Digest Number 18
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Posts: 46,084
>
> I don't understand how to activate 12 volt relays using a ULN2003. I'm
> working off of a schematic from Parallax. On the diagram they sent me,
>
> Stamp 04 goes to ULN pin 14 and to a relay.
Stamp pin 4 is ground and ULN 14 is an output, do you mean P4(pin9) on the
Stamp?
> Stamp 13 goes to ULN 3 and to an LED to indicate the status .
This is In3 on the ULN. therefore Out3(pin 14) on the ULN should
go to the coil on the relay, and the othere side of the relay coil to
+12V.
> I can get the LED to light, but not the light on the relay. I have
> two leads coming from the relay that drives the lights. ON the
> schematic, the 12V+ from the relay goes to ULN 2003 pin 09(the pin
> bottom right, opposite the ground pin 08).
>
Pin 9 is a test pin on the ULN, should be no connect. Pin 8 ground
needs to connect to Stamp ground, pin4 or 23.
The ULN2003 is an inverter so a high on the input should cause the
output to sink to ground. You will want a back EMF diode across
the coil.
> I don't understand how to activate 12 volt relays using a ULN2003. I'm
> working off of a schematic from Parallax. On the diagram they sent me,
>
> Stamp 04 goes to ULN pin 14 and to a relay.
Stamp pin 4 is ground and ULN 14 is an output, do you mean P4(pin9) on the
Stamp?
> Stamp 13 goes to ULN 3 and to an LED to indicate the status .
This is In3 on the ULN. therefore Out3(pin 14) on the ULN should
go to the coil on the relay, and the othere side of the relay coil to
+12V.
> I can get the LED to light, but not the light on the relay. I have
> two leads coming from the relay that drives the lights. ON the
> schematic, the 12V+ from the relay goes to ULN 2003 pin 09(the pin
> bottom right, opposite the ground pin 08).
>
Pin 9 is a test pin on the ULN, should be no connect. Pin 8 ground
needs to connect to Stamp ground, pin4 or 23.
The ULN2003 is an inverter so a high on the input should cause the
output to sink to ground. You will want a back EMF diode across
the coil.
Comments
transient protect diodes making back EMF diodes unnecessary if this is done.
Regards,
Ray McArthur
Original Message
From: Mike DeMetz <miked@t...>
To: <basicstamps@egroups.com>
Sent: Sunday, April 16, 2000 10:07 AM
Subject: Re: [noparse][[/noparse]basicstamps] Digest Number 18
>
> >
> > I don't understand how to activate 12 volt relays using a ULN2003. I'm
> > working off of a schematic from Parallax. On the diagram they sent me,
> >
> > Stamp 04 goes to ULN pin 14 and to a relay.
> Stamp pin 4 is ground and ULN 14 is an output, do you mean P4(pin9) on the
Stamp?
> > Stamp 13 goes to ULN 3 and to an LED to indicate the status .
> This is In3 on the ULN. therefore Out3(pin 14) on the ULN should
> go to the coil on the relay, and the othere side of the relay coil to
> +12V.
> > I can get the LED to light, but not the light on the relay. I have
> > two leads coming from the relay that drives the lights. ON the
> > schematic, the 12V+ from the relay goes to ULN 2003 pin 09(the pin
> > bottom right, opposite the ground pin 08).
> >
> Pin 9 is a test pin on the ULN, should be no connect. Pin 8 ground
> needs to connect to Stamp ground, pin4 or 23.
> The ULN2003 is an inverter so a high on the input should cause the
> output to sink to ground. You will want a back EMF diode across
> the coil.
>
>
>
>
>
>
> > Stamp 04 goes to ULN pin 14 and to a relay.
> Stamp pin 4 is ground and ULN 14 is an output, do you mean P4(pin9) on the
Stamp?
>
Yes, "4" is the pin labelled on the board of education and the carrier board
as
"P4" on the Stamp. my mistake(ignorance) about syntax..
> > Stamp 13 goes to ULN 3 and to an LED to indicate the status .
> This is In3 on the ULN. therefore Out3(pin 14) on the ULN should
> go to the coil on the relay, and the othere side of the relay coil to
> +12V.
> >
> Pin 9 is a test pin on the ULN, should be no connect. Pin 8 ground
> needs to connect to Stamp ground, pin4 or 23.
> The ULN2003 is an inverter so a high on the input should cause the
> output to sink to ground. You will want a back EMF diode across
> the coil.
MAY I send you a copy of the schematic that I'm working off of? I'm thinking
that
either I am misunderstanding the design or else there is a mistake in it. the
file
is a 43k pdf file, and might just be the ticket <G>....Thanks!
--
ARC in Lago Vista, TX
Keep this in mind when training animals - if you beat a cat with a loaf of
bread,
there is *no* way you'll ever train him to make you a sandwich!(Thomas M.
Shaltry)
drivers to control a relay that switches the +12v to the motors. A spare Stamp
pin is then toggled to turn the motors on before movement and off after
movement.
Dennis
rjmca wrote:
> Pin 9 of the ULN2003 should be connected to +12. Allegro provided internal
> transient protect diodes making back EMF diodes unnecessary if this is done.
>
> Regards,
> Ray McArthur
>
>
Original Message
> From: Mike DeMetz <miked@t...>
> To: <basicstamps@egroups.com>
> Sent: Sunday, April 16, 2000 10:07 AM
> Subject: Re: [noparse][[/noparse]basicstamps] Digest Number 18
>
> >
> > >
> > > I don't understand how to activate 12 volt relays using a ULN2003. I'm
> > > working off of a schematic from Parallax. On the diagram they sent me,
> > >
> > > Stamp 04 goes to ULN pin 14 and to a relay.
> > Stamp pin 4 is ground and ULN 14 is an output, do you mean P4(pin9) on the
> Stamp?
> > > Stamp 13 goes to ULN 3 and to an LED to indicate the status .
> > This is In3 on the ULN. therefore Out3(pin 14) on the ULN should
> > go to the coil on the relay, and the othere side of the relay coil to
> > +12V.
> > > I can get the LED to light, but not the light on the relay. I have
> > > two leads coming from the relay that drives the lights. ON the
> > > schematic, the 12V+ from the relay goes to ULN 2003 pin 09(the pin
> > > bottom right, opposite the ground pin 08).
> > >
> > Pin 9 is a test pin on the ULN, should be no connect. Pin 8 ground
> > needs to connect to Stamp ground, pin4 or 23.
> > The ULN2003 is an inverter so a high on the input should cause the
> > output to sink to ground. You will want a back EMF diode across
> > the coil.
> >
> >
> >
> >
> >