Can I increase the amperage output from digital or analog pins to be similar to the 5V pin?

[abandonedsquirrel]

I am trying to make a basic circuit to power a water mister module. The only way I can get the 'uno R3' or 'nano every' to produce enough power for the module is when they are directly connected to the 5V pin. When I use any other pin, digital or analog, the mister activates but is significantly weaker.
I even attached my arduino to my external adjustable power supply and played with the voltage settings via Vin pin going all the way up to 12V but the output was always the same (weak).
I noticed that the amperage the module was drawing was always 100mA from the digital and analog pins, even though it is designed to function at 300mA but I couldn't get it to draw more amperage.

I can only assume there is a built in hardware limit within the arduino restricting the amperage output on every pin except the 5V pin. Is there a way to modify this?

My current code:

void setup() {
pinMode (7,OUTPUT);
}
void loop() {
digitalWrite(7,HIGH);
}

Module: Atomization drive circuit board
Model: QDB-1
Rated voltage: DC5V
Rated current: 300mA
Power: 1.5-2W

Thank you for your help.

[UKHeliBob]

Welcome to the forum

Arduino boards are not designed to be used as power supplies beyond the small current required to power sensors.

What you could do is to use an Arduino pin to control a MOSFET and have the MOSFET switch an external supply to the mister on and off.

If you continue to use a digital pin to provide power directly to the mister then you may damage the Arduino board

[jim-p]

@abandonedsquirrel

The only way I can get the 'uno R3' or 'nano every' to produce enough power for the module is when they are directly connected to the 5V pin.

Then do it that way.
Why do you want to connect to a diferent pin?

[abandonedsquirrel]

I want to be able to control how long and how often the module activates.

[UKHeliBob]

Then consider using a MOSFET controlled by an Arduino pin or, if you want to go "old school", use a relay controlled by an Arduino pin to switch the mister

[kmin]

@abandonedsquirrel

I can only assume there is a built in hardware limit within the arduino restricting the amperage output on every pin

Correct. You can safely draw only max 20mA from pins. You are risking to damage your arduino trying to draw more.

You need different approach here.
Post a link to that exact mister you have.

[Brazilino]

Hi! Welcome to the Forum!

@abandonedsquirrel

I even attached my arduino to my external adjustable power supply and played with the voltage settings via Vin pin going all the way up to 12V but the output was always the same (weak).

Beyond the tips that were given, keep in mind that raising the voltage to Vin pin increases the difference that the onboard regulator will have to spend in heat. The overall effect is exactly the opposite of what you want –> it decreases the amount of current the board can provide without overheating.

[jim-p]

@abandonedsquirrel

I want to be able to control how long and how often the module activates.

Then do this:

[GolamMostafa]

@abandonedsquirrel

Can try the following buffer circuit:

[jim-p]

Or you can use a MOSFET module.

[abandonedsquirrel]

Thank you all for the recommendations and ideas. A MOSFET is obviously a great solution to this problem. Thank you all for sharing your wisdom! I am ordering the parts now and will give it try. Thanks again!

[mikedb]

@abandonedsquirrel

I am ordering the parts now and will give it try. Thanks again!

Get Mosfets that is capable to switch with 5V or less on the gate.

[jim-p]

This is the MOSFET module I show in the diagram, it's avaliable from many different places including Amazon.

High-Power Dual MOSFET Switch Module - ProtoSupplies

[hammy]

@GolamMostafa

Can try the following buffer circuit:

For future reference : That will not works ( too many drops , Vbe , op amp won’t swing to rails, output to emitter - you might get 2 volts there !!) ) - you just need to drive the transistor via a resistor to its base and put the load in the collector .

[GolamMostafa]

@hammy

you might get 2 volts there !!) ) -

Why not ~= 4.3 Volt?

V_OH at DPin-5 (4.2V to 5.0V) is hold at emitter of Q1 by the feedback path.

[jim-p]

@GolamMostafa

Why not ~= 4.3 Volt?

Doesn't matter, the 741 won't work at 5V. Read the datasheet.

[GolamMostafa]

@jim-p

the 741 won't work at 5V.

If single power supply is used, then would it be minimum 20V bias voltage for proper operation of 741?

When you say “won’t work,” do you mean that the op-amp will fail to respond even to input variations below 3 V DC when operated from a single +5 V supply?

[jim-p]

@GolamMostafa

If single power supply is used, then would it be minimum 20V bias voltage for proper operation of 741?

Yes

even to input variations below 3 V DC when operated from a single +5 V supply?

It's already been established that for proper operation the supply voltage needs to be >=20V. There is no point in asking what it will do at lower voltages.

[herbschwarz]

Why use an analog IC when the MCU can drive the transistor via a base resistor?

[GolamMostafa]

@jim-p

=20V

This is a recommended operating condition. Does the user not have the flexibility to use a single +5 V supply and still make the circuit functioning to meet his requirements? Fig-1 is a 741 circuit which is expected to work at single +5V bias supply.

Figure-1: