update docs

docs/source/index.rst

@@ -14,6 +14,7 @@ Welcome to ardas documentation!
    parse_and_push_to_db
    build_arduino_sketch
    commands
+   sensors
    settings
 
 Indices and tables

docs/source/sensors.rst

@@ -0,0 +1,28 @@
+Describe your sensors
+=====================
+
+Sensors are described in special files named `sensorXXXX.ssr` where XXXX stands for the sensor that contain `raspardas.py`.
+
+``CREATE THE .SSR FILEs``
+------------------------
+In the example below, four sensors are created and saved to `.ssr` files.
+::
+
+    from ardas import sensor_tools as st
+    # Saves a set of sensors including its calibration in a binary '.ssr' file
+    sensors = (st.FMSensor(sensor_id='0001', processing_parameters=(-16.9224032438, 0.0041525221, -1.31475837290789E-07,
+                                                                2.39122208189129E-012, -1.72530800355418E-017),
+                       quantity='temp.', units='°C', output_format='%6.3f', log_output=True),
+           st.UncalibratedFMSensor(sensor_id='0002', log_output=False),
+           st.UncalibratedFMSensor(sensor_id='0003', log_output=True),
+           st.UncalibratedFMSensor(sensor_id='0004', log_output=True),
+           )
+
+    if __name__ == '__main__':
+        for s in sensors:
+            print(s.sensor_id + ' - ' + s.quantity + ' : ' + s.output_repr(10000))
+            s.save()
+        print('reload sensor...')
+        s = st.load_sensor('1401')
+        print(s.sensor_id + ' - ' + s.quantity + ' : ' + s.output_repr(10000) + ' Log:' + str(s.log))
+