diff --git a/libraries/AP_Airspeed/AP_Airspeed.cpp b/libraries/AP_Airspeed/AP_Airspeed.cpp
index d5b805ee21..5c2bfccdf3 100644
--- a/libraries/AP_Airspeed/AP_Airspeed.cpp
+++ b/libraries/AP_Airspeed/AP_Airspeed.cpp
@@ -8,10 +8,14 @@
  *   of the License, or (at your option) any later version.
  */
 
-#include <FastSerial.h>
+#include <math.h>
+
 #include <AP_Common.h>
+#include <AP_HAL.h>
 #include <AP_Airspeed.h>
 
+extern const AP_HAL::HAL& hal;
+
 // table of user settable parameters
 const AP_Param::GroupInfo AP_Airspeed::var_info[] PROGMEM = {
 
@@ -44,7 +48,7 @@ const AP_Param::GroupInfo AP_Airspeed::var_info[] PROGMEM = {
 
 // calibrate the airspeed. This must be called at least once before
 // the get_airspeed() interface can be used
-void AP_Airspeed::calibrate(void (*callback)(unsigned long t))
+void AP_Airspeed::calibrate()
 {
     float sum = 0;
     uint8_t c;
@@ -53,7 +57,7 @@ void AP_Airspeed::calibrate(void (*callback)(unsigned long t))
     }
     _source->read();
     for (c = 0; c < 10; c++) {
-        callback(100);
+        hal.scheduler->delay(100);
         sum += _source->read();
     }
     _airspeed_raw = sum/c;
@@ -69,6 +73,8 @@ void AP_Airspeed::read(void)
         return;
     }
     _airspeed_raw           = _source->read();
-    airspeed_pressure       = max((_airspeed_raw - _offset), 0);
-    _airspeed               = 0.7 * _airspeed + 0.3 * sqrt(airspeed_pressure * _ratio);
+    airspeed_pressure       = ((_airspeed_raw - _offset) < 0) ?
+                                (_airspeed_raw - _offset) : 0;
+    _airspeed               = 0.7 * _airspeed +
+                              0.3 * sqrt(airspeed_pressure * _ratio);
 }
diff --git a/libraries/AP_Airspeed/AP_Airspeed.h b/libraries/AP_Airspeed/AP_Airspeed.h
index a4b94217d5..5e5c63fe05 100644
--- a/libraries/AP_Airspeed/AP_Airspeed.h
+++ b/libraries/AP_Airspeed/AP_Airspeed.h
@@ -4,24 +4,25 @@
 #define __AP_AIRSPEED_H__
 
 #include <AP_Common.h>
+#include <AP_HAL.h>
 #include <AP_Param.h>
-#include <AP_AnalogSource.h>
 
 class AP_Airspeed
 {
 public:
     // constructor
-    AP_Airspeed(AP_AnalogSource *source) {
+    AP_Airspeed() {};
+
+    void        init(AP_HAL::AnalogSource *source) {
         _source = source;
     }
-
     // read the analog source and update _airspeed
     void        read(void);
 
     // calibrate the airspeed. This must be called on startup if the
     // altitude/climb_rate/acceleration interfaces are ever used
     // the callback is a delay() like routine
-    void            calibrate(void (*callback)(unsigned long t));
+    void            calibrate();
 
     // return the current airspeed in m/s
     float           get_airspeed(void) {
@@ -48,10 +49,10 @@ public:
         _airspeed = airspeed;
     }
 
-    static const struct AP_Param::GroupInfo         var_info[];
+    static const struct AP_Param::GroupInfo var_info[];
 
 private:
-    AP_AnalogSource *                               _source;
+    AP_HAL::AnalogSource *_source;
     AP_Float        _offset;
     AP_Float        _ratio;
     AP_Int8         _use;
diff --git a/libraries/AP_Airspeed/examples/Airspeed/Airspeed.pde b/libraries/AP_Airspeed/examples/Airspeed/Airspeed.pde
index a62630be48..5036f72ffc 100644
--- a/libraries/AP_Airspeed/examples/Airspeed/Airspeed.pde
+++ b/libraries/AP_Airspeed/examples/Airspeed/Airspeed.pde
@@ -8,46 +8,37 @@
  *   of the License, or (at your option) any later version.
  */
 
-#include <FastSerial.h>
 #include <AP_Common.h>
 #include <AP_Param.h>
 #include <AP_Math.h>
-#include <AP_AnalogSource.h>
-#include <AP_AnalogSource_Arduino.h>
-#include <Arduino_Mega_ISR_Registry.h>
-#include <AP_PeriodicProcess.h>
+#include <AP_HAL.h>
+#include <AP_HAL_AVR.h>
+
 #include <Filter.h>
 #include <AP_Buffer.h>
 #include <AP_Airspeed.h>
 
-Arduino_Mega_ISR_Registry isr_registry;
-AP_TimerProcess scheduler;
+const AP_HAL::HAL& hal = AP_HAL_AVR_APM2;
 
-FastSerialPort0(Serial);
-
-AP_AnalogSource_Arduino pin0(0);
-AP_Airspeed airspeed(&pin0);
+AP_Airspeed airspeed;
 
 void setup()
 {
-    Serial.begin(115200, 128, 128);
-    Serial.println("ArduPilot Airspeed library test");
+    hal.uart0->begin(115200, 128, 128);
+    hal.console->println("ArduPilot Airspeed library test");
 
-    isr_registry.init();
-    scheduler.init(&isr_registry);
-    AP_AnalogSource_Arduino::init_timer(&scheduler);
-
-    pinMode(0, INPUT);
-
-    airspeed.calibrate(delay);
+    airspeed.init(hal.analogin->channel(0));
+    airspeed.calibrate();
 }
 
 void loop(void)
 {
     static uint32_t timer;
-    if((millis() - timer) > 100) {
-        timer = millis();
+    if((hal.scheduler->millis() - timer) > 100) {
+        timer = hal.scheduler->millis();
         airspeed.read();
-        Serial.printf("airspeed %.2f\n", airspeed.get_airspeed());
+        hal.console->printf("airspeed %.2f\n", airspeed.get_airspeed());
     }
 }
+
+AP_HAL_MAIN();
diff --git a/libraries/AP_Airspeed/examples/Airspeed/Arduino.h b/libraries/AP_Airspeed/examples/Airspeed/Arduino.h
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/libraries/AP_Airspeed/examples/Airspeed/nocore.inoflag b/libraries/AP_Airspeed/examples/Airspeed/nocore.inoflag
new file mode 100644
index 0000000000..e69de29bb2