Can you lower the voltage output of the Arduino UNO, from 3.3v to 2.2v without a resistor?

Other Hardware General Electronics
21

Two blue LEDs in series would likely be perfect for a 5V Arduino.

22

I

I couldn't duplicate this assertion from a Google search. The best I can verify is 1.1Ohm from 6cm of 2B Pentel lead.

23

A toaster should be in the right order of magnitude....

24

Worth a try. Be sure to unplug it from the wall socket first. :sparkler:

Our Dualit is 17R5. Maybe several in series. :sunglasses:

25

You have 110V?

26

Yes, 120V 60Hz 1100W

27

You need to remember that a cold toaster will have a lower resistance than one at it's operating temperature.

28

Correct, but I don't expect it to heat up much from LED level current.

29

Maybe a 30 or 50W bulb light would be better then...

30

I checked some and it looks like 12V automotive bulbs would be in the right range.

The real solution is to Amazon Prime a resistor assortment though unless the whole purpose of the exercise is to not use any resistance,

32

But a bulb may also count as a resistor...

33

@steelcrest
Do you still need help?

34 
pinMode(12,INPUT_PULLUP);

seems to work.

35

So how many pencils did you use to make your resistor?

36

To turn on the LED, use an input with pin mode INPUT_PULLUP.

To turn off the LED switch to pin mode INPUT.

To burn out the LED wired between the pin and ground, cathode on the ground side, use pin mode OUTPUT and write HIGH to the pin.

LEDs have come a long way, not much current from the weak pull-up mechanism.

I file it under "I never would have thought of that".

a7

37 
void setup()
{
}

void loop()
{
  pinMode(12, INPUT_PULLUP);
  delay(500);
  digitalWrite(12, LOW);
  delay(500);
}

Blinks peacefully

38

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