Add readme and increment version

apps.json

@@ -1178,7 +1178,8 @@
     "name": "Battery Chart",
     "shortName":"Battery Chart",
     "icon": "app.png",
-    "version":"0.07",
+    "version":"0.08",
+    "readme": "README.md",
     "description": "A widget and an app for recording and visualizing battery percentage over time.",
     "tags": "app,widget,battery,time,record,chart,tool",
     "storage": [

apps/batchart/ChangeLog

@@ -5,3 +5,4 @@
 0.05: Display temperature and LCD state in chart
 0.06: Fixes widget events and charting of component states
 0.07: Improve logging and charting of component states and add widget icon
+0.08: Fix for Home button in the app and README added.

apps/batchart/README.md

@@ -0,0 +1,67 @@
+# Summary
+
+Battery Chart contains a widget that records the battery usage as well as information that might influence this usage.
+
+The app that comes with provides a graph that accumulates this information in a single screen.
+
+## How the widget works
+
+The widget records data in a fixed interval of ten minutes.
+
+When this timespan has passed, it saves the following information to a file called `bclogx` where `x` is
+
+the current day retrieved by `new Date().getDay()`:
+
+- Battery percentage
+- Temperature (of the die)
+- LCD state
+- Compass state
+- HRM state
+- GPS state
+
+After seven days the logging rolls over and the previous data is overwritten.
+
+To properly handle the roll-over, the day of the previous logging operation is stored in `bcprvday`.
+
+The value is changed with the first recording operation of the new day.
+
+## How the App works
+
+### Events
+
+The app charts the last 144 (6/h * 24h) datapoints that have been recorded.
+
+If for the current day the 144 events have not been reached the list is padded with
+
+events from the previous `bclog` file(s).
+
+### Graph
+
+The graph then contains the battery percentage (left y-axis) and the temperature (right y-axis).
+
+In case the recorded temperature is outside the limits of the graph, the value is set to a minimum of 19 or a maximum of 41 and thus should be clearly visible outside of the graph's boundaries for the y-axis.
+
+The states of the various SoC devices are depicted below the graph. If at the time of recording the device was enabled a marker in the respective color is set, if not the pixels for this point in time stay black.
+
+If a device was not enabled during the 144 selected events, the name is not displayed.
+
+## File schema
+
+You can download the `bclog` files for your own analysis. They are `CSV` files without header rows and contain
+
+```
+timestamp,batteryPercentage,temperatureInDegreeC,deviceStates
+```
+
+with the `deviceStates` resembling a flag set consisting of 
+
+```
+const switchableConsumers = {
+ none: 0,
+ lcd: 1,
+ compass: 2,
+ bluetooth: 4,
+ gps: 8,
+ hrm: 16
+};
+```