Re: Using a LED for 12V Tractor
Dave Plowman (News)
<lett...@invalid.com> wrote:
> To use the least amount of power
> and eliminate having to replace bulbs, I want a LED indicator. I was
> looking on the Radio Shack website and this looks like what I want.
> http://tinyurl.com/5al49d
> My question is this:
> I know a LED requires a resistor. It says this is rated at 12V, but
> then it says it contains a LED (does not mention a resistor). I was
> hoping for a complete unit with the resistor built in, but it appears
> they do not sell them. I can add a resistor, but what size (ohms) do
> I need?
I'm pretty sure the one shown does indeed contain a resistor suitable for
working from 12 volts. There'd be no point in mentioning 12 volts
otherwise - since LEDs aren't voltage driven like ordinary bulbs. In other
words you can use any LED with near any DC voltage by using the correct
resistor to set the current flowing through it.
To answer your question about choosing the correct resistor, you really
need to know the parameters of the particular LED as they are not all the
same. These are normally given in the data for the device.
This site calculates the value for it after you enter those parameters.
http://led.linear1.org/1led.wiz
So saying for most non critical applications and most common indicator
LEDs 1000 ohms (1k) will do well enough for a 12 volt car supply.
I'd be inclined to get a flashing one for your purpose. The flashing
electronics are built in to the LED which can be connected to 12 volts
directly.
--
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Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.
William Sommerwerck
wouldn't work. Of course, a lead-acid battery can hit 13.2 volts, but that
shouldn't be a problem.
Dave Plowman (News)
On charge the voltage can be even higher. About 14.4v or so - depending on
the type of charging system. But if a LED indicator lamp is said to be 12
volts they almost certainly anticipate car type use.
--
*Honk if you love peace and quiet.
Bryce
> I have a farm tractor with a 12Volt battery (like in a car). I
> regularly forget to turn off the power switch when the tractor runs
> out of gas, or powers down under load. It only takes a few hours and
> the battery is dead. I've decided that I need a power indicator light
> to remind me that the switch is on. To use the least amount of power
> and eliminate having to replace bulbs, I want a LED indicator. I was
> looking on the Radio Shack website and this looks like what I want.
> http://tinyurl.com/5al49d
>
> My question is this:
> I know a LED requires a resistor. It says this is rated at 12V, but
> then it says it contains a LED (does not mention a resistor). I was
> hoping for a complete unit with the resistor built in, but it appears
> they do not sell them. I can add a resistor, but what size (ohms) do
> I need?
>
> Thanks
>
> LM
I don't have a tractor, but my car has an indicator that lights up when
the ignition is on and the alternator is not charging. Seems like that
would be a good solution for your need. I'm surprised a tractor doesn't
have that already, but it would be easy to add your LED across the
alternator blocking diode.
Bryce
Michael A. Terrell
lett...@invalid.com wrote:
>
> I have a farm tractor with a 12Volt battery (like in a car). I
> regularly forget to turn off the power switch when the tractor runs
> out of gas, or powers down under load. It only takes a few hours and
> the battery is dead. I've decided that I need a power indicator light
> to remind me that the switch is on. To use the least amount of power
> and eliminate having to replace bulbs, I want a LED indicator. I was
> looking on the Radio Shack website and this looks like what I want.
> http://tinyurl.com/5al49d
>
> My question is this:
> I know a LED requires a resistor. It says this is rated at 12V, but
> then it says it contains a LED (does not mention a resistor). I was
> hoping for a complete unit with the resistor built in, but it appears
> they do not sell them. I can add a resistor, but what size (ohms) do
> I need?
I would use a 12 VDC Sonalert, or generic Piezo sounder with a diode
in series. Connect it between he headlight circuit, and the inanition
switch so that it makes noise when you shut off the ignition, and still
have the light on. They sell these for cars. Here ids the first hit
from a Google search, and they are available at most care parts places.
