3.3V and 5V pins

Hello! Recently I’ve been starting to design an rc car using arduinos, and I was wondering if the 3.3V and 5V pins on the uno and nano to power things.
The 3.3V would only be powering a NRF24L radio module on both boards. I’ve planned to use just these pins to output power to components since the LiPos are a high voltage. Ive researched this all over and can’t find an exact answer so here I am!
How would I code this in if it’s possible? The digitalwrite() command? Thank you!

The the Arduino boards are microcontrollers, not power supplies. You should not use them to power anything. Use a buck converter to get the voltage you need.

Ah okay, I figured it would just be easier to do that seeing as it’s only powering 2 joysticks and a NRF24L.

The on board 5V regulator current capability depends on the regulator's power source. The higher the supply voltage, the less current that the 5V regulator will supply without heating and shutting down. You are better off using a buck regulator to drop the supply voltage to 5V and connect that to the 5V pin. You may be OK without the buck regulator, but make an educated choice.

The 3.3V regulator may supply enough current for the rf24 (with a 10uF cap across the rf24 supply terminals), but, for reliability, I use a separate 3.3V regulator supplied by 5V for the radio (LM1117 3.3).

You need to check the current draw of the devices to be powered and make sure that the total current draw is significantly less than the specified current capabilities of the outputs.

The 5 and 3.3V outputs are intended for a couple of LEDs or perhaps low power sensors.

The NRF24L is actually a rather heavy load when transmitting.

jremington:
The NRF24L is actually a rather heavy load when transmitting.

No experience with the NRF24L, but spec sheets say 115 mA peak current.
The 3.3volt pin of an Uno has no problems with that, because it has a dedicated 3.3volt/150mA regulator.
A Nano however does not have a 3.3volt regulator.
That 3.3volt supply is 'stolen' from the USB chip, and starts to sag above ~30mA.

cameronshep:
...since the LiPos are a high voltage.

What exactly is "high voltage". 2-cell, 3-cell packs?
The 3.3volt regulator of an Uno might be ok with that current draw,
but the 5volt regulator that powers the Arduino and the 3.3volt regulator might get into trouble (too hot).
Leo..