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Re: Looking for a Low Cost On Delay Timer



"Spehro Pefhany" <speffSNIP@xxxxxxxxxxxxxxxxxxxxxxx> wrote in message =
news:0n2v19dqcu9kb569k6ul3s2mktal1tr4m2@xxxxxxxxxx
> On Thu, 29 Aug 2013 10:18:17 -0700, "Guv Bob"
> <guvbob2003@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>=20
> >"Guv Bob" <guvbob2003@xxxxxxxxxxxxxxxxxxxxxx> wrote in message =
news:lKednb_fcOnJU4bPnZ2dnUVZ_oWdnZ2d@xxxxxxxxxxxxxxxx
> >"Spehro Pefhany" <speffSNIP@xxxxxxxxxxxxxxxxxxxxxxx> wrote in message =
news:l20n191irlkc14q13f9on9l0tctgtihjva@xxxxxxxxxx
> >> On Sun, 25 Aug 2013 23:29:54 -0700, "Guv Bob"
> >> <guvbob2003@xxxxxxxxxxxxxxxxxxxxxx> wrote:
> >>=20
> >> >"Guv Bob" <guvbob2003@xxxxxxxxxxxxxxxxxxxxxx> wrote in message =
news:1_udnQ7rBpNjRo7PnZ2dnUVZ_sidnZ2d@xxxxxxxxxxxxxxxx
> >> >Names can be confusing, so here's what I'm doing....
> >> >
> >> >http://img43.imageshack.us/img43/7434/wvm.gif
> >> >
> >> >When 12VDC is applied to the input, I need a 12VDC output for 5 =
seconds.  Then output will go back off and stay off until the input goes =
to zero.  Then cycle starts again.
> >> >
> >> >Current for both legs is in the 10-50ma range.
> >> >
> >> >A simple on-delay timer would work but I'm having trouble finding =
one with NC contacts.  Tons of stuff $100+, but for this application, it =
has to be under $20.
> >> >
> >> >=3D=3D=3D
> >> >
> >> >Thanks for all the tips and good info.  I had wanted to put =
something together from components but my brain is too far behind these =
days.  I'm going to give this a shot and hopefully I'm not picking the =
wrong one.  It's $5 at Frys...
> >> >
> >> >Velleman MK111
> >> =
>http://www.vellemanusa.com/downloads/0/minikits/manuals/manual_mk111.pdf=

> >>=20
> >> It can be modified to do what you say you want.=20
> >
> >- Hmmmm....... in that case, forget the electronics!  ;O)
> >
> >
> =
>http://www.vellemanusa.com/downloads/0/minikits/manuals/manual_mk111.pdf=

> >
> >If I disconnect pin 7, would that make it a one-shot pulse?
>=20
>=20
> Try leaving out R2 & RV1* and D2*, and jumper the free end of R1
> (R1-D2 junction) to pin 8.=20
>=20
>=20
> If you can't quite get 5s with RV2 cranked up all the way, increase R1
> to 10K or 20K.=20
>=20
> *optionally; if they're already in there, don't bother taking them
> out. =20

Well, I made a real mess of the first board, thanks to a new Weller =
soldering iron.   Ended up digging out my old Radio Shack iron which =
worked 10 times better - same type and wattage as the Weller.  Here's =
the soldering job on each board....
http://img401.imageshack.us/img401/6528/9oag.jpg

Anyway, I made the changes Spehro mentioned and it works perfectly!

First I snipped the R3 out of the circut which caused the LED to act as =
a one-shot as needed.  So with that good news, I added the jumper and =
now the relay is in the circuit and I am in Fat City!

FYI, on the left is the assembled board from the kit.  Right shows it =
with the jumper added.
http://img835.imageshack.us/img835/6691/0wxx.jpg
http://img17.imageshack.us/img17/4276/g1k.gif

Thanks again to all for this very educational journey!

Bob



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