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it. Look here:I am trying to make a 30 led bargraph to display the output from a MAP
sensor.
Found this circuit - http://cp_www.tripod.com/rotary/pg27.htm#30ledaf
My question is - How do I incorporate pots to adjust zero and full scale ?
Any help gratefully received.
RexT.
That's the purpose of the pot's in the circuit, as described in the note on
"RexT" <r.turner@bigpond.net.au> wrote in message
news:2KtJd.134237$K7.131837@news-server.bigpond.net.au...
I am trying to make a 30 led bargraph to display the output from a MAP
sensor.
Found this circuit - http://cp_www.tripod.com/rotary/pg27.htm#30ledaf
My question is - How do I incorporate pots to adjust zero and full scale
?
Any help gratefully received.
RexT.
That's the purpose of the pot's in the circuit, as described in the note
on
it. Look here:
http://www.national.com/pf/LM/LM3914.html
for a more detailed description on how to use this IC ("Application Hints"
section is useful).
Ken
Thanks Ken,
Have read the spec sheet but with my limited experience I have trouble
joining the dots.
If the only way of zero adjust and span is to use the multiple trim pots
then my original idea is out of the window.
I am building two of these to tune a twin cylinder motor and was going to
use a ganged pot to control zero and another for span.
This would give me the ability to tweak the displays on the bike (as it is
also destined to tune other machines for friends)
I was going to include a left/right switch to prove that both sides are
equal.
I normally use a mercury in glass pair of manometers on my own bike, but
it
is not portable and friends tend to want their machines tuned at their own
locations (then I get to drink their tea/coffee).
I was hoping that someone would come up with a mod for the circuit - just
pop a ..... in next to part A and that would give me the external
adjustment
I need.
Thanks for your reply - it was a big ask to hope for someone to jump in
and
do some design work for me.
Best regards,
RexT.
"Ken Taylor" <ken123@xtra.co.nz> wrote in message
news:35nho2F4papevU1@individual.net...
"RexT" <r.turner@bigpond.net.au> wrote in message
news:2KtJd.134237$K7.131837@news-server.bigpond.net.au...
I am trying to make a 30 led bargraph to display the output from a MAP
sensor.
Found this circuit - http://cp_www.tripod.com/rotary/pg27.htm#30ledaf
My question is - How do I incorporate pots to adjust zero and full
scale
?
Any help gratefully received.
RexT.
That's the purpose of the pot's in the circuit, as described in the note
on
it. Look here:
http://www.national.com/pf/LM/LM3914.html
for a more detailed description on how to use this IC ("Application
Hints"
section is useful).
Ken
Well, you can get twin pot's which are independently variable, if that's
what you need. The fact that the schematic description says 'trimpot' and
you want to use pot's doesn't change the fact that they are both variable
resistors - they'll do the same job, just the pot's being larger (and more
unstable, AOTBE). Try it out, you may be pleasantly surprised.
Cheers.
Ken
"RexT" <r.turner@bigpond.net.au> wrote in message
news:kcCJd.134575$K7.71087@news-server.bigpond.net.au...
Thanks Ken,
Have read the spec sheet but with my limited experience I have trouble
joining the dots.
If the only way of zero adjust and span is to use the multiple trim pots
then my original idea is out of the window.
I am building two of these to tune a twin cylinder motor and was going
to
use a ganged pot to control zero and another for span.
This would give me the ability to tweak the displays on the bike (as it
is
also destined to tune other machines for friends)
I was going to include a left/right switch to prove that both sides are
equal.
I normally use a mercury in glass pair of manometers on my own bike, but
it
is not portable and friends tend to want their machines tuned at their
own
locations (then I get to drink their tea/coffee).
I was hoping that someone would come up with a mod for the circuit -
just
pop a ..... in next to part A and that would give me the external
adjustment
I need.
Thanks for your reply - it was a big ask to hope for someone to jump in
and
do some design work for me.
Best regards,
RexT.
"Ken Taylor" <ken123@xtra.co.nz> wrote in message
news:35nho2F4papevU1@individual.net...
"RexT" <r.turner@bigpond.net.au> wrote in message
news:2KtJd.134237$K7.131837@news-server.bigpond.net.au...
I am trying to make a 30 led bargraph to display the output from a
MAP
sensor.
Found this circuit -
http://cp_www.tripod.com/rotary/pg27.htm#30ledaf
My question is - How do I incorporate pots to adjust zero and full
scale
?
Any help gratefully received.
RexT.
That's the purpose of the pot's in the circuit, as described in the
note
on
it. Look here:
http://www.national.com/pf/LM/LM3914.html
for a more detailed description on how to use this IC ("Application
Hints"
section is useful).
Ken
Where do I put a Zero adjust pot in that circuit ?
How do I amend it to run off a MAP sensor instead of a Lambda sensor ?
Is there anyone that I can chat to who can design these things ?
"Ken Taylor" <ken@home.nz> wrote in message
news:WVGJd.11748$mo2.900303@news.xtra.co.nz...
