Completed README.md, added Arduino Sketch

ArduinoExplorerbotSketch/explorerbot.ino

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+/*
+    Copyright 2014 Daniele Verducci
+    This file is part of ArduinoExplorerbotSketch.
+
+    ArduinoExplorerbotSketch is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ArduinoExplorerbotSketch is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with ArduinoExplorerbotSketch.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+
+/*
+ * PIN
+ *  7  Steering servo yellow cable
+ *  3  to H-Bridge ENABLE
+ *  9  to H-Bridge logic pin 1
+ * 10  to H-Bridge logic pin 2
+ *
+ * SERIAL (9600)
+ * 2 bits: the first is the steering from 1 to 127,
+ * the second the acceleration.
+ */
+
+const int servoPin = 7; 
+const int hBridgeEnable = 3;
+const int hBridge1pin = 9;
+const int hBridge2pin = 10;
+ 
+#include <Servo.h>
+Servo steeringServo;
+byte gamepadPosition[2];
+
+void setup(){
+  steeringServo.attach(servoPin);  //steering servo to pin 7
+  pinMode(hBridgeEnable, OUTPUT);
+  pinMode(hBridge1pin, OUTPUT);
+  pinMode(hBridge2pin, OUTPUT);
+  Serial.begin(9600);
+}
+
+void loop(){
+  if(readGamepadPositionFromSerial()){
+    steerTo(gamepadPosition[0]);
+    accelerateTo(gamepadPosition[1]);
+  }
+  delay(100);
+}
+
+boolean readGamepadPositionFromSerial(){
+  if(Serial.available()>1){   //Bytes received in pairs
+    gamepadPosition[0] = Serial.read();
+    gamepadPosition[1] = Serial.read();
+    return true;
+  } 
+  return false;
+}
+
+void steerTo(byte steeringByte){
+  steeringServo.write(steeringByte);  //Angles from 0° to 127°
+}
+
+void accelerateTo(byte speedByte){
+  if(speedByte<64){
+    //Go forward
+    digitalWrite(hBridge1pin, HIGH);
+    digitalWrite(hBridge2pin, LOW);
+    //speedByte = 1/speedByte;
+  } else {
+    //Go backward
+    digitalWrite(hBridge2pin, HIGH);
+    digitalWrite(hBridge1pin, LOW);
+    //speedByte = speedByte-64;    
+  }
+  //analogWrite(hBridgeEnable, speedByte*2);
+  if(speedByte<32 || speedByte>96) digitalWrite(hBridgeEnable, HIGH);
+  else digitalWrite(hBridgeEnable, LOW);
+}