Adding interrupt example

interrupts/README.md

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+# Interrupts
+
+While a great amount of logic can be handled within our code, `while` loops are not very conducive to event driven
+ behavior. [Enter interrupts](https://randomnerdtutorials.com/micropython-interrupts-esp32-esp8266/). When a change is detected interrupts trigger a handler function. 
+
+When an interrupt occurs the processor halts execution of the main program and executes the interrupt handling routine
+then returns control back to the main program.
+
+On the ESP32 you can use all pins as interrupts with the except of pins 6 - 11. 
+
+## Basics
+
+Let's use a button and an LED to demonstrate the basics of interrupts.
+
+Your interrupt handler must accept a single parameter, a `Pin` object, which will be set to the pin triggering the interrupt.
+
+````
+def hangle_interrupt(pin):
+    pass
+````
+
+Set the GPIO that will be used as the input pin. 
+```
+pin = Pin(14, Pin.IN)
+```
+
+Attach an interrupt to pin.
+```
+pin.irq(trigger=Pin.IRQ_RISING, handler=handle_interrupt)
+```
+
+There are 3 different trigger modes you can use:
+* IRQ_RISING - Trigger on the rising edge
+* IRQ_FALLING - Trigger on the falling edge. For example when a button is released.
+* 3 - Trigger the interrupt on both edges.
+

interrupts/printer.py

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+from machine import Pin
+
+# Enable input pin. We will put a button on this pin
+pir = Pin(34, Pin.IN)
+
+
+# Create handler
+def handle_interrupt(pin):
+    print("You triggered the interrupt")
+
+
+# attach interrupt to pin
+pir.irq(trigger=Pin.IRQ_RISING, handler=handle_interrupt)
+
+# You don't need a While loop here. If you leave it off you will get a REPL with your objects still set.

webserver/README.md

@@ -1,3 +1,10 @@
 # ESP32 Web server
 
 This project makes use of the ESP32's wifi capabilities and the `usocket` library to respond to a simple get request and return and HTML response.
+
+### Web page auto refresh
+
+You can make use the of the meta tag to tell the web browser to refresh the page on a certain interval:
+```
+<meta http-equiv="refresh" content="10">
+```