Tag Archives: PIC-IO

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.

Mummy’s Curse Puzzle Door of Doom

Seven years ago we had a Halloween party that involved the construction of a life-sized moving sarcophagus and half a dozen mummies. Since these things are just taking up space in the basement, we decided to reuse them this year.  Reduce, reuse, recycle. That’s our motto.

Except (always a dangerous word), we also decided that after last year’s success of adding interactive elements to the display, we would make the trick-or-treaters jump through some sort of hoop, metaphorically speaking.

This lead to re-watching mummy movies and discussing the appropriateness of using live spiders or beetles to make gags more “interactive”. In ancient Egypt, there were always insects or snakes that lived forever to protect the tomb of the Pharaoh. We should have the same, but the important part of the experience is the challenge one has to face before being thrown into the pit full of asps.

The challenge, we decided, would be to make the kids solve a puzzle. The movies always have a puzzle – translate the hieroglyphics, find the hidden lever on the wall, pull the lever – then run like hell when the floor opens up to a pit full of asps. Clearly, some of this idea has merit.

What we decided on was placing four buttons on the door that had to be pressed in order to be granted candy. While there would be hieroglyphics on the door, you wouldn’t need to translate them. You would need only to match the pattern of icons on the door to those on the buttons. A clever person could get it straight away. A determined person could get it within 16 tries.

Here is where we get in trouble. Since the theme is set in a mummy’s tomb, the door, the buttons, and ideally everything else need to be made out of stone. Or something that looks like stone.

In building our sarcophagus, we had learned some things about carving foam and coating the foam with a hard resin. The picture above show the work-in-progress of making the buttons. Each foam button was cast over a 1/9th size steam table pan. The outer surface of the buttons were carved then the Foam Coat product was mixed with sand to create a hard textured surface. The foam could then be slid back over the steel pan to create a durable mount for each button.

Each button was supported by a small pneumatic cylinder. This was done both to provide a pushing mechanism to reset the buttons and to provide some resistance as the buttons are manually pushed in. The air flow out of the cylinders was controlled so that it took some effort to press against a button. This added to the spooky “should I be doing this?” aspect of the gag. It also provided feedback to the control circuit so the sound of scraping stone could be played while the button was in motion.

Once the button was fully seated, a limit switch triggered the sound of a large stone coming to rest with a thud. The control system waited for all buttons to be set, then either played the sound of a door unlocking or the sound of rattlesnakes (it should be noted that we decided not to use real snakes). The buttons were then pushed back out by the air cylinders.

Since the Foam Coat seemed to be holding up, we decided to fabricate the entire door facade with foam. It had a wooden base that allowed the foam to standoff from the actual door far enough to give space for the button mechanism and to clear the door handle which was completely covered. Indeed, the only way to enter the house was for the door to be unlatched from the inside.

We had a bunch of ideas about the reward/penalty nature of the system. Given our time constraints, we didn’t really get much more done than the sound effects. Remember when this was all about reusing props from past years? We had one more goal and that was to make sentinel snakes hiss with waving tongues. It ended up be a subtle detail that was widely overlooked. On Halloween we barely had time to get the mummies out of the basement.

At 8:04 pm, our neighbor sent a text message: “You’ve created a monster!”

At its peak, there were about 100 kids and parents in the street. We had a line of willing participants jammed on the stairs. The wait was exacerbated by our having been merciless. No one got candy unless the the correct combination was set. When the door opened, kids in the front got served, then the door closed to the protests of the screaming children in line behind them.

Forcing people to solve the puzzle was the best thing we could have done. There would have been no fun in gaining reward without accomplishment. Little kids got a thrill out of finding the solution. Older kids appreciated being able to manipulate what would otherwise have been static decoration. Only the parents of toddlers had misgivings. Adults don’t like to be put on the spot.

We learned a lot about human behavior, but some things remain a mystery. Most kids and parents patiently waited their turn. After all, it took only a few seconds to try a combination and there were plenty of people to help. But some people – parents and kids – walked past, stating they didn’t have time.

In conclusion, 207 kids received candy. Maybe 20 were denied. We tried to keep count, but at times things were out of control. The only down side to the whole event was that we had to be constantly vigilant with the opening of the door. Next year, creating a automated candy dispersal system will be a goal.