servo help

[Sickie Ickie]

I have a question concerning servos that I'm hoping people will be able to help me with.

It seems as if many of the types of movement that look neat for animatronic props have servos. I'm not knowledgeable in electronics. Yes, I can wire a light and jerryrig a flickering fire via how-tos, but if there is no how-to when it comes to electronics- I'm lost. (relays, transisters, resisters, etc are gooblygook!)

While I know the movement of a servo, I have no idea how to hook one up. I can't imagine I just solder in a lamp cord to it. That seems insane. I can't find any basic how tos with servos and haunt props. I find some that say to use them and how to insert them, but how the heck do I hook it up...and to what????

I know some of the more complicated ones can use computers, but does that mean I have to know how to write programs???

If I have to learn somehow on my own I'll keep trying, but I'm hesitant to even buy a servo before I know more about them for fear I'll have a nice new servo gathering dust in my carport.

Help?

-Bryce/Sickie Ickie

[Zombie-F]

Servos are a lot trickier than a regular old motor with two wires. It is operated via a connection to a dc power supply AND a third wire that needs to be connected to a pulse. The pulse controls the position of the motor at any given time.

These are a lot more involved, and unless you already have some level of electronics/programming know-how, this will be a difficult thing to walk you through.

First of all, what is it you are plan to do with the servo(s)? If you're trying a simple thing like running a Scary Terry audio servo driver to make a skeleton's mouth move in sync with audio, that is something that can be easily taught. If you're trying to do complicated animations, then you'll need a little more knowledge and some guidance in the right direction in regards to what you need to read to learn what you need to learn.

[DeathTouch]

Here you go. This guy can really help. Mr. Unpleasant. This is his witch head for his ScareFX witch. He did a nice job.

Witch :: pre-witchwmv.flv video by daboes - Photobucket@@AMEPARAM@@http://vid10.photobucket.com/player.swf?file=http://vid10.photobucket.com/albums/a148/daboes/Witch/pre-witchwmv.flv@@AMEPARAM@@vid10@@AMEPARAM@@10@@AMEPA RAM@@a148/daboes/Witch/pre-witchwmv

[Sickie Ickie]

Thanks for the dougie hack Deathtouch. :-)

Actually I'm looking more to making working servo units that move arms, turn heads, etc. rather than a hack, but I appreciate your link.

Zombie-F, you wrote " If you're trying a simple thing like running a Scary Terry audio servo driver to make a skeleton's mouth move in sync with audio, that is something that can be easily taught."

Well, I'm willing to learn from the ground up. I love Scary Terry's site, but once again I get lost with trying to understand connecting up the servo stuff. I understand how to place it and the movements, but connecting...

Eventually I'd like to get to remote control servos, and then preprogrammed servos...but I realize I need to start somewhere...

[Zombie-F]

Cowlacious sells Scary Terry kits and fully-assembled kits, so you could use that as a way to teach yourself if you want to build it yourself.

Here, have a link: http://www.cowlacious.com.

It's a good little board. Pretty easy to solder and really easy to hook up. I buy mine from them, but get the skulls from ACC and the servo itself from the place Scary Terry suggests and do the modifications and installation myself.

[Sickie Ickie]

Do the servos already come prewired? Do you just plug it into the board?

[Zombie-F]

You just plug it into the board. You can either get a servo from them, or buy one from the site Scary Terry lists on his site.

[Sickie Ickie]

Do you personally prefer using a sound source or do you prefer a soundchip?

[Sickie Ickie]

If I want to control the servo directly...um...such as lifting an arm or turning the head, what would I have to hook the servo up to?

[Zombie-F]

If I want to control the servo directly...um...such as lifting an arm or turning the head, what would I have to hook the servo up to?

For that, a prop-1 board would work best. You'd need to learn how to program it to do what you want/when you want though. It can seem very intimidating at first, but once you get the hang of it, it's nothing.

Parallax makes a Basic Stamp 2 "Starter Kit" that helps teach you a little about electronics and how to program the basic stamp 2 board. The prop-1 is based on a Basic Stamp 1 board and the programming/hookup is a bit different, but the basic stamp 2 starter kit is a good jumping off point as it will teach you A LOT about this sort of thing.

Here's a link to the product on Parallax's web site:
http://www.parallax.com/detail.asp?product_id=90005

[Zombie-F]

Do you personally prefer using a sound source or do you prefer a soundchip?

I personally prefer a sound source such as a CD player or an MP3 player... the sound quality is much better. For convenience, and as long as the sound you want to play isn't longer than 120 seconds, a chip may be the way to go. However, the sound quality on the chips is a lot less than that of a CD or MP3.

[Sickie Ickie]

You are awesome Zombie-F!

I appreciate your trouble to help explain some of this to me. Thanks!

[BuriedAlive]

How much do the arms weigh that you are planning to move? And . . . how exactly do you plan on moving them with the servo? I ask because if your arm's heavy, a servo and the manner of the armiture, can be drastically affected. If it weighs something like a latex skeletons arm, the servo should have no problem. If it weighs closer to a Buckies arm, a servo and the way its hooked up, may have problems moving the arm.
Of course, there are other ways of accomplishing the action. If a repetitious action is what you're looking for, you could always mount an electric motor somewhere and "marionette" the prop. Or, you could go Disney and do pneumatics.
What exactly are you trying do?

