Hi All,

I'm looking for some help with a Halloween project; we hold a halloween dinner party every year and this year we are doing a "Saw" theme- I really want a billy the puppet type creation but I am a completely clueless in this sector. (link below) - I can sort the puppet out, but I need to get a tricycle that moves on it's own. Is there anyone that would be willing to take this job, with payment of course?
I don't know if it's a case of it being "easy when you know how" or if it's really complicated but if at least know it's not going to be possible to get hold of then I can move on to something else

https://www.instructables.com/Remote-Controlled-Billy-From-Saw/

Thanks in advance!
Faye

 

Welcome to AAC.

Motorizing a tricycle isn't going to be al that hard. But hiding a motor, battery and controller is going to present a challenge. As for complexity, look to remote control toy cars and planes. Most simply there's throttle and steering. But the remaining problem is how much of a Frankenstein tricycle do you want to build.

Personally, I'm not interested in tackling this project. So no need to ask me if I'm willing to help. All things necessary are out there. Plug and play. There will be some mechanical work to be done, such as motorizing the drive wheel, and steering the front wheel.

 

Looks like you have all the information you need in your link. Put the power source and electronics inside the doll body. The only external parts you'll need is the drive motor and steering motor. As for where you can GET a powered tricycle - I think you're going to have to fabricate one.

Look around for an old power wheel child's ride on toy. It should have two motors that drive the rear wheels. That part should be straight forward. As for steering you'll probably need a servo motor to control that part of it. Everything you're asking for is going to have to be created from the ground up.

 

Rather than friction drive the front wheel, why not drive one or both rear wheels?? A drive gear reduction could easily be added on the inner side of each rear wheel, with the motors hidden under that rear foot-platform.. And if the traction is right, they could also steer by means of differential drive. You might need to adjust the castor angle a bit, though. But that would completely do away with complex linkage to steer it and any hard to hide front wheel drive. ALSO, much simpler and a lot cheaper. AND, less torque required to drive it.
Certainly the trike in the video is a mechanical marvel, but if creating that is not the goal, simple is the better way to go.

 

The front wheel is slightly forward of the steering column.

To steer that by dual rear wheel drive would tend to send the front wheel opposite of the desired turn. Best I can imagine is using the doll to steer the trike. Though I didn't suggest it, I was always thinking about rear wheel drive.

Look around for an old power wheel child's ride on toy. It should have two motors that drive the rear wheels. That part should be straight forward. As for steering you'll probably need a servo motor to control that part of it.

Actually, there is sort of a hint toward rear wheel drive. But since @MisterBill2 said it clearly I have to agree, the drive mechanism should be under the rear deck. As for steering, I don't think you're going to achieve steering by simply driving the left wheel to make the bike turn to the right. I still think some sort of servo will be needed for steering. Servo's can be found in old printers. That's where I've come up with several servo motors of various sizes. But then you still need some electronics to control it as well as some sort of feedback to sense the position of the servo. Just like a remote control airplane @ThePanMan suggests.

I don't see this being cheap. But then again the effect may be well worth it.

 

OK, so presently the bike has some negative castor. If the handle bars can be reversed it would work, and as human will never drive it, that should not be an issue. The doll or whatever can simply hang on, and tipping will not be an issue. That can be verified, or disproved, simply by flipping the front wheel around and manually driving it by rotating the rear wheels by hand while forcing them against the floor.
Keep in mind that the whole thing does not need to resemble reality at all.

 

OK, so presently the bike has some negative castor. If the handle bars can be reversed it would work, and as human will never drive it, that should not be an issue. The doll or whatever can simply hang on, and tipping will not be an issue. That can be verified, or disproved, simply by flipping the front wheel around and manually driving it by rotating the rear wheels by hand while forcing them against the floor.
Keep in mind that the whole thing does not need to resemble reality at all.

Thought about the possibility of reversing the front wheel. That's certainly an option. From my perspective (opinion - and everyone has an opinion) I don't think that would look right. Me? I'd notice it right away. But yes, reversing it will allow steering by two controlled motors on the back wheels. But if the steering shaft is tilted then a reversed wheel would want to roll over (turn left or right) to equalize the forces. It's like an airplane with negative dihedral. They tend to roll over without input whereas positive dihedral tends to make an airplane want to fly upright, straight and wings level.

 

Of course it might not look right. But the creature on the bike is not quite right to start with. so if it looks abnormal, is that a problem?? And the check to see if it would steer correctly is simple, easy, and free, making iit reasonable to try.

 

As far as animating the puppet, I suggest that you research a “Flying Crank Ghost”. This is a popular Halloween DIY project to create the illusion of a moving ghost. A puppet (marionette-style) could be used in place of the ghost. Only requires one motor that you can turn on and off.