Users Guide

Retrieve the raw data from the sensors by running the following commands. Then, apply the formula in the table to convert the

data collected into measurements such as relative humidity and temperature.

Retrieving raw data from sensors

● To query sensor devices, run the command.

$ cat /sys/bus/iio/devices/iio:device*/name

hts221 <-- device0, Humidity and temp.

lng2dm_accel <-- device1, G-sensor

lps22hb <-- device2, Pressure

● To retrieve data from the humidity and temperature sensor, run the command.

$ cat in_humidityrelative_offset

$ cat in_humidityrelative_raw

$ cat in_humidityrelative_scale

$ cat in_temp_offset

$ cat in_temp_raw

$ cat in_temp_scale

● To retrieve data from the motion sensor, run the command.

$ cat in_accel_scale_available

$ cat in_accel_*_scale

$ cat in_accel_*_raw

● To retrieve data from the pressure sensor, run the command.

$ cat in_pressure_raw

$ cat in_pressure_scale

Converting raw data for use

Apply the formula in the table to convert the raw data collected into usable measurements.

Table 12. Convert relative humidity and temperature sensor raw data

Relative humidity and temperature sensor ST Micro HTS221

RH (in %) = (in_humidityrelative_raw + in_humidityrelative_offset) * in_humidityrelative_scale

Temperature (degC) = (in_temp_raw + in_temp_offset) * in_temp_scale

Table 13. Convert motion sensor raw data

Motion sensor—Accelerometer ST Micro LNG2DMTR

accel_{x/y/z} (m/s^2) = in_accel_{x/y/z}_raw * in_accel_{x/y/z}_scale

Table 14. Convert pressure sensor raw data

Pressure sensor ST Micro LPS22HB

Pressure (hPa) = in_pressure_raw * in_pressure_scale * 10

Temperature (m degC) = in_temp_raw * in_temp_scale

Ignition Pin

The ignition pin can be used to wake the system from S3, S4, and S5 power states. The user can use the operating system

power management to configure S3, S4, and S5 power states and shutdown.

Setting up the operating system