Calibration states (#820)

* color calibration

libs/gyro-sensor/docs/reference/sensors/gyro/reset.md

@@ -22,6 +22,15 @@ To properly reset the gyro, the brick must remain still (undistrurbed) while the
 
 ## ~
 
+## Calibration states
+
+Calibration happens in the following phases and each phase is tracked by the brick status light.
+
+* **orange**: sensor initialization. This phase ensures that the sensor is in the desired mode and ready to collect data.
+* **orange pulse**: data collection. Light information is being collected, move the sensor over the various light sources to detect.
+* **green**: calibration success. The calibration data has been saved.
+* **red flash**: sensor failure. We were unable to connect to the sensor.
+
 ## Example
 Set the brick on a flat surface. Reset `gyro 2` and tilt the brick slighly. Reset it again while it's still tilted. Lay the brick down flat again and display the angle measurement.
 
@@ -36,4 +45,4 @@ brick.buttonRight.onEvent(ButtonEvent.Pressed, function () {
 
 ## See also
 
-[angle](/reference/sensors/gyro/angle), [rate](/reference/sensors/gyro/rate)
+[angle](/reference/sensors/gyro/angle), [rate](/reference/sensors/gyro/rate)

libs/gyro-sensor/gyro.ts

@@ -92,6 +92,9 @@ namespace sensors {
         reset(): void {
             if (this.calibrating) return; // already in calibration mode
 
+            const statusLight = brick.statusLight(); // save current status light
+            brick.setStatusLight(StatusLight.Orange);
+
             this.calibrating = true;
             // may be triggered by a button click,
             // give time for robot to settle
@@ -101,9 +104,22 @@ namespace sensors {
             // switch back to the desired mode
             this.setMode(this.mode);
             // wait till sensor is live
-            pauseUntil(() => this.isActive());
+            pauseUntil(() => this.isActive(), 5000);
+
+            // check sensor is ready
+            if (!this.isActive()) {
+                brick.setStatusLight(StatusLight.RedFlash); // didn't work
+                pause(2000);
+                brick.setStatusLight(statusLight); // restore previous light
+                return;
+            }
+
             // give it a bit of time to init
             pause(1000)
+
+            // calibrating
+            brick.setStatusLight(StatusLight.OrangePulse);
+
             // compute drift
             this._drift = 0;
             if (this.mode == GyroSensorMode.Rate) {
@@ -113,6 +129,11 @@ namespace sensors {
                 }
                 this._drift /= 200;
             }
+
+            brick.setStatusLight(StatusLight.Green); // success
+            pause(1000);
+            brick.setStatusLight(statusLight); // resture previous light
+
             // and we're done
             this.calibrating = false;
         }