I thought I would post some details around a prop I made for Halloween as it seems to get a pretty good response wherever I go.
We live in the UK and have a US military housing area near us where they do Halloween properly.
All the local kids head there every year, making it a popular attraction. The rest of the town has the usual pretty basic trick-or-treat type evening, the Americans take it to the next level with many houses opened to the public and set up as mini theme parks inside, with buckets of US sweets, moving displays, etc.
All great fun and a good cross-community event for everyone, but makes our usual trip out with a hollowed-out swede and candle look pretty unappealing for my teenage kids.
I started thinking that they do all this for the good of the community, so maybe we should give something back, something to give them a quick scare and a few laughs; I like this kind of mission.
I had the idea that it would need to be something portable and experimented with backpacks, wheelie bins and other ideas that never panned out. Trying to find something that gave a quick scare, without causing a security incident was a bit of a head scratcher.
Eventually, my wife had a call to come and pick me up from the town centre as I had bought some stuff from the charity shops!
A brief moment of panic when she saw me stood there with a baby stroller and an armful of toddler clothes, shoes, etc. Quickly had to explain that it wasn’t what it looked like had had a great idea for a project to keep me busy for a while.
With a stroller, it’s easily portable and you can build almost anything you want around the frame and in the seat. Perfect.
The plan was to have a realistic toddler sat in the seat, which would hide a scary skeleton internally and would break open and jump out of the seat, accompanied by some mood lighting and loud sound effects.
Step 1: Bones
I searched the local stores and found a skull and arm set to use for the prop which was pretty cheap and effective, but struggled to get any sort if useful skeleton, so opted to make my own from PVC conduit and various associated joints. Fairly simple to build and pretty rigid. It sat quite nicely in the seat, easy to work with and interfaced well to the rest of the moving parts.
The skull came with some plastic arm bones and hands which looked perfect.
Step 2: Legs
I wanted the legs to move so engineered a few joints in the PVC so that I could attach fishing line to them and run it down to the rear wheels. On the wheels I drilled and attached some posts to make a cam system to pull on the line and move the legs realistically as the stroller is pushed forward. Elastic is used in the legs to allow the legs to return to their original position once the cam has finished drawing them back.
The good thing about fishing line is that it may look a bit naff in daylight, but in the dark it is invisible, so I have used it all over to improve the realism of the movements.
Step 3: Skull and Arms
The skull I purchased was pretty easy to mount on the skeleton and had a moving jaw so I used more fishing line to ensure that as the torso moved forward, the head tiled up and the jaw opened.
When the torso springs forward, the arms need to fly up and out towards the victim, so I toyed with all sorts of mechanisms to get this to work, but most were unreliable so opted for the fishing line again to pull the arms out of cover and create the finished pose.
Step 4: Mechanism
Lots of options were tested, including motors and pneumatics, but the simplest system was to use a bungee cord to form a type of crossbow arrangement that would fire the body forward at a good speed. Needed a lot of tweaking, but eventually I built enough adjustability into the design so that it could be fine-tuned for correct operation.
On the handles of the stroller there is a lever that pulls up on a release catch that releases the bungee and shoots the torso forward.
It’s hard not to laugh hysterically every time I test it.
Step 5: Clothing
Tested with lots of kids clothes, eventually used a pair of trousers, T-shirt, socks and shoes to hide as much of the mechanism as I could.
Starting to look a little creepy now, I occasionally find myself saying sorry and excuse-me when I reach in to make adjustments!
Hiding the arms was a bit of a struggle as they were quite knobbly and would foul on any material that came in contact with them. I ended up using a very silky headscarf that would cover the arms, but allow them to jump out without snagging.
For the hair I have a kid’s party wig that is loosely fitted to cover the skull. When the body shoots forward, the hair is tied back so stays where it is and drops out of sight.
Step 6: Electronics
I made an audio amplifier from a kit and connected it to a cheap mp3 player board that could be activated using different switches for each sound. The cables for two switches were fed up to the handles and mounted so that pressing one give a haunting “la la la” nursery rhyme type sound and the other switch is used when firing the mechanism to produce a much louder “roar”.
There is a LIPO battery under there to power the amplifier and a smaller 9v battery for the MP3 player.
The speaker was stripped out of an old hi-fi and is hidden in the frame at the front of the stroller. Also some mood lighting was connected so that the baby is illuminated with white LEDs when walking along, but when triggered, a micro-switch then changes the lighting to red and is directed from below to give a good ghoulish effect.
All the wires were a bit unsightly so tied them back to the frame and wound tape around the frame to hide them.
The electronics were mounted at the back of the stroller in a Tupperware tub containing easy access power switches, etc. My only concern was that moving about in an area patrolled by US forces with something with wires poking out of it might end up with me having a gun pointed at me. so I made sure all the electronics were covered by cloths, but nothing was boxed in and un-inspectable, so just removing a few cloths would show that it was not a threat and hopefully the night wouldn’t finish with a controlled explosion!
Step 7: Operation
Once built and de-bugged, we tested it on a friend of the family with the full permission of her husband.
The scream could be heard far and wide. Only then did her husband remember she had an on-going heart complaint! Luckily no need for emergency services, but we all looked a bit sheepish afterwards.
I enlisted the help of my teenage daughter to dress up as a ghostly woman in white and push the contraption around the estate, going up to people and asking “Would you like to see my baby” in the creepiest way possible. Once they bent in a little, she would launch the baby forward and send most people running for the hills.
We had to pick our victims carefully to make sure there were no very young kids and people that didn’t look like they could survive a quick fright!
The reactions and comments were amazing and everyone took it in the spirit it was intended, so a huge success and worked better than I could have hoped.
A few possible improvements would be to look at the resetting procedure as arming the bungee, putting the wig back in place and securing the arms takes a fair bit of time. Also, the wheel driven leg motion was a bit too frantic when walking quickly, looked pretty weird to see the legs firing out in a kind of Irish jig as we moved between houses, so will probably find a way to unhook it when moving from place to place.
Enjoy the videos and let me know if you can think of any ideas for next year.
First Prize in the
Halloween Props Contest 2016