<http://www.carparts.com/LIGHTS-ON-ALARM/GP_2001371_N_111+10718+600021987_10618.car>
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1PW
> lett...@invalid.com wrote:
>> I have a farm tractor with a 12Volt battery (like in a car). I
>> regularly forget to turn off the power switch when the tractor runs
>> out of gas, or powers down under load. It only takes a few hours and
>> the battery is dead. I've decided that I need a power indicator light
>> to remind me that the switch is on. To use the least amount of power
>> and eliminate having to replace bulbs, I want a LED indicator. I was
>> looking on the Radio Shack website and this looks like what I want.
>> http://tinyurl.com/5al49d
>>
>> My question is this:
>> I know a LED requires a resistor. It says this is rated at 12V, but
>> then it says it contains a LED (does not mention a resistor). I was
>> hoping for a complete unit with the resistor built in, but it appears
>> they do not sell them. I can add a resistor, but what size (ohms) do
>> I need?
>
>
> I would use a 12 VDC Sonalert, or generic Piezo sounder with a diode
> switch so that it makes noise when you shut off the ignition, and still
> have the light on. They sell these for cars. Here ids the first hit
> from a Google search, and they are available at most care parts places.
>
> <http://www.carparts.com/LIGHTS-ON-ALARM/GP_2001371_N_111+10718+600021987_10618.car>
>
>
Hello to All:
I believe everyone has given good information to the OP.
I believe Michael's idea is the closest to ideal. A variant I have
used, for decades, uses the same Sonalert/diode arrangement. However,
while I did connect the positive Sonalert/diode side to the ignition
circuit, I connect the negative side to oil pressure sensor switch.
An additional diode (1N400X) can also be connected between the
headlights and the positive side of the Sonalert/diode unit to provide
dual protection. Total cost; about $10.00USD. Total labor time; about
one hour. YMMV.
Best wishes to all.
--
1PW
@?6A62?FEH9:DE=6o2@=]4@> [r4o7t]
Dave Plowman (News)
Michael A. Terrell <mike.t...@earthlink.net> wrote:
> I would use a 12 VDC Sonalert, or generic Piezo sounder with a diode
> in series. Connect it between he headlight circuit, and the inanition
> switch so that it makes noise when you shut off the ignition, and still
> have the light on.
Have you actually read the question?
--
*Why is the man who invests all your money called a broker?
Michael A. Terrell
"Dave Plowman (News)" wrote:
>
> In article <-tednUhLfcF_-CDV...@earthlink.com>,
> Michael A. Terrell <mike.t...@earthlink.net> wrote:
> > I would use a 12 VDC Sonalert, or generic Piezo sounder with a diode
> > in series. Connect it between he headlight circuit, and the inanition
> > switch so that it makes noise when you shut off the ignition, and still
> > have the light on.
>
> Have you actually read the question?
Yes. did you? The solution I posted is used in cars for the same
reason. It is connected between to points that are at +12 VDC when the
engine is running, and the lights are on. if you shut off the engine,
the sounder goes off. they are used in cars, because you can miss a
small indicator when you are in a hurry, or have sunlight shining on
it. I built my first one over 30 years ago, and built several for
family & friends, until they were available over the counter. It draws
zero power when not giving an alarm, and less current than a bright LED.
Do whatever you want. At this point in my life, I'm not going to
argue.
jakdedert
> In article <-tednUhLfcF_-CDV...@earthlink.com>,
> Michael A. Terrell <mike.t...@earthlink.net> wrote:
>> I would use a 12 VDC Sonalert, or generic Piezo sounder with a diode
>> in series. Connect it between he headlight circuit, and the inanition
>> switch so that it makes noise when you shut off the ignition, and still
>> have the light on.
>
> Have you actually read the question?
>
alone or in conjunction with visible indication. Tractors get used in
full sunlight, where an LED would have to be pretty bright to attract
attention.
He may have missed that it was an ignition on/engine off situation--as
opposed to a *lights* on/ignition off issue--but the principle is the same.
jak
William Sommerwerck
By a most amazing coincidence, I was perusing an electronics catalog last
night, looking for items I could add to an order to two switches, when I
found the Sonalert page. When these were introduced around 45 years ago,
they cost from $5 to $9. Today they start at around $50. That's insane.
The lights-on alarm makes a lot more sense.
http://www.carparts.com/LIGHTS-ON-ALARM/GP_2001371_N_111+10718+600021987_10618.car
DaveM
news:osmdna_lzOWfQCDV...@comcast.com...
