DC Voltage level sensing

[Jan Panteltje]

PS 2
When I drove my LPG car the solenoid that opened the tank were controlled by the
drive to the ignition coil.
As long as there were pulses there, the liquid gas could flow.
A much better way, engine stopped -> camera off.

Simple circuit too, only needs one transistor and a relay

 

[Cursitor Doom]

On Mon, 11 Nov 2019 05:50:36 +0000, Jasen Betts wrote:

Otherwise It's easier to tap into the accessory or ignition circuit
behind the dash, and not bother with sensing anything...

I wish. Not with modern cars. Trying to get behind the dash is a
nightmare and could even be seriously injurious if the airbags behind it
get accidentally triggered in the process!




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[Cursitor Doom]

On Mon, 11 Nov 2019 05:55:46 +0000, Jasen Betts wrote:

On 2019-11-10, Winfield Hill <winfieldhill@yahoo.com> wrote:
whit3rd wrote...

Maybe the 12V after the 'acc' switch would be better?

How easy is it to access that node?

It's typically in the steering column, and in the fuse panel, also at
the back of the radio etc... the wiring diagram for the automoibile in
question will have all the answers.

It was so much simpler in the 'old days' when you had access to the
rotary switch behind the ignition lock. Unfortunately, the vehicle in
question is one of these 'keyless ignition' types that neatly removes
that option. And they label all these unnecessary and undesirable changes
as "advances"!



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[Cursitor Doom]

On Mon, 11 Nov 2019 05:43:57 +0000, Jasen Betts wrote:

TL341 seems rated for automotive use.

http://www.ti.com/lit/ds/symlink/tl431.pdf

This is what Win suggested earlier and since these are simple to
configure and cheap as chips, I intend to go down that route for the sake
of expediency. The cig lighter sockets on this car are 'always on' so to
speak so there's another good reason.



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[Winfield Hill]

Cursitor Doom wrote...

On Mon, 11 Nov 2019, Jasen Betts wrote:

TL341 seems rated for automotive use.

http://www.ti.com/lit/ds/symlink/tl431.pdf

This is what Win suggested earlier and since these are
simple to configure and cheap as chips, I intend to go
down that route for the sake of expediency. The cig
lighter sockets on this car are 'always on' ...

Jasen Betts also wrote...

http://www.ti.com/lit/ds/symlink/tl431.pdf figure 25

No, sorry, not Figure 25. Although this is a perfect
application for a TL431, none of the figures in any of
the datasheets show it. Here's the circuit I had in
mind, time for an ASCII drawing:

.. turn-on output, if Vin > Vp
..
.. --+--- S D ---- switched Vout
.. | G p-channel
.. | | MOSFET
.. +- R3 -+ pass voltage Vp:
.. | | Vp = 2.5 (1 + R2/R1)
.. R2 | R1 = 2.49k
.. | K R2 = R1 ( Vp/2.5 - 1 )
.. +-- REF e.g. R2 = 11.0k for 13.5V
.. | A TL431
.. R1 | R3 = 3.3k pullup
.. | gnd
.. gnd R2 could include a trimpot


--
Thanks,
- Win

 

[Winfield Hill]

Rick C wrote...
>

Yep, you had the temerity to criticize P.A.,
and as predicted, that set him off on a rant.
Haha, now he'll probably go after me as well.
But unlike P.A., at least I posted a useful
circuit, with formula, for my suggestion.


