antonvh · September 29, 2015 20:02 · Sep 29, 2015 · Sep 29, 2015 · Sep 29, 2015 · Sep 28, 2015
diff --git a/get_voltage.py b/get_voltage.py
@@ -28,7 +28,7 @@ def get_voltage():
             vratio = (last_4 << 6) | first_6
 
             # Now we can calculate the battery voltage like so:
-            ratio = 0.0179     # this is 0.1/5.5V Still have to find out why...
+            ratio = 0.0179     # This is an empyrical value based on several different batteries
             voltage = vratio * ratio
 
             return voltage

diff --git a/get_voltage.py b/get_voltage.py
@@ -28,7 +28,7 @@ def get_voltage():
             vratio = (last_4 << 6) | first_6
 
             # Now we can calculate the battery voltage like so:
-            ratio = 0.01818     # this is 0.1/5.5V Still have to find out why...
+            ratio = 0.0179     # this is 0.1/5.5V Still have to find out why...
             voltage = vratio * ratio
 
             return voltage

diff --git a/get_voltage.py b/get_voltage.py
@@ -34,7 +34,7 @@ def get_voltage():
             return voltage
 
     except:
-            return False
+            return 0.0
 
 if __name__ == "__main__":
     print get_voltage()
diff --git a/get_voltage.py b/get_voltage.py
@@ -21,7 +21,7 @@ def get_voltage():
 
             # from this data we need the last 4 bits and the first 6.
             last_4 = data & 0b1111 # using a bit mask
-            first_6 = data >> 10 # left shift 10 because data is 16 bits
+            first_6 = data >> 10 # right shift 10 because data is 16 bits
 
             # together they make the voltage conversion ratio
             # to make it all easier the last_4 bits are most significant :S

diff --git a/get_voltage.py b/get_voltage.py
@@ -11,10 +11,11 @@ def get_voltage():
 
     :return: voltage (float)
     """
-    bus = smbus.SMBus(1)            # SMBUS 1 because we're using greater than V1.
-    address = 0x48
-    # time.sleep(0.1) #Is this necessary?
     try:
+            bus = smbus.SMBus(1)            # SMBUS 1 because we're using greater than V1.
+            address = 0x48
+            # time.sleep(0.1) #Is this necessary?
+
             # read data from i2c bus. the 0 command is mandatory for the protocol but not used in this chip.
             data = bus.read_word_data(address, 0)
 

diff --git a/get_voltage.py b/get_voltage.py
@@ -18,16 +18,16 @@ def get_voltage():
             # read data from i2c bus. the 0 command is mandatory for the protocol but not used in this chip.
             data = bus.read_word_data(address, 0)
 
-            # from this data we need the last 4 bites and the first 6.
-            last_4 = data & 0b1111 # using a byte mask
+            # from this data we need the last 4 bits and the first 6.
+            last_4 = data & 0b1111 # using a bit mask
             first_6 = data >> 10 # left shift 10 because data is 16 bits
 
             # together they make the voltage conversion ratio
             # to make it all easier the last_4 bits are most significant :S
             vratio = (last_4 << 6) | first_6
 
             # Now we can calculate the battery voltage like so:
-            ratio = 0.01818
+            ratio = 0.01818     # this is 0.1/5.5V Still have to find out why...
             voltage = vratio * ratio
 
             return voltage

diff --git a/get_voltage.py b/get_voltage.py
@@ -24,7 +24,7 @@ def get_voltage():
 
             # together they make the voltage conversion ratio
             # to make it all easier the last_4 bits are most significant :S
-            vratio = ((last_4 << 6) | first_6) / 1024.0
+            vratio = (last_4 << 6) | first_6
 
             # Now we can calculate the battery voltage like so:
             ratio = 0.01818

diff --git a/get_voltage.py b/get_voltage.py
@@ -35,5 +35,5 @@ def get_voltage():
     except:
             return False
 
-if __name__ == "main":
+if __name__ == "__main__":
     print get_voltage()
diff --git a/gistfile1.txt → get_voltage.py b/gistfile1.txt → get_voltage.py
@@ -27,10 +27,13 @@ def get_voltage():
             vratio = ((last_4 << 6) | first_6) / 1024.0
 
             # Now we can calculate the battery voltage like so:
-            RPi_voltage = 5.0
-            voltage = RPi_voltage / vratio
+            ratio = 0.01818
+            voltage = vratio * ratio
 
             return voltage
 
     except:
-            return False
+            return False
+
+if __name__ == "main":
+    print get_voltage()
diff --git a/gistfile1.txt b/gistfile1.txt
@@ -1,3 +1,5 @@
+import smbus
+
 def get_voltage():
     """
     Reads the digital output code of the MCP3021 chip on the BrickPi+ over i2c.

diff --git a/gistfile1.txt b/gistfile1.txt
@@ -0,0 +1,34 @@
+def get_voltage():
+    """
+    Reads the digital output code of the MCP3021 chip on the BrickPi+ over i2c.
+    Some bit operation magic to get a voltage floating number.
+
+    If this doesnt work try this on the command line: i2cdetect -y 1
+    The 1 in there is the bus number, same as in bus = smbus.SMBus(1)
+    Google the resulting error.
+
+    :return: voltage (float)
+    """
+    bus = smbus.SMBus(1)            # SMBUS 1 because we're using greater than V1.
+    address = 0x48
+    # time.sleep(0.1) #Is this necessary?
+    try:
+            # read data from i2c bus. the 0 command is mandatory for the protocol but not used in this chip.
+            data = bus.read_word_data(address, 0)
+
+            # from this data we need the last 4 bites and the first 6.
+            last_4 = data & 0b1111 # using a byte mask
+            first_6 = data >> 10 # left shift 10 because data is 16 bits
+
+            # together they make the voltage conversion ratio
+            # to make it all easier the last_4 bits are most significant :S
+            vratio = ((last_4 << 6) | first_6) / 1024.0
+
+            # Now we can calculate the battery voltage like so:
+            RPi_voltage = 5.0
+            voltage = RPi_voltage / vratio
+
+            return voltage
+
+    except:
+            return False
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