Hello again folks! If you recall, last post I did a little bit of house cleaning and finally go to one of my Halloween prop projects from last year’s Haunted Trial of Tears. I must say, that gave me some extra motivation to get going on this year’s planned new additions. If I manage to get all my honey-do items taken care of this weekend, I’ll definitely head down into the lab and try to make some progress (also excited as some new electronic parts I’ve been waiting for have finally arrived). Since the last post was so much fun, thought I’d go ahead and double up on the Halloween prop posts and bring out the latest edition to the Posey line (link here and here and here).
As with the previous walk through, hit the jump and see how our new evil looking addition to the trail came to be.
I’m will skip a lot of the details regarding the structure as those were detailed in the previous Posey links. I did use the plunging neckline design from the Demon build as I really like how that brings the neck back down to the shoulders. The key element of the Westworld 2.0 line was the introduction of servos into the design. This is the first time I had worked with those and ended up learning a lot thanks to some pretty dramatic failures – speed kills people – remember that ha! Core to the idea was having the ability to move the shoulders (and body) and the head independently – unlike the Westworld 1.0 line which required the head and arm to move pretty much together. To accomplish this, I would need two servos and decided that having them inline with the structure would simplify the design – offset motors require linkages and can end up being a pain with costumes etc.
It took awhile, but finally landed on a configuration that would allow the desired movement. The shoulders would be attached to the spine and would turn within a cross connector near the waist. That allowed me to simply add a servo to the top of the spine that allow the head to move with the shoulders or be triggered to a different angle whenever I wanted. Reused my proprietary spinner adapters to allow the spine to rotate within the cross connector and then 3D modeled and printed out some holders for the servos so they would stay in place. Note, the spinner adaptors on the spine also take the weight off the Servo so it simply has to turn freely along the axis making a smooth and noise free animation.
Then I had to go to work on the electronics. Arduino have a very nice servo library and relatively easy to use as soon as you understand that a 180 degree turn represents the full movement of the servo from 0 to max. Makes sense if you have a 180 degree servor, but I used 270 degree versions to allow for maximum movement. First time I told the servo to go to 180 and it went to 270 instead totally freaked me out – not to mention almost took out everything on top of a nearby cabinet. With that understood, it was just a matter of creating a program that would randomly select a location for the head and the body to move to and then interlacing the movements so it turned smoothly versus the instant snaps that will result if you simply give it the final position to move. Once the core algorithm was figured out, added capabilities to randomly choose which body part to move (head, body or both), randomized the distance each would travel and then went ahead and randomized the speeds each part would take to get to the final position. You can see an early capture of the movement below.
There was a couple of things that were tweaked after watching the movement for a while. First off, having the shoulders move one way and the head move the other way was a bit odd – after going back and forth between “that just makes it creepier” to “I don’t want my guests to laugh at him” I decided to fix it and if the randomizer resulted in that scenario happening, I just took the head direction and changed the shoulders to go the same way. Note, I did keep the scenario where the shoulders moved and the head stayed in the current position (meaning it rotated with the shoulders) – you will see it in the video, but unlike the diverging directions, this looked creepy in a good way. The other change I made is a snap mode where if randomly selected it would instantly move the head and shoulder to the same spot – rapidly, no interlaced smooth movement. The concept was the creature heard or saw something and quickly turned to figure out what it was versus the default random searching scenario. The intent was to put sensor triggers at various spots and when those spots were fired it would instantly move to look at whoever was standing there. Didn’t have time to get to that feature wired in, but still hoping to add it for this year’s trail. The random snap did have a nice effect in the darkness.
Okay, with all the electronics and programming figured out, it was time to productionize it for the trail. Put a new based under it, added the leg structure and used a Great Stuff chest I had laying around from a previous build. Also put forearms on it with some plumbing insulation to beef up the arms. Most important, I put all the electronics in conduit boxes to protect it from the elements. Unlike the wiper motors, the servos only required 9V to power making this line extremely portable (and a lot lighter).
Talk about cutting it close. I procrastinated on getting the final touches on the costume and before I realized it, we were one day from the party. Figured a robe would be the best way to go so begged Linda to make a run to Spirit to pick up the cheapest one she could find – yes, that cost me future favors big time. She was able to find what I needed although it could have been one size bigger as it didn’t go all the way to the base. Not a big issue since you it would be hard to see in the dark anyway. Once the robe was on, positioned they arms the way I wanted them and ran self-drilling screws through the joints to hold them there (better than glue as I can change the positions whenever I felt like it.
Slap the head back on and it’s ready for the trail.
Based on the success of this project, the Westworld 3.0 line is under development for a whole new level of fright. Hope you enjoyed the build walkthrough – one more large project from 2019 still in the queue.
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