add sleep/wake so the sensor (fan) can be shut off

examples/hourly.py

@@ -0,0 +1,50 @@
+#!/usr/bin/env python
+
+from pms5003 import PMS5003
+import time
+
+print("""hourly.py - Run (approximately) hourly.
+
+Press Ctrl+C to exit!
+
+""")
+
+# Configure the PMS5003 for Enviro+
+pms5003 = PMS5003(
+    device='/dev/ttyAMA0',
+    baudrate=9600,
+    pin_enable=22,
+    pin_reset=27
+)
+
+last_read_epoch = 0
+
+try:
+    while True:
+        # has it been an hour since our last reading?
+        now = int(time.time())
+        if (now - last_read_epoch) > 3600:
+            last_read_epoch = now
+
+            print("waking")
+            pms5003.wake()
+
+            # give sensor time to wake up and calibrate
+            print("sleeping")
+            time.sleep(60)
+            print("reading")
+
+            # take several readings, good for a median
+            for _ in range(9):
+                data = pms5003.read()
+                print("PM2.5 ug/m3 (combustion particles, organic compounds, metals): {}".format(data.pm_ug_per_m3(2.5)))
+
+            # done reading, shut down sensor (and its fan)
+            print("sleeping")
+            pms5003.sleep()
+        else:
+            time.sleep(10)
+
+except KeyboardInterrupt:
+    pass
+

library/pms5003/__init__.py

@@ -105,6 +105,15 @@ def setup(self):
 
         self.reset()
 
+    def sleep(self):
+        '''Turn off enable (SET). This stops the fan, aka sleeping
+           mode. Note this is different than active/passive.'''
+        GPIO.output(self._pin_enable, GPIO.LOW)
+
+    def wake(self):
+        '''Enable (SET). This starts the fan and sensor. Wait 30sec for values.'''
+        GPIO.output(self._pin_enable, GPIO.HIGH)
+
     def reset(self):
         time.sleep(0.1)
         GPIO.output(self._pin_reset, GPIO.LOW)