port 'cli' code from light_meter to cli_meter.

cli-meter.py

@@ -1,21 +0,0 @@
-"""
-CLI Meter
-====================================================================
-Takes a reading of the light using the meter attached via to the
-intended Raspberry PI. The reading is the sent to a server where the
-reading is stored. The intended use for this script is to be run via
-the command-line without the need for a G.U.I. This should be the
-version used when the "Return to Ritherdon" project is live.
-"""
-import json
-import RPi.GPIO as GPIO
-import time, math
-import requests
-from datetime import datetime
-
-# Using BCM (Broadcom) names when referencing the GPIO pins.
-GPIO.setmode(GPIO.BCM)
-
-a_pin = 18 # Charges the capacitor.
-b_pin = 23 # Discharges the capacitor.
-

cli_meter.py

@@ -0,0 +1,87 @@
+"""
+CLI Meter
+====================================================================
+Takes a reading of the light using the meter attached via to the
+intended Raspberry PI. The reading is the sent to a server where the
+reading is stored. The intended use for this script is to be run via
+the command-line without the need for a G.U.I. This should be the
+version used when the "Return to Ritherdon" project is live.
+"""
+
+import json
+import RPi.GPIO as GPIO
+import time, math
+import requests
+from datetime import datetime
+import pdb
+
+# Using BCM (Broadcom) names when referencing the GPIO pins.
+GPIO.setmode(GPIO.BCM)
+GPIO.setwarnings(True)
+
+a_pin = 18 # Charges the capacitor.
+b_pin = 23 # Discharges the capacitor.
+
+api_url = "http://35.176.14.135/api/readings/add/1"
+
+def discharge():
+    GPIO.setup(a_pin, GPIO.IN)
+    GPIO.setup(b_pin, GPIO.OUT)
+    GPIO.output(b_pin, False)
+    time.sleep(0.01) # 0.01 -- initial value
+
+def charge_time():
+    GPIO.setup(b_pin, GPIO.IN)
+    GPIO.setup(a_pin, GPIO.OUT)
+    GPIO.output(a_pin, True)
+    t1 = time.time()
+    while not GPIO.input(b_pin):
+        pass
+    t2 = time.time()
+    return (t2 - t1) * 1000000
+
+def analog_read():
+    discharge()
+    return charge_time()
+
+def read_resistance():
+    n = 20
+    total = 0;
+    for i in range(1, n):
+        total = total + analog_read()
+    reading = total / float(n)
+    resistance = reading * 6.05 - 939
+    return resistance
+
+def light_from_r(R):
+    return math.log(1000000.0/R) * 10.0
+
+def get_timestamp():
+    return datetime.now().strftime(("%Y-%m-%d %H:%M:%S"))
+
+def push_reading(lvalue):
+    time = get_timestamp()
+    headers = {"content-type": "application/json"}
+    payload = { "reading": int(lvalue), "time": time}
+    print(payload)
+    res = requests.post(api_url, data=json.dumps(payload), headers=headers)
+
+def update_reading():
+    light = light_from_r(read_resistance())
+    reading_str = "{:.0f}".format(light)
+    print(reading_str)
+    push_reading(light)
+
+def main():
+    try:
+        while True:
+            #pdb.set_trace()
+            update_reading()
+    except:
+        print("Error updating light reading.")
+    finally:
+        print("clean up")
+        GPIO.cleanup() # cleanup all GPIO     
+
+if __name__ == "__main__":
+    main()