Tag Archives: halloween

Arduino pumpkin lights

Lacking creativity this year, I kind of phoned in the pumpkin carving. We went with regular old triangle-eyed Jack-o-lanterns. It turned out this suited Alex fine: he has decided lately that a certain level of traditionalism is called for. Watching keenly as I cut away bits of pumpkin, he was quick to point out whenever I was doing it the wrong way.

Anyhow, not wanting Halloween to pass buy without doing something new, I decided I’d write a pumpkin light control sketch for Arduino. I have the original board with the Atmega8, and the last time I touched it, the SDK was arduino-0011, which was released about seven years, three domiciles, and one country ago. Since then, I’m happy to see that arduino-mk landed in Debian, and the SDK hasn’t changed APIs in any noticeable way, so it was easy to get back up and running.

The concept is pretty simple: write PWM patterns to an output pin to control the brightness or on/off state of the pumpkin light. I came up with three patterns: fade up and down; random toggle; and sequential stepping. The sketch code is over here.

Arduino light controllerOn the hardware side, I used 3 LEDs for each pumpkin, snipped from a roll that I had left over from my cabinet lighting project. The LEDs expect a +12V supply. On the spool, they are wired in series with a 150 ohm resistor and each LED has a 2.7V voltage drop. Powering that would stretch the Arduino, so I used a separate 12V power supply for those, and used the Arduino to switch an NPN transistor corresponding to each light. I soldered the LEDs to some speaker wire and put the rest of the components on an Arduino protoshield inside a box. This was essentially a lunch hour’s worth of work to get the basic functionality going, and then a little more time to make it neat.

This year Alex and Ian went as Bumblebee and Iron Man respectively (-ENOTPICTURED). Sadly, with store bought costumes — homemade ones will have to wait until one of us learns to sew something other than kites.

Halloween, 2014 ed.

2014 Halloween CostumesI believe I added just enough blog posts this year that there are not two years’ Halloween posts on the front page at the same time. That would be sad.

Alex told me in September that October was his favorite month of the year, “because Halloween.” And every day for the last few weeks, he would ask, “is it Halloween today?” I can only hope that this year’s candy crawl met his expectations. He went as Captain America, a decision that was entirely his own. Ian went as a penguin, or at least he wore parts of his penguin costume throughout the night, rarely all at once.

2014 PumpkinsFor jack-o-lanterns we went with a space theme this year: a space shuttle on one and Kodos on the other. I tried etching rather than carving but I couldn’t get the technique down, so I wound up carving for the most part. One fun addition, albeit short-lived, was the use of sparklers instead of LED candles as lighting. Next year we’ll use rocket engines.

Pumpkins all Pumpkiny

It is a bit late for a Halloween post, but insert lame excuse here. Consider it a counter-balance to the force that causes Christmas decorations to show up in stores in September.

IMG_4305This year I chose Toopy and Binoo, a Canadian children’s cartoon pair that you have probably never heard of, as subjects for my pumpkin carving. Unfortunately, the pumpkins shriveled quite quickly, and the designs didn’t lend themselves well to preservation, so by Halloween, they grew a toothpick scaffolding to maintain their facade. Next year, I believe I’ll try not cutting all the way through to avoid such issues. (I’m not sure what that technique is called, but some of the more artistic neighbors employed it to great effect.)

5 minute pumpkinImprovised pumpkin lightInside these gourds I used little battery-powered LED lights made for the purpose instead of actual candles. While LED lights don’t look nearly as nice as real candles, one need not care so much about potentially setting things on fire. On the evening of the 31st, as a few groups of kids had already arrived and absconded with their hard-earned treats, I found myself with a third pumpkin untouched by blade, but no light (or candle) to go in it, should I decide to carve it. Then, I remembered my extra spools of SMT LEDs from the cabinet lighting project. I calculated that a 9 volt battery could power three such LEDs for about 10 hours (that estimate was conservative by a factor of 3, it turned out — I need to go back to EE school). Thanks to various other projects, I already had some speaker wire with alligator clips on each end, so, in the course of 5 minutes, I threw together a functional pumpkin light, carved a few holes in the pumpkin, and called it a day. No need to clean out the guts when open flames are not a factor.

IMG_4423For his first Halloween, Ian went as a dragon. Typical of his recent enthusiasm for all things space-related, Alex went as an astronaut. Instead of saying “trick-or-treat,” he would announce, “Hi, I’m Alex. I’m an astronaut!” Much candy was received, all the same.


Jack-o-lanterns 2011 I made two Jack-o-lanterns this year. On the left we have Elmo and Cookie Monster, a nod to our 16-month-old’s second Halloween. On the right, my best attempt at a cacodemon from the old video game Doom. My general technique is to sketch up the design in Inkscape, print it out, transfer the design to the pumpkin somehow, then go to work with one of those little pumpkin carving saws. The cacodemon was a bit simpler so I skipped Inkscape and free-handed it with a sharpie.

Pumpkin seedsWe tried toasting the pumpkin seeds. While edible, I found the eating experience akin to that of eating un-popped popcorn kernels. I’ll probably give this experiment a miss next year.

IMG_9177 In Canada, giving out chips is almost as popular as giving out candy. As new Canadians, we are following suit: visitors to our house will get tiny bags of Doritos. I guess that means no Coffee Crisps, Aero bars, or Smarties for me (these locally available confections have yet to cross the Lake).

IMG_9175I also had grandiose plans to make Alex a costume, but faith in my fabric sewing skills waned a bit as the deadline approached. Angeline saved the day by picking up a costume at the local Carter’s, so he’ll be a tiger this year. Fear.