Tag Archives: buttons

<span data-mce-type="bookmark" style="display: inline-block; width: 0px; overflow: hidden; line-height: 0;" class="mce_SELRES_start"></span> In the video lesson above, we show how to incorporate IRQ interrupts on the Pi Pico PIO State Machines. The state machines will monitor the buttons, watching for button presses. When a button is pressed, an interrupt is set. That interrupt can then be used by that same state machine, a different state machine on the same PIO, or in the main micropython program. Our first example will be to toggle the LED in the main python program, based on the interrupt from the state machine. In the second example, one state machine monitors the button, and the second state machine controls the LED. This is a schematic for the circuit we will be using.

Circuit Schematic for Button Control LED Interrupts

This first code controls the LED from the main python program.

import rp2
from machine import Pin
import time

# Define PIO program for SM0 to trigger an interrupt on button press
@rp2.asm_pio()
def button_irq():
    wrap_target()
    wait(1, pin, 0)  [31]  # Wait for the button press (low signal on GPIO 11)
    nop() [31]
    nop() [31]
    nop() [31]
    nop() [31]
    irq(block, 0)      # Trigger interrupt 0
    wait(0, pin, 0)    # Wait for the button release (high signal on GPIO 11)
    nop() [31]
    nop() [31]
    nop() [31]
    nop() [31]
    wrap()
# Initialize State Machine 0 for the button (GPIO 11)
button_pin = Pin(11, Pin.IN, Pin.PULL_DOWN)
sm_button = rp2.StateMachine(0, button_irq, freq=2000, in_base=button_pin)
# GPIO pin for the LED (GPIO 18)
led_pin = Pin(18, Pin.OUT)
# Interrupt handler for the button press
def button_handler(sm):
    led_pin.value(not led_pin.value())  # Toggle LED state
# Attach the interrupt handler to the State Machine's IRQ
sm_button.irq(button_handler)
# Activate the state machine
sm_button.active(1)

# Keep the program running
while True:
    time.sleep(1)

import rp2

from machine import Pin

import time

# Define PIO program for SM0 to trigger an interrupt on button press

@rp2.asm_pio()

def button_irq():

wrap_target()

wait(1, pin, 0) [31] # Wait for the button press (low signal on GPIO 11)

nop() [31]

irq(block, 0) # Trigger interrupt 0

wait(0, pin, 0) # Wait for the button release (high signal on GPIO 11)

nop() [31]

wrap()

# Initialize State Machine 0 for the button (GPIO 11)

button_pin = Pin(11, Pin.IN, Pin.PULL_DOWN)

sm_button = rp2.StateMachine(0, button_irq, freq=2000, in_base=button_pin)

# GPIO pin for the LED (GPIO 18)

led_pin = Pin(18, Pin.OUT)

# Interrupt handler for the button press

def button_handler(sm):

led_pin.value(not led_pin.value()) # Toggle LED state

# Attach the interrupt handler to the State Machine's IRQ

sm_button.irq(button_handler)

# Activate the state machine

sm_button.active(1)

# Keep the program running

while True:

time.sleep(1)

This next program uses only the state machines. Interrupts and LED control are both done in the state machines.

import rp2
from machine import Pin
import time

@rp2.asm_pio()
def button_irq():
    wrap_target()
    wait(1, pin, 0) [31]
    nop() [31]
    nop() [31]
    nop() [31]
    nop() [31]
    irq(block,0)
    wait(0,pin,0)
    nop() [31]
    nop() [31]
    nop() [31]
    nop() [31]
    wrap()

@rp2.asm_pio(out_init=rp2.PIO.OUT_LOW)
def led_control():
    set(x,0b00000)
    wrap_target()
    wait(1, irq, 0)
    mov(x,invert(x))
    mov(pins,x)
    irq(clear, 0)
    wrap()

button_pin = Pin(11,Pin.IN,Pin.PULL_DOWN)
sm_button=rp2.StateMachine(0,button_irq, freq=2000, in_base=button_pin)

led_pin = Pin(18, Pin.OUT)
sm_led=rp2.StateMachine(1, led_control, freq=2000, out_base=led_pin)
sm_button.active(1)
sm_led.active(1)

import rp2

from machine import Pin

import time

@rp2.asm_pio()

def button_irq():

wrap_target()

wait(1, pin, 0) [31]

nop() [31]

irq(block,0)

wait(0,pin,0)

nop() [31]

wrap()

@rp2.asm_pio(out_init=rp2.PIO.OUT_LOW)

def led_control():

set(x,0b00000)

wrap_target()

wait(1, irq, 0)

mov(x,invert(x))

mov(pins,x)

irq(clear, 0)

wrap()

button_pin = Pin(11,Pin.IN,Pin.PULL_DOWN)

sm_button=rp2.StateMachine(0,button_irq, freq=2000, in_base=button_pin)

led_pin = Pin(18, Pin.OUT)

sm_led=rp2.StateMachine(1, led_control, freq=2000, out_base=led_pin)

sm_button.active(1)

sm_led.active(1)

Arduino, Tutorial

Arduino Tutorial 29: Using Push Buttons to Create Dimmable LED

September 24, 2019 admin

In this lesson we show you how to create a Dimmable LED using two pushbuttons. Pressing one button will gradually increase the brightness, while pressing the other button will gradually decrease the brightness. The project also includes an active buzzer to provide the user feedback that either maximum or minimum brightness have been reached. I encourage you to try and build this yourself before watching the video. Then see if you can do it on your own, and then see if you are doing the way I do it, or if you find an alternative suitable solution.