[Zombie-F]

How much do the arms weigh that you are planning to move? And . . . how exactly do you plan on moving them with the servo? I ask because if your arm's heavy, a servo and the manner of the armiture, can be drastically affected. If it weighs something like a latex skeletons arm, the servo should have no problem. If it weighs closer to a Buckies arm, a servo and the way its hooked up, may have problems moving the arm.
Of course, there are other ways of accomplishing the action. If a repetitious action is what you're looking for, you could always mount an electric motor somewhere and "marionette" the prop. Or, you could go Disney and do pneumatics.
What exactly are you trying do?

Yes, he brings up a very good point. Servos are too weak for arms and legs.

[Sickie Ickie]

How do I figure out what kind of servos I need for what job? It's all based on torque, right?

I've considered pneumatics, but can they go small enough to fit inside a skull for up/down/left/right movement? I just recently saw the organ thread and it's spurred me on to learn more. It's a goal I would love to strive to reach!

[Zombie-F]

Well, a servo can move a head with no problem. Again, what exactly are you wanting to do with the servo?

For arms and legs, pneumatics is the most reliable way to go. The weight of an arm coupled with it's long length make it pretty impossible to move with a little servo motor.

[BuriedAlive]

I don't know if you've seen the Abraham Lincoln animatronic at Disney, but that's all pneumatics.

[Sickie Ickie]

Well, the main thing on my mind right now is moving a head back and forth, up and down. I saw the pictures of the organ grinder, amd in awe of it, and am trying to figure out more about the head and what the servos are connected to.

[randyaz]

Another great way to control servos is with the Visual Show Automation (VSA)

http://www.brookshiresoftware.com/vsa_overview.htm

Pros:
No programming skills required, can lip sync with audio
Cons:
requires a servo controller board, must remain connected to a PC

I use VSA and think its a great product. Most of the more complex prop "shows" utilize it...

http://www.custommusic.tv/haunts/VideoClips/terribletrio.html

[Sickie Ickie]

Thanks Randyaz! I never knew this existed!

So, is the prop-1 a servo controller board? Or what is it?

[Zombie-F]

The prop-1 is a microcontroller. It's a mini computer you can program to do various functions... controlling a servo is among those functions. :D

[Sickie Ickie]

Gotcha! So, prop-1 requires me to know programming and is a means unto itself.

The VSA requires no programming and needs to be constantly hooked up to a computer.

What's a servo controller board?

[randyaz]

a servo is controlled by timed pulses of voltage technically called pulse width modulation (PWM).

A prop1 is a Parallax Basic Stamp 1 microcontroller on a board which has additional components to allow the stamp to work with higher volage and current required by devices used in props than the stamp was designed for. The stamp/prop1 alone will generate PWM to control 2 or 3 servos...but then the stamp is dedicating most of its processing power to this. Enter the servo controller...

The servo controller takes most of the tasks off the stamp relieving it to do other things. All the stamp then has to do is give the controller a short instruction and the controller executes the instruction and maintains control of the servo. There are many vendors of servo controllers... Parallax, Pololu, Scott Edwards... that interface with the Prop1 which allow it to control from 8 to 16 individual servos.

The VSA has to be programmed...but allows the user to use a mouse to "visually" set an event on a time line and set the servo position for that event. It takes those settings and automatically genertates the PWM instructions (the programming) and sends to the servo controller board and in turn to the servos.

The Prop1 must be programmed directly which is not that difficult to do for a few servos doing minimal motions (head turns, eye blinks, etc) but when trying to lip sync or do numerous servo motions the direct programming of the Prop1 becomes very very tedious and quickly consumes the memory storage capacity of the stamp.

http://www.parallax.com/detail.asp?product_id=28023
http://www.pololu.com/products/pololu/0240/
http://www.seetron.com/ssc.htm

[Zombie-F]

Couldn't have said it better myself randy. And welcome back to the forums. :D

[Sickie Ickie]

Man, you guys are smart!

You have so much information in that post, I'll have to re-read it several times- but I think I finally understand.

Thank you and again and again!

[darryl]

So, while we are on the subject of servos if I get the Cowlacious(Scary Terry) voice chip, how do I get the head side to side movement incorporated into the design. Such as Krough is doing in his Organ grinder prop? Any ideas?

[Dr Morbius]

I believe he is using both a cowlacious board for jaw movement, and a Parallax servo controller board for head movement. He may have changed to VSA for jaw movement though.

[darryl]

Man the more i read about this VSA the more excited I get. I think I'm going to try it!!

[darryl]

Found this on the ghost ride site. WOW!!
http://www.ghostride.com/products/animated_skulls/talking_skeleton.html

[ruafraid]

Has anyone ever used the Hauntbots controller ? I was not at IS but I am fairly sure it was there this year as a vendor. I have looked at so many of these my head is still spinning. I just wanted to know if anyone has any opinions on it also how does it compare to the Prop1. I wish someone had the time to put a web page up with coparisons on the different controllers and pros cons.