analog joystick controlling stepper motor

frogdogbb

Hi all,
I want to use an analog joystick to control a stepper motor and also power a relay which powers a second circuit. When the joystick is pressed side to side I want the stepper motor to turn at a rate dependant upon the position of the joystick. If the joystick is pressed forward or backward I want to close a relay. I want both to be on in the intermediate positions like forward and left ...etc. I am trying to figure out the cheapest and best solution for this. I thought about using a 68hc12 microcontroller with the A/D converter only because I have experience with these. But I am open to easier cheaper solutions. I would like to use C programming. Any ideas on how to get my idea off the ground would be much appreciated. Thanks

NoTime

Sounds like you have a good start.

I'd use one of the joystick buttons to activate the relay, simpler than a 2nd AD.
I don't remember off the top if the 68hc12 has built in AD, but if it doesn't I'd change to a Up that does.
Also you would need a Stepper Controller, the Up won't be able to drive that directly.
And you might need some sort of position feedback from the stepper, unless all you care about is rotation speed and direction.

frogdogbb

the 68hc12 has an A/D in it. I really need the relay to operate off the joystick so I figured I could just use two channels of the A/D, one for each direction. I don't need a position sensor it is not neccesary.

NoTime

You could probably still get away with one channel AD.
If the joystick centered(null) position is <stop> define the dead band to disengage the relay.
Joystick mechanical centering is kinda sloppy, so you need this dead band anyway to keep the thing from hunting.

young e.

try Z8 encore flash microcontroller, it is programmable in C
8 bit architecture, flashed base RAM..
for more info visit:

www.zilog.com