Logic 5V-3.7V converter for Arduino & Imp setup

According to the sparkfun setup for serial comms, there is a logic converter needed. Other blogs to set up the same system say it shoudl work without (at least that how I interpret it).

How necessary is it to get one of those : https://www.sparkfun.com/products/8745
to have arduino(nano) and imp talk to each other?

My Arduino Imp shield doesn’t have one on the serial connection

one of the features of the Sparkfun imp shield is that it has a logic level converter for serial communications.

There are simpler ways to do level shifting depending on the required speed and direction of communication.

On our Breakout&Shield we applied level shifters on every pin:


@DolfTraanberg your shield does have the converter on the serial, based on the same technique we use, with FETs. It was originally designed for I2C at Philips, more than 15 years ago:



yes you are right. I missed them.

I have this one: http://proto-pic.co.uk/electric-imp-breakout/
its sparkfun, does it have logic converters built in, and if not do I need them?

According to the schematics, it doesn’t, and yes, better save then sorry

@uncleunvoid you must absolutely use some kind of converter, as the imp001 is not 5V tolerant.

In the previous post I’ve forgot to mention the Texas Instrument’s TXB0108 that’s a very cool level shifter with multiple channels and can be a good solution for the translation of all the 6 pins, but a little pricey compared to the use of FETs.

This is the link to the datasheet:


and this is a breakout board from Adafruit:


In any case, even if you just use a simple resistive divider (1K + 2K2 can be OK) you must translate the signal from 5V to 3.3V.


I am using this one (I am UK based) http://proto-pic.co.uk/logic-level-converter/

Those US taxes on the adafruit gear are killing my budget! :wink: