pi-top blog

Give your pi-top or pi-topCEED a haunted feel this Halloween with this spooky jack-o’- lantern tutorial!

Before we get started, this is the boo-tiful equipment required to achieve the ghastliest effects:

• 5x yellow witches boil LEDs
• 1x blood red LED
• 6x 100 Ω reVolting resistors
• 1x pi-topPROTO (or breadboard)
• A few standard wires
• 1x acrylic slice (included with your pi-top or pi-topCEED)
• Access to a laser etcher (optional)
• 1x pi-top or pi-topCEED

So, let's get started by transforming our pi-topPROTO board into a magic dancing candle.

Step 1: Wire LEDs to your pi-topPROTO board

• The red LED should be wired to pin 22(GPIO 25) on your pi-topPROTO board
• The yellow LEDs should be wired to pins 11(GPIO 17), 13(GPIO 27), 16(GPIO 23). 29(GPIO 5), 32(GPIO 12)

The red and yellow lights will create a spook-tacular orange hue for your laser etched jack-o’- lantern acrylic slice!

Step 2: Wire LEDs to ground

• Wire the cathode (negative pin) to the ground rail on your pi-topPROTO board, to keep things neat we have done this on the back of our pi-topPROTO board as seen in the image above!

Step 3: Use resistors to connect your LEDs to GPIO pins

• Next, we need to wire the yellow LEDs to RPI pins 11, 13, 16, 29 and 32
• The red LED should be wired to pin RPI pin 22
• This will complete the full circuit

Now, we are almost there! Put the following Python code into the pi-topCODER editor and click run to test it:

import random

from time import sleep

from gpiozero import PWMLED
RED_LED = PWMLED(25)
YELLOW_LEDS = [

    PWMLED(17),

    PWMLED(23),

    PWMLED(27),

    PWMLED(5),

    PWMLED(12)

]
while True:

    RED_LED.value = random.uniform(0, 0.5)
    for led in YELLOW_LEDS:     

        led.value = random.uniform(0, 0.5)
    sleep(random.uniform(0, 0.5))

The code uses randomised pulse width modulation (PWM) in order create a candle flicker effect!

Finally, we need to etch our spooky acrylic slice - the design can be downloaded in .dxf format (see below).

Download the dxf file here: halloween

Here is our ghastly haunted pi-top acrylic slice:

Eerie green halloween……. ;)

So, for the final effect. Let’s run our code again!

Here is your spooky phantom pumpkin finished project!