eyes.on('data', function() {
    console.log( "Raw Values: ", this.raw );
  });

  eyes.on('line', function() {
    console.log( "Line Position: ", this.line);
  });

  eyes.enable();
});

API

  • enable() Turn the light emitters on.

    var eyes = new five.IR.Reflect.Array({
      emitter: 13,
      pins: ["A0", "A1"]
    });
    
    eyes.enable();
  • disable() turn the light emitters off

    var eyes = new five.IR.Reflect.Array({
      emitter: 13,
      pins: ["A0", "A1"]
    });
    
    eyes.disable();
  • calibrate() Read all of the sensors and store the min/max values. Used to calculate calibrated values and line values. You should call calibrate() multiple times.

    var eyes = new five.IR.Reflect.Array({
      emitter: 13,
      pins: ["A0", "A1"]
    });
    
    for (var i = 0; i < 100; i++) {
      eyes.calibrate();
    }
  • calibrateUntil(predicate) A convenience function that will call calibrate until a predicate function returns true. This allows you to decide when calibration is done. This trigger may be user input, time, or execution count. You decide.

    var eyes = new five.IR.Reflect.Array({
      emitter: 13,
      pins: ["A0", "A1"]
    });
    
    var calibrating = true;
    eyes.calibrateUntil(function() {
      return !calibrating;
    });
    
    // calibrate for one second
    setTimeout(function() { 
      calibrating = false; 
    }, 1000); 
  • loadCalibration(calibration) Prime the array with calibration data. This allows you to load calibration data from a file. You can get it from the device using the calibration after it has been calibrated.

    var eyes = new five.IR.Reflect.Array({
      emitter: 13,
      pins: ["A0", "A1"]
    });
    
    eyes.loadCalibration({
      min: [37, 39],
      max: [1010, 1015]
    });

Events

  • data The "data" event is fired as frequently as the user defined freq will allow in milliseconds. It includes an array of the RAW data from the sensors.

  • calibratedData The "calibratedData" event is fired as frequently as the user defined freq will allow in milliseconds. It also requires that the device has been calibrated. It includes an array of calibrated values between 0 and 1000.

  • line The "line" event is fired as frequently as the user defined freq will allow in milliseconds. It also requires that the devide has been calibrated. It is a single value between 0 and (n-1)*1000+1. An array with 6 sensors will yield a value between 0 and 5001.

Examples

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