How do you interface arduino to 3.3V input pin?

Other Hardware General Electronics
1

Hi

What is the easiest way to interface arduino output pin of 5V to a sensor input pin of 3.3V?

thanks

2

I stole this from Grumpy Mike:

Connect a 1.8K resistor from the Arduino pin to the 3.3V input pin

Connect a 3.3K resistor from the 3.3V input pin to ground

In other words, this:

with Z1 = 1800 ohms & Z2 = 3300 ohms

Good luck!

3

Sparkfun has a good page on this:

http://www.sparkfun.com/tutorials/65

If the sensor has protection diodes a series resistor is the easiest method. Is this a digital or analog connection?

4

Others use the 74HC125 gates as buffers.

5

use the 74HC125 gates as buffers.

Or the TXB0101/2/4/6/8 chips.

Rob

6

Its digital data. Will the voltage divider method be good enough, because it is easy than other methods?

7

If it's 1s and 0s then I think the voltage divider will be fine. I've been using this setup to interface a WiFly serial module with a Duemilanove, Nano, and custom 328 board for a few weeks now with no problems. I confirmed via voltmeter the 5v output from the gets reduced to 3.3v.

8

Depends on how fast the data needs to change as well.
If you are connecting to a high speed SD card, then the buffer method is better.
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