Updated readme with JSON example

README.md

@@ -1,4 +1,23 @@
 CargoCollector
 ==============
 
-Cargo Collector Service.  Android service that interfaces with car.
+Cargo Collector Service.  Android service that interfaces with car via a standard ELM327 compatable OBD-II reader.
+
+Data points are gathered from the car and various sensors on the mobile phone on an interval and/or as changes occur.  These data points are marshalled to JSON, compressed, and sent to an attached ZeroMQ server on a set interval.
+
+Data points
+___________
+  ```json
+  {
+      "location": {
+          "lat": 123.456789,
+          "lng": 123.456789,
+          "timestamp": 1234567890
+      },
+      "timestamp": 1234567890,
+      "speed": 45.2,
+      "engine_temp": 202.3,
+      "maf": 2.324,
+      "rpm": 3948
+  }
+  ```