--
Thanks,
- Win

 

[Cursitor Doom]

On Mon, 11 Nov 2019 06:00:03 -0800, Winfield Hill wrote:

No, sorry, not Figure 25. Although this is a perfect application for a
TL431, none of the figures in any of the datasheets show it. Here's
the circuit I had in mind, time for an ASCII drawing:

. turn-on output, if Vin > Vp .
. --+--- S D ---- switched Vout . | G p-channel . | |
MOSFET . +- R3 -+ pass voltage Vp:
. | | Vp = 2.5 (1 + R2/R1)
. R2 | R1 = 2.49k . | K R2 = R1 (
Vp/2.5 - 1 )
. +-- REF e.g. R2 = 11.0k for 13.5V . | A TL431 . R1
| R3 = 3.3k pullup . | gnd . gnd R2 could
include a trimpot

Win, did you create this in plain text, because for the life of me I
cannot get it to render correctly this end, not even when trying 3
different text editors and different fonts. Just wondering if you
accidentally got some formatting in there or something?



--
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protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.

 

[Winfield Hill]

Cursitor Doom wrote...

On Mon, 11 Nov 2019 06:00:03 -0800, Winfield Hill wrote:

No, sorry, not Figure 25. Although this is a perfect
application for a TL431, none of the figures in any of
the datasheets show it. Here's the circuit I had in
mind, time for an ASCII drawing: [reposted below]

#
# turn-on output, if Vin > Vp
#
# --+--- S D ---- switched Vout
# | G p-channel
# | | MOSFET
# +- R3 -+ pass voltage Vp:
# | | Vp = 2.5 (1 + R2/R1)
# R2 | R1 = 2.49k
# | K R2 = R1 ( Vp/2.5 - 1 )
# +-- REF e.g. R2 = 11.0k for 13.5V
# | A TL431
# R1 | R3 = 3.3k pullup
# | gnd
# gnd R2 could include a trimpot
#

Win, did you create this in plain text, because for
the life of me I cannot get it to render correctly
this end, not even when trying 3 different text
editors and different fonts. Just wondering if you
accidentally got some formatting in there or something?

It's simple mono-spaced, fixed-pitch, non-proportional
ASCII text, which is the original standard for usenet.
I can see it fine with NewsGuy on both of my computers.
Hopefully your newsreader doesn't munge the text, by
removing lines, symbols, spaces, periods, etc. If it
behaves, you can copy and paste it into notepad, or
some other editor. If I paste it into Word, I have to
then select the text, and change the font to courier.

Google Groups displays with a proportional font. I
brought this post up in Google Groups, then copied and
pasted into notepad, and it came out fine. Try that.


--
Thanks,
- Win

 

[Winfield Hill]

Winfield Hill wrote...

Cursitor Doom wrote...

On Mon, 11 Nov 2019 06:00:03 -0800, Winfield Hill wrote:

No, sorry, not Figure 25. Although this is a perfect
application for a TL431, none of the figures in any of
the datasheets show it. Here's the circuit I had in
mind, time for an ASCII drawing: [reposted below]

#
# turn-on output, if Vin > Vp
#
# --+--- S D ---- switched Vout
# | G p-channel
# | | MOSFET
# +- R3 -+ pass voltage Vp:
# | | Vp = 2.5 (1 + R2/R1)
# R2 | R1 = 2.49k
# | K R2 = R1 ( Vp/2.5 - 1 )
# +-- REF e.g. R2 = 11.0k for 13.5V
# | A TL431
# R1 | R3 = 3.3k pullup
# | gnd
# gnd R2 could include a trimpot
#

Jan suggested a filter, add a cap across R1. And he
suggested hysteresis, add resistor R4 from the R1 R2
REF node to switched Vout, R4 = 1.0M for 0.2 volts.


--
Thanks,
- Win

 

[Cursitor Doom]

On Mon, 11 Nov 2019 10:24:01 -0800, Winfield Hill wrote:

Jan suggested a filter, add a cap across R1. And he suggested
hysteresis, add resistor R4 from the R1 R2 REF node to switched Vout,
R4 = 1.0M for 0.2 volts.

Thanks, Win (and Jan) I'll do that. For the P-MOSFET, I've got dozens of
IRF5305 devices I bought from Farnell years ago. They're hexfets and way
OTT for this application, but I plan to use one just to get some more
value out of the original purchase!

