Power draw from 5v pin

Official Hardware UNO Family UNO R4 WiFi
21

I want to use the barrel connector so i can use the off pin. it says that the off pin is for the vin and barrel jack only. is there some other way to turn the board off if i use the usb-c cable?

22

If there is some low cost power supply that would have two voltages outputted, one for the arduino and one for the neopixels, please let me know

23

Something like this, maybe?

https://www.amazon.com/CY-Switch-Button-Keyboard-Raspberry/dp/B0D91PQX3K

24

No there is not

25

Both need 5V.

Use an external 5V power supply. Use splitter cables or similar to supply the neopixels and the Uno.

26

I think i will just give up trying to use the off pin and use the usb-c instead

27

That would simplify things

28

is there some way i could still lower the power use. possibly a compatible low power library that would activate when a switch is flipped and deactivate when the switch is flipped the other way

29

Just put the switch on the 5V power lead from the power supply

30

i am going to use a usb-c so i can get enough amperage so i dont want to have to disasemble the wire just to turn it off. is there a library that can do low power mode instead?

31

Not an R4 expert, so can't help there.

32

will the Arduino low power library work for the uno r4?

33

Use 3in1 Usb charging cable. One connector to power Arduino, another stripped to connect to LEDs.

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34

Probably not.
This website lists which libraries that are compatible with the R4

Why do you need to reduce power?
Doesn't your power source have an on/off switch?

35

I would like to make a lamp that when not in use can have as little power consumption as possible

36

Well the R4 was a bad choice for a low power application.

Doesn't your power source have an on/off switch?

37

no it doesn't. I am using a standard usb-c cable. i want to use the uno r4 because the led matrix will be part of the project.

38

So what is the source of the power, a battery?

i want to use the uno r4 because the led matrix will be part of the project.

In that case how are you connecting the neopixils to the USB-C

39

i am using a wall block with a good amperage. i am connecting the neopixels to the 5v pin. when i said the led matrix i am talking about the built in matrix. the neopixels are a seperate light. i want to use both

40

Well you never mentioned using the led matrix before, it will also draw current through the USB plus the current required by the processor and the neopixels.

It may not be a good idea to power the neopixels from the 5V pin.
I suggest you make some current measurements before you go any further.