clicking relays

Archiver

Are you driving the relay directly from the stamp or through a
driver?
Also, is there any other places in the program that would besetting
the pin low, or as an input that may be overlooked?

Doug

> To: <basicstamps@yahoogroups.com>
> From: "Haskew family" <PandL.Haskew@b...>
> Date: Sat, 27 Jan 2001 15:51:40 -0000
> Reply-to: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] clicking relays

> Friends, may have to come back to you on this one! Have built an interface
> board for the BS2 with a couple of 5v relays and a ULN 2803a. driver. With
> the command:
> high 1
> ' relay 1 pulls up and the motor trundles backwards.....Great!
> BUT there is an audible clicking of the relay all the time. The board has
> its own 9v power supply, grounded to the Stamp. Stamp's battery has been
> replaced. But why the clicking please?
>
>
> FURTHERMORE if we add:
> high 0 '
> relay 2 pulls up
> high 1 '
> relay 1 pulls up and the motor trundles forwards....Great! But still the
> clicking?
> Finally, with the single command high 0 the reversing relay alone pulls up
> but still this 1hz or so clicking all the time!! Please help or advise if
> you can. Thanks.
> Paul.
>
>
>
>
>
>

Archiver

Friends, may have to come back to you on this one! Have built an interface
board for the BS2 with a couple of 5v relays and a ULN 2803a. driver. With
the command:
high 1
' relay 1 pulls up and the motor trundles backwards.....Great!
BUT there is an audible clicking of the relay all the time. The board has
its own 9v power supply, grounded to the Stamp. Stamp's battery has been
replaced. But why the clicking please?


FURTHERMORE if we add:
high 0 '
relay 2 pulls up
high 1 '
relay 1 pulls up and the motor trundles forwards....Great! But still the
clicking?
Finally, with the single command high 0 the reversing relay alone pulls up
but still this 1hz or so clicking all the time!! Please help or advise if
you can. Thanks.
Paul.

Archiver

Because upu are pulsing the servo via the relay and every time the pulse
stops the relay opens. You might try handing a capacitor across the relay to
hold the voltage up, or perhaps reducinmg the 20ms pause between pulses to
15ms.

Sid

Archiver

Doug,
Thanks for your response, we are driving the relays via two
outputs from the ULN 2038a driver, which is powered by , at the moment an
external 9v supply. There is no more program yet! We are still making
tentative steps with a newly made interface board. (Looking ahead though,
this mystery pulse if that is what it is! may cause us servo problems, hence
our desire to learn from the expertise of other Stampers).
Regards Paul.