Picture of Animatronic Rat
This is a prop you can use on Halloween to greet the kids. And maybe give them a surprise to boot. Put it in a scene or just by the front door. You can leave it plain or dress him up.

This rat can move about in place, talk with a wireless microphone and spit acid (really just water). Watch the videos to see how he moves.

The star of the show is a latex rubber rat I found at Wal-Mart for $7. It's about 14" tall and was filled with some kind of poly stuffing. The goal is to build a movable skeleton that conforms to the inside of the latex rat. You don't have to use a rat, any kind of hollow latex creature that is flexible can be used like a cat, gargoyle, snake, bat ect... But look for something that can be easily animated. For example if the mouth has no depth to it you really can't animate that.

I had no plans drawn up for this project and created it as I went with stuff I scrounged up around the house and at home improvement stores. This is a crudely built prop with rusted bits and popsicle sticks, but hey it actually works! You will have to use your imagination to come up with substitutions if needed.

The most expensive part of this project is getting hold of a 4 channel radio control. I used one from an old RC airplane that I never could fly. It doesn't have to be fancy or programmable, look on ebay, there are deals to be found there. You could even use a RC car radio with 2 channels and just animate the mouth and something else.

If you want to see more follow the steps to see how it was done.

Here are some videos to give you an idea of what he does.

Demo of Rat in motion Video YouTube messed up the audio sync on this one. The mouth is supposed to be synced with my voice.

Internal Skeleton video

Rat shooting water Video

Putting the skin on Video

This one below is a little dark but it was from this Halloween.

cobinrox1 year ago
I think your rat is MY rat's (Egor's) long lost brother Ivan ! Egor is an internet-ronic rat (controlled over the internet). Here is Egor out on Hallowe'en this year (2013) posing with someone's alligator at the office. I'll have to post an 'able for Egor.
UConTroll1 year ago
I like your armature - simple but functional. I have the same exact rat. I'm going to animate mine using one on my Sprockitz boards: www.Sprockitz.com.
J-Five2 years ago
Ahhhh, I'll get the animatronic cat.
Falcon_3dee (author) 6 years ago
Operationivy123 and Spazman unfortunately I do not have a comprehensive parts list as each persons creation is going to be unique. I did add a general list to the first step but you will have to use your imagination and adjust as you go when making yours. I do not belive you can get that specific rat anymore. I did not see it in the stores this past Halloween. The servos are the standard size, not the micro or the heavy duty as they do not need much tourqe. The servos that come with a run of the mill radio will do. I dont have the model of the squirtgun and I tried to find it online just now with not luck. I bought it at Kmart for $4. However the type of pump it uses is a Peristaltic Pump: In this system, a rotary motor is used to move rollers along a compressible piece of tubing. As the rollers move along the tubing, they push water along. The force exerted by the pump is dependent both on the speed of rotation as well as the thickness of tubing used. Now your pump doesnt have to be this type. Any small pump will do. Hope that helps
for the pump i used a new windscreen washer pump from ebay for less than £10
works really well.
thank you very much that helps alot. I have one other question though. in the video when the water would spay his eyes would turn on. how was this accomplished?
Nelyan3 years ago
Ooh, it's made this way... I thought that you had just taken a dancing Santa-decoration apart and inserted the rats outsides over it. Of course, then you couldn't have a radio-controller and you'd have to tweak the soundchip a bit.
Falcon_3dee (author)  Nelyan3 years ago
Repurposing some other commercial anamatronic would have been much easier beleive me. But like you said I wouldn't be able to "control" it like I can. Plus the interactivity with the Trick or Treaters is what makes it so cool.
mary candy4 years ago
very funny!
sweet instructable man! nice work!
zack2475 years ago
his skeleton looks kinda like a duck... but this is awesome! if i had the stuff i would make this
siddhanth5 years ago
LOL DUDE that video is hilarious.. CANDY!!! LOL... nice project.. will definately get my hands on this..
this might work well with the taxidermy mice!
hey man, i don't really get how the water pump works? if you could explain it to me that'd be dandy and if you have a parts list that would also be pretty sweet
Spazman6 years ago
Very nice but if you dont mind sending me an email of the parts list such as the servo size water pump squirt gun name etc. I am only a beginner but would love to build this and maybe become a better builder with some help my email is BUGGYJMAN@YAHOO.com thanks.
mckeephoto6 years ago
Wow, this looks so cool. I think I am going to have to start planning my projects for next halloween. And I will have to start building in January to get them all done! (and this one just made the top of the list!)
JellyWoo6 years ago
very nice, love it!
Lftndbt6 years ago
My GF doesn't like rats, I can't make this.... What am I talking about, It's halloween perfect oppotunity!!! I'll put it in her make-up draw.....I'm so mean..
CameronSS6 years ago
Alcreion6 years ago
Lol nice ible very clear, and very nice.