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Discussion Starter #1
I have just gotten preliminary wife approval (it must be my birthday or something!) to do a 3-axis or 4-axis servo setup on our stirring cauldron witch to kick her up a notch this year. This will go great with the new shed/shack we just built her. I want to do all the programming myself, partly because I love programming and the challenges that go along with it and partly because I think it will save me some money since I won't have to buy software. I'm thinking about using the Phidgets USB 4-servo controller kit from Trossen Robotics found here:

4-Motor Servo Kit

Does anybody have experience with these? They look easy to program from C# or VB.NET (I program in both). The main question I have is how far away can I locate the servos from the controller board? In other words, can I locate my laptop and controller board in the garage and then run some cat 5 out to the servos on the witch in the yard? I think this would be about 30-40 feet away. Any feedback will be greatly appreciated!
 

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The Evil Apparitionist
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I have just gotten preliminary wife approval (it must be my birthday or something!) to do a 3-axis or 4-axis servo setup on our stirring cauldron witch to kick her up a notch this year. This will go great with the new shed/shack we just built her. I want to do all the programming myself, partly because I love programming and the challenges that go along with it and partly because I think it will save me some money since I won't have to buy software. I'm thinking about using the Phidgets USB 4-servo controller kit from Trossen Robotics found here:

4-Motor Servo Kit

Does anybody have experience with these? They look easy to program from C# or VB.NET (I program in both). The main question I have is how far away can I locate the servos from the controller board? In other words, can I locate my laptop and controller board in the garage and then run some cat 5 out to the servos on the witch in the yard? I think this would be about 30-40 feet away. Any feedback will be greatly appreciated!
That servo kit seems really expensive. You can get a Pololu 8 servo serial controller for $20, $18 in kit form.
Pololu - Pololu Micro Serial Servo Controller (assembled)

A really nice Lynxmotion SSC-32 (32 servo controller) is only $39
SSC-32 Servo Controller

Both controllers are easily controlled by simple serial commands or you can get VSA (brookshire.software) if you really want to make things easy and not re-invent the wheel.

http://www.brookshiresoftware.com/vsa_order.php

Servocity.com has a ton of servos and mechanical linkages to choose from.

You can extend the servo data lines pretty far (in excess of 50 feet) with cat 5. You can also double up the unused cat5 leads to send power to the servos (power leads need to carry mich more current).

Lots of people have gone this route so you will have lots of help too.
 

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Discussion Starter #3
Thanks for the information about the Pololu Micro Servo controller and the SSC-32. The Pololu makes me a little nervous, but the SSC-32 seems easy enough. Keep in mind that the kit from Trossen does include 4 servos and a power supply for the servos, so the cost doesn't seem so bad when you factor that in. Anything I should know when selecting a servo? I'm just guessing that the servos that come with the Trossen kit are fine.
 

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The Evil Apparitionist
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Thanks for the information about the Pololu Micro Servo controller and the SSC-32. The Pololu makes me a little nervous, but the SSC-32 seems easy enough. Keep in mind that the kit from Trossen does include 4 servos and a power supply for the servos, so the cost doesn't seem so bad when you factor that in. Anything I should know when selecting a servo? I'm just guessing that the servos that come with the Trossen kit are fine.
Better quality servos have single or dual ball bearing races for smooth rotation.
Stall torque is the maximum rotational force you can expect the servo to push or pull before it stops dead (and can fail comletely in some cases). Most servos are pretty tough animals as long as you keep the power supply voltages below the maximum ratings. More voltage equals more torque to a point. I've built about 23 3-axis skulls so far and the biggest servo maxes out at about 4.5Kg/cm at 6 volts. Metal gear servos are for higher torques like 10Kg/cm and up.

I buy my servos all the time for less than $9 each in small quantities, plug in regulated power supplies are around $5 (allelectronics.com or mpja.com or goldmine-elec.com)
 

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The Evil Apparitionist
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Okay, so you think I should be going with something stronger? Any recommendations? I'm also trying to parse through the tons of threads on servos in the props forum here. Information overload! ;)
If you are going to build a basic 3-axis skull you could use Hitec 425BBs or Tower Pro 5010s just pick a lighter weight skull to house everything (Lindberg type). I use the 5010s all the time, they are dirt cheap ball bearing servos with plenty of torque. Then just cover it with a skin or mask.
 

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Discussion Starter #8
Well this isn't a skull build. The head will have a witch mask on it and witch's hat. I'm thinking it will be heavier than a lighter weight skull. I'm obviously going to have to scratch build a new lighter weight form for the head to be able to move via servos and to allow room for the jaw servo and possibly an eye servo or two. I'll probably just concentrate on 3 axis for now. Thanks for the all the info, by the way!
 

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The Evil Apparitionist
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Well this isn't a skull build. The head will have a witch mask on it and witch's hat. I'm thinking it will be heavier than a lighter weight skull. I'm obviously going to have to scratch build a new lighter weight form for the head to be able to move via servos and to allow room for the jaw servo and possibly an eye servo or two. I'll probably just concentrate on 3 axis for now. Thanks for the all the info, by the way!
You could always make a paper mache copy of what you've got. I do that all the time and then shoot it with clear laquer, light and strong.
 

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Discussion Starter #10
I decided to go ahead with the Lynxmotion SSC-32. I also decided to try the Tower Pro 5010's. Just bought 5 of 'em. What power supply would you recommend? Actually I need 2 power supplies, don't I? One for the board (9 volt?) and a 6 volt for the servos, right?
 

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Discussion Starter #11
I saw that you can use the same 6 volt power supply to power the microcontroller, assuming you don't have too many servos moving at the same time. I went ahead and bought a 6v regulated 2.5 amp power supply for now. Will buy a 9 volt power supply for the microcontroller later if I need it. Just spent $138.31 tonight. Phew! Time to go to bed before I realize what I've gotten myself into! :)
 
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