dietpi_button.sh

#!/bin/bash
# dietpi version, install gpiod

# The GPIO chip (usually 0 on a Pi) and line number (BCM number), timeout in seconds
GPIO_CHIP="gpiochip0"
GPIO_LINE=3
TIMEOUT=4

# --- Your commands ---
PAUSE_CMD="echo PAUSE_CMD"
STOP_CMD="echo STOP_CMD"

# --- LED Control Functions ---
set_led() {
    # Arguments: 1=LED (PWR/ACT), 2=TRIGGER (heartbeat, timer, none, default-on)
    if [ -n "$2" ]; then
        echo "$2" | sudo tee "/sys/class/leds/$1/trigger" > /dev/null
    fi
}

# --- Initial State ---
echo "Starting GPIO button handler for pin ${GPIO_LINE}..."
set_led PWR heartbeat
set_led ACT timer

push_count=0

# Use 'process substitution' to open the output of gpiomon as a file on file descriptor 3
exec 3< <(gpiomon -p 50 --edge falling -c "${GPIO_CHIP}" "${GPIO_LINE}")

# Ensure the file descriptor is closed when the script exits
trap "exec 3<&-" EXIT

while true; do
    # Wait for an event from file descriptor 3 (-u 3), with a timeout
    if read -r -u 3 -t $TIMEOUT event; then
        # If an event is read, increment the count
        push_count=$((push_count + 1))
        echo "Button push detected. Count is now: ${push_count}"

        # Visual feedback on each press: Green LED blinks once
        set_led ACT default-on
        set_led PWR default-on
        sleep 0.2
        set_led ACT heartbeat
        set_led PWR timer

        # Reset if count exceeds 8
        if (( push_count > 8 )); then
            echo "Push count exceeded 8. Resetting."
            push_count=0
            set_led PWR heartbeat
            set_led ACT timer
        fi
    else
        # If read times out, it means the user stopped pressing the button.
        # Now we check the final count and execute the action.
        if (( push_count > 0 )); then
            echo "Timeout reached. Final push count: ${push_count}. Executing action..."

            case $push_count in
                2)
                    echo "Two pushes: PAUSE_CMD."
                    set_led PWR timer
                    set_led ACT default-on
                    eval $PAUSE_CMD
                    ;;
                4)
                    echo "Four pushes: STOP_CMD."
                    set_led PWR default-on
                    set_led ACT heartbeat
                    eval $STOP_CMD
                    ;;
                6)
                    echo "Six pushes: Powering off!"
                    set_led PWR none
                    set_led ACT heartbeat
                    sudo poweroff
                    ;;
                *)
                    echo "No action for ${push_count} pushes."
                    set_led PWR heartbeat
                    set_led ACT timer
                    ;;
            esac
            # Reset for the next sequence
            echo "Resetting push_count to 0."
            push_count=0
        fi
    fi
done