Add IR Remote project to module 3

Author: ColinKerr

03_sensors/03_09_ir_remote.md

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+# Infrared Remote Control
+
+An infrared(IR) remote control is a device with buttons and an IR emitter. Pressing down different buttons will make the infrared emitter send infrared pulses unique for each button. Infrared remote control technology is widely used in electronic products such as TV, air conditioning, etc. The receiver decodes those pulses into a binary code so the receiving device knows which button was pressed on the remote. 
+
+![IR Remote Component](../images/ir_remote_component.png)
+
+> NOTE: pull out the plastic tab before you use the remote.  If the plastic tab is not present the remote might have run down the battery while sitting.  
+
+>Save the tab and put it back after you are done with the remote.
+
+
+## New Concepts
+
+- IR Remote
+- IR Receiver
+
+### IR Remote
+
+An IR Remote sends a unique value to the IR Receiver for each key pressed.  This particular IR Remote sends the following values for each key.
+
+![IR Remote key/value table](../images/ir_remote_key_value_table.png)
+
+### IR Receiver
+
+An infrared(IR) receiver is a component which can receive the infrared light and convert it into a data signal.  That data signal returns the key or code value sent by the IR Remote when a button is pressed. 
+
+![IR Receiver Component](../images/ir_receiver_component.png)
+
+## Component List
+
+![Component List](../images/03_09_components.png)
+
+## Circuit
+
+### Wiring Diagram
+
+> Disconnect all power before building the circuit. Reconnect once verified.
+
+![Wiring Diagram](../images/03_09_wiring_diagram.png)
+
+### Schematic Diagram
+
+![Schematic Diagram](../images/03_09_schematic_diagram.png)
+
+## Code
+
+```python
+from irrecvdata import irGetCMD
+
+def commandHandler(hexValue):
+    print(hex(hexValue))
+
+recvPin = irGetCMD(21, commandHandler)
+```
+
+The `irGetCMD` class listens to the pin specified in the constructor and calls the `commandHandler` callback when it decodes a button press.
+
+## Key Concepts
+
+- **Key Codes**: Each button value is encoded as a hex value or code.  
+
+## Further Exploration
+
+- Add code to turn a light on and off when the power button is pressed.

03_sensors/code/Infrared_Remote.py

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+from irrecvdata import irGetCMD
+
+def commandHandler(hexValue):
+    print(hex(hexValue))
+
+recvPin = irGetCMD(21, commandHandler)

03_sensors/code/irrecvdata.py

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+from machine import Pin, Timer
+import time
+
+
+"""
+Class to read signals from the IR Remote
+
+gpioNum - The number of the GPIO pin the IR Receiver is connected to
+commandHandler - The callback function that will be called after a command has been
+  decoded from the IR Remote.  
+  The Callback function must take an integer in as a parameter, this integer is the 
+  hex code for the button pressed.
+"""
+class irGetCMD(object):
+    def __init__(self, gpioNum, commandHandler):
+        self.irRecv = Pin(gpioNum, Pin.IN, Pin.PULL_UP)
+        self.irRecv.irq(trigger=Pin.IRQ_RISING | Pin.IRQ_FALLING, handler=self.__logHandler)
+        self.logList = []
+        self.start = 0
+        self.cmdHandler = commandHandler
+        self.timer = Timer(0)
+
+    def __logHandler(self, source):
+        thisComeInTime = time.ticks_us()
+        if self.start == 0:
+            self.start = thisComeInTime
+            self.timer.deinit()
+            self.timer.init(mode=Timer.ONE_SHOT, period=120, callback=self.readCommand)
+            return
+        self.logList.append(time.ticks_diff(thisComeInTime, self.start))
+        self.start = thisComeInTime
+                        
+    def readCommand(self, t):
+        if len(self.logList) < 67:
+            print("Error reading command")
+            self.reset()
+        else:
+            bufferedBits = []
+            for i in range(3, 66, 2):
+                if self.logList[i] > 800:
+                    bufferedBits.append(1)
+                else:
+                    bufferedBits.append(0)
+            
+            irValue=0x00000000
+            for b in bufferedBits:
+                irValue = irValue<<1
+                irValue += b
+            
+            self.reset()
+            self.cmdHandler(irValue)
+    
+    def reset(self):
+        self.logList = []
+        self.index = 0
+        self.start = 0
+       

images/03_09_components.png

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+from machine import Pin, Timer
+import time
+
+
+"""
+Class to read signals from the IR Remote
+
+gpioNum - The number of the GPIO pin the IR Receiver is connected to
+commandHandler - The callback function that will be called after a command has been
+  decoded from the IR Remote.  
+  The Callback function must take an integer in as a parameter, this integer is the 
+  hex code for the button pressed.
+"""
+class irGetCMD(object):
+    def __init__(self, gpioNum, commandHandler):
+        self.irRecv = Pin(gpioNum, Pin.IN, Pin.PULL_UP)
+        self.irRecv.irq(trigger=Pin.IRQ_RISING | Pin.IRQ_FALLING, handler=self.__logHandler)
+        self.logList = []
+        self.start = 0
+        self.cmdHandler = commandHandler
+        self.timer = Timer(0)
+
+    def __logHandler(self, source):
+        thisComeInTime = time.ticks_us()
+        if self.start == 0:
+            self.start = thisComeInTime
+            self.timer.deinit()
+            self.timer.init(mode=Timer.ONE_SHOT, period=150, callback=self.readCommand)
+            return
+        self.logList.append(time.ticks_diff(thisComeInTime, self.start))
+        self.start = thisComeInTime
+                        
+    def readCommand(self, t):
+        if len(self.logList) < 67:
+            print("Error reading command")
+            self.reset()
+        else:
+            bufferedBits = []
+            for i in range(3, 66, 2):
+                if self.logList[i] > 800:
+                    bufferedBits.append(1)
+                else:
+                    bufferedBits.append(0)
+            
+            irValue=0x00000000
+            for b in bufferedBits:
+                irValue = irValue<<1
+                irValue += b
+            
+            self.reset()
+            self.cmdHandler(irValue)
+    
+    def reset(self):
+        self.logList = []
+        self.index = 0
+        self.start = 0
+