add module octoliner

modules/@amperka/octoliner.js

@@ -0,0 +1,83 @@
+var Octoliner = function(opts) {
+  opts = opts || {};
+  this.expander = require("@amperka/gpio-expander").connect(opts);
+  this.expander.pwmFreq(60000);
+  this._sensePin = 0;
+  this._ledBrightnessPin = 9;
+  this._sensorPinMap = [4, 5, 6, 8, 7, 3, 2, 1];
+  this._lineState = [];
+  this.setSensitivity(0.8);
+  this.setBrightness(1);
+};
+
+Octoliner.prototype.setSensitivity = function(sense) {
+  this.expander.analogWrite(this._sensePin, sense);
+};
+
+Octoliner.prototype.setBrightness = function(brightness) {
+  this.expander.analogWrite(this._ledBrightnessPin, brightness);
+};
+
+Octoliner.prototype.analogRead = function(sensor) {
+  sensor &= 0x07;
+  return this.expander.analogRead(this._sensorPinMap[sensor]);
+};
+
+Octoliner.prototype.digitalRead = function(sensor){
+  sensor &= 0x07;
+  return this.expander.digitalRead(this._sensorPinMap[sensor]);
+};
+
+Octoliner.prototype.changeAddr = function(nAddr) {
+  this.expander.changeAddr(nAddr);
+};
+
+Octoliner.prototype.saveAddr = function(){
+  this.expander.saveAddr();
+};
+
+Octoliner.prototype.getBinaryLine = function(treshold) {
+  treshold = treshold || 0.5;
+  var result = 0;
+  for (var i = 0; i < 8; ++i) {
+    var value = this.analogRead(i);
+    if (treshold < value)
+      result |= 1 << i;
+  }
+  return result;
+};
+
+Octoliner.prototype.mapLine = function(binaryLine) {
+  var sum = 0;
+  var avg = 0;
+  var weight = [4, 3, 2, 1, -1, -2, -3, -4];
+  if (Array.isArray(binaryLine)) {
+    for (var i = 0; i < 8; i++) {
+      if (binaryLine[i]) {
+        sum += binaryLine[i];
+        avg += binaryLine[i] * weight[i];
+      }
+    }
+    if (sum != 0) {
+      return avg / sum / 4.0;
+    }
+      return 0;
+  } else {
+    this._lineState = [];
+    for (var i = 0; i < 8; i++) {
+      var mask = 1 << i;
+      if (binaryLine & mask) {
+        this._lineState[i] = 1;
+      }
+    }
+    return this.mapLine(this._lineState);
+  }
+};
+
+Octoliner.prototype.reset = function(){
+  this.expander.reset();
+};
+
+exports.connect = function(opts) {
+  return new Octoliner(opts);
+};