Servo operation

[Drew]

I'm guessing someone here can answer this...

I want to incorporate servo motion in a mod, but have no idea how to implement it.

I was thinking of using the type of servo as used in RC cars etc., but wouldn't know how to go about connecting and controlling it.

I'd like it to move upon powering up, and also be controllable through the o/s as well (ideally I'd like to be able to control more than one too).

I'd guess that some electronics will be involved, like a circuit board of some description (not a problem in itself), but really don't know where to start looking for info or a how to.

A little help?

[rendermandan]

I used to be into rc cars and can tell you the rc servos can be run off of the +5v power lead. can hook them into a spdt switch to provide power to it. just hook up the neg. wire and then each side of the switch to the other 2 wires. when you flip the switch each direction the servo should respond. -I don't know how you can control this with software other than to find something that will have a controled switched 5v output. Maybe Paul can chime in here.

[Crimson Sky]

Try this link (http://www.lynxmotion.com/Product.aspx?productID=395&CategoryID=52). There are many servo controllers with USB and serial interface. Just do a google.

My fave shop is BPE Solutions (http://www.bpesolutions.com/conproduct.html#anchor1593518). Call this man and he will gladly talk to you and find exactly what you need. been using him and his products for years. Mention Paul Capello from TBCS if ya want. Used his boards to control the servo parts for Doom3 and the fetus for Matrix Rebirth. It's even in those worklogs.

[Drew]

This one looks to be the kiddy.

http://i49.photobucket.com/albums/f253/drew555/ssc32.jpg

Thanks for the link Crimson.

Just a couple of n00bish questions....

Those 3 pin headers... would they be where the servos plug in?

And the interface... I take it that's the input... would that be a connector for something like a PS2 controller?

Could I perhaps connect it to a USB header on my Mobo or something?

Yeah, I'm seriously a robotics n00b.

Feeling outta my depth...

:edit: this one looks a bit more user friendly.... any opinions?

http://www.servocity.com/html/servo_controllers.html

[Crimson Sky]

well yes, it has 32 channels for up to 32 servos. Much more than you will need. It plugs into your computer's serial port and using software available (sold seperately, or free if you can find it) can controll those servos with ASCII commands to do just about anything. USB controlled boards are usually easier to program, but you will have to get the software. ASCII commands are easy to create in windows.

I suggest finding a simple board to start.

[Drew]

Yeah... I concur.

Should have refreshed before I edited....

:edit: Looks like it runs from 9V, is there a simple way of stepping 12V down?

[Crimson Sky]

These boards can usually take between 9-12V, no need to worry about some extra juice. They are pretty flexible and robust.

EDIT: I've used that same exact controller from ServoCity. Its pretty good for the price. The software is OK too, although I'm not sure if it can be programmed for specific moves, or if its "On the fly" movement using the sliders in the application.

[Drew]

Good man, many thanks.

Expect to see more robo-n00b questions another day....

[Crimson Sky]

Here is a pic of the one I have. I think the serial connector is sold seperately.

http://thebestcasescenario.com/misc/PICT0086.jpg

[Drew]

aaaaaaaaaaaaahhhhhhhhhhh... right.

9V into the board, servos onto the board headers and connector into the serial port on the back of the PC.

Much clearer now, thanks a million.

You know what, this might actually happen.

:edit: even if it is just on the fly motion, I bet I can think of summat cool to do with it.... think lowriders... just need to find a decent 1/5 scale lowrider and I'm off.

[Crimson Sky]

Some boards also allow you to use momentary switches to control the servos. The ServoCity model only uses software. Also, most newer motherboards do not have serial connectors on the back--instead, its an optional header on the motherboard, and they give you a PCI bracket/cable. Makes it nice for internal connections. The touchscreen for the 7" monitor for the Doom3 mod is serial controlled; the motherboard had the serial header option, so its all internal and neat.


here's a tip: basic hobby servos have a very limited range of rotation. If you need a greater range of motion, use what's known as a retract servo. these are used for landing gears on model aircraft. They are all pricey, so shop around.

[Drew]

Thanks for the tips dude.

Appreciate you taking the time out.

[Redundant]

If you're looking for what brand of servos to get, I recommend Hitec (http://www.hitecrcd.com/) servos. They're cheap and well built. Your local hobby store should have them.

[Mach]

I'd also recommend phidgets if you're looking for USB interface servo controllers. You can program them with a variety of languages including vb or windows scripting. They also have a wide range of other input and output devices.

http://www.phidgets.com/index.php?module=pncommerce&func=categoryview&CID=7&KID=