From 5ffdc6e63c5775acf53ea6c7962baef6dfadc305 Mon Sep 17 00:00:00 2001
From: androiddrew <bednar.andrew@gmail.com>
Date: Tue, 24 Dec 2019 15:53:18 -0500
Subject: [PATCH] Adding interrupt example

---
 interrupts/README.md         | 36 ++++++++++++++++++++++++++++++++++++
 interrupts/printer.py        | 15 +++++++++++++++
 threading/hello_threading.py |  2 +-
 webserver/README.md          | 11 +++++++++--
 4 files changed, 61 insertions(+), 3 deletions(-)
 create mode 100644 interrupts/README.md
 create mode 100644 interrupts/printer.py

diff --git a/interrupts/README.md b/interrupts/README.md
new file mode 100644
index 0000000..bd69957
--- /dev/null
+++ b/interrupts/README.md
@@ -0,0 +1,36 @@
+# 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.
+
diff --git a/interrupts/printer.py b/interrupts/printer.py
new file mode 100644
index 0000000..c49195d
--- /dev/null
+++ b/interrupts/printer.py
@@ -0,0 +1,15 @@
+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.
\ No newline at end of file
diff --git a/threading/hello_threading.py b/threading/hello_threading.py
index 255bd3f..281e77b 100644
--- a/threading/hello_threading.py
+++ b/threading/hello_threading.py
@@ -5,7 +5,7 @@ import time
 def testThread():
     while True:
         print("Hello threading")
-        time.sleep(15) # Time is so high so that we can actually get a repl.
+        time.sleep(15)  # Time is so high so that we can actually get a repl.
 
 
 _thread.start_new_thread(testThread, ())
diff --git a/webserver/README.md b/webserver/README.md
index eaa93fc..70a698c 100644
--- a/webserver/README.md
+++ b/webserver/README.md
@@ -1,3 +1,10 @@
-# ESP32 Webserver
+# 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.
\ No newline at end of file
+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">
+```