put example into readme

Author: ladyada

README.rst

@@ -28,7 +28,32 @@ This is easily achieved by downloading
 Usage Example
 =============
 
-.. todo:: Add a quick, simple example. It and other examples should live in the examples folder and be included in docs/examples.rst.
+.. code-block:: python	
+
+	import time
+	import board  # comment this out if using pyserial
+	import busio  # comment this out if using pyserial
+	import adafruit_tfmini
+
+	# Use hardware uart
+	uart = busio.UART(board.TX, board.RX)
+
+	# Or, you can use pyserial on any computer
+	#import serial
+	#uart = serial.Serial("/dev/ttyS2", timeout=1)
+
+	# Simplest use, connect with the uart bus object
+	tfmini = adafruit_tfmini.TFmini(uart)
+
+	# You can put in 'short' or 'long' distance mode
+	tfmini.mode = adafruit_tfmini.MODE_SHORT
+	print("Now in mode", tfmini.mode)
+
+	while True:
+	    print("Distance: %d cm (strength %d, mode %x)" %
+		  (tfmini.distance, tfmini.strength, tfmini.mode))
+	    time.sleep(0.1)
+
 
 Contributing
 ============