I've managed to manually re-edit your schematic it's fine now; many
thanks indeed as ever.



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This message may be freely reproduced without limit or charge only via
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protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.

 

[Winfield Hill]

Cursitor Doom wrote...

On Mon, 11 Nov 2019 10:24:01 -0800, Winfield Hill wrote:

Jan suggested a filter, add a cap across R1. And he suggested
hysteresis, add resistor R4 from the R1 R2 REF node to switched Vout,
R4 = 1.0M for 0.2 volts.

Thanks, Win (and Jan) I'll do that. For the P-MOSFET, I've got
dozens of IRF5305 devices I bought from Farnell years ago.
They're hexfets and way OTT for this application, but I plan to
use one just to get some more value out of the original purchase!

Those are very nice parts.


--
Thanks,
- Win

 

[Steve Wilson]

Winfield Hill <winfieldhill@yahoo.com> wrote:

Cursitor Doom wrote...

On Mon, 11 Nov 2019 06:00:03 -0800, Winfield Hill wrote:

No, sorry, not Figure 25. Although this is a perfect
application for a TL431, none of the figures in any of
the datasheets show it. Here's the circuit I had in mind, time for
an ASCII drawing: [reposted below]

#
# turn-on output, if Vin > Vp
#
# --+--- S D ---- switched Vout
# | G p-channel
# | | MOSFET
# +- R3 -+ pass voltage Vp:
# | | Vp = 2.5 (1 + R2/R1)
# R2 | R1 = 2.49k
# | K R2 = R1 ( Vp/2.5 - 1 )
# +-- REF e.g. R2 = 11.0k for 13.5V
# | A TL431
# R1 | R3 = 3.3k pullup
# | gnd
# gnd R2 could include a trimpot
#

Win, did you create this in plain text, because for
the life of me I cannot get it to render correctly
this end, not even when trying 3 different text
editors and different fonts. Just wondering if you accidentally got
some formatting in there or something?

It's simple mono-spaced, fixed-pitch, non-proportional
ASCII text, which is the original standard for usenet.
I can see it fine with NewsGuy on both of my computers.
Hopefully your newsreader doesn't munge the text, by
removing lines, symbols, spaces, periods, etc. If it
behaves, you can copy and paste it into notepad, or
some other editor. If I paste it into Word, I have to
then select the text, and change the font to courier.

Google Groups displays with a proportional font. I
brought this post up in Google Groups, then copied and
pasted into notepad, and it came out fine. Try that.

Post it in LTspice. There will be no problems with pasting fonts back and
forth, and we can see it run.

You cannot run an ASCCI file.

 

[Chris]

On Mon, 11 Nov 2019 19:34:35 +0000, Steve Wilson wrote:

Winfield Hill <winfieldhill@yahoo.com> wrote:

Google Groups displays with a proportional font. I brought this post
up in Google Groups, then copied and pasted into notepad, and it came
out fine. Try that.

Post it in LTspice. There will be no problems with pasting fonts back
and forth, and we can see it run.

You cannot run an ASCCI file.

Yeah, come on Win, throw us plebs a bone here. What will it cost you? 5
minutes of your time?

 

[Phil Allison]

Winfield Hill is a Cunt wrote:

----------------------------------

Yep, you had the temerity to criticize P.A.,

** What bullshit.

I copped mindless abuse from a TROLLING IDIOT


> and as predicted, that set him off on a rant.

** Find it - you lying asshole.

But unlike P.A., at least I posted a useful
circuit,

** Doubt that.

The OP can ask me to detail the idea, anytime.

I always reply, unlike slimy cunts like you.




.... Phil

 

[George Herold]

On Monday, November 11, 2019 at 5:26:34 PM UTC-5, Chris wrote:

On Mon, 11 Nov 2019 19:34:35 +0000, Steve Wilson wrote:

Winfield Hill <winfieldhill@yahoo.com> wrote:

Google Groups displays with a proportional font. I brought this post
up in Google Groups, then copied and pasted into notepad, and it came
out fine. Try that.

