WWYD?

[Shagreobe]

What would you do? Im going to be using an arduino nano (clone) in a project that has a 12v wall wart input. I know the nano is supposed to be able to run off of up to 12v but Id rather use 5v, just to feel safe. Anyway, the ways I'm thinking are A. Voltage divider resistors, B. Buck converter, C. Zener diode, or D. Other suggestion. What y'all think? I'm leaning towards the Zener

 

[ronsimpson]

A. Resistor divider donot work well for power.
B. There are a number of small buck PWM boards. What current level?

TPSM84205​

C. Maybe. Do you care if most of the power is waisted?
D. There are others.

 

[tronitech]

A & C wouldn't work. A Buck convertor would but I'd go D and get a 5V wallwart, they don't cost much!

 

[Shagreobe]

Everything else runs on 12 volts (Led's, motors, etc) I just need the Nano powered up to turn on a couple of 5v relays once in awhile

 

[rjenkinsgb]

Everything else runs on 12 volts (Led's, motors, etc)

Use a miniature switching regulator.

The type of thing Ron posted in the second photo - there are a few variants of those; I've use the Recom R-78-E series ones, those are available for many places and are industrial grade parts.
eg.

Recom 80000046 R-78E5.0-0.5 DC/DC Converter 7-28V In 5V Out

Recom - R-78E5.0-0.5 - Recom 80000046 R-78E5.0-0.5 DC/DC Converter 7-28V In 5V Out - <P>The <STRONG>Recom Power R-78E5.0-0.5 Switching Regulator Module

www.rapidonline.com

https://www.mouser.co.uk/ProductDetail/RECOM-Power/R-78E5.0-0.5?qs=JeAkOuORR2UvBuiB2kZVZQ%3D%3D

 

[Nigel Goodwin]

What would you do? Im going to be using an arduino nano (clone) in a project that has a 12v wall wart input. I know the nano is supposed to be able to run off of up to 12v but Id rather use 5v, just to feel safe. Anyway, the ways I'm thinking are A. Voltage divider resistors, B. Buck converter, C. Zener diode, or D. Other suggestion. What y'all think? I'm leaning towards the Zener

No disrespect, but you obviously have no clue what you're doing

A. Resistive divider - 100% completely useless.

B. Buck converter - best solution, and dirt cheap using a Chinese module.

C. Zener diode - very poor, on all counts, and incredibly inefficient.

D. Standard analogue regulator, like an LM7805 - efficiency fairly poor - and cost higher than a Chinese buck converter.

 

[eTech]

The wallwart supplied by arduino provides a 12 VDC output.
The arduino has internal circuitry the regulates the supply voltage down to 5V.
It can safely operate using a 12v supply if the supply is connected via the arduino supply barrel jack.
There is no need to use a buck, divider,...etc, etc..

 

[Shagreobe]

Nigel... I have a small clue on electronics, but ask me anything about airplanes or heating and air conditioning and I got you covered

eTech... It is a cheap chinese knockoff nano, and, quite honestly, I dont want to blow up the board I spent a whole dollar fol LOL I know They are supposed to take 12v but...

 

[Nigel Goodwin]

Nigel... I have a small clue on electronics, but ask me anything about airplanes or heating and air conditioning and I got you covered

eTech... It is a cheap chinese knockoff nano, and, quite honestly, I dont want to blow up the board I spent a whole dollar fol LOL I know They are supposed to take 12v but...

But - all but one of your suggestions are far worse than the on-board regulator - the Nano doesn't 'take' 12V, it has a 5V regulator on-board which converts the incoming voltage down to 5V.

 

[schmitt trigger]

I would also suggest the buck regulator mentioned previously.
The shortcoming I have seen with these modules is very poor filtering. Add to its output a SMPS-rated 1000 uF electrolytic, paralleled with at least 10uF ceramic.

 

[eTech]

eTech... It is a cheap chinese knockoff nano, and, quite honestly, I dont want to blow up the board I spent a whole dollar fol LOL I know They are supposed to take 12v but...

you are worried about a "non-existent" problem.

 

[Pommie]

If still worried then use a buck converter to step down to 7V(or 9 or even 12) and feed this into the Vin pin of the Nano.

Mike.

 

[ZipZapOuch]

Nigel... I have a small clue on electronics, but ask me anything about airplanes or heating and air conditioning and I got you covered

eTech... It is a cheap chinese knockoff nano, and, quite honestly, I dont want to blow up the board I spent a whole dollar fol LOL I know They are supposed to take 12v but...

You are posting about your fears that voltage regulator on a Chinese-made arduino nano-like board using (quite probably) a Chinese made iPhone, Android phone or tablet. Most of the chips onboard of those devices run at 3.3v or 1.8v even though they charge on USB-C up to 18v when "fast charging".

So, I assume, since your phone is much more important to you than an Arduino nano clone, you have somehow addressed the voltage regulators in your Chinese-made phone already. I would recommend that you use the same methods to improve your Arduino that you used on your phone.

 

[eTech]

you are worried about a "non-existent" problem.

eTech... It is a cheap chinese knockoff nano, and, quite honestly, I dont want to blow up the board I spent a whole dollar fol LOL I know They are supposed to take 12v but...

Just to clarify, my statement above refers to the supply voltage. If, however, you mean using the arduino inputs at 12v, don't do that. Instead use a voltage divider, or opto, etc., at each input to reduce the 12v signal to a safe level (5v).

 

[For The Popcorn]

As I recall, some Arduinos will tolerate +12 to the barrel jack, but a lower voltage is recommended.

Remember, with all linear regulators, excess voltage is converted to heat.

Pd = (Vin – Vout) × i

Vin must account for the overhead of the regulator, but if the current draw is large, a high delta-V may cause issues

 

[Shagreobe]

You are posting about your fears that voltage regulator on a Chinese-made arduino nano-like board using (quite probably) a Chinese made iPhone, Android phone or tablet. Most of the chips onboard of those devices run at 3.3v or 1.8v even though they charge on USB-C up to 18v when "fast charging".

So, I assume, since your phone is much more important to you than an Arduino nano clone, you have somehow addressed the voltage regulators in your Chinese-made phone already. I would recommend that you use the same methods to improve your Arduino that you used on your phone.

Nah, actually I use my laptop, which is a Dell (american) not sayin it aint got no chinese parts of course, everything does nowadays. My phone (android, wont pay for a name) is for calling and texting

 

[Shagreobe]

Basically, on some arduino forum I have seen something about 12v being the absolute most you want to run an arduino on. I really dont to risk anything. Not to mention, I already have a ton of 5v parts left over from a job at work the boss left me have

 

[Tony Stewart]

Verify your initial post.
The Nano has no DC jack for 7 to 12V and is powered by 5V on USB unlike the UNO which does.

 

[Pommie]

Verify your initial post.
The Nano has no DC jack for 7 to 12V and is powered by 5V on USB unlike the UNO which does.

True, the Nano doesn't have a DC jack. The top post doesn't mention one just some posters replying. It does have a Vin pin which supplies the onboard voltage regulator (LM1117 type I believe which can tolerate up to 15V in). As the OP is only powering a couple of relays I don't think the power consumption will be much and the regulator should (hopefully) run cool.

OP, do you have details of the relays?

Mike.

 

[ZipZapOuch]

OP, do you have details of the relays?

And if you're using a MOSFET or even a BJT to drive the relay coils, much less total current draw from the Arduino clone.