Add support for compass. (#42)

Author: microbit-robert

src/board/compass.ts

@@ -0,0 +1,33 @@
+import { RangeSensor, State } from "./state";
+
+type StateKeys = "compassX" | "compassY" | "compassZ" | "compassHeading";
+
+export class Compass {
+  state: Pick<State, "compassX" | "compassY" | "compassZ" | "compassHeading">;
+
+  constructor() {
+    const min = -2_000_000;
+    const max = 2_000_000;
+    this.state = {
+      compassX: new RangeSensor("compassX", min, max, 0, "nT"),
+      compassY: new RangeSensor("compassY", min, max, 0, "nT"),
+      compassZ: new RangeSensor("compassZ", min, max, 0, "nT"),
+      compassHeading: new RangeSensor("compassHeading", 0, 360, 0, "deg"),
+    };
+  }
+
+  setValue(id: StateKeys, value: any) {
+    this.state[id].setValue(value);
+  }
+
+  getFieldStrength() {
+    const x = this.state.compassX.value;
+    const y = this.state.compassY.value;
+    const z = this.state.compassZ.value;
+    return Math.sqrt(x * x + y * y + z * z);
+  }
+
+  initialize() {}
+
+  dispose() {}
+}

src/board/index.ts

@@ -2,6 +2,7 @@ import svgText from "../microbit-drawing.svg";
 import { Accelerometer } from "./accelerometer";
 import { Audio } from "./audio";
 import { Button } from "./buttons";
+import { Compass } from "./compass";
 import {
   MICROBIT_HAL_PIN_FACE,
   MICROBIT_HAL_PIN_P0,
@@ -10,11 +11,11 @@ import {
 } from "./constants";
 import { Display } from "./display";
 import { FileSystem } from "./fs";
-import { WebAssemblyOperations } from "./wasm";
 import { Microphone } from "./microphone";
 import { Pin } from "./pins";
 import { Radio } from "./radio";
-import { EnumSensor, RangeSensor, Sensor, State } from "./state";
+import { RangeSensor, State } from "./state";
+import { WebAssemblyOperations } from "./wasm";
 
 const stoppedOpactity = "0.5";
 
@@ -43,6 +44,7 @@ export class Board {
   temperature: RangeSensor;
   microphone: Microphone;
   accelerometer: Accelerometer;
+  compass: Compass;
   radio: Radio;
 
   public serialInputBuffer: number[] = [];
@@ -89,6 +91,7 @@ export class Board {
     this.audio = new Audio();
     this.temperature = new RangeSensor("temperature", -5, 50, 21, "°C");
     this.accelerometer = new Accelerometer(onChange);
+    this.compass = new Compass();
     this.microphone = new Microphone(
       this.svg.querySelector("#LitMicrophone")!,
       onChange
@@ -124,6 +127,11 @@ export class Board {
       accelerometerZ: this.accelerometer.state.accelerometerZ,
       gesture: this.accelerometer.state.gesture,
 
+      compassX: this.compass.state.compassX,
+      compassY: this.compass.state.compassY,
+      compassZ: this.compass.state.compassZ,
+      compassHeading: this.compass.state.compassHeading,
+
       lightLevel: this.display.lightLevel,
       dataLogging: {
         // Placeholder.
@@ -144,6 +152,13 @@ export class Board {
         this.accelerometer.setValue(id, value);
         break;
       }
+      case "compassX":
+      case "compassY":
+      case "compassZ":
+      case "compassHeading": {
+        this.compass.setValue(id, value);
+        break;
+      }
       case "buttonA": {
         this.buttons[0].setValue(value);
         break;
@@ -198,6 +213,7 @@ export class Board {
     this.pins.forEach((p) => p.initialize());
     this.display.initialize();
     this.accelerometer.initialize(this.operations.gestureCallback!);
+    this.compass.initialize();
     this.microphone.initialize(this.operations.soundLevelCallback!);
     this.radio.initialize();
     this.serialInputBuffer.length = 0;
@@ -292,6 +308,7 @@ export class Board {
     this.pins.forEach((p) => p.dispose());
     this.display.dispose();
     this.accelerometer.dispose();
+    this.compass.dispose();
     this.microphone.dispose();
     this.radio.dispose();
     this.serialInputBuffer.length = 0;

src/board/state.ts

@@ -19,6 +19,11 @@ export interface State {
   accelerometerZ: RangeSensor;
   gesture: EnumSensor;
 
