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Pumpkinator: Overview

The Pumpkinator is a Halloween prop built by Fahrenheit Robotics Team 6882 students. When someone walks past, it triggers spooky sound effects and a colorful RGB light show, all from inside a real pumpkin.

tip

Check out the Pumpkinator landing page.

Cartoon of a kid walking up to a glowing pumpkin that flashes colorful lights and plays music, with a peek inside at the electronics

What It Does​

  1. While it waits, the LEDs flicker like a candle burning inside the pumpkin.
  2. A PIR motion sensor detects someone approaching.
  3. The Arduino triggers a pre-loaded Halloween sound effect through a small speaker.
  4. WS2812B RGB LEDs flash a light show in sync with the effect.
  5. Everything resets to the candle flicker and waits for the next visitor.

Why This Project​

Building the Pumpkinator teaches students real-world skills across multiple disciplines:

  • Electronics: wiring, power rails, connectors, crimping
  • Programming: Arduino C++, sensor input, audio/LED libraries
  • CAD: designing a functional enclosure in Onshape
  • Manufacturing: 3D printing, assembly-line techniques for batch production

It also gives the team a tangible fundraiser item with a story behind it.

Components​

Arduino Nano​

The main controller. It reads the motion sensor, plays sounds through the JQ6500, and drives the LEDs.

Arduino Nano on a breadboard
Arduino Nano on a breadboard
Arduino Nano pinout diagram
Pinout (from Components101)

More details: Arduino Nano on Components101. The official Arduino Nano pinout PDF is also available.

JQ6500 MP3 module​

Plays audio from onboard flash storage.

The board shown here is actually marked HW-896V2.0.2, a clone of the JQ6500 module. It works the same way and is sold under both names. Some kits use a true JQ6500 instead, and the two load sounds differently (see Light and Sound Shows).

HW-896V2.0.2 JQ6500 clone MP3 module
HW-896V2.0.2 (JQ6500 clone)
JQ6500 pinout diagram
Pinout (from Components101)

More details: JQ6500 on Components101.

PIR motion sensor​

Detects movement about 1 ft away. This is an HC-SR501, which has two onboard dials for sensitivity and how long the output stays on.

HC-SR501 PIR sensor, lens side
Lens side
HC-SR501 PIR sensor, side view showing the two adjustment dials
Side view with the two dials
HC-SR501 PIR sensor, back side showing the 3 pins
Back side with the 3 pins
HC-SR501 PIR sensor pinout diagram
Pinout (from Components101)

More details: HC-SR501 on Components101.

WS2812B LEDs (2 to 3)​

RGB light effects inside the pumpkin.

Reel of WS2812B LED strip with a length unrolled
The LED strip comes on a reel
Close-up of the WS2812B LED strip showing the +5V, Din, GND and DO pads
Close-up of the pads between LEDs
Cutting the LED strip between two LEDs with a pair of cutters
Cut the strip at the pads between LEDs
A two-LED piece of strip with wires soldered on
A cut piece with wires soldered on

More details: WS2812B on Components101.

Small speaker (8Ω)​

Sound output.

The speaker with its red and black wires, plus the short wires and resistor that connect the sound card to the Arduino
The speaker, along with the wires needed to connect the sound card to the Arduino

4× AA battery box​

About 6V of power.

4 AA battery box with red and black wires
4× AA battery box

KCD11 rocker switch​

On/off switch built into the enclosure. It's a simple two-terminal on/off (SPST) rocker, so the generic SPST rocker pinout applies.

SPST rocker switch pinout diagram
SPST rocker pinout (from Components101)

More details: SPST rocker switch on Components101.

3D Printed Case​

All electronics mount inside a custom 3D-printed enclosure (roughly 110mm × 70mm × 40mm). The box sits inside the pumpkin with:

  • LED strip mounted in a channel on top, shining up through the pumpkin lid
  • Speaker fitted into a compartment built specifically to hold it, facing down so sound bounces off the inside of the pumpkin
  • Motion sensor on a detachable pigtail wire that pokes out the back
The 3D-printed case in two pieces, the lid and the base
The 3D-printed case, lid and base

View the design in Onshape.

Battery Life​

Running on 4× AA alkaline batteries (~2500 mAh), a unit draws roughly 100–160 mA when active. Expect 15–20+ hours of runtime, more than enough for a full Halloween night.

About Fahrenheit Robotics Team 6882​

We're FIRST Robotics Team 6882, formed in 2017. We welcome public, private, and homeschool high school students (and ambitious 8th graders) from Fredericksburg and the surrounding area. We meet throughout the school year, learning not just how to build a competition robot, but how to manage and run a successful team, then compete against other high school teams at regional events.

The Pumpkinator is one of our student-led fundraiser projects. Every kit given out (in exchange for a donation, or just for fun) helps fund our team's travel, parts, and competition fees.

Live near Fredericksburg and in 8th–12th grade? Love STEAM? We'd love to have you: