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Servos

D

D3DAiM

Limp Gawd
Joined
Sep 30, 2006
Messages
413
How do I control a servo to rotate forward a certain amount and rotate backward that same certain amount?

Do I need some sort of controller?

thanks.

d3d
 
I don't have a spare PCI slot..

Is there another way I can do this?
 
I was talking to some other people in this forum on a different post and they were talking about how I could put a start and stop button for the servo. Possible? Is it absolutely necessary to have a microcontroller for the servo to run? Can't I just feed it 5V somehow? Then could I revers the polarity to make it run reverse?

I really can't do anything about PCI slots. Maybe USB or something.

I want to be able to solder on a forward switch, that makes it run forward a certain amount, and a reverse switch that does the same thing.

thanks

d3d
 
If you only need to rotate the servo to one position or the other, you could build a pulse width modulation (PWM) circuit. The switch would be used to cause the PWM circuit to change the pulse timing for the servo making it rotate to the desired positions.
 
Frank4d said:
If you only need to rotate the servo to one position or the other, you could build a pulse width modulation (PWM) circuit. The switch would be used to cause the PWM circuit to change the pulse timing for the servo making it rotate to the desired positions.
Click to expand...

I agree. If all you want to do is have a servo motor rotate to a specified position, an expensive PCI/PCI-E solution is not necessary.

EDIT: Here is a good guide: http://home.earthlink.net/~tdickens/68hc11/servo/servo.html
 
http://www.kronosrobotics.com/xcart/customer/product.php?productid=16298&cat=271&page=2

I'm actually thinking more now about using a microcontroller. This package will allow me to program the microcontroller how I see fit. It actually doesn't seem to hard to code and setup. The good thing about this is that I may be using a 20X4 LCD down the line, and I can use this micontroller to have it display things :)

What do you guys think?
 
If you are going to just do this once and not go any further with this, just get a Basic Stamp or PICAXE, which is a PIC chip with an interpreter / operating system on it. It's simple to program, but it's expensive and limited in functionality.

If you want to go further with microcontrollers, get a programmer for a real mocrocontroller, like for a PIC, AVR, or what I use Z8 Encore!. The Z8 Encore! is a great deal. USB programmer is $20.00 and C/assembler programming environment is free. It's so simple to write the firmware to the chip compared to the other uC's it's a big benefit.
 
You can do a basic servo controller with a LM347 and some pots to vary the PWM length and such.

I might still have the diagram from the board we built freshmen year for some cheesy robobug. The servos all had their little boards which were linked to a master board which did have a 68K on board.
 
That old development kit is not all that great. You would be better off spending $40.00 for the USB smart cable development kit from Mouser.com if you want the development board, or just $20.00 on the smart cable programmer and get a few chips and passives and a breadboard.
 
I really want to take the cheapest route though lol. This is a one time, basic thing, for one servo. That is all.

I am interested in this pot method, do explain.

:)

d3d
 
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