Turning On/Off Component from Arduino

Projects General Guidance
1

I have an Arduino board with a USB Output that I am using to power an external component (Adafruit AirLift).

I have to use USB Output since the 3V regulator on the board won't supply enough current to power the AirLift. The AirLift is connected to the GND of the Arduino board.

I want to be able to switch power (via code) to the AirLift from the Arduino to the component. Do I need to add a MOSFET to the circuit or can I just use one of the pins as a GND pin on the Arduino and set it's OUTPUT to HIGH for Off and LOW for On? Or is a MOSFET required?

2

You must observe the current limitation of an Arduino output pin: no more than about 20 mA, source or sink.

For high side switching, one of the Pololu Power Switches would be convenient.

3

It sounds like I'll need a FET. Will this circuit work? I just want to ensure the component is OFF when the Arduino is Powered On. What's confusing me is that the external component shares the GND of the Arduino. I just want to be able to control when the component gets power.

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4

Consider reading the second line of reply #1.

5

I have an Arduino board with a USB Output

Just as a matter of interest which Arduino board is this ?

6

Just as a matter of interest which Arduino board is this ?

Adafruit Feather nRF52840 Express : ID 4062 : $24.95 : Adafruit Industries, Unique & fun DIY electronics and kits All of the Feathers have a USB Output that is the voltage supply off of the USB.

I don't need high side switching right?

7

What's confusing me is that the external component shares the GND of the Arduino.

So true.

I don't need high side switching right?

Evidently you are more interested in a voyage of discovery, than in taking advice.

8

I just read this...

However, an active device like a Microcontroller needs its ground to be ground! So when you have a load that requires ground, you NEED to use a high-side switch.

As a quick rule of thumb, if you are turning a device on and off, a low-side switch is a simple solution. However, if you are delivering power to an entire circuit or a voltage sensitive device, then you want to use a high-side switch.

Thank you for the hint.

9

I ended up going with the SparkFun P Channel MOSFET and a 10K pull-up resistor to ensure the value is off when the uC is powered up.

I also wanted to add I found there are Load Switches from TI that can do the same thing (I think) that seem to be a viable option as well. Thank you for the help.