+  compassX: RangeSensor;
+  compassY: RangeSensor;
+  compassZ: RangeSensor;
+  compassHeading: RangeSensor;
+
   pin0: RangeSensor;
   pin1: RangeSensor;
   pin2: RangeSensor;

src/demo.html

@@ -84,6 +84,7 @@ <h1>MicroPython-micro:bit simulator example embedding</h1>
               <option value="audio">Audio</option>
               <option value="background">Background music and display</option>
               <option value="buttons">Buttons</option>
+              <option value="compass">Compass</option>
               <option value="display">Display</option>
               <option value="microphone">Microphone</option>
               <option value="music">Music</option>

src/examples/compass.py

@@ -0,0 +1,11 @@
+# Imports go at the top
+from microbit import *
+
+# Code in a 'while True:' loop repeats forever
+while True:
+    print("x: ", compass.get_x())
+    print("y: ", compass.get_y())
+    print("z: ", compass.get_z())
+    print("heading: ", compass.heading())
+    print("field strength: ", compass.get_field_strength())
+    sleep(1000)

src/jshal.h

@@ -59,6 +59,12 @@ int mp_js_hal_accelerometer_get_z(void);
 int mp_js_hal_accelerometer_get_gesture(void);
 void mp_js_hal_accelerometer_set_range(int r);
 
+int mp_js_hal_compass_get_x(void);
+int mp_js_hal_compass_get_y(void);
+int mp_js_hal_compass_get_z(void);
+int mp_js_hal_compass_get_field_strength(void);
+int mp_js_hal_compass_get_heading(void);
+
 void mp_js_hal_audio_set_volume(int value);
 void mp_js_hal_audio_init(uint32_t sample_rate);
 void mp_js_hal_audio_write_data(const uint8_t *buf, size_t num_samples);

src/jshal.js

@@ -139,6 +139,26 @@ mergeInto(LibraryManager.library, {
     board.accelerometer.setRange(r);
   },
 
+  mp_js_hal_compass_get_x: function () {
+    return board.compass.state.compassX.value;
+  },
+
+  mp_js_hal_compass_get_y: function () {
+    return board.compass.state.compassY.value;
+  },
+
+  mp_js_hal_compass_get_z: function () {
+    return board.compass.state.compassZ.value;
+  },
+
+  mp_js_hal_compass_get_field_strength: function () {
+    return board.compass.getFieldStrength();
+  },
+
+  mp_js_hal_compass_get_heading: function () {
+    return board.compass.state.compassHeading.value;
+  },
+
   mp_js_hal_audio_set_volume: function (value) {
     board.audio.setVolume(value);
   },

src/microbithal_js.c

@@ -337,45 +337,30 @@ void microbit_hal_accelerometer_set_range(int r) {
 }
 
 int microbit_hal_compass_is_calibrated(void) {
-    /*
-    return uBit.compass.isCalibrated();
-    */
-    return 0;
+    // Always calibrated in the simulator.
+    return 1;
 }
 
 void microbit_hal_compass_clear_calibration(void) {
-    /*
-    uBit.compass.clearCalibration();
-    */
+    // No calibration to clear.
 }
 
 void microbit_hal_compass_calibrate(void) {
-    /*
-    uBit.compass.calibrate();
-    */
+    // No calibration to set.
 }
 
 void microbit_hal_compass_get_sample(int axis[3]) {
-    /*
-    Sample3D sample = uBit.compass.getSample();
-    axis[0] = sample.x;
-    axis[1] = sample.y;
-    axis[2] = sample.z;
-    */
+    axis[0] = mp_js_hal_compass_get_x();
+    axis[1] = mp_js_hal_compass_get_y();
+    axis[2] = mp_js_hal_compass_get_z();
 }
 
 int microbit_hal_compass_get_field_strength(void) {
-    /*
-    return uBit.compass.getFieldStrength();
-    */
-    return 0;
+    return mp_js_hal_compass_get_field_strength();
 }
 
 int microbit_hal_compass_get_heading(void) {
-    /*
-    return uBit.compass.heading();
-    */
-    return 0;
+    return mp_js_hal_compass_get_heading();
 }
 
 const uint8_t *microbit_hal_get_font_data(char c) {