add gain=2, non-blocking operation, led abstracted

led.h

@@ -0,0 +1,32 @@
+#ifndef _LED_H_
+#define _LED_H_
+
+#include <Arduino.h>
+#include <stdint.h>
+
+class LED {
+public:
+  LED() : m_state(0) {};
+  void begin(const uint8_t pin) { 
+    m_pin = pin;
+    pinMode(m_pin, OUTPUT);
+    digitalWrite(m_pin, m_state);
+  };
+  void on() {
+    m_state = 1;
+    digitalWrite(m_pin, m_state);
+  }
+  void off() {
+    m_state = 0;
+    digitalWrite(m_pin, m_state);
+  }
+  void toggle() {
+    m_state ^= 1;
+    digitalWrite(m_pin, m_state);
+  }
+private:
+  uint8_t m_state;
+  uint8_t m_pin;
+}
+
+#endif // _LED_H_