Halloween 2020: Le Petit Chien Qui Fait Caca

Writing the title in French is a poor attempt at classing-up this year’s Halloween theme. You will quickly see past that because this year we leaned in hard on childish humor. There’s no covering it up.

2020 being what it is, it seemed problematic to do something scary. Not that a good scare would be inappropriate. It seemed inappropriate to do the expected or the usual. In a year when nothing is usual, it felt like a little levity was needed. To that point, we give you The Little Pooping Dog.

We had already started building our intended theme: A highly interactive multi-media display with several tactile components. Then it sank-in that anything involving touching wasn’t going to fly. Moreover, Halloween itself was in question. Putting more time and money into a project that would encourage people to group together seemed misguided. Then we saw the candy chute.

Some genius came up with the idea of simply sliding the candy down to kids through a pipe. Not only is sliding the candy more civilized than chucking the candy at them or using a slingshot, the pipe itself can be decorated to make the method of transport more festive! But how to decorate?

At some point we were talking about just putting out a talking skeleton from our last use of a talking skeleton and calling it a day. Never mind that it’s a pirate skeleton. We are way past helping people make sense of things. But what if the skeleton pirate had a skeleton dog with him?

Why this made sense at the time no longer matters. The fact that a skeleton dog could easily be acquired and that the dog was able to straddle the pipe such that the dog appeared to be crapping out candy, appeared to us like comedy gold.

By the way, a wiener dog? It just doesn’t get any better and the suggestion for temperament from more conservative advisors was justifiably ignored.

Let’s get down to brass tacks. If the pirate is going to talk, the dog needs to fart, right? The pirate had already been wired-up with an Adafruit Audio FX sound board. Luckily, the sound board could be programmed to take triggers from more than one input, so it could have one sensor for activating the pirate spiel and another sensor for detecting the passing (out) of candy.

The light weight of the candy put into question the use of a physical limit switch. Since we were already using a retroreflective light sensor for the pirate, it seemed reasonable to use a short-range light sensor for the candy.

By now you’re probably already seeing a problem. The sensor has a reset time of <2.5 ms. The Audio FX board requires a 200 ms pulse to activate playback. If the candy is moving at 2 m/s, a typical “fun size” candy bar is going to pass over the detector for only 20 ms. What we need is a pulse stretcher.

Fortunately, we had an old Olimex PIC-IO board laying around that could be programmed to turn 20 ms pulses into 200 ms; thus, ensuring that each candy bar would trigger the audio. Sure, we might have gotten away with using a capacitor and a couple of diodes, but we are software people by trade and using the microcontroller made absolute sure the dog would fart.

Over the course of the night we got 140 kids – about 100 short of a typical night. Still, it was great to see that many people out in the fresh air. The danger is real, but our neighbors were committed to find safe ways to trick-or-treat. For the parents and kids that ventured out, we hope that the laugh was worth as least as much as the candy.

Halloween 2019: Bats

The last couple of years has caused us to undertake a review of our technical capabilities. Too much had gone wrong or become unreliable. While the theme is usually our chief concern, this year the goal was to lock-down some of the basic building blocks of our theatrical show system.

The first item was video. The video is played back on a MedeaWiz Sprite with a DMX interface. We had tried to use video last year and it failed miserably because of a bad cable connection. It was a stupid problem to have, so that got addressed. But how to use it? A quick search of Halloween related videos on the Internet results in the idea of making bats fly out of the doorway.

Creating the video was fairly straightforward, but the key to making it feel creepy was in the audio. Without the sound, the images looked a bit like a Rorschach test. They needed that squeaky sound that bats make to add context. More importantly, it needed to sound like the bats were getting closer.

To make the bats sound menacing, multiple tracks were played across five channels of surround sound. The most distant chirping sounds were at the corners of the house. Closer-up were large wing flapping sounds nearest to the stairs. The wing flapping was not a real bat sound, but the idea of a bat flying close to your head.

The last channel was placed across the street. We used long-range Bluetooth to transmit the bats sounds to a speaker in our neighbor’s yard. This is a technical advance we will probably use in the future because it really messed with people. It was fun to watch people during the first three seconds of the video where they thought: There are bats. The bats are coming at me. The bats are everywhere.

One new piece of tech that we will definitely use every year was a new light beam trigger. We have used a light beam at the base of the stairs to start the show for years, but it always had the problem of re-triggering the show when people exited. We used to mitigate this problem by adding a delay before the show could be restarted, but that works only if people arrive at given rate.

The new trigger has two light beams. This is similar to the electronic turnstiles Disney used about a decade ago. A microcontroller board was programmed to check the order in which the beams were broken so we could determine the direction of movement. Going up the stairs starts the bat video. Going down the stairs made a cat screeching sound – just because we could.

Lastly, we upgraded our speaker system. The new speakers are more weather resistant and handle a lot more power. This was needed to reduce stress as much as wanting to improve sound quality. Rain is inevitable and this year was a perfect example. It was nice to have the speakers out all day in the rain without worrying about them. It was also nice to drive the smaller speakers by the stairs as hard a we wanted to.

The video below was mixed to be in surround sound, but YouTube re-mixes it down to stereo, so you can’t really get the full effect. Next time we invite you over, make sure to ask to see the version on the home server.

Halloween 2018: Tibetan Yeti

The plan was to recreate a Disney World attraction. Not just put on costumes and play It’s a Small World over and over, but create a fully immersive, multimedia walk-through with interactive video projection and animated props. It was to be the greatest Halloween decorating effort to ever exist. Then a computer interface broke and none of it happened.

The plan was conceived of while on vacation several years ago. There is a spot on Expedition Everest at Disney’s Animal Kingdom where the roller coaster stops and an image of a yeti is shown tearing up the track. We recorded a video of the ride and noticed that the yeti image came through pretty well. It was then that we had the thought that if you had the right seat on the train and had a camera set-up with the right lens, one might be able to acquire a copy of the yeti projection.

Fast forward to this year. Camera in hand, we ride through a few times and get the video in question:

Having the video was only a small part of the plan. As in the ride, the video is only a distraction to misdirect the viewer from seeing the big scary surprise moment. For that we would need a seven-foot tall animated yeti.

For the body of the yeti, we cheated and bought a costume. In retrospect, it might have been a better plan to hire some kid to wear the costume and simply jump out of the bushes periodically, but in true Disney style we built a frame to support the costume with pneumatic arm lifts and animated eyes.

The animated eyes gave the yeti life. They would look around and blink just like a real yeti. The eye animation was executed from a Raspberry Pi single board computer separate from the rest of the system, so they would work even if everything else failed.

The rest was lighting, music and staging. With a tent in the yard, Tibetan music playing and fluttering prayer flags, you were supposed to be transported to a hiking camp on the way to climb Everest. However, with all the lighting, video and the yeti movement under computer control, everything was left dark when the computer died.

Ultimately, the plan was probably flawed from the start. We overestimated how many families would have visited Disney World. It seemed like not that many people got the references to Tibet. Presence of the tent just confused people. Most concluded that the theme was “winter camping.” Hard to argue with that.