fixed pylint issues in examples

Author: fourstix

README.rst

@@ -14,7 +14,7 @@ Coming Soon
     :alt: Build Status
 
 CircuitPython library for Sparkfun Qwiic Single Relay.  This library is ported from examples
-at `SparkFun Qwiic Single Relay <https://github.com/sparkfun/SparkFun_Qwiic_Releay>`_
+at `SparkFun Qwiic Relay <https://github.com/sparkfun/Qwiic_Relay>`_
 
 .. image:: https://cdn.sparkfun.com//assets/parts/1/3/4/5/1/15093-SparkFun_Qwiic_Single_Relay-01.jpg
     :target: https://www.sparkfun.com/products/15093

examples/example2_change_i2c_address.py

@@ -5,19 +5,21 @@
 
 """
   Qwiic Relay Example 2 - example2_change_i2c_address.py
-  Written by Gaston Williams, June 13th, 2019
+  Written by Gaston Williams, June 19th, 2019
   Based on Arduino code written by
-  Wes Furuya @ SparkFun Electronics, February 5th, 2019
-  The Qwiic Relay is a I2C controlled analog relay
+  Kevin Kuwata @ SparkX, March 21, 2019
+  The Qwiic Single Relay is a I2C controlled relay
 
   Example 2 - Change I2C Address:
   This program uses the Qwiic Relay CircuitPython Library to change
   the I2C address for the device. You enter in the DEC value (8-119) or
-  HEX value (0x08-0x77) for the new Relay address.  After the address is
-  You can run i2c_scanner.py to validate the address after the change.
+  HEX value (0x08-0x77) for the new Relay address.  After the i2c address
+  is changed, you can run the example3_i2c_scanner.py program to validate
+  the i2c address.
 
   Syntax: python3 change_i2c_address.py [address]
-    where address is an optional address value in decimal or hex
+    where address is an optional current address value in decimal or hex
+
     The default value for the address is 24 [0x18]
 """
 

examples/example3_i2c_scanner.py

@@ -10,50 +10,66 @@
 
   Example 3 - I2C Scanner
   This progam uses CircuitPython BusIO library to find the current
-  address of the Qwiic Relay. It uses the I2C Scanner Example from
+  address of the Qwiic Relay. It uses information from
   https://learn.adafruit.com/circuitpython-basics-i2c-and-spi/i2c-devices
+  to manually scan for the Qwiic Single Relay.
+
+  Since the Qwiic Single Relay responds to any byte read request after it's
+  base address is written, i2c.scan()cannot be used.
+
+  This code manually scans addresses from 0x03 to 0x80, using only writes,
+  not writes and reads,to find i2c devices.
 
   The factory default address is 0x18.
 """
 
-import time
+from time import sleep
 
 import board
 import busio
 
 i2c = busio.I2C(board.SCL, board.SDA)
 
-# For some reason i2c.scan() returns all addresses above the relay address
-# So we will manually look for the really address
+# Since i2c.scan() returns all addresses above the relay address,
+# we look for the relay address using only write requests.
 
-def test_i2c_address(addr):
-    "test an address to see if there's a device there"""
+def test_i2c_write(addr):
+    "Write to an address to see if there's an device there"""
     while not i2c.try_lock():
         pass
 
     try:
+        # Make an empty write request to an address
         i2c.writeto(addr, b'')
+        return True
+
     except OSError:
-        # some OS's dont like writing an empty bytesting...
-        # Retry by reading a byte
-        try:
-            result = bytearray(1)
-            i2c.readfrom_into(addr, result)
-        except OSError:
-                return False
-        finally:
-            i2c.unlock()
+        return False
+
+    # Always unlock the i2c bus, before return
+    finally:
+        i2c.unlock()
 
-    return True
 
+print('Press Ctrl-C to exit program')
 
-addresses = []
+try:
+    while True:
+         found = []
 
-for address in range(0x08, 0x80):
-    if(test_i2c_address(address)):
-        print('Found relay at address ' + hex(address))
-        exit()
+         # scan through all possible i2c addresses doi
+         for address in range(0x03, 0x80):
+             if(test_i2c_write(address)):
+                  found.append(address)
 
-print('No I2C device found.')
+         if(len(found) > 0):
+             print('I2C addresses found:',
+                   [hex(device_address) for device_address in found])
+         else:
+             print('No I2C device found.')
 
+         # wait a bit and scan again
+         sleep(5)
 
+except KeyboardInterrupt:
+    pass

examples/example4_get_relay_status.py

@@ -5,16 +5,16 @@
 
 """
  Qwiic Relay Example 4 - example4_get_relay_status.py
- Written by Gaston Williams, June 13th, 2019
+ Written by Gaston Williams, June 18th, 2019
  Based on Arduino code written by
  Kevin Kuwata @ SparkX, March 21, 2018
  The Qwiic Single Relay is an I2C controlled relay produced by sparkfun
 
  Example 4 - Get Relay Status:
  This program uses the Qwiic Relay CircuitPython Library to
- get the current status of the Qwiic Relay. The relay responds 
+ get the current status of the Qwiic Relay. The relay responds
  with a 1 for on and a 0 for off.
- 
+
  Default Qwiic relay address is 0x18.
 """
 

examples/example5_get_firmware_version.py

@@ -11,10 +11,10 @@
  The Qwiic Single Relay is an I2C controlled relay produced by sparkfun
 
  Example 5 - Get Firmware Version:
- This program uses the Qwiic Relay CircuitPython Library to get the 
+ This program uses the Qwiic Relay CircuitPython Library to get the
  firmware version of Qwiic Single Relay breakout.  If using version prior
- to (excluding) 1.0 the version number will be 25.5 or 26.5. Starting at
- version 1.0, the relay  will respond with the correct firmware version.
+ to version 1.0 the version number will be 25.5 or 26.5. Starting at
+ version 1.0, the relay will respond with the correct firmware version.
 
  Default Qwiic relay address is 0x18.
 """