diff --git a/average_period.py b/average_period.py
new file mode 100644
index 0000000..d996544
--- /dev/null
+++ b/average_period.py
@@ -0,0 +1,51 @@
+import math
+import numpy
+
+from saleae.range_measurements import DigitalMeasurer
+
+AVERAGE_PERIOD = 'averagePeriod'
+
+class AveragePeriodMeasurer(DigitalMeasurer):
+    supported_measurements = [AVERAGE_PERIOD]
+
+    # Initialize your measurement extension here
+    # Each measurement object will only be used once, so feel free to do all per-measurement initialization here
+    def __init__(self, requested_measurements):
+        super().__init__(requested_measurements)
+
+        # We always need rising/falling edges
+        self.edges_rising = 0
+        self.edges_falling = 0
+        self.first_transition_type = None
+        self.first_transition_time = None
+        self.last_transition_of_first_type_time = None
+
+    # This method will be called one or more times per measurement with batches of data
+    # data has the following interface
+    #   * Iterate over to get transitions in the form of pairs of `Time`, Bitstate (`True` for high, `False` for low)
+    # `Time` currently only allows taking a difference with another `Time`, to produce a `float` number of seconds
+    def process_data(self, data):
+        for t, bitstate in data:
+            if self.first_transition_type is None:
+                self.first_transition_type = bitstate
+                self.first_transition_time = t
+            elif self.first_transition_type == bitstate:
+                current_period = t - (self.last_transition_of_first_type_time if self.last_transition_of_first_type_time is not None else self.first_transition_time)
+                self.last_transition_of_first_type_time = t
+            if bitstate:
+                self.edges_rising += 1
+            else:
+                self.edges_falling += 1
+
+    # This method is called after all the relevant data has been passed to `process_data`
+    # It returns a dictionary of the request_measurements values
+    def measure(self):
+        values = {}
+
+    
+        if AVERAGE_PERIOD in self.requested_measurements:
+            if self.first_transition_time is not None and self.last_transition_of_first_type_time is not None:
+                period_count = (self.edges_rising if self.first_transition_type else self.edges_falling) - 1
+                values[AVERAGE_PERIOD] = 1 / (float(period_count) / (self.last_transition_of_first_type_time - self.first_transition_time))
+
+        return values
diff --git a/extension.json b/extension.json
new file mode 100644
index 0000000..f4fef30
--- /dev/null
+++ b/extension.json
@@ -0,0 +1,20 @@
+{
+  "version": "0.0.1",
+  "apiVersion": "1.0.0",
+  "author": "Tim Reyes",
+  "description": "",
+  "name": "Average Period",
+  "extensions": {
+    "AvgPeriod": {
+      "type": "DigitalMeasurement",
+      "entryPoint": "average_period.AveragePeriodMeasurer",
+      "metrics": {
+        "averagePeriod": {
+          "name": "Average Period",
+          "notation": "T<sub>avg</sub>",
+          "units": "s"
+        }
+      }
+    }
+  }
+}