Hmmm.... Almost all of the Sonalerts at Mouser are $10 US or less; in fact,
most are under $5 US... http://tinyurl.com/6abr8x
You have to provide your own circuitry to make it sound when the ignition is on
but the engine not running, but it's not $50 worth.
--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)
Life is like a roll of toilet paper; the closer it gets to the end, the faster
it goes.
Dave Plowman (News)
Michael A. Terrell <mike.t...@earthlink.net> wrote:
> "Dave Plowman (News)" wrote:
> >
> > In article <-tednUhLfcF_-CDV...@earthlink.com>,
> > Michael A. Terrell <mike.t...@earthlink.net> wrote:
> > > I would use a 12 VDC Sonalert, or generic Piezo sounder with a
> > > diode in series. Connect it between he headlight circuit, and the
> > > inanition switch so that it makes noise when you shut off the
> > > ignition, and still have the light on.
> >
> > Have you actually read the question?
> Yes. did you? The solution I posted is used in cars for the same
> reason.
The OP obviously has little technical knowledge and you've said to connect
it between the headlamp circuit and ignition switch.
> It is connected between to points that are at +12 VDC when the
> engine is running, and the lights are on.
I know how a lights on alarm works.
> if you shut off the engine,
> the sounder goes off. they are used in cars, because you can miss a
> small indicator when you are in a hurry, or have sunlight shining on
> it.
A warning light for lights on wouldn't seem a good idea, would it?
> I built my first one over 30 years ago, and built several for
> family & friends, until they were available over the counter. It draws
> zero power when not giving an alarm, and less current than a bright LED.
> Do whatever you want. At this point in my life, I'm not going to
> argue.
But you could try reading the question...
--
*Experience is something you don't get until just after you need it *
Dave Plowman (News)
Principles are fine to those with a decent technical knowledge. But I
don't think the OP has. So concise instructions are needed in that sort of
case.
--
*I want it all and I want it delivered
William Sommerwerck
news:reCdnY9O_9a8fCDV...@comcast.com...
> "William Sommerwerck" <grizzle...@comcast.net> wrote in message
> news:osmdna_lzOWfQCDV...@comcast.com...
>>> I would use a 12 VDC Sonalert...
>> By a most amazing coincidence, I was perusing an electronics catalog last
>> night, looking for items I could add to an order to two switches, when I
>> found the Sonalert page. When these were introduced around 45 years ago,
>> they cost from $5 to $9. Today they start at around $50. That's insane.
>> The lights-on alarm makes a lot more sense.
>>
http://www.carparts.com/LIGHTS-ON-ALARM/GP_2001371_N_111+10718+600021987_10618.car
> Hmmm.... Almost all of the Sonalerts at Mouser are $10 US or less;
> in fact, most are under $5 US... http://tinyurl.com/6abr8x
We're both right. The Sonalerts at Mouser are all board-mount. But the
original panel-mount types are still made, and they are very expensive.
Michael A. Terrell
"Dave Plowman (News)" wrote:
>
> In article <-cydnU4XL8meDyDV...@earthlink.com>,
> Michael A. Terrell <mike.t...@earthlink.net> wrote:
>
> > "Dave Plowman (News)" wrote:
> > >
> > > In article <-tednUhLfcF_-CDV...@earthlink.com>,
> > > Michael A. Terrell <mike.t...@earthlink.net> wrote:
> > > > I would use a 12 VDC Sonalert, or generic Piezo sounder with a
> > > > diode in series. Connect it between he headlight circuit, and the
> > > > inanition switch so that it makes noise when you shut off the
> > > > ignition, and still have the light on.
> > >
> > > Have you actually read the question?
>
> > Yes. did you? The solution I posted is used in cars for the same
> > reason.
>
> The OP obviously has little technical knowledge and you've said to connect
> it between the headlamp circuit and ignition switch.
Because that is the accepted way to do it in the US. The two
switched sources provide the needed logic for free, even if you can't
see it. It works the way the OP asked, and will do what he wants without
spending a lot of money, or having reliability problems. After reading
a lot of your messages over the years it appears you are more interested
in pushing your way, and to hell with everyone else.
