TP / External Connection to Motor 
Author Message
 TP / External Connection to Motor

Hi all.

I'm planing to build a very simple camera crane.
I want to use 2 motors to ensure movement in 2 axes.

I've been working with TP7 for a while and thought about controlling
the motors over a simple joystick interface to input the variables and
then let the code send the signals over a serial port to the motors.

Getting the Variables from the Joystick (or other interface) into the
computer isn't the problem. But I have never experimented with motor
interfaces before.

Is there any good advice on the net or can somebody help?

thx
Gidion



Sat, 02 Aug 2003 00:02:44 GMT  
 TP / External Connection to Motor

Quote:

>Hi all.

>I'm planing to build a very simple camera crane.
>I want to use 2 motors to ensure movement in 2 axes.

>I've been working with TP7 for a while and thought about controlling
>the motors over a simple joystick interface to input the variables and
>then let the code send the signals over a serial port to the motors.

>Getting the Variables from the Joystick (or other interface) into the
>computer isn't the problem. But I have never experimented with motor
>interfaces before.

>Is there any good advice on the net or can somebody help?

>thx
>Gidion

The power you will be able to get through the serial port is unlikely to be
able to control any motor so you're going to have to use some other control
system and other output cards.

If you're using a DC motor I think you'll struggle because it won't be
easily controlled from a PC, apart from turning it on/off and reversing
direction.  Variable speed will be harder to obtain.  You may be better with
a servo-motor, like you get with radio control, or a stepper motor which is
used in precision positioning (in a printer, hard drive, things like that).

A quick search gives www.robotics.com that may answer a few questions and
point you in the right direction.

http://www.seattlerobotics.org/websites.html has lots of links to robotics
sites.

Andy



Sat, 02 Aug 2003 07:04:47 GMT  
 TP / External Connection to Motor

Quote:
> But I have never experimented with motor
> interfaces before.

> Is there any good advice on the net or can somebody help?

The most simple design is using two stepping motors with ???? (no kidding,
forgot the English name :( ).
Let's say it in other words. The motor has six wires: two pair of six wires.
Each three wires are connected to two coils. See it like this

   +----Coil1---+---Coil2----+
   |            |            |            same for Coil3 and 4
   0            0            0
   1           +12V          2

The coils are placed like this:

                   coil1

           coil3   ====>    coil4           =====> is a magnet

                   coil2

From each coil either line 1 or line 2 is tied to ground which turns the
corresponding coil in a magnet. The magnet points to the active coil.
Activating the coils one by one makes the magnet turn. The trick is to
activate the coils in the right order. To make a very smooth run, you
activate everything like:
- coil1
- coil1 + coil4
- coil4
- coil4 + coil2
etc. etc.

You could skip step 2 and 4, activating both coils, but then you run the
risk that a heavy load could twist the motor between activations

What wire is for which coil? That is just try and error. But with so few
wires, that cannot be hard to find out.

What motor to use? That depends on the load. Good tip: old printers,
diskdrives, 5.25" diskdrives.

Interface to the computer:
There are several ICs you can use like the uA2003 family. When scrapping a
printer or whatever, take the IC out as well.

You only need one TTL-output for the activation of each wire. With two
motors you'll need 8 outputs ie. you can use the datapart of your LPT-port.
You can program it by using with port[...]

Good luck.

Groetjes, Ruud

http://home.hccnet.nl/g.baltissen/index.htm



Sat, 02 Aug 2003 22:17:58 GMT  
 
 [ 3 post ] 

 Relevant Pages 

1. Connection with a external Paradox Database

2. Delaying small amounts of time to Control the Speed of a Stepper Motor - help needed

3. Establish Dial-Up connection in WIN95/98 from TP

4. External program call from TURBO PASCAL ??

5. How do I evoke external files?

6. Help closing external apps with PostMessage function...

7. Running external programs

8. Help: 'External Exception C000001D'?

9. External Exception C0000006

10. Executing External Programs

11. External Data Import - Impossible ???

12. External program call from TURBO PASCAL ??

 

 
Powered by phpBB® Forum Software