Servo - September 2015

Does this sound like a scene straight from a horror movie? It quite possibly does, but it could also be a reality for your Halloween display. Having the ability to control a prop that can directly interact with your guests can provide many exciting scare opportunities.

This month, we are going to explore the use of a wireless radio controller to communicate with a remote controlled vehicle. This setup cannot only be used as a Halloween prop, but could provide locomotion for a variety of different characters where direct interaction with guests is desirable.

This project has been on my to-do list for quite some time. Others have used a remote control car to deliver a scare, but I wanted to put my own twist to it. My haunt already utilizes several spider scares including a lunging spitting spider, as well as one that attacks from its overhead perch atop my front porch. Being able to deploy one more at just the right time that could actually chase my intended scare victims would be epic!

Some of you already have experience working with R/C vehicles and may have many of the components necessary to put this type of project together. This was my first foray into this field, so I had to come up with all the pieces to put the puzzle together.

There is a wide variety of controllers available, but I chose to go with a fairly simple model. It did all that was required for this application so I didn’t feel there was any reason to go with a more complicated and expensive device. The model I chose was the four-channel Tactic TTX410 system from ServoCity (see Resources). It comes with a receiver and is priced under $80. It was the perfect fit for me.

Since I was starting from scratch on this build, I could choose a platform that would be just right. I found what I was looking for in one of the new robot chassis also put out by ServoCity. When I saw the robot kits, I was convinced that I could find one which would satisfy all of my requirements. They offered large platforms that would accept the Actobotics components I wanted to add, and the supplied motors and tires gave them great performance over a variety of terrain.

If having a large spider chase you down the street wasn’t enough, I also wanted to be able to raise its head. In order to accomplish this, I needed to have something that was both controllable and provided the necessary torque to lift the head of the spider. Although a servo would give me the control I wanted, it lacked the necessary torque to lift the spider I had planned on using for this project. This led me to the decision to go with a linear servo — something I have wanted to try since first discovering them.

I also wanted to add moving pincers to its mouth. Once again, I found just what I needed from ServoCity as they have several different models of grippers to choose from that would be perfect for my needs. These use a standard servo and can also be activated using the wireless controller.

The big night is finally here and all your preparations are complete. A light fog smelling of decay drifts through the dimly lit neighborhood as a group of boisterous teenagers descends upon your haunt. Suddenly, out of the darkness charges a creature from their worst nightmares! A huge, hissing spider emerges from its hiding place to attack, sending them screaming and running in fear!