Hi there, may I introduce you to Toto, the remote controlled dog. He was one of the stage actors in the 2014 play "The Wizard of Oz" in our city theatre. If his name instead of Toto was Pinocchio you maybe could call me Gepetto, because I built Toto and he came alive (at least sort of)...
I work as a propsmaster in the formentioned city theatre. During my job I get a lot of interesting things to build. One of my last highlights was "Toto".
The director of the play (it was our annual pre-christmas childrens play) wanted the dog to be able to move on its own for example to chase another actor over the stage (that's what dogs do). So it was clear for me that I had to implement some sort of remote control. The easiest way to do this is obviously to integrate a remote controlled car into a plush dog.
So I ordered two plush dogs (just in case something went wrong and to have something for rehearsals) and a cheap RC-car in the right size (I usually have to operate on a very tight budget) and went on to building....
Step 1: The Starting Point: Stuffed Dog, Cheap RC Car and Voided Warranties
First I removed all unnecessary parts from the car body, to get it to a size that would fit into the dog.
Then I opened up the dog an removed most of the stuffing, so I could fit the stripped down body into the dog.
Step 2: Modify the Chassis
I quickly realized that I needed to cover the wheels to avoid getting the fur all around the wheels and axles. Therefore I took some cardboard tubes an fitted them with lots of hot glue as tight as possible onto the chassis and around the wheels.
Chassis and wheels and lower parts of the body were spray painted in black.
I had a rolling prototyp.
It looked nice and it worked.
As long I used it in my workshop.
It should be usable on stage! Too much distance and interferences for the remote control... :-(
And there was it again, the big problem of buying cheap: you usually buy twice. Now I had to invest real money!
The first step was to go to a RC-shop to talk to some pros and get inspired. I talked a lot with the shop owner about what I wanted to accomplish. He recommended me to buy a 6 channel RC system which was intended for airplanes and put me up for the idea to make the head moveable as well with the additional channels available. So I left a few hundred Euro in the shop and took home a nice new RC system (sender/controller, receiver, transmitter, ...) and some additional servos.
Step 3: Pimp That Dog/RC Car
Still thinking cheap I tried to integrate the new system into the car I already had:
larger battery, better servos, transmitter, receiver, new motor,...
As you can see on the pictures there was lot of tinkering, tapeing and hotglueing involved, but hey, it worked. Even the head was now able to move almost in a natural way.
But the motor was to fast, so I had to use a resistor to slow it down, this produced a lot of heat inside the dog, and made the car sometimes very hard to control. And due to the thin plastik of the cheap body the head was wobbling around the whole time...
All in all it was a cheap (at least some parts still were) and functional prototype, but for a stage run of about 35 shows it would not hold up.
So I again decided to invest some more money and buy a new chassis to rebuild the whole thing from scratch.
Step 4: Throw Away That Cheap Stuff and Start Over
As I told in the step before, the first chassis/body were a bit of a "Murks" as we call it in german (g00gle translates it as botch or botch-up).
So I went on another shopping spree (as said before: Who buys cheap, buys twice) and bought a nice but expensive chassis (Carisma GT14 Mk2, was on sale. I think it's not produced anymore) and some metal construction sets for kids (eitech) as highly adaptable connecting elements between chassis and body.
The new body I made out of some waste pipe, I had laying around. The wheel wells are made from two infusion bags (it always amazes me what we have stowed away in our props storage rooms). Finally a slow enough motor was found in a shop nearby (the WWW was of no help here). Add in some drilling, cutting and filing combined with some hot glue and zip ties and it was almost done.
By looking at the pictures you will probably get, how I put it all together, if not ask me...
Step 5: Fit That Fur
The plush dog was already taken apart and it fitted almost on the new body. Almost, as in: I had to add some extra fur in the front. To fix the fur to the body I (hand)sewed some smooth velcro on the edges of the fur. On the matching edges of the body I applied some self adhesive rough velcro. For the tail I added some welding wire to the rear end of the body. After it all was fitted, I spray painted the wheels black to make them disappear underneath the dog.
Step 6: Charging
It was important for easy handling that the dog could be recharged without beeing taken apart. So I attached the charging cable to the battery in a way that you could pull it out easily to connect it to the charger. The problem was that it came out to easy and after a while the insulation rubbed of.
So I installed two female plugs. Now you can just plug in the charger with the corresponding plugs an go for it. (for the moment no picture here, have to make one next time at work)
Step 7: Stageready
Now Toto was ready for it's stagelife. He made quite an entrance, because except of the director nobody new it could move it's head :-)
During the shows it was controlled by an assistant to the director. At first she overdid it a bit, but after a short while she got really good at moving the dog around on stage and making the head movements small, slow and realistic (the stage scenes in the attached video are from a early stage rehearsal).
The final dog was constructed in a way, that if necessary everything can be taken apart and used for another project with RC involved. But until now the dog still sits in its box on the shelf. Sometimes I take it out to recharge the battery or to show off in front of an intern. It always amazes the people, when it moves its head...
It was a very fun project. If you have questions, feel free to ask in the comments. If you like this little furball feel free to vote for me in the contest! ;-)