Hi Lovely People

I'm using a joystick to control a ready made motor controller.

The input required is 0v to 5v with a centre point at 2.5v. However, the joystick, which is connected across a 0-5v tap from the controller, doesn't use the full potentiometer track and I can't reach anywhere near 0v or 5v.

I feel that an op-amp used as a differential amp is the way to go, but all the circuits I've seen here rely on a small negative voltage to achieve 0v at the output.

Is there another solution?

In this motor control context, it'll be acceptable to not quite reach 0v or 5v.

I should also mention that the motors are fed from a 12v supply, just in case a solution may be found by using, say, 0-9v.

Thanks in advance for any help on this.

Keith

 

Hi,

Yes you will need a small neg voltage to achieve 0 volts. I do this quite often when building battery operated equipment. Just use an ICL7660.

If you need more details, let me know...

Daniel.