ads1x15: added elaborate examples for TI ADS1015 ADC

Signed-off-by: Mihai Tudor Panu <mihai.tudor.panu@intel.com>

examples/python/ads1015.py

@@ -0,0 +1,86 @@
+# Author: Mihai Tudor Panu <mihai.tudor.panu@intel.com>
+# Copyright (c) 2016 Intel Corporation.
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+
+# This example demonstrates how to use one of the ADS1015 ADCs on the
+# DFRobot Joule Shield with devices that output a small differential
+# voltage (e.g. geophones, piezoelectric bands or pads, thermocouples).
+
+from __future__ import print_function
+from threading import Timer
+from time import sleep
+from upm import pyupm_ads1x15 as upm
+
+def stop():
+    global running
+    running = False
+
+def main():
+    global running
+    running = True
+    fileName = './ads1015.data' # Output filename
+    id = 0 # Sample number
+
+    # Initialize and configure the ADS1015 for the SM-24 Geophone
+    # There are two ADS1015 chips on the DFRobot Joule Shield on the same I2C bus
+    #     - 0x48 gives access to pins A0 - A3
+    #     - 0x49 gives access to pins A4 - A7
+    ads1015 = upm.ADS1015(0, 0x48)
+
+    # Put the ADC into differential mode for pins A0 and A1,
+    # the SM-24 Geophone is connected to these pins
+    ads1015.getSample(upm.ADS1X15.DIFF_0_1)
+    
+    # Set the gain based on expected VIN range to -/+ 2.048 V
+    # Can be adjusted based on application to as low as -/+ 0.256 V, see API
+    # documentation for details         
+    ads1015.setGain(upm.ADS1X15.GAIN_TWO)
+    
+    # Set the sample rate to 3300 samples per second (max) and turn on continuous
+    # sampling    
+    ads1015.setSPS(upm.ADS1015.SPS_3300)
+    ads1015.setContinuous(True)
+
+    # Open the output file
+    try:
+        f = open(fileName, 'w')
+    except OSError as e:
+        print('Cannot open output file:', e)
+        return
+
+    # Setup a timer to stop logging after 10 seconds
+    t = Timer(10, stop)
+    t.start()
+
+    # Read sensor and write to file every 1 ms
+    while running:
+        f.write(str(id) + ' %.7f' % ads1015.getLastSample() + '\n')
+        id += 1
+        sleep(0.001)
+
+    # Close and exit
+    f.close()
+    print('Wrote', id, 'samples to file:', fileName)
+    return
+
+if __name__ == '__main__':
+    main()
+