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Topic: Variable 12 voltage remotely (Read 3717 times) previous topic - next topic

GeronimoDK

Now in terms of building something to do a simple task like this, that makes no sense at all.  The smallest practical unit to implement a microprocessor control for something is an Arduino Pro Mini.  It has all the necessary support parts on it, directly wired for programming with a cheaply available USB to serial adaptor.

Yes, there are also some other modules using the ATtiny and such, but frankly, no cheaper than a Pro Mini from China.  However, trying to assemble the parts yourself from scratch - a futile exercise.  :smiley-eek:
I totally agree with you, Arduino or something similar is the way to go for a one-off project, proof of concept or whatever this is... Not that a bare chip is not doable, but it's just a lot more work initially, especially if you don't have the tools or knowledge!

But OP did also ask what options he had if he didn't want to use an Arduino! I guess we're back at the XY-problem ;)

TonyStarkC10

I wire up this diagram on the breadboard and for increasing and decreasing it works good but I face two issues, the first one is the circuit drop a lot of voltage and L293D gets too hot (but not hand burning) and then another one is the fan noise in the low speed caused of PWM.

https://circuitdigest.com/microcontroller-projects/dc-motor-control-with-arduino-uno-pwm

wvmarle

Why are you using an H-bridge to control a fan - which normally runs in only one direction - in the first place? A single MOSFET switch is much more efficient and all you need.

And the L293D is an old BJT based H-bridge, and as you can see in the data sheet as well drops some 2V by itself. That's also where the heat comes from. There are much better options out there.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

TonyStarkC10

I try to use IRF530N and connect it to pin 3 of Arduino but after that, it just gives me about 3.75V on output and then I try to increase it but it was so slow and just go up about 4V.

wvmarle

That's because that's not a logic level MOSFET. See data sheet... it won't open properly at 5V VGS.

Try e.g. the IRL530 (or another IRLxxx) instead. The L stands for "logic level". Those will open properly with 5V signals. Look for a value for RDS, ON for VGS = 4.5V. If that's not given in the specifications, it's not suitable for use with 5V Arduinos.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

Paul__B

I try to use IRF530N and connect it to pin 3 of Arduino but after that, it just gives me about 3.75V on output and then I try to increase it but it was so slow and just go up about 4V.
That does not make sense at all.  You need to illustrate how you have attempted to connect it.  I suspect a gross blunder.

Figure 2 in the datasheet (you did say an IRF530, didn't you?) suggest that drawing 2 Amps at a gate voltage of 4.5 V would result in a voltage drop of about 1 V and it would dissipate 2 Watts - and need a small heatsink.  But it would still work satisfactorily.

TonyStarkC10

That's because that's not a logic level MOSFET. See data sheet... it won't open properly at 5V VGS.

Try e.g. the IRL530 (or another IRLxxx) instead. The L stands for "logic level". Those will open properly with 5V signals. Look for a value for RDS, ON for VGS = 4.5V. If that's not given in the specifications, it's not suitable for use with 5V Arduinos.
Unfortunately, I don't have any kind of IRL--- MOSFET around they're all just IRF--- type and going to buy a new one takes a lot of time so do you have any other solution for me?

wvmarle

Find what other MOSFETs your supplier does have on hand. Read the data sheets; see which ones are logic level. Buy a few of those.

Find other sources - are vendors like RS Components, Digikey or Mouser not active in your area?
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

TonyStarkC10

Find what other MOSFETs your supplier does have on hand. Read the data sheets; see which ones are logic level. Buy a few of those.

Find other sources - are vendors like RS Components, Digikey or Mouser not active in your area?
okay, thank you.
Unfortunately, they're not providing services here.

GeronimoDK

Where are you located, country and maybe city? Maybe there's another option!

TomGeorge

#40
Jan 22, 2019, 11:38 am Last Edit: Jan 22, 2019, 11:38 am by TomGeorge
Hi,
Are you showing us a speed controller that already comes with the fan?

If so why not just parallel up the existing speed up/down buttons with  another set of buttons and place them where you need them?

Tom... :)
Everything runs on smoke, let the smoke out, it stops running....

TonyStarkC10

#41
Jan 22, 2019, 06:26 pm Last Edit: Jan 22, 2019, 06:27 pm by TonyStarkC10
That does not make sense at all.  You need to illustrate how you have attempted to connect it.  I suspect a gross blunder.

Figure 2 in the datasheet (you did say an IRF530, didn't you?) suggest that drawing 2 Amps at a gate voltage of 4.5 V would result in a voltage drop of about 1 V and it would dissipate 2 Watts - and need a small heatsink.  But it would still work satisfactorily.
sorry, I didn't get you.
I double check everything but still not working I think wvmarle is right.

Where are you located, country and maybe city? Maybe there's another option!
there are some vendors in the center of town (I live in the west part) shipping cast from there to here is a lot so I have to go there and buy the parts by myself but it takes about 5 hours and I don't have any plan to go there these days so I'm looking for the other possible solutions.

Hi,
Are you showing us a speed controller that already comes with the fan?

If so why not just parallel up the existing speed up/down buttons with  another set of buttons and place them where you need them?

Tom... :)
hi there
yes
there are three buttons (one for change the color mode - one for the speed of that color change effect - another one for fan speed which just has two modes (low speed (i think about 7V) and high speed (about 12V)))

TonyStarkC10

hello
recently I bought IRL530A and IRL530N and then the same issue on being not able to adjust the voltage.

TomGeorge

Hi,
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
Please include power supply.


Can you post a picture of your project so we can see your component layout?


Thanks.. Tom.. :)
Everything runs on smoke, let the smoke out, it stops running....

Paul__B


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