AVR-Chat

Hi Elham,

There are several things that may be causing the problem and several things
you can do to try to prevent it.

I am assuming that the motor draws a fair amount of current, since you're
driving it with some fairly good-sized FET's. I would not acquire the
voltage to power the ultrasonic module or the AVR from the same power
supply that provides 12-volt power for the motor. Also, is the wire between
the ultrasonic module and the AVR circuit shielded? You might want to try a
shielded wire (with the shield grounded) on this line. Also, bypass the
power for the module and the AVR with several capacitors in parallel -
maybe a few microfarads in parallel with a 1000 pF and a 10 pF. This would
cover a wide frequency range of noise that may be getting into the circuit.
Also, you can enclose the AVR circuit in a metal case and bring the "Input
A" and "Input B" leads out through bypass capacitors.

Maybe you have tried some of these already? Do you have an oscilloscope? I
would look at the waveform on the lead to PD3 to see how clean it actually
is.

Zack


On Wed, Oct 10, 2012 at 2:49 PM, Elham B <elhamb88@ymail.com> wrote:

> **
>
>
> an ultrasonic module connected to interrupt,
> i upload the attachment into the photos,,,
> in this circuit dc motor connected to micro,,if output of ultrasonic pull
> down the INT1 ,dc motor running...but the interrupt is
>
> getting interrupted unintentionally by the noise
> what's happening???
>
> ________________________________
> From: Jim Wagner <wagnejam99@comcast.net>
> To: AVR-Chat@yahoogroups.com
> Sent: Wednesday, October 10, 2012 8:58 AM
> Subject: Re: [AVR-Chat] noise problem
>
>
> There is not enough information to provide any help.
>
> What is PD3 connected to?
>
> Why do you have an interrupt for PD3?
>
> What do you mean by "operating uncaused"? Every action must have a cause!
>
> What do you mean by "driving a dc motor in the interrupt"? (I assume you
> mean driving instead of deriving).
>
> Jim Wagner
> Oregon Research Electronics
>
> On Oct 9, 2012, at 12:50 PM, Elham B wrote:
>
> > noise!!!
> > my project is with micro avr,atmega32.
> > pinD.3 , external interrupt ,operating uncaused!!
> > because of noise!!
> > I deriving a dc motor in the interrupt ,
> > i using capacitors in every where that was nesseccery for solving this
> problem...
> > pleesssee help meeeee :-(
> > what can i do????
> >
> >
>
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>
> ------------------------------------
>
> Yahoo! Groups Links
>
> [Non-text portions of this message have been removed]
>
>  
>


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