Real battery switch turning off Real gear lights

Help creating logic scripts for Air Manager Instruments

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Kaellis991
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Re: Real battery switch turning off Real gear lights

#21 Post by Kaellis991 »

jph wrote: Sun Sep 25, 2022 2:10 pm Oh goodie :) :mrgreen: ;)

It MUST be a P Channel... can you check what you have and give me the part number ?

Meanwhile I will draft a detailed schematic with my schematic editor....
This is what I have...I think this is NOT a P channel
image.png

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jph
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Re: Real battery switch turning off Real gear lights

#22 Post by jph »

That won't work.

Anyway, after loads of toil - here is the schematic (it MUST be P channel )- you can open it in your favourite schematic editor - it takes bugger all current to drive it. The arduino micro port is protect from 15V via the ULN darlington output.
p channel mosfet  uln.jpg
Joe. CISSP, MSc.

Kaellis991
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Re: Real battery switch turning off Real gear lights

#23 Post by Kaellis991 »

Is this what I would need?
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image.png

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jph
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Re: Real battery switch turning off Real gear lights

#24 Post by jph »

Yup ;)
That would be marvellous.

Have you built it yet ? ;)
Joe. CISSP, MSc.

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Re: Real battery switch turning off Real gear lights

#25 Post by jph »

Just a quick 2 points -
you are running the meanwell at 15 yes ?

also, take t as read that the ground on the meanwell is connected to the same ground as the ULN Darlington and the Arduino - which I know it already is, but I didn't show it on my amazing ultra modern schematic and it take hours to edit .........
Joe. CISSP, MSc.

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Re: Real battery switch turning off Real gear lights

#26 Post by jph »

Also, see if you can find a p channel mosfet with a lower Rds on value - that is a bit high...

Something <=20 mOhms (milli ohms) Rds on at around 10 to 13 V ..

Which is your preferred supplier, I will have a look
Joe. CISSP, MSc.

Kaellis991
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Re: Real battery switch turning off Real gear lights

#27 Post by Kaellis991 »

jph wrote: Sun Sep 25, 2022 2:19 pm That won't work.

Anyway, after loads of toil - here is the schematic (it MUST be P channel )- you can open it in your favourite schematic editor - it takes bugger all current to drive it. The arduino micro port is protect from 15V via the ULN darlington output.

p channel mosfet uln.jpg
Before I build it, can you elaborate on those last two sentences? I know we are both writing in english, "bugger all current" ? What does that mean in american english? The shorthand in that last sentence is confusing.
Also the ground symbol always confuses me. I have a wire connected to the meanwell -V terminal and it goes to a connector on my board which also goes to the arduino GND and to the darlington GND. That stays the same correct?

There are a couple of your hand written symbols I can't quite read / understand.

image.png

Kaellis991
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Re: Real battery switch turning off Real gear lights

#28 Post by Kaellis991 »

jph wrote: Sun Sep 25, 2022 2:34 pm Also, see if you can find a p channel mosfet with a lower Rds on value - that is a bit high...

Something <=20 mOhms (milli ohms) Rds on at around 10 to 13 V ..

Which is your preferred supplier, I will have a look
I will do that
I either use Mouser or Digikey....sometimes I can find what I need on Amazon.

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jph
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Re: Real battery switch turning off Real gear lights

#29 Post by jph »

https://www.digikey.com/en/products/det ... E3/2623132 will do the job. Much better Rds on.

Colloquial English 'bugger all current' means it wont draw any noticeable current from your arduino as it isn't a relay coil. It will draw a small amount for a fraction of a second when energised as the gate capacitance charges, but that's not an issue.

The G S and D on the diagram (the amazing diagram) are (G)ate (S)ource and (D)rain of the mosfet
Extremely important for when you wire it up.

As for GND, yes, correct on both. It stays as it is.

Joe
Joe. CISSP, MSc.

Kaellis991
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Re: Real battery switch turning off Real gear lights

#30 Post by Kaellis991 »

jph wrote: Sun Sep 25, 2022 3:05 pm https://www.digikey.com/en/products/det ... E3/2623132 will do the job. Much better Rds on.

Colloquial English 'bugger all current' means it wont draw any noticeable current from your arduino as it isn't a relay coil. It will draw a small amount for a fraction of a second when energised as the gate capacitance charges, but that's not an issue.

The G S and D on the diagram (the amazing diagram) are (G)ate (S)ource and (D)rain of the mosfet
Extremely important for when you wire it up.

As for GND, yes, correct on both. It stays as it is.

Joe
Joe,

MOSFET is ordered...I already have the resistor.
And yes...it is an amazing diagram and very educational.

I should have it built by the end of the week.
Thanks for the help.

Kirk

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