Published September 22, 2020

Microcontroller Jack-o-Lantern

Using a microcontroller to emulate a flickering candle with a jack-o-lantern cardboard cutout.

BeginnerFull instructions provided203

Things used in this project

Hardware components

Adafruit Circuit Playground Express

Rotary potentiometer (generic)

Toggle Switch, Toggle

Software apps and online services

Microsoft MakeCode

Story

For my project I decided to do something seasonal, so I settled on an idea I call the Microcontroller Jack-O-Lantern. It is a cardboard cutout jack-o-lantern standee that is adhered to a box and has a microcontroller behind it to use LEDs to emulate a candle. It's utility is mostly decorative but can also function as a rudimentary light. It has one toggle to tell it to execute the code and a potentiometer to change the brightness of the lights.

To make it I started by sketching the jack-o-lantern on a large piece of scrap cardboard, carving it out with a utility blade, carving out wedges and making notches for the wedges, painting it, and then adhering it all together with super glue. I glued the flat piece of cardboard the jack-o-lantern was glued to a shoe box as a housing for the wires, then cut out two holes for the switch and knob to be secured. For the code it initializes with given values for the potentiometer and the toggle, then a forever loop is triggered then the toggle is flipped, the code then randomizes which pixels light up, randomizes their hue (from red to yellow), randomizes the value, and then brightness is controlled by the potentiometer. After that the board is placed and the excess wirelength is secured under the cardboard shelf and a small foiled lined box is placed over the microcontroller to help focus the light.

Initial Sketch and Cutout Process

Fully Cutout

Painted

Cardboard Components Adhered

Wiring for Circuit Playground Express

Wired and Secured Toggle and Potentiometer

Demo Of Working Completed Jack-O-Lantern

Candle Code

pins.A4.setPull(PinPullMode.PullUp)
pins.A1.analogWrite(200)
forever(function () {
    if (!(pins.A4.digitalRead())) {
        light.setPixelColor(Math.randomRange(0, 10), light.hsv(Math.randomRange(5, 40), 255, Math.randomRange(100, 255)))
        pause(Math.randomRange(0, 50))
        light.setBrightness(pins.A1.analogRead())
    } else {
        light.clear()
    }
})