settings 0.45: Add calibrate battery option

apps/setting/ChangeLog

@@ -48,3 +48,4 @@
 0.43: Add some Bangle 1 colours to theme customizer
 0.44: Add "Start Week On X" option (#1780)
       UI improvements to Locale and Date & Time menu
+0.45: Add calibrate battery option

apps/setting/README.md

@@ -13,7 +13,6 @@ This is Bangle.js's settings menu
 * **LCD** Configure settings about the screen. How long it stays on, how bright it is, and when it turns on - see below.
 * **Theme** Adjust the colour scheme
 * **Utils** Utilities - including resetting settings (see below)
-* **Turn Off** Turn Bangle.js off
 
 ## BLE - Bluetooth Settings
 
@@ -61,5 +60,7 @@ The exact effects depend on the app.  In general the watch will not wake up by i
 * **Compact Storage** Removes deleted/old files from Storage - this will speed up your Bangle.js
 * **Rewrite Settings** Should not normally be required, but if `.boot0` has been deleted/corrupted (and so no settings are being loaded) this will fix it.
 * **Flatten Battery** Turns on all devices and draws as much power as possible, attempting to flatten the Bangle.js battery. This can still take 5+ hours.  
+* **Calibrate Battery** If you're finding your battery percentage meter isn't accurate, leave your Bangle.js on charge for at least 3 hours, and then choose this menu option. It will measure the battery voltage when full and will allow Bangle.js to report a more accurate battery percentage.
 * **Reset Settings** Reset the settings (as set in this app) to defaults. Does not reset settings for other apps.
 * **Factory Reset** (not available on Bangle.js 1) - wipe **everything** and return to a factory state
+* **Turn Off** Turn Bangle.js off

apps/setting/metadata.json

@@ -1,7 +1,7 @@
 {
   "id": "setting",
   "name": "Settings",
-  "version": "0.44",
+  "version": "0.45",
   "description": "A menu for setting up Bangle.js",
   "icon": "settings.png",
   "tags": "tool,system",

apps/setting/settings.js

@@ -546,6 +546,18 @@ function showUtilMenu() {
         var i=1000;while (i--);
       }, 1);
     },
+    /*LANG*/'Calibrate Battery': () => {
+      E.showPrompt(/*LANG*/"Is the battery fully charged?",{title:/*LANG*/"Calibrate"}).then(ok => {
+        if (ok) {
+          var s=require("Storage").readJSON("setting.json");
+          s.batFullVoltage = (analogRead(D3)+analogRead(D3)+analogRead(D3)+analogRead(D3))/4;
+          require("Storage").writeJSON("setting.json",s);
+          E.showAlert(/*LANG*/"Calibrated!").then(() => load("settings.app.js"));
+        } else {
+          E.showAlert(/*LANG*/"Please charge Bangle.js for 3 hours and try again").then(() => load("settings.app.js"));
+        }
+      });
+    },
     /*LANG*/'Reset Settings': () => {
       E.showPrompt(/*LANG*/'Reset to Defaults?',{title:/*LANG*/"Settings"}).then((v) => {
         if (v) {