Fixed RMS calculation

main.py

@@ -0,0 +1,75 @@
+import utime
+import gc
+from delayedswitch import DelayedSwitch
+from ntptime import settime
+from config import DELAY
+from machine import ADC    
+
+import machine
+
+from machine import Pin
+# Wemos D1 pin14 = D5
+d5 = Pin(14, machine.Pin.IN, machine.Pin.PULL_UP)
+
+# voltage meter ZMPT101B is attached to pin A0
+ad0 = ADC(0)   
+
+def read_voltage():
+    nsamples = 50
+    total = 0
+    sq_total = 0
+    for _ in range(nsamples):
+        v = ad0.read()
+        total += v
+        sq_total += v * v
+        utime.sleep_ms(2)
+    mean = total / nsamples
+    return (sq_total / nsamples - mean * mean) ** 0.5
+
+# check if voltage is over a threshold
+# read_voltage returns between 2-3 when there is no AC input
+# read_voltage returns between 123-127 when there is AC input
+# it seems 100 is a reasonable threshold
+def high_voltage():
+    v = read_voltage()
+    hv = v > 100
+    # if hv:
+    #     print("High voltage: ", v)
+    return hv
+
+# setup rtc
+settime()
+rtc = machine.RTC()
+utime.sleep_ms(750)
+print('\nRTC Set from NTP to UTC:', rtc.datetime())
+
+def pir_thread(switch):
+    pir_on = False
+    while True: # change this!
+        utime.sleep_ms(20)
+        if high_voltage():
+            # was PIR on in previous cycle?
+            if not pir_on:
+                # print some debug info
+                if not switch.is_light_on():
+                    d = "%d %d %d %d, %02d:%02d:%02d" % rtc.datetime()[0:7]
+                    print("Presence detected at: %s." % d)
+
+                switch.presence()
+                pir_on = True
+        else:
+            if pir_on:
+                d = "%d %d %d %d, %02d:%02d:%02d" % rtc.datetime()[0:7]
+                print("Absense detected at: %s." % d)
+                switch.absence()
+                pir_on = False
+
+        gc.collect()
+
+
+print("Starting pir thread")
+switch = DelayedSwitch(DELAY,rtc) # delay in ms
+pir_thread(switch)
+
+# Not reached
+print("Done")