raspberry-pi-neon-sign-flicker-effect.py

import RPi.GPIO as GPIO
import time
import random

# Setup GPIO
GPIO.setmode(GPIO.BCM)
GPIO.setup(17, GPIO.OUT)
pwm = GPIO.PWM(17, 1000)  # 1kHz PWM frequency
pwm.start(100)

def flicker_burst():
    """Rapid on-off flicker like a dying neon tube"""
    flicker_count = random.randint(4, 12)
    for _ in range(flicker_count):
        # Off time (dark)
        pwm.ChangeDutyCycle(255 - random.randint(0, 50))
        time.sleep(random.uniform(0.02, 0.08))
        
        # On time (bright)
        pwm.ChangeDutyCycle(255 - random.randint(200, 255))
        time.sleep(random.uniform(0.02, 0.07))

def slow_dim():
    """Gradually dim from bright to dim"""
    for brightness in range(255, 100, -3):
        pwm.ChangeDutyCycle(brightness)
        time.sleep(random.uniform(0.01, 0.05))

def slow_brighten():
    """Gradually brighten from dim to bright"""
    for brightness in range(100, 255, 3):
        pwm.ChangeDutyCycle(brightness)
        time.sleep(random.uniform(0.01, 0.05))

def power_surge():
    """Sudden bright flash then dim"""
    pwm.ChangeDutyCycle(0)  # Full bright
    time.sleep(0.3)
    for brightness in range(0, 180, 2):
        pwm.ChangeDutyCycle(brightness)
        time.sleep(0.01)

def struggling_start():
    """Struggling to turn on - multiple attempts"""
    attempts = random.randint(2, 4)
    for _ in range(attempts):
        # Try to turn on
        pwm.ChangeDutyCycle(255 - random.randint(100, 180))
        time.sleep(random.uniform(0.15, 0.4))
        
        # Failed - turns off
        pwm.ChangeDutyCycle(255)
        time.sleep(random.uniform(0.1, 0.3))
    
    # Finally turns on
    pwm.ChangeDutyCycle(0)

def intermittent_flicker():
    """Occasional quick flickers while otherwise on"""
    base_brightness = random.randint(20, 60)
    
    for _ in range(random.randint(3, 8)):
        # Normal on
        pwm.ChangeDutyCycle(base_brightness)
        time.sleep(random.uniform(0.5, 2))
        
        # Quick flicker off
        pwm.ChangeDutyCycle(220)
        time.sleep(random.uniform(0.03, 0.1))

try:
    print("Starting Dying Neon Sign Effect...")
    print("Press Ctrl+C to stop")
    
    while True:
        effect = random.randint(1, 6)
        
        if effect == 1:
            # Rapid death flicker
            print("Effect: Rapid flicker burst")
            flicker_burst()
            time.sleep(random.uniform(0.5, 1.5))
            
        elif effect == 2:
            # Struggling to stay on
            print("Effect: Struggling to power on")
            struggling_start()
            time.sleep(2)
            
        elif effect == 3:
            # Dim and brighten cycle
            print("Effect: Gradual dim and brighten")
            slow_dim()
            time.sleep(random.uniform(0.3, 0.8))
            slow_brighten()
            time.sleep(1)
            
        elif effect == 4:
            # Power surge
            print("Effect: Power surge")
            power_surge()
            time.sleep(random.uniform(1, 2))
            
        elif effect == 5:
            # Intermittent flickers
            print("Effect: Intermittent flicker")
            intermittent_flicker()
            time.sleep(random.uniform(0.5, 1))
            
        else:  # effect == 6
            # Stay bright normally then suddenly flicker
            print("Effect: Normal bright then sudden flicker")
            pwm.ChangeDutyCycle(255 - random.randint(240, 255))
            time.sleep(random.uniform(1, 4))
            flicker_burst()
            time.sleep(random.uniform(0.5, 1))
        
        # Random pause between effects
        time.sleep(random.uniform(0.3, 1))

except KeyboardInterrupt:
    print("\nShutting down...")
    pwm.ChangeDutyCycle(255)  # Turn off
    time.sleep(0.5)
finally:
    pwm.stop()
    GPIO.cleanup()
    print("Goodbye!")

Dying Neon Sign Effect - Raspberry Pi LED Controller

A Python script that creates a realistic dying neon sign flicker effect on a 12V LED strip controlled by a Raspberry Pi (4, Zero WH, or Pico). Uses PWM (Pulse Width Modulation) on GPIO pin 17 to simulate the unpredictable behavior of a failing vintage neon sign.

Features:

• Rapid flicker bursts (like a tube dying)
• Struggling power-on sequences (multiple failed attempts)
• Gradual dimming and brightening cycles
• Power surge effects (sudden bright flash)
• Intermittent random flickers
• Smooth transitions between effects

Hardware Required:

• Raspberry Pi (4, Zero WH, or Pico)
• 12V LED Strip (3.5m or longer)
• 12V Power Supply (5A)
• Gate driver circuit (2N4124 transistor, IRF510 MOSFET, 1N4004 diode, 10kΩ and 1kΩ resistors)

Circuit Details:
The script controls the LED strip through a PWM gate driver circuit that safely amplifies the GPIO signal from 3.3V (16mA) to 12V (5A). This protects the microcontroller while providing full brightness control.

Code Features:

• 6 different flicker effect functions
• Random effect cycling
• Configurable timing and randomness
• Easy to modify for different effects
• Graceful shutdown

Usage:
python3 dying-neon-sign-effect.py

Press Ctrl+C to stop (if connected to terminal). For headless operation, unplug power or SSH in and kill the process.