Wired the way I stated, you have +12 VDC on point 'A' when the
headlamp(s) are on. If the ignition switch is on, you also have +12 VDC
on point 'B' and no current will flow. Shut the ignition switch off, and
the voltage drops to zero, applying power to the enunciator. I'm sorry
that you either can't, or won't see this. Because of this, I would never
try to explain anything complex to you. You would be completely lost on
the equipment I last worked on, with over 20 processors, multiple signal
paths and interface systems you can't grasp. Or any of the TV stations I
built or maintained. Apparently attacking a problem with logic has been
supplanted with making wild assed guesses and accusations.
> > It is connected between to points that are at +12 VDC when the
> > engine is running, and the lights are on.
>
> I know how a lights on alarm works.
>
> > if you shut off the engine,
> > the sounder goes off. they are used in cars, because you can miss a
> > small indicator when you are in a hurry, or have sunlight shining on
> > it.
>
> A warning light for lights on wouldn't seem a good idea, would it?
Yawn. Re-read the thread. Where did I say to use a warning light?
take your time this time, because you've misread it every time,. so far.
>
> > I built my first one over 30 years ago, and built several for
> > family & friends, until they were available over the counter. It draws
> > zero power when not giving an alarm, and less current than a bright LED.
>
> > Do whatever you want. At this point in my life, I'm not going to
> > argue.
>
> But you could try reading the question...
Yawn. Idiot. This group is going to pot because of lousy attitudes
like yours. If the OP doesn't understand a suggestion they can ask for
clarification. your race to the bottom doesn't do anyone any good, and
continues to make things worse. In case you haven't noticed, most of
the good techs have left the group, rather than put up with the dropping
IQs and sloppy service attitudes.
The question should have been asked in news:sci.electronics.basics
instead of here, then they are hit with attitude rather than help.
greenpjs
<mike.t...@earthlink.net> wrote:
You have the perfect solution for the WRONG problem. The OP is
concerned about leaving the ignition switch on after the tractor runs
out of gas or stalls. He never mentioned headlights at all.
Dave Plowman (News)
greenpjs <gree...@neo.rr.com> wrote:
> You have the perfect solution for the WRONG problem. The OP is
> concerned about leaving the ignition switch on after the tractor runs
> out of gas or stalls. He never mentioned headlights at all.
Indeed.
--
*All men are idiots, and I married their King.
Michael A. Terrell
All the farm tractors I've seen (That were built after WW-I) have
headlights, and are on when the tractor is in use, for safety reasons.
Now, tell everyone how a LED and resistor connected to the ignition
switch will help if they don't notice the key is on, or aren't close
enough to hear it run out of fuel. Someone else mentioned the oil
pressure, but some tractors use a pressure gauge, instead of a switch.
The only fool proof method would be a contactor that is controlled by
sensing the lack of the voltage to the coil being pulsed. That would
require a detector, amplifier and coil driver, plus a contactor or relay
to open the power to everything except the starter switch and solenoid.
You would have to hold down a switch, or use a timer to let you start
it, adding more circuitry to fail on the tractor.
I am waiting for any USEFUL answer.
cuh...@webtv.net
Brian's Military Jeeps, on the web.
cuhulin
Dave M
wrote:
>In article <in7tb4pl4hplqcsf2...@4ax.com>,
> greenpjs <gree...@neo.rr.com> wrote:
>> You have the perfect solution for the WRONG problem. The OP is
>> concerned about leaving the ignition switch on after the tractor runs
>> out of gas or stalls. He never mentioned headlights at all.
>
>Indeed.
Back to the Sonalert issue that came up on this thread a few days ago. I was
browsing the BG Micro web site just now and came across a couple of the panel
mount Sonalerts for less than $3.00 US each. Both will operate on 12 volts; one
emits a continuous tone, the other pulsates.
http://www.bgmicro.com/index.asp?PageAction=VIEWPROD&ProdID=9098
and
http://www.bgmicro.com/index.asp?PageAction=VIEWPROD&ProdID=9097
--
Dave M
Never take a laxative and a sleeping pill at the same time!!
