Detect overheating in Google Glass programmaticaly

问题:

As many of other I am facing the google glass overheating issue. My question is how to detect it in the application?

I was looking through the log but nothing that indicates it expect a message on the screen.

回答1:

Google Glass have (at least) two temperature probes.
One for the battery, and the other for the CPU board.
You can read them as a regular file.

Battery
/sys/devices/platform/omap_i2c.1/i2c-1/1-0055/power_supply/bq27520-0/temp

CPU Board
/sys/devices/platform/notle_pcb_sensor.0/temperature

But keep in mind that these files may change location as new versions of Google Glass are shipped.

The code (simplified version)

private String readTemperature(String path) throws IOException {
    return new BufferedReader(new InputStreamReader(new FileInputStream(new File(path)))).readLine();
}

Interpretation

The values you'll get from these files are in different units.
The CPU Board temperature must be divided by 1000 to get the temperature in °C.
The battery temperature must be divided by 10 to get the temperature in °C.

Logcat

The logcat also gives you the temperatures every minutes or so in a one line log.
You could even parse it:

I/UserEventService(568): [GlassUserEventPerformanceStats ... battery_temperature_milli_centigrade: 34000 board_temperature_milli_centigrade: 44000 ]

Values

From what I've experience, values of the CPU board can go from 25°C to 70°C.
If you go above 70°C, you app or any active app is likely to be killed by the system and you'll see the message "Glass must cool down to run smoothly".