If you want to follow along at home, you can order the Arduino Kit we are using HERE.

Below is the code we used to achieve the toggle operation. The video gives details on how to connect up the circuit.

int buttonPin1=12;
int buttonPin2=11;
int buzzPin=2;
int LEDPin=3;
int buttonVal1;
int buttonVal2;
int LEDbright=0;
int dt=500;
void setup() {
  // put your setup code here, to run once:
pinMode(buttonPin1,INPUT);
pinMode(buttonPin2,INPUT);
pinMode(LEDPin,OUTPUT);
pinMode(buzzPin,OUTPUT);
Serial.begin(9600);
}

void loop() {
buttonVal1=digitalRead(buttonPin1);
buttonVal2=digitalRead(buttonPin2);
Serial.print("Button 1 = ");
Serial.print(buttonVal1);
Serial.print(", ");
Serial.print("Button 2 = ");
Serial.println(buttonVal2);
delay(dt);
if (buttonVal1==0){
  LEDbright=LEDbright+5;
}
if (buttonVal2==0){
  LEDbright=LEDbright-5;
}
Serial.println(LEDbright);
if (LEDbright>255){
  LEDbright=255;
  digitalWrite(buzzPin,HIGH);
  delay(dt);
  digitalWrite(buzzPin,LOW);
  Serial.println("Buzz HIGH");
  
}
if (LEDbright<0){
  LEDbright=0;
  digitalWrite(buzzPin,HIGH);
  delay(dt);
  digitalWrite(buzzPin,LOW);
  Serial.println("Buzz LOW");
}

analogWrite(LEDPin, LEDbright);
}

int buttonPin1=12;

int buttonPin2=11;

int buzzPin=2;

int LEDPin=3;

int buttonVal1;

int buttonVal2;

int LEDbright=0;

int dt=500;

void setup() {

// put your setup code here, to run once:

pinMode(buttonPin1,INPUT);

pinMode(buttonPin2,INPUT);

pinMode(LEDPin,OUTPUT);

pinMode(buzzPin,OUTPUT);

Serial.begin(9600);

}

void loop() {

buttonVal1=digitalRead(buttonPin1);

buttonVal2=digitalRead(buttonPin2);

Serial.print("Button 1 = ");

Serial.print(buttonVal1);

Serial.print(", ");

Serial.print("Button 2 = ");

Serial.println(buttonVal2);

delay(dt);

if (buttonVal1==0){

LEDbright=LEDbright+5;

}

if (buttonVal2==0){

LEDbright=LEDbright-5;

}

Serial.println(LEDbright);

if (LEDbright>255){

LEDbright=255;

digitalWrite(buzzPin,HIGH);

delay(dt);

digitalWrite(buzzPin,LOW);

Serial.println("Buzz HIGH");

}

if (LEDbright<0){

LEDbright=0;

digitalWrite(buzzPin,HIGH);

delay(dt);

digitalWrite(buzzPin,LOW);

Serial.println("Buzz LOW");

}

analogWrite(LEDPin, LEDbright);

}

Arduino, Tutorial

Arduino Tutorial 27: Understanding Pushbuttons and Pull Up and Pull Down Resistors

September 10, 2019 admin

Being able to add push buttons to your projects adds important new capabilities to your prototypes. It is a clever way you can get input from a user. You could imagine using push buttons to turn something on or off, or they could be used to set motor speed or direction. In order to incorporate buttons into a project, you need to understand the concept of pull up and pull down resistors. In this tutorial we show you how to include buttons in a project, by demonstrating a simple on/off function on an LED.

If you want to follow along at home, you can order the Arduino Kit we are using HERE.

This is the code we used in this project to switch the LED on and off.

int LEDPin=8;
int buttonPin=12;
int buttonRead;
int dt=100;
void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
pinMode(LEDPin, OUTPUT);
pinMode(buttonPin, INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
buttonRead=digitalRead(buttonPin);
Serial.println(buttonRead);
delay(dt);
if(buttonRead==1){
  digitalWrite(LEDPin,LOW);
}
if(buttonRead==0){
  digitalWrite(LEDPin, HIGH);
}

}

int LEDPin=8;

int buttonPin=12;

int buttonRead;

int dt=100;

void setup() {

// put your setup code here, to run once:

Serial.begin(9600);

pinMode(LEDPin, OUTPUT);

pinMode(buttonPin, INPUT);

}

void loop() {

// put your main code here, to run repeatedly:

buttonRead=digitalRead(buttonPin);

Serial.println(buttonRead);

delay(dt);

if(buttonRead==1){

digitalWrite(LEDPin,LOW);

}

if(buttonRead==0){

digitalWrite(LEDPin, HIGH);

}

Technology Tutorials

Tag Archives: buttons

Raspberry Pi Pico PIO State Machine IRQ Interrupts

Arduino Tutorial 29: Using Push Buttons to Create Dimmable LED

Arduino Tutorial 27: Understanding Pushbuttons and Pull Up and Pull Down Resistors

Making The World a Better Place One High Tech Project at a Time. Enjoy!