Post it in LTspice. There will be no problems with pasting fonts back
and forth, and we can see it run.

You cannot run an ASCCI file.

Yeah, come on Win, throw us plebs a bone here. What will it cost you? 5
minutes of your time?

Are you being funny? If you want to see an ascii circuit from
google groups go the the little triangle in the (URH) corner..
'other message actions', and select 'show original'.

George H.

 

On Sunday, 10 November 2019 22:44:34 UTC, Robert Baer wrote:

tabbypurr wrote:
On Sunday, 10 November 2019 18:51:50 UTC, Cursitor Doom wrote:
Greetings, Gentlemen,

What's the simplest way of implementing this:

The 'quiescent voltage' (so to speak) of a car battery is typically
12.4V. With the engine running, however, this rises to 14V due to the
charging current from the alternator. How most reliably to sense when the
battery voltage exceeds 13V so a dashcam can be activated?

comparator. Manually adjusted relays were once used but electronics be more reliable, assuming it's designed to handle car electric nasties. You could also use the charging light.


NT

"Electronics be more reliable"?
In a rather hot, almost still air environment?
When cars are expected to run reliably in a desert?
Give me a break.

yes, that's precisely why car charge regulators changed from vibrating relay type to electronic.


NT

 

[Phil Allison]

Chris wrote:

-----------------------

George Herold wrote:

Are you being funny? If you want to see an ascii circuit from google
groups go the the little triangle in the (URH) corner..
'other message actions', and select 'show original'.

I just tried it. Are you being funny? Because *nothing* you describe is
visible. NONE of it.

** Same here, he must be seeing a different screen.

ASCII diagrams come up a jumbled mess.

JL has the right idea, post a sketch or file somewhere.


..... Phil

 

[Chris]

On Mon, 11 Nov 2019 15:24:07 -0800, George Herold wrote:

Are you being funny? If you want to see an ascii circuit from google
groups go the the little triangle in the (URH) corner..
'other message actions', and select 'show original'.

I just tried it. Are you being funny? Because *nothing* you describe is
visible. NONE of it.

 

[Winfield Hill]

George Herold wrote...

On Monday, November 11, 2019 at 5:26:34 PM UTC-5, Chris wrote:
On Mon, 11 Nov 2019 19:34:35 +0000, Steve Wilson wrote:

Winfield Hill <winfieldhill@yahoo.com> wrote:

Google Groups displays with a proportional font. I brought
this post up in Google Groups, then copied and pasted into
notepad, and it came out fine. Try that.

Post it in LTspice. There will be no problems with pasting
fonts back and forth, and we can see it run.

You cannot run an ASCCI file.

Yeah, come on Win, throw us plebs a bone here. What will it
cost you? 5 minutes of your time?

Are you being funny? If you want to see an ascii circuit
from google groups go the the little triangle in the (URH)
corner.. 'other message actions', and select 'show original'.

Hey, George, do me, and them, a favor and make an LTspice
schematic for them. I'm not a LTspice user, and I don't
know how to make one. I'm a serious user of Intusoft's
SPICE, with its superior schematic and graphing capability.
Whenever someone puts up an LTspice file, I have to copy
the relevant text part, and paste it into notepad, then
save it on my computer, but with an .asc extension, and
then go open it with LTspice, to see the drawing. Sheesh,
that's so much more work than simply looking at an ASCII
drawing. Whatever happened to all the dyed-in-the-wool
usenet denizens of old, and our beautiful ASCII schematic
drawings? I posted hundreds of them, back in the day.


--
Thanks,
- Win

 

[Winfield Hill]

Phil Allison wrote...

Winfield Hill is a Cunt wrote:
----------------------------------

Yep, P.A. is so predictable.


--
Thanks,
- Win