Well, you can get twin pot's which are independently variable, if that's
what you need. The fact that the schematic description says 'trimpot' and
you want to use pot's doesn't change the fact that they are both variable
resistors - they'll do the same job, just the pot's being larger (and
more
unstable, AOTBE). Try it out, you may be pleasantly surprised.
Cheers.
Ken
"RexT" <r.turner@bigpond.net.au> wrote in message
news:kcCJd.134575$K7.71087@news-server.bigpond.net.au...
Thanks Ken,
Have read the spec sheet but with my limited experience I have trouble
joining the dots.
If the only way of zero adjust and span is to use the multiple trim
pots
then my original idea is out of the window.
I am building two of these to tune a twin cylinder motor and was going
to
use a ganged pot to control zero and another for span.
This would give me the ability to tweak the displays on the bike (as it
is
also destined to tune other machines for friends)
I was going to include a left/right switch to prove that both sides are
equal.
I normally use a mercury in glass pair of manometers on my own bike,
but
it
is not portable and friends tend to want their machines tuned at their
own
locations (then I get to drink their tea/coffee).
I was hoping that someone would come up with a mod for the circuit -
just
pop a ..... in next to part A and that would give me the external
adjustment
I need.
Thanks for your reply - it was a big ask to hope for someone to jump
in
and
do some design work for me.
Best regards,
RexT.
"Ken Taylor" <ken123@xtra.co.nz> wrote in message
news:35nho2F4papevU1@individual.net...
"RexT" <r.turner@bigpond.net.au> wrote in message
news:2KtJd.134237$K7.131837@news-server.bigpond.net.au...
I am trying to make a 30 led bargraph to display the output from a
MAP
sensor.
Found this circuit -
http://cp_www.tripod.com/rotary/pg27.htm#30ledaf
My question is - How do I incorporate pots to adjust zero and full
scale
?
Any help gratefully received.
RexT.
That's the purpose of the pot's in the circuit, as described in the
note
on
it. Look here:
http://www.national.com/pf/LM/LM3914.html
for a more detailed description on how to use this IC ("Application
Hints"
section is useful).
Ken
You need to give a little more information.
Like, what is the expected output voltage range from the MAP sensor for
the
range of pressures expected.
Then using the design information in the LM3914 data sheet you can set up
the required reference and offset voltages with (trim)pots and resistors.
Richard.
"RexT" <r.turner@bigpond.net.au> wrote in message
news:0_PJd.135613$K7.70981@news-server.bigpond.net.au...
Where do I put a Zero adjust pot in that circuit ?
How do I amend it to run off a MAP sensor instead of a Lambda sensor ?
Is there anyone that I can chat to who can design these things ?
"Ken Taylor" <ken@home.nz> wrote in message
news:WVGJd.11748$mo2.900303@news.xtra.co.nz...
Well, you can get twin pot's which are independently variable, if
that's
what you need. The fact that the schematic description says 'trimpot'
and
you want to use pot's doesn't change the fact that they are both
variable
resistors - they'll do the same job, just the pot's being larger (and
more
unstable, AOTBE). Try it out, you may be pleasantly surprised.
Cheers.
Ken
"RexT" <r.turner@bigpond.net.au> wrote in message
news:kcCJd.134575$K7.71087@news-server.bigpond.net.au...
Thanks Ken,
Have read the spec sheet but with my limited experience I have
trouble
joining the dots.
If the only way of zero adjust and span is to use the multiple trim
pots
then my original idea is out of the window.
I am building two of these to tune a twin cylinder motor and was
going
to
use a ganged pot to control zero and another for span.
This would give me the ability to tweak the displays on the bike (as
it
is
also destined to tune other machines for friends)
I was going to include a left/right switch to prove that both sides
are
equal.
I normally use a mercury in glass pair of manometers on my own bike,
but
it
is not portable and friends tend to want their machines tuned at
their
own
locations (then I get to drink their tea/coffee).
I was hoping that someone would come up with a mod for the circuit -
just
pop a ..... in next to part A and that would give me the external
adjustment
I need.
Thanks for your reply - it was a big ask to hope for someone to jump
in
and
do some design work for me.
Best regards,
RexT.
"Ken Taylor" <ken123@xtra.co.nz> wrote in message
news:35nho2F4papevU1@individual.net...
"RexT" <r.turner@bigpond.net.au> wrote in message
news:2KtJd.134237$K7.131837@news-server.bigpond.net.au...
I am trying to make a 30 led bargraph to display the output from
a
MAP
sensor.
Found this circuit -
http://cp_www.tripod.com/rotary/pg27.htm#30ledaf
My question is - How do I incorporate pots to adjust zero and
full
scale
?
Any help gratefully received.
RexT.
That's the purpose of the pot's in the circuit, as described in the
note
on
it. Look here:
http://www.national.com/pf/LM/LM3914.html
for a more detailed description on how to use this IC ("Application
Hints"
section is useful).
Ken