Differences

This shows you the differences between two versions of the page.

--- using_a_breakout_button [2026/07/15 19:29] – [Introduction] walkeradmin
+++ using_a_breakout_button [2026/07/15 20:02] (current) – walkeradmin
@@ Line 14: / Line 14: @@
 \\
 In this example, again we are going to use the traffic light example, we are going to use a button to breakout of our code. This is very simple to do, first lets look at the wiring diagram for our traffic lights.
-\\
 \\
 {{ :traffic-light-breakout-button.png?400 |}}
 \\
+This is our original traffic light build, but with an additional push button on pins GP16 and GND.
+\\
+\\
+----
+==== The Code ====
+\\
+Below is the code, there are two blocks that have been added. The are:
+\\
+  * Block1 - Sets up GP16 as an input that is pulled up (so we need to set it to GND for it to work)
+  * Block2 - Monitors the button to see if it is pressed (looking for a zero on Pin16)
+  * Block1 is at the program start, and is only run once.
+  * Block2 is in the loop, and is checked every time the code loops.
+The Micro Python Code we are using.
+\\
+<code:python | download>
+#Traffic light LEDs using an array
+from machine import Pin
+import time
+#######################    ADD BREAKOUT BUTTON #############################
+# Configure the button on GPIO16
+# PULL_UP means the pin reads HIGH (1) until the button connects it to GND
+button = Pin(16, Pin.IN, Pin.PULL_UP)
+#######################    ADD BREAKOUT BUTTON #############################
+# Define GPIO pins for the LEDs
+RED = Pin(2, Pin.OUT)
+AMBER = Pin(6, Pin.OUT)
+GREEN = Pin(10, Pin.OUT)
+# Put them in an array
+lights = [RED, AMBER, GREEN]
+# Helper function to turn all lights off
+def all_off():
+    for light in lights:
+        light.off()
+while True:
+    # Red
+    all_off()
+    RED.on()
+    time.sleep(3)
+    # Red + Amber
+    AMBER.on()
+    time.sleep(1)
+    # Green
+    all_off()
+    GREEN.on()
+    time.sleep(3)
+    # Amber
+    all_off()
+    AMBER.on()
+    time.sleep(1)
+####################### CHECK BREAKOUT BUTTON ##########################
+    # Read the button
+    if button.value() == 0:   # Button pressed (LOW)
+        print("Button pressed — stopping program.")
+        all_off()
+        break                 # Exit the loop and end main.py
+####################### CHECK BREAKOUT BUTTON ##########################
+# Code End
+</code>
+There is on limitation on pressing the button, we need to look at this part of the code to understand it.
+\\
+<code:python | download>
+    # Red
+    all_off()
+    RED.on()
+    time.sleep(3)
+    # Red + Amber
+    AMBER.on()
+    time.sleep(1)
+    # Green
+    all_off()
+    GREEN.on()
+    time.sleep(3)
+    # Amber
+    all_off()
+    AMBER.on()
+    time.sleep(1)
+</code>
+In our code, to delay the LEDs so they cycle in time like a set of traffic lights would, we have four <color #ed1c24>time.sleep</color> statements, the total delay of these is 8 seconds. This means, when we press the button, depending on where we are in the loop, we might have to hold the button for up to 9 seconds before the button value is read.
+\\
+\\
+However, if you read the code, you can see the button value is read as the <color #ffc90e>Amber</color> LED is turned on after the <color #22b14c>Green</color> LED>. So it is quite easy to time right if you don't want to hold the button for 8 seconds.
+\\
+\\
+=== Example ===
+\\
+<color #ed1c24>***Remember*** - We must save this code to our Raspberry Pi Pico as a file called main.py.</color>
+\\
+\\
+This will enable to code to run on the Pico boot up.
+\\
+\\
+Here is the button in action.
+\\
+\\
+{{ :traffic-light-breakout-button-sim.mp4?900x634 |}}
+\\
+Using a button like this means you can never get you Pico stuck in a software loop with little to no way of recovery (without wiping it completely).
+